It addresses building and design issues from an environmentally neutral perspective. It obviously includes energy neutral building, but adds the challenge of water use, use and producing of materials, and use of land. 0-impact should result in a built environment that is in balance with its environment in all senses, and truly sustainable in the long run. This book is a compilation of key notes and papers of the SB 2010, initiated by iiSBE, CIB and UNEP, organised by RiBuilT Research institute Built environment of Tomorrow.
Techne Press, Amsterdam
Towards 0-Impact Buildings & Built Environments
0-impact goes one step further than 0-energy.
Towards
0-Impact
Buildings & Built Environments Editors: Ronald Rovers Jacques Kimman Christoph Ravesloot
Toward 0-Impact Buildings and Built Environments
Towards 0-Impact Buildings and Built Environments Edited by Ronald Rovers, Jacques Kimman and Christoph Ravesloot
Techne Press Amsterdam
Towards 0-Impact Buildings and the Built Environments edited by Ronald Rovers, Jacques Kimman and Christoph Ravesloot 2010, Amsterdam, 220 pages ISBN: 978-90-8594-031-9
This publication has become possible with the financial support of the RiBuilt Institute Published and distributed by Techne Press, Amsterdam, The Netherlands www.technepress.nl
© 2010 All rights reserved. No part of this publication may be reproduced or stored by any electronic or mechanical means (including copying, photocopying, recording, data storage, and retrieval) or in any other form or language without the written permission from the publisher.
Table of Contents
Introduction The concept of O Ronald Rovers
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The 0-impact transition approach Jacques Kimman
27
Bringing science to practice Christoph Maria Ravesloot
31
Pa r t I I Realism and illusion Hermann Scheer
39
Güssing, a model for other regions Peter Vadasz
43
The goal is PlusEnergy! Rolf Disch
51
Architecture of conglomerates Lucien Kroll
57
A life cycle tower for a better future Hubert Rhomberg
65
Rapid GHG reductions in the built environment under extreme conditions Nils Larsson The energy transition model John Kerkhoven
73 85
Pa r t I I I From space habitats to zero emission buildings Julien S. Bourrelle, Arild Gustavsen, Bjørn Petter Jelle Towards a definition of zero impact buildings Shady Attia and André De Herde
95 105
Field study of retrofit solutions for residential housing Davide Calì, Tanja Osterhage and Dirk Mueller
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Applications of appropriate renewable energy technologies in Chinese rural houses in Qinghai-Tibetan Plateau 125 Wang Yan, Zhang Peng, Ju Xiaolei, Zhang Yabin ) Planning 0-energy cities using local energy sources Wouter Leduc
137
Towards 0-impact industrial sites Katleen De Flander
155
Urban morphology and the quest for zero carbon cities Serge Salat and Caroline Nowacki
165
The Urban Harvest Plus approach to 0-impact on built environments case study Kerkrade West Ronald Rovers, Herwin Sap, Wouter Leduc, Vera Rovers, LEO Gommans, Ferry van Kann Prefabricated timber as a means of achieving zero carbon Gavin White Photo catalytic degradation as a tool for the reduction of ambient air pollution Cyriel Mentink, Toon Peters, Paul Donners, Jan Theelen, Wouter Snippe, Martijn Janssen, Jacob Pijnenburg, Paul Borm
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183
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Zero-impact water use in the built environment M.M. Nederlof and J. Frijns
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Tilburg: a road map for becoming a zero-carbon city in 2045 Erik Alsema, Jappe Goud, Geurt Donze, Martin Roders
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Part I Introduction
Introduction This book has been produced as part of the SB10 Sustainable Building Western Europe Conference, one of nine SB10s that have been held worldwide. These have been organised under the umbrella of the iiSBE, CIB and UNEP, as part of a world series in preparation for the 2011 Sustainable Building World Conference in Helsinki. A challenging theme was chosen: towards 0-impact buildings and built environments. This is the challenge that lies ahead of us - making the transition from resource depletion and impacts to balanced management of our resources, with an acceptable standard of living for all. We are happy to have received numerous papers focusing on the ‘0’ target, which we believe will be at the top of agendas in the near future (if not before). A more detailed analysis of this issue is given in the introductory chapters. The keynote speakers during the Western Europe Conference have all been involved to a greater or lesser extent in bringing about 0-impact situations in their own fields of business. Herman Scheer set off a change in Germany with his Renewable Energy Policies, and is now active in broadening this approach to a change for a fully renewable energy-based market. He is a determined and successful fighter for this transition. Many cities claim to be pursuing the 0-energy or ‘climate-neutral’ target, but few succeed. One such is the town of Güssing in Austria. Under Mayor Peter Vadasz, the city turned a negative spiral with high energy costs, unemployment, and CO2 emissions, into a lively region with ample jobs that is operating entirely on renewable energy: proof that the 0energy city is possible. And soon the region is to follow. Nils Larsson, however, fears that most will not succeed. He advocates designing a plan for rapid reduction of greenhouse gases. It often takes a disaster to open people’s eyes, and when that happens we will all be looking for a good plan to enact immediately. Such a plan has yet to be devised. A good plan requires adequate figures and understanding of consequences and assumptions. John Kerkhoven has developed a computer model that shows the consequences of policies and practical measures, which he uses to show workshop participants the outcomes of their choices. Although this generates much discussion, it also enables mutual understanding and ultimately agreement on 90% of measures. That helps! Rolf Disch is an outstanding architect when it comes to changing our building approach. Disch has a long history in energy-efficient buildings and integration of renewable energy devices including his masterpiece in Freiburg, Germany: Sonnenschiff - an energyproducing building with retail premises, offices and housing which was enabled through the creation of a revolving fund. So is Thomas Rau who follows the One Planet principle advocated by the World Wildlife Fund and akin to the 0 or 0-approach concept we at RiBuilT pursue, of which 09
energy, 0-waste and 0-water are a part. He has created a range of buildings not only with outstanding energy performance, but which are also exemplary from the materials point of view. His latest work is a 0-CO2-neutral school in Eindhoven, the Netherlands. No articles by Rau are to be found in this book as he prefers to let the actual work speak for itself. We can, however, refer you to the websites on his buildings to review his work and principles. Kroll takes the position that it is not architecture but the context that dictates form, primarily the inhabitants, emotions, and environment. His long life experience has taught him that a design process should not start from the technologically possible but from context needs. In fact, architects do not design anymore: they guide the process that automatically leads to the right form and materialisation for the owners, users or inhabitant. They are no longer the solitary genius but merely one among others, mainly non-architects. This results in interesting and very well received ‘sustainable living environments’. These chapters by keynote speakers are followed by a selection of papers from the conference, selected for their scientific quality and relevance, or for practical relevance in implementing research findings and results. We were happy to include a few descriptive and analytical practical cases since this is not about researching for our future but about applying it, today and tomorrow. Some explore the possibilities at the building level, both new and restored. Others look into urban approaches or a resource-oriented approach such as 0water neighbourhoods, and even 0-air (avoiding polluted air). Together they provide an overview of the challenge that lies ahead of us, for which this book hopes to stimulate more research and in particular results and insights on how to establish and implement this. The transition must be made, whether we like it or not. It is up to us to choose. Happy reading and be inspired,
The editors
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The Concept of O Towards 0-impact Building and Built Environments Ronald Rovers
1)
For the past 150 years or so, we have enjoyed an abundance of resources. In fact, we have so many resources that we have lost sight of how we actually depend on these resources, as we used to. We have created such a complex system that it’s hard to see how we could change it and start the transition to a renewable resource-based society. But there is a way. We need to look back and see where we came from. We are all familiar with Robinson Crusoe, a castaway on an uninhabited island. Imagine if you were to end up like him after a shipwreck with some basic survival gear—a fishing rod, axe, hammer, and so on, but nothing else. Suppose the island is fairly small, say the size of a soccer field, around 0.5 hectare. Most of the island is forested with maybe 170 trees. The remaining 1000 m2 land is agricultural and includes a small water well and a white beach. The island is a vacationer’s dream—except for one thing: you can’t leave.
1) Chairman SB10 Western Europe Conference; Professor Built Environment, Research Institute Built environment of Tomorrow, RiBuilT/Zuyd University
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As luck would have it, the 1000 m2 of land is just enough to grow vegetables so you can survive as a vegetarian. And each year the 170 trees grow an additional 2.5 m3 meters of wood for you to harvest, enough to cook your meals since this happens to be approximately the amount Africans need to cook their meals each year. So no worries—assuming the climate is nice. If your island happens to be in Northern Europe, you won’t have enough wood to build a house (10-15 m3). Or if your island has cold winters, you won’t have enough wood to heat your house (3 m3 a year for one stove). You definitely won’t have enough wood to build a boat for fishing. Anyway, let’s not complicate the picture too much. The next island has 100 times the land and 100 times the people. The islanders there do things efficiently. By dividing the labour and saving some wood by cooking together, they have managed to construct a fishing boat and appoint a fisherman. He sails out each day and returns with fish in return for some cooked vegetables. And each year, the islanders are able to reserve some wood to construct houses, repair the fishing boat, and so on. Everybody is happy, everything is in balance. Is this second island imaginary? Not entirely. A few years ago I heard about the Uros people. They withdrew to artificial islands in Lake Titicaca on the border between Peru and Bolivia to protect themselves from the Incas. For thousands of years now they have been constructing floating islands from dried and bundled reeds that they replenish every three months. Reeds are also used to build houses and fishing boats, and even to make medicines. The Uros have maintained equilibrium by replenishing their resources for a thousand years. They are reasonably content and now also have some (imported) modern resources such as solar cells for telephones, the Internet, and televisions. The Uros are probably the first society that operates fully on sustainable energy and sustainable resources! Smart cookies, those Uros.
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Now let’s look at the way most of us live. We are far from living in a resource-balanced environment. Using bricks for building construction is forbidden in China’s northern region. The quantity of bricks required is great, and the cost in fertile land and soil to produce these is too much. Do you know why the Chinese started building with bricks in the first place, some 150 years ago? They ran out of wood and forests; wood was cut in such huge quantities for construction and other purposes that it became scarce… The climate in China is so dry, the river that used to flow through Beijing no longer has any water; all the river water is used upstream. A huge aqueduct has been constructed to transport water thousands of kilometres from the wetter south to the north. At the same time the Gobi Desert is growing. An attempt is being made to halt its growth with a green wall, a band of trees planted on the borders of the desert. This project will be ongoing for the next 50 years... The Gobi Desert is just one of many examples of desertification. The Sahara Desert in Africa is growing too, and a similar greenbelt of trees over thousands of kilometres is planned. The Colorado River in North America barely reaches the ocean now and will cease doing so at all if construction and water demands in the desert continue to increase. Currently more then 50 % of people live in cities, all depending on resources from far away. We depend on products from China and other parts of the world. We are part of an urban organism, a parasitic “orbanism.” Take oranges, for example. . Oranges don’t grow in Northern Europe, but we ship them in from such faraway places as Israel. Israel grows oranges by tapping irrigation water from beneath Palestinian land, from an old aquifer under the West Bank. The water table in the aquifer drops, and Palestinians, who are only allowed to use wells, see their wells running dry. Palestinians lack water because we eat oranges. The chain of resource use has become very complex. And we are in an extremely vulnerable position. If the chain breaks somewhere, we are trapped. We have nowhere to go for more supplies. We are all familiar with the problems associated with energy consumption. What will happen if China matches the number of cars per capita that we currently have in the industrialised world? Add the oil needed to fuel those cars to China’s current oil demands, and all the oil in the world will need to go to China. We already fight wars for oil in the Middle East. Within three months after Afghanistan’s invasion, contracts had been signed for gas and oil pipelines there. The fight over oil in the Middle East leads to another fight, that against climate change. As a result of climate change, a new wine industry is growing in Sweden, but in most cases the effects are more troublesome. A problem with climate change is we don’t know where it will hit and how hard it will hit. How did we end up here? Let’s return to our imaginary island and the “parable of the fisherman”. One day a yacht arrives at the island. The yachtsman, a rich man, looks around and takes a seat next to the fisherman, who had gone out fishing in the morning and is now taking an afternoon nap on the beach. 13
“Hi, there”, says the yachtsman. “What you doing for a living?” “I am a fisherman”, replies the fisherman. “Then what’re you doing on the beach?” asks the yachtsman. “I finished fishing this morning”, the fisherman answers. “Ah”, our yachtsman says. “Why don’t you go out in the afternoon and catch more fish?” “Why should I?” the fisherman asks. “Well, you can catch twice as much and can sell to another island”. “So what?” the fisherman says. “Well, if you do that every day, you can buy a second boat”. “Oh?” says the fisherman. “More fish means more profit”. “Yes?” “You can become a millionaire just like me”. “And then?” the fisherman asks, bored. “Well, then you can have people do the work for you while you lie on the beach”. “But I am lying on the beach”, the fisherman replies.
The parable ends here, but in the real world the fisherman probably would have been persuaded to go out fishing again. It happens all the time: although we understand the problem, we become trapped between the dream and the deed. We dream of a paradise, a safe haven with clean water and clean air and happy people, an oasis like a holiday camp or our fisherman’s island. In real life we focus on immediate gratification of materialistic needs. Take, for instance, a road. Everybody agrees it shouldn’t be built and in turn shouts objections: “It creates too much noise, it stinks, it violates nature”. At the same time we cry for more roads, tired of getting stuck in traffic jams. Then the minister shows up, proclaiming, “Mobility is a right! Figures show only seven percent of the country is covered in asphalt” (as is the case in the Netherlands). Then someone mentions that roads create problems that aren’t limited to the road but extend for kilometres around. The minister answers, “Technology development! 14
We’ll build silent asphalt and clean cars!” When someone else points out that producing the asphalt and cars depletes resources and causes climate change, the minister responds, “Cleaner production!” This is collectively running forward, away from the problem, thereby causing other problems. And we follow and let him, since we want to drive and since there is a difference between the dream and the deed. So we have a huge problem, and we react the wrong way. How can we get out of this loop? For an answer, let us visit another island, that of Japan 150 years ago. Like a number of other countries, Japan has a long history of constructing wood houses. But unlike the Chinese, they still build with wood. This change has its origins around 1600. The Tokugawa came to power at this time, and the period that followed is mainly known as Edo Japan (based on the name of the capital, the city that is now Tokyo). In an attempt to retain control over the various population groups, the country was sealed off from the outside world, and a 200-year period of isolationism followed. This literally creates an island situation. Edo Japan is the only large-scale historic example of a society that operated in a closed cycle (Edo City alone had approximately 1 million inhabitants at the time), its supplies limited to those within its own borders. The traditional Japanese house was further perfected since everything for living had to be based on very efficient use of renewable and reusable resources. The Japanese even standardised building panels, and stocked wood building supplies to ensure they could quickly repair and reconstruct buildings after city fires. In fact, 99% of resource and energy needs were met with direct and indirect solar energy, particularly from wood. While deforestation was taking place everywhere else in the world, the Japanese developed a highly innovative forestry plan that is managed to perfection even today. Japan is still famous for its lush forests.
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This period was forced to an end around 1860 when Western countries began searching for raw materials that were already becoming scarce. A small US fleet forced Edo Japan (which was essentially unarmed, since no resources for a military were available) to open its borders for trade. Until then, growth was generally minimal, due to the limited availability of resources, and the need to access them locally, since only local transport was available. For the most part, an equilibrium was maintained, with too fast growth corrected by disappointing harvests or depleted stocks: Communities faced ups and downs proportionate to population size, food availability, and distances to other resources. At this same time, again around 1860, a big “party” got under way around the world. Humanity bought itself time with new technologies driven by fossil fuels, and materials and fossil fuels could be deployed in an accelerated manner. Raw materials could be obtained from places that were further and further away. If an “undeveloped” country in a distant place still tried to manage its resources, its efforts were completely thrown into disarray in the 20th century. The entire world became the hunting ground of the industrialised world. Every time a short-lived crisis loomed in “developed” countries, we could avert disaster by obtaining resources from other regions. Hunting and gathering had again risen in all its glory. So our fisherman on his imaginary island is persuaded to enter the market and go into what is euphemistically called “business”. He soon encounters his first problem: where to take the fish, and how to construct a second boat. The solution involves importing wood—in other words, placing his burden on someone else. To increase his wood use beyond his own system limits, he needs something to negotiate with. This has to be the fish, one of the main resources within his island system. So he catches more fish than he needs to eat to compensate for an increased need for wood. Clearly, in order to use more wood than is available on his island, the fisherman has to create a surplus of both wood and fish. So long as others have forests and the fisherman has fish, the system works.
In building and construction, we do our share of over-consumption. Up to 40% of resources are transported around the world for construction. Architects and developers build skyscrapers, which progressively waste more resources per m2 floor the higher they grow. And architects can squander resources creating “wasteful architecture”. (For example, Calatrava buildings require two to four times more tonnes of material per m2 than the average building.) All stakeholders use steel and cement wherever they can, further depleting resources. Cement production alone is already responsible for 7% of all CO2 emissions. Now 150 years following the Edo Japan period, earth’s human population is nearly 7 billion, and all available land has been subdivided and is being developed or is occupied. No virgin territories remain to be claimed except, perhaps, Antarctica, which is, for the time being, still under ice. Fossil energy resources are running out, and humanity is bumping up against a new limit on resources. The days of an open-cycle system are numbered: the hunter can only secure resources by force of arms (as in Afghanistan). The gatherer is stripping the last
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available areas using beads and mirrors (as the Chinese are currently doing in Africa, offering roads in exchange for raw materials). You might say that hunting and gathering has turned into stealing and plundering. After 150 years, the physical and political limits of the system have been reached. The 150-year interim, bought with depleting fossil fuels, has come to an end. Again we must search for balance, but now with almost 7 billion people and with an unprecedented consumption pattern. We frantically continue to search for fossil fuels that are becoming scarcer by the day, and we are plundering the entire world. When fossil fuels are found, they are more and more difficult to extract. Continuing to rely on fossil fuels is an assault on financial and energy resources, resulting in further price increases and economic crises. How will this play out if we don’t change anything? In researching the operation of financial markets, Barclays Bank arrived at the following conclusion: “Major risk is business-as-usual, which equates to a degeneration into widespread resource conflict and ecosystem collapse.” Perhaps we can stretch things a little by developing technologies, but the hunting grounds of yesterday are no more. The hunting grounds have been subdivided, they are in use and there is no way out. The only hunting grounds are those of our own species: The world itself has become an island.
We are all now in the same situation as the fisherman, the Uros, and the Edo-Japanese. We must reduce our resource consumption to the limits of the island. A surplus of resources is impossible. Given the earth’s finite limits, the only possibility is a closed-cycle approach. The only resource that reaches our island is solar radiation on our island, that’s it. So we have to get back to basics. If the whole world is an island, we have to start living like islanders. We have to realize there is no one else with whom we can do business outside our “globisland”. We can’t run away from problems anymore; there is nowhere to go. We must face our limits. We are running out of oil and many other resources that could have made life a bit easier (and have done so, for the happy few). We have to learn to manage our resources again in
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a different way, a way that involves reusing everything and depleting nothing. From now on, we must maintain a closed-cycle system. How do we do this? How do we manage our globisland (Island Earth) in a balanced way? How do we design new buildings and districts with optimised energy and water systems, and with materials that do not deplete resources and do not create CO2 emissions? How do we re-develop our neighbourhoods and districts using 0-impact approaches? How do we plan cities that are immune to system crashes? Most important, our strategy must clearly define where we want to go, the desired state, instead of improving on where we came from. We don’t have time to gradually improve on the past. We need to evaluate how far we are from achieving a balanced resource-based management system, in this case in our building stock. To move forward, we must understand where we went wrong. Two decades ago we began exploring a more rational approach to resource management, especially energy. This has led to a holistic approach, in which everyone should be happy: the planet, the people and the profit We could calls this the “PPP syndrome”, trying to save the “old” and combine it with the “new”. Everything is included, and glory is where the three will meet. But as history teaches, when you’re on an island, its resources establish the basis for society: food, energy, water, and raw materials. If they are not available or if they are not managed properly, a society cannot exist and certainly cannot grow. And these basic resources are used to create people’s affluence and wellbeing. If there is abundance, society and culture can thrive, freeing people (the non-producers) to invest in other interests. Without resources, we have to adapt. That covers the first two P’s: planet and people. The next P is profit, consisting of economy and policy. We should realize that these exist simply to facilitate and give direction to the other two P’s, to create our desired state. Economy and policy can be adjusted, since they are not natural phenomena. We invented them ourselves sometime in the Early Middle Ages. And it is only logical: when you manage resources based on an economic profit principle that aims for the opposite of sustainability, then sustainability will remain a farce. Remember our fisherman, who is already lying on the beach … However, it’s a typical behaviour in times of change: Facing the threat to business as usual, change is denied In this case, a smart strategy was found: instead of addressing the energy threats of the nineties, stakeholders developed an ever-growing list of so-called “sustainable” ambitions, thereby diminishing and hiding the real problem. In all sectors, but especially in the building sector. Tools have been developed which result in a high score without even having saved a single Joule (except some minimal improvement for countries with mandatory energy standards) and results are compared with failed buildings from the past. Because both people and profit should score well, it’s more like “People making profit depleting Planet”. For examples of this type of thinking we have only to look at the Netherlands. We preach reducing energy use by 20% and increasing renewable energy by a modest 20% by 2020. But oil extraction is again being pursued in the north of the country, with huge investments in “efficiently produced” steam to make this oil fluid. Energy efficiency drops 18
considerably with this technology. Gas exploration has begun again, and we have five new coal-fired power plants planned under the guise that we will be able to store the CO2. In 20 years’ time. Perhaps. Maybe. Nevertheless, we are seeing the first signs of an alternate approach to energy use. The cause of impending climate change, CO2 emissions are at the heart of new strategies and directly related to pure energy consumption. The increased interest and discussion about 0energy buildings popping up in almost every country are a visible sign of a new approach. Each building is an “island” with balanced energy use. In the Netherlands, stakeholders agreed with the government to gradually increase the building of new 0-energy houses. The UK has already adopted a policy stipulating all houses should be CO2 neutral by 2016. In Belgium, industrial areas have developed 0-CO2 strategies, and in Germany we find the first energy-producing buildings and houses. In June 2010 the EU adopted the new EPBD (Energy Performance of Buildings Directive) policy specifying that by 2020 all new buildings should be near 0-energy. The notion is growing that we should no longer improve bad concepts from the past. Instead we should look to the future and ask how far we are from our ideal—in this case, buildings that run on renewable energy from sources that do not deplete faster than regenerated, in balance with reduced need. However, there is more at stake, as we will see later.
More and more often even cities are introducing and exploring policies to become energy neutral or climate neutral. And we’re still talking only about energy. With water, food, and raw materials, we need to take a similar approach. These resources are becoming scarcer and requiring more energy to harness or produce. Strategies for 0-water districts have been tested, and a few pilot projects have been conducted. Food supply will become more critical as more people move to the cities. Urban farming is gaining ground and is being integrated in new town planning. With the G20 in July 2009 agreeing on 80 % CO2 reduction by 2050 (although this was not realized in Copenhagen), it’s obvious there is no option but to explore designs for buildings and built environments that meet 0- or near 0-energy strategies. 19
Such strategies simplify things. In the case of 0-energy buildings (defined as buildings that on site provide the renewable energy to meet the buildings’ energy demands), measuring CO2 is no longer an issue. By converting to renewable energy, we have both tackled the depletion of fossil fuels and by definition have eliminated the side effect of CO2 emissions. The same holds true for materials in buildings. They should be constructed with renewable materials using renewable energy sources. Let’s be clear: the future will depend on closing cycles, on maintaining an acceptable level of living while using a circular management of resources—circular as O in a circle, or 0 as in zero impact (emissions, depletion, dilution, pollution) for ages to come. A closed-cycle resource management system can be maintained over a long period. There are, however, limits to this system. The use of renewable resources requires that we renew them, and the potential for renewable resources worldwide is limited. For this system to work, most likely we will not only need to: 1. make a shift to renewables, but also 2. reduce the volume of resources cycling through the system, and 3. slow down the time it takes for renewables to cycle, as well as 4. limit the energy driving the cycle. In other words, we will have to balance growth of renewable resources with human consumption. For energy this doesn’t pose a great problem (the solar route provides an easy way out); for materials, it’s another story. We will need to develop a highly efficient system to manage resources and maintain building stocks. The same holds for any other resource. Use should balance with regeneration of the resource. Balance is at the heart of a closed-cycle approach, at the heart of operating an island, which the Easter Islanders didn’t manage, and the Japanese did, and the Uros still do. But the same applies for any system, whether an island, a city, a building, or a country. Balance needs to be established, and if it cannot be maintained, demand for the resource must be reduced. We already know from research, as well as from the Japanese Edo period, that in the end everything runs on solar radiation. Solar energy is our only source outside our island that continues flowing and can never be depleted—at least not for the next 5 billion years or so. Solar energy is the driving force behind our well being. Solar energy was also the driving force behind the formation of oil, via biomass. We now know converting biomass is a very inefficient way to create energy. A rough calculation suggests that only 14,000 litres of oil were produced per day on average via the biomass route (using solar energy to grow plants which were later compressed in sediments), and if we divide this over time and the earth’s surface, we get only 0.0006 kWh electric output per hectare per year. Compare this to solar PV panels for producing energy: these produce 1,000,000 kWh electric output per hectare per year. As the example shows, land and solar radiation are essential elements for creating closed cycles and establishing a balance. Clearly our present economic system does not favour the best solution.
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There is, however, another threat we need to think about. Looking only at energy will result in a system that is less than optimal. Food and (renewable) materials depend on available land and solar radiation as well. Our fisherman knows that. He is able to use the wood from the forest only once for cooking, and he can grow crops on the agricultural land. No land is left over for growing wood for a house. The only things of real value on the island are the m2 and the solar energy. (Though the situation is somewhat different, the same applies to the sea surface.) A strategy of closing cycles and 0-impacts can be regarded as a technocratic approach, typical of Western and industrialised countries. But we are not alone. If we look at the Asian countries, traditionally coming from a more spiritual point of view, we see similar approaches. In Japan, Wa, the principle of harmony, is at the basis of society. Wa is actually an old name for Japan, and its symbol is a circle. In China the Yin and Yang has been a guiding principle for thousands of years. Balance is important, especially in relation to nature. The principle has somehow lost its appeal lately, but it is still around and embedded in Chinese culture. A central message from Lao Tse expresses the principle: let nature do its work. These words point to another cultural principle in China: Wu Wei, or let things flow, freely translated. Compare these Eastern expressions to Western thought in general and to the teachings of Heraclites in particular, who said, "You cannot step in the same river twice.” This leads to the famous notion that everything flows, panta rei. This last is a clinical, technocratic conclusion: it flows. The Eastern approach gives guidance: let it flow. It’s interesting to realize that by living within our limits, we will also have to add a direction to the flow that, so far, we have only interrupted. We will have to make the cycle flow again, in a circular way. The closing cycles, the 0-impacts, nature’s work, the flows and harmonic balances: all of them together give us guidance for the future. All can be summed up in the Concept of O.
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The Concept of O As it relates to building and construction, the concept of O can be described as follows: O-energy No life without energy… But only life with 0-energy: the use of energy without impact on the climate or depletion of resources. 0- fuel degradation, or 100 % renewable. With buildings and built environments that manage their energy needs within their system borders. O-materials Energy and mass are two parts of the same thing, and materials, as the earthly form of mass, are diluted and depleted, unless they are based on a renewable source. Indeed, here comes the sun, again. 0-materials, therefore, is similar to 0-energy: the use of renewable sources, and renewing them in a similar time-space frame, to compose and maintain buildings and built environments. O-water Water is at the heart of life, and there is enough for everyone, in principle. Like energy, water is never lost as well, only degraded, by dilution, contamination and poisoning. No problem using it, but it needs to be cleaned up for re-use, and remain available in the area: Leading to a 0-water approach and eco-sanitation concepts for built environments. O-land Land is where it all comes together: to collect and convert solar radiation into food, biomass and energy. And with 7 billion people and counting, land is the most scarce ‘resource’. How can we create buildings and built environments that place the least demand on land? Productive buildings instead of consumptive built environments, housing 7 billion with an acceptable level of welfare. O-air The air carries rain, lets sun rays pass, distributes seeds and lets us breathe. If we change the balance, everything else changes. To live, without unbalancing the air around us, is about designing built environments that are free of smog, fine dust and other nasty elements. Leading to the concept of 0-air (pollution). 22
Change We are slowly starting to learn, and are seeing some signs of change in that direction, though the changes are not always recognised or well guided within an overall approach. Think of FSC (Forest Stewardship Council) wood. An attempt to manage wood in a controlled, closed-cycle manner. We see similar trends in fish (fish-farming) and food in general (slow food movements). We see the trend even in biofuels (fuels that can be grown and are renewable); though this is a faulty strategy due to the scarcity of land, it is nevertheless an example of an effort to manage resources. The landscape is already slowly changing, as can be observed in Germany, with its windmills, rapeseed fields, solar plants and solar roofs, and fuel stations with biofuel, hydrogen, and even PV (photovoltaic) power for cars. What we don’t understand very well are the consequences of using different conversion technologies for different renewable sources. Now let’s return to the island. Success depends on our working with the resources at hand and converting them to useful forms. Whether we’re talking about food, materials for boats, houses, and equipment, or fuel to lighten the workload, it all comes down to a decision on what to spend on what. And the “what” turns out to be the m2’s available. Research on exergy principles and analyses shows that in the end, solar energy drives all processes on earth, and solar radiation hitting a m2 is the main requirement for production and conversion. That’s how oil got its start (via biomass, sediments and pressure over millions of years), and the requirement holds for renewable energy, for food and for renewable materials.
Managing the island Non-renewable sources can be used without employing solar energy directly. But in the end this will cause problems, since like oil they run out. Take the “island”, the Netherlands. Everyone thinks the Dutch claimed land from the sea. In fact a main part of Holland that is now below sea level was above sea level 1000 years ago. Centuries of digging the land to 23
harvest peat for heating houses sank the land lower and lower, until it flooded and we started dredging. And then, when it was too deep to dredge, we built dykes to dry out the land and inhabit it. Now we face flooding due to climate change. Ironically, we exploited the land not for a non-renewable resource, but for peat, a renewable energy source. A question for the islanders is what has priority. The solar radiation falling on the land can only be intercepted once for conversion to food, materials or energy. Growing biomass for energy consumes a great deal of land, which then cannot be used for growing food. Using wind turbines or PV panels requires less “solar radiation access” and leaves more land for food. The islanders soon realize that what they need first is water (and for that, they need to secure land). Second they require food. Third are raw materials, and last is extra energy (aside from labour energy). In our research, we use two principles to evaluate the maximum value in a built environment. First, the m2 (space access to solar radiation) is an overall indicator of the value of a closed-cycle-based society (and of its productivity). Second, the importance of each resource is relative to the other resources (and the ways humans know to convert one resource into another) in making decisions about land (space, surface) use. The principles are part of the Concept of O, of closing cycles, and of 0-impacts, meaning capable of running forever. In our recently established Research Institute Built environment of Tomorrow, RiBuilT, we strive for these 0-options and are trying to develop an integrated approach to projects and urban areas. One of our main areas of research involves trying to develop an m2 indicator to evaluate the space needed to produce the resources for all areas in the least spaceconsuming way. Urban Harvest+ looks at existing urban areas and asks to what extent they can be re-developed as 0-impact or closed-cycle managed areas. The M-exergy project aims to develop a space-time indicator for the evaluation of new construction. In addition, there is technology research, for instance, on improving the harvest from a m2 by developing new types of solar panels. One study involves developing an organic solar panel which can be used in window areas. Other studies investigate new (nano) materials as well as (building) process innovations.
Our "District of Tomorrow" project: trying to treat it as an island
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To start by measuring the amount of m2 solar access that that can be made productive overcomes the disadvantages of systems like carbon credits or LCA (Life Cycle Analysis). These are no longer relevant: the value is directly related to the capability of generating permanent quality in the system itself, ( a building site, a district, a region). Only the surplus can be exchanged with other areas, not the shortages… During the SB10 Western Europe Conference, we will introduce the initial results for an existing area pilot with what we call the Urban Harvest+ approach, and for new buildings, with what we call the MExergy approach. What holds true for an island holds true for the earth. Earth is just a slightly larger island. And you know what? Remember the fisherman on the island with 170 trees? At this moment a rough calculation from FAO (Food and Agriculture Organization) data indicates that the total number of trees on earth divided by world population is around 170 trees each…
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The 0-Impact Transition Approach Jacques Kimman
2)
It is now apparent that we must change society in terms of how we manage health, energy, food and material resources. With respect to energy, fossil energy sources are not sustainable, stocks are decreasing rapidly and needs are increasing. As such, prices are certain to increase dramatically. Based on this kind of trend, as early as 2008 the IEA predicted an energy crisis in 2015 (Annual World Energy Outlook 2008: www.worldnenergyoutlook.org) due to stagnated fossil fuel production, a decrease in resources and increasing energy needs, especially in rapidly developing countries like India and China. In fact, we will be facing new crises very soon: Food prices will increase due to high transport costs; food prices will increase due to competition with bio-energy;uUranium prices will rocket; and resources such as silver, manganese and others will be depleted. Some problems will be solved very smoothly and automatically by means of market mechanisms. For instance, there will be a rise in home farming movements and local food markets. However, resource depletion requires dramatic system changes and the solutions need long-term R&D and change management. Therefore, we need to properly organise and coordinate actions along a timeline (road map) to achieve an ultimate, defined goal. This ultimate goal is to organise society in such a way that our behaviour has zeroimpact on our surroundings both now and in the future. But how can this be achieved? What are the steps needed to reach this goal and what order do they come in? Furthermore, who has the overview; who is responsible for coordinating all of this? In order to reach this ultimate goal, we must first come up with a road map and secondly, analyse the actions set out therein and put them in a logical order. This approach is known as transition management. Such a process should also factor in as many best practices as possible (forecasting).
2) RiBuilT / Zuyd University, Heerlen, the Netherlands
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Some of the best local solutions regarding energy supply are solar energy and geothermal energy, as described in Leduc’s paper on planning 0-energy cities using local energy sources. Solar energy needs about six times less space than wind energy and 35 times less than bio-energy. Furthermore, solar energy can be integrated into the built environment which allows for the principle of avoided costs by façade, window and roof integration, in addition to minimising energy transport. Besides space requirements, another drawback to bio-energy is that biomass and the land involved are needed for construction materials. The cycle management of materials and energy should be tightly coordinated so as to avoid competition with other chains such as the food chain. Taking this to the larger scale, we need energy potential mapping, and we must not overlook aspects like materials (Rovers et al.) and water (Nederlof et al.). At RiBuilT we perform road map analyses by making an inventory of all of the bottlenecks that stakeholders face when trying to bring about change in their sector. As soon as these have been identified, the search for solutions commences. For this we build on the experiences of frontrunners (forecasting). This is knowledge exchange at its optimum: somebody else has already solved your problem! Moreover, this type of solution generally works far better than a textbook result since it leads to a tailor-made response. However, having pinpointed the bottlenecks and found some answers from frontrunners, the question of how to organise the process remains: Which players should be involved and who will take the lead? What products must be developed and what R&D is necessary? Who is going to initiate and who is going to support the R&D? 28
Searching for knowledge on solutions and distributing this knowledge by bringing the relevant regime and niche players into contact with each other is an important task. A Task Force to coordinate the transition to a renewable energy supply is currently being set up at the level of the Province of Limburg. However, it is also important for municipalities to take on this new role of coordinating and creating the right boundary conditions for the transition. RiBuilT (Research Institute for the Built Environment of Tomorrow) is supporting this knowledge generation and information exchange for the transition (see www.ribuilt.eu). In the case of energy, the city of Tilburg in the Netherlands is a perfect example of such a frontrunner (TRANSEP-DGO project, see www.duurzamegebiedsontwikkeling.nl). This city plans to be energy-neutral by 2040, for which some 10 PJ of renewable energy production is required. Solar energy will provide 2.25 PJ, geothermal energy 3 PJ, and the rest will come from energy savings. Applying the backcasting method leads to the conclusion that every new house that is built should be zero-energy. If we then apply the forecasting method using the results of the frontrunners in the field - it transpires that local renewable energy companies are a basic need to achieve the ultimate goal. A further important step is retrofitting existing buildings, which account for the lion’s share of our building-related demand (see paper by Cali) since the existing building stock is dominant. Research shows that in rental schemes, the benefits of zero-energy and zeroimpact retrofitting will directly compensate for higher rents (see results of IEA Annex 51, Energy Efficient Communities: www.annex51.org). For home owners, retrofitting costs should be included in their mortgage. Financial schemes such as these are a necessary boundary condition for the transition to a renewable energy supply.
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Two pilot projects entitled ‘The Existing District of Tomorrow’ and ‘District of Tomorrow’ have been jointly set up by Zuyd University and RiBuilt to create an environment in which these findings can be tested and demonstrated (see www.dewijkvanmorgen.nl). The projects engage students, with knowledge and support from teachers and cooperating frontrunners, to (re-)design and construct houses. All of the applied techniques used for the houses and buildings are available now for future implementation. Most of the effort in the design phase entails making all existing knowledge of best practices available and coming up with a balanced, all-encompassing concept. The installations include heat pumps, cold and heat storage, LED, domotics, smart grids, solar modules, passive house techniques, and so forth. When the house is finished it provides a ‘real-life laboratory’ for students to use and try out. New innovations such as electricity-producing windows and new functional façade coatings (see the Interreg-project ORGANEXT and the Pieken in de Delta Chematerials project) will also be tested in this laboratory. Educating architects and other professionals in the building industry is an essential boundary condition for the road map to a zero-impact society and, as such, is arguably one of the most important steps we can take. This has already been recognised by the EU, which has created a scheme for fifteen universities across Europe to teach students and professionals how to develop 0-energy buildings as part of the updated EPBD directive (Intelligent Europe; IDES-EDU 2010 project). If education is the first step, the next is to create environments in which changes will be applied. Stakeholders must agree on what needs to be done first without envisaging or creating too many hindrances (see paper by Kerkhoven et al.). To do this an atmosphere must be created that fosters consensus among stakeholders. One example of how this can be brought about was demonstrated during the conference: the ‘Café Concept’, which is described in the following chapter.
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Bringing Science to Practice The Concept of Cafeterias - Implementing zero-concept options and using a roadmap Christoph Maria Ravesloot 1
3)
Introduction: the roadmap
The Zuyd University Ribuilt Institute envisions the zero concept. The main activity is to perform applied research with partners from society who are willing and able to practically change products, services and processes towards the more sustainable zero impact. During the SB10 scientific conference in October 2010, a further step was taken: a roadmap was drawn up. This roadmap makes it possible for motivated partners from the international region of Maastricht, Aachen and Liege to absorb and transform knowledge from the scientific presentation directly into practical use for short term operational execution, medium term tactical project planning and long term strategic organization. The SB10 conference was organized around sixteen themes with each receiving several contributions from the scientific research field. The authors of the papers were asked to bring their knowledge to one of six ‘climate cafeterias’. These were set up according to six phases of the design and construction process in the building industry, from a large-scale city and town planning to the smallest scale of building maintenance and building services. Research at the Ribuilt Institute has found that design and construction processes need to be changed because we cannot expect to solve the sustainability problem using the same method that caused it (Huovila and Ravesloot, 2010). Changes in design and construction processes must be made and methods must be evaluated and re-established.
Figure 1 . The ten phases of the design and construction process (Huovila, Portious, Ravesloot 2010).
3) RiBuilT / Zuyd University, Heerlen, the Netherlands; Avans University, Tilburg, the Netherlands
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2
Framework and goal of the SB10 roadmap
The aim of the SB10 roadmap is to transfer knowledge from scientists to the partners in society who perform the actual changes to design and construction processes and who actually produce sustainable products and services. The goal of Ribuilt and SB10 is to show zero-concept potential, which social partners are kindly invited to exploit. The method to achieve a roadmap for practical use is by means of the climate cafeteria, as shall be explained later. The climate cafeteria provides a safe social platform to reflect upon the knowledge offered by scientists to partners in the building industry, and shows the need and potential of changes in that industry. Likewise, the building industry partners offer food for thought on how to continue scientific research to accelerate the development of zero-impact products and services.
3
The climate cafeteria method
Concept cafeteria sessions will run in parallel to the scientific presentations. In these sessions representatives from science will meet companies and public authorities (social partners) to make a joint effort in putting the conference results to practical use. The ‘climate cafeterias’ will generate a problem-solving capacity with unanimous decision making and the themes of the six concept cafeterias will follow the content of the scientific paper sessions and the usual design and construction process in the building industry. The zero-concept will be the foundation for all the transition ambitions. The climate cafeteria involves collaborative data mining and data selection processes. In four rounds, participants from all fields of expertise mingle and sit at four-person tables, as in a cafeteria. One of the four people is the ‘linking pin’ and table secretary. His/her job is to write down sentences, hypotheses and remarks as one-liners on blank playing cards, and to be the linking pin to the next round of four guests. As in a cafeteria there will be drinks, nibbles and background music. As in a real cafeteria, creativity will be boosted and ideas will flow. However, unlike in a real cafeteria, the ideas will not be lost. All ideas will be written down and discussed extensively with a view to making knowledge transfer possible and making it possible to combine all valuable ideas in a roadmap for future cooperation. Every round has its own specific assignment. The first is always a brainstorming session. Playing cards containing hypotheses taken from scientific papers are handed out to give the discussion a direction. The aim of round one is to make a complete list of items on the theme of the climate cafeteria. This is the general data mining phase. On average, every table should be able to produce about twenty cards within twenty-five minutes. At the end of round one the linking pin stays at the table and is joined by three new guests. New refreshments might be welcome. The second round is an elimination round to distinguish which cards are relevant to the theme in the short term and specifically to the zero concept. The table secretary goes over the cards on the table. During discussion, cards can be elaborated upon, changed, thrown away and substituted. At the end of the round each table keeps only the cards that could be executed by one person, without outside assistance, next Monday morning. Only cards that 32
Figure 2 A typical climate cafeteria setting, here with graduate students from Avans University and regional companies discussing sustainable procurement.
fit this criterion are put aside. Even if only one person has an objection to a card, that card is removed. At the end of the second round, a new secretary is assigned as the linking pin to a new group of table guests. Round three is a specification round to ascertain which cards can significantly contribute to the general issue of zero concept in the medium term. Is there an existing project that supports such a significant contribution? If not, could such a project be set up? If the answer is no, the card will be left on the table for the next round, providing that nobody at the table has a justified objection. From the third round on, it is possible to analyze and select the cards more precisely. During the fourth and last round, a selection is made between cards that fit in existing paradigms, strategies and policies, and those that do not. Cards in this last category form a stack of wild cards. The cards that do fit in, have been positively chosen because nobody at the cafeteria table has any argued objections to them. The remaining wild cards, which did cause objections, have to be scrutinized closely for unexpected valuable ideas. Every round should follow the same rules: • A card is only selected for inclusion if all four table guests have given their consent. Consent means that no valid objection has been given. • One person is secretary and stays at the table for at least two rounds. If he wants to leave, the role of secretary is transferred to another person at the table. • During any round, it is permitted to make new cards, to split cards, to elaborate cards, etc. It is not allowed to eliminate cards other than with consent of all four table guests. • The climate cafe rounds are open space. If you need to get something to drink, if you want to answer the phone, if you need to use the bathroom, you just go where your feet take you. • No more than four people are permitted at a table; fewer is not recommended. 33
•
Because of expected language problems, English will be used; during the climate cafeteria, coaches will ensure that English is being used during the rounds.
Sponsors of a climate cafeteria can use the problem solving capacity of the people at the tables. The facilitator can formulate questions to make the process of data mining and data selection more efficient. During the climate cafeteria, concept coaches will circulate through the café to guide the guests; preferably these will be representatives from local companies or planning authorities, or scientists involved in the conference. The climate cafeteria will produce stacks of sorted cards that contain directions how to implement knowledge from the scientific sessions into practice. They will point out obstructions, practical and legal questions, risks and chances. The questions that have to be answered during the playing rounds are tuned to the problem that has to be solved. During the climate cafeteria, concept coaches walk around, managing the tables. During short breaks, when guests change tables, a concept coach can give a short presentation and a brief pep-talk with instruction for the participants to continue their work at the tables. The facilitator hands out the assignments, closes and opens the rounds and summarizes the results. During the second round, the first stack of cards that has been put aside, is already being processed into a computer .xls database. Double cards can be counted and a brief validity check can be performed. If a card clearly does not fit the exclusion criteria, it can be put back on a playing table. At the end of the fourth round, a brief presentation can be put on a screen to show the results of the climate cafeteria. A bigger presentation of all results of all four climate cafeterias can be shown at the end of the conference.
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Input from scientific papers
To stimulate an integrated approach between scientists, entrepreneurs and authorities, and to encourage interdisciplinary collaboration, the themes were all used as input for one climate cafeteria. A division in scale was made to avoid scale adulteration as much as possible, since this would slow down decision making. The content of 16 scientific papers was used as input for six climate cafeterias, approaching the problem on six different levels: 1 regional development, 2 city planning and town planning, 3 area development, 4 building design, 5 product development, and 6 materials development. At each level, both design products and process were considered. In addition, each climate cafeteria considered both the approach to new built objects and the renovation and refurbishment of existing built objects. This encourages a cross fertilization between platforms and actors, and speeds up the transfer of innovations from new built objects to the existing built environment. In other words, the content of the scientific papers is discussed and can be transferred into practical use. 34
The results of the six climate cafeterias were allocated to an individual or team who can bring the idea to execution. This is called the road map for the coming year. Ideas of scientists are matched with interested companies and authorities. Knowing that ideas can be applied in actual projects will speed up the overall process towards the zero-concept.
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Part II Keynotes
Realism and Illusion Realists and Idealists on the Energy Question -- The Order of the Century Hermann Scheer
Over 150 years ago, the German philosopher Schopenhauer wrote that any new idea is ridiculed at first. When it begins to make its mark, people fight it tooth and nail. This is followed by a third phase, in which everyone claims to have been in favour of it from the very beginning. That’s why the most important question is, “In which phase do we currently find ourselves?” I would answer that we are in all three phases at the same time! Of course, people continue to sneer, which can even be seen in the language used by advocates of the move towards renewable energies. I would like to give two examples of this, the first of which concerns passive buildings. I was due to give a speech in Bremen at the unveiling of Germany’s first office building to be heated exclusively by solar energy. After arriving in Bremen by train, I got into a taxi and told the driver where I wanted to go. At this moment, it was announced on the radio that Germany’s first passive office building was about to be inaugurated on that day. The taxi driver then asked, “What’s a passive building then?” I said that it is a building which is heated exclusively by solar energy. He then asked why it is called a “passive building,” as the word “passive” is not often used in advertising. He felt that it sounded off-putting and rather unattractive. I explained, “It simply means that the building does not use any special technology to convert energy.” As a matter of fact, the word “passive house” is not quite right. It is rather “negative advertising”. Of course, I gave the project all the praise that it deserved. But something else was not quite right. There was actually a brochure about the building, with “House without Heating!” printed in large letters on its title page, which I humorously described as a strange choice of words. The house is heated, but exclusively with solar energy. The word “heating” was therefore being unconsciously reserved for heating systems that use conventional energy, which had the effect of unintentionally playing down solar heating. For several decades, the preconception has been nurtured that mineral oil, natural gas, coal, and nuclear power were real energy, whereas renewable energy could not really be used for modern energy needs. It is therefore incredibly important that we pay close attention to the language that we use, which can reinforce or confirm mental barriers instead 39
of breaking them down. We have to break down these barriers, together with actual conflicts of interest, because the changeover to renewable energy will trigger all kinds of structural changes in the energy sector. Nothing works without energy, and it is crucial what energy we use and how we use it for everything that we do. This means that this question is in no way restricted to specialists. It is a fundamentally important sociological and energy-related question! The conscious or unconscious ridiculing and downplaying continue still. The same can be said for the fighting, which often takes place in the guise of ostensible endorsement. There is a great deal of “greenwashing” nowadays; in other words, pretending to be green. At the same time, growing numbers of players in the fields of technology, business, and politics are increasingly gaining the public’s attention by recognising and opting for this way forward. Solar construction and urban planning represent a key area.
The Ministry of Construction becomes the most important Ministry of Energy In the context of these objectives, the ministry of construction really is the most important ministry of energy. But not everyone realises this yet. Energy policy debates frequently skirt around this question, although the bare figures highlight its importance. In Central Europe alone, 40% of all energy is used exclusively for heating buildings. If you add electricity, the amount of energy consumed in buildings clearly exceeds 40%. We can therefore see that half of the problem which we have to overcome lies within the field of construction, which also provides half of the answer to the problem. This will clearly require different structures from those used to generate power over the last 100 years. This reminds me of a few past events, one of which took place in Berlin, when Emil Rathenau (founder of the AEG Group and Germany’s first light bulb manufacturer) attempted to light a Berlin street with electrical light bulbs, instead of the gaslights that were then the norm. Electric lighting was installed along one street. As the street began to light up, Emil Rathenau said, “In less than 20 years there will be electric lighting in every Berlin home,” which led to him being seen as a nutcase. But this was about how long it took. The second event was the argument between Edison and Westinghouse in America, both of whom were forefathers of the modern electricity industry. Edison’s vision was that every house would independently generate its own direct current power. Westinghouse believed that external power stations would generate alternating current electricity. Westinghouse’s concept prevailed in the end, for very forward-looking reasons for the time, as there were not yet very many coal power stations during this period, but water energy was being converted into electricity. The hydroelectric power stations would have had to be abandoned in favour of a small coal power station in every home. But cities already very serious air pollution. Westinghouse’s plan was superior for urban-ecological reasons, while Edison’s concept would have meant more coal being delivered to every household and more air pollution in cities. We are now faced with a completely different situation when it comes to the use of solar energy. The possibility of generating electricity directly from solar radiation energy now gives us an even faster and unsurpassed primary energy source which is completely free 40
and does not require any complex technology. It is therefore now possible to harvest and convert primary energy into electricity in every house - sustainably and without any emissions or transport costs. The vision of generating electricity in your own home is becoming a reality and has already happened in many cases. Furthermore, this reality does not harm the environment in any way. In this sense we are, against the backdrop of modern possibilities for the use of solar energy and well over 100 years after the WestinghouseEdison controversy, in a completely new situation, representing a completely new opportunity to truly put energy autonomy into practice. The structural change has therefore been pre-programmed, which makes it very clear that it will also coincide with a cultural change. We will not therefore develop a copy of the conventional energy system using solar energy, but a new decentralised energy supply structure for energy consumption which is always decentralised. The conventional energy system requires the areas where energy is generated to be separate from the areas where it is consumed, as sources of coal, mineral oil, natural gas, and uranium only exist in very few places. With renewable energies, we have the opportunity – together with the environmental benefits and provision of a sustainable power supply – to re-connect the areas where energy is produced and consumed. This is the cultural process facing us.
Architecture as a mirror of the times This process will, of course, also transform urban living and lifestyles in general. It is not a process that will take place overnight, but will take the form of a cultural shift. It will also make architecture develop in a more interesting way than has been the case over the last 100 years. Architecture always reflects social and political conditions, contemporary thinking and contemporary challenges. If we consider the nature of the challenge currently facing society as a whole, there seem to be contradictory tendencies. One of these tendencies is the increasing need for individual autonomy in modern societies, which is, however, frequently in an apparently irresolvable conflict with the greater shared social responsibility which at the same time is needed to prevent the consequences of individual actions becoming a burden on society. This can be seen very clearly in the case of fossil and nuclear energy consumption. The classic philosophical question is that of how we can reconcile individual freedom with the common good. This problem now seems more impossible to resolve than ever before. By switching over to renewable energies, particularly with the move towards solar energy in buildings and its impact on urban planning, we have a massive opportunity to make these two values compatible. The use of solar energy provides greater social, economic, regional-urban, and individual autonomy. It also represents a major benefit for society, which can thus be freed from the environmental burden of conventional energy and the damage that it causes. This unique process is so fundamental that it cannot be measured according to whether it currently costs a few cents more or less per kilowatt hour. At the same time, today’s open society calls for greater transparency in all our processes. Solar construction is a more transparent construction method and opens up the way for new designs. The first conference on solar energy in architecture was took place in Munich in 1987, and was purely technical and mainly an opportunity to present solar 41
collectors/systems and show how they could be installed on rooftops. This actually had little to do with architecture and only demonstrated possible applications of solar technologies. This was also the case at the second conference, which was held in Paris in 1989, when we sat down together and agreed that we must focus on architecture and new designs. This paved the way for the next conference, which was held in Florence in 1993 and was chaired by an architect and a politician - Sir Norman Foster and myself. A new model was developed, which led to the “Charter for Solar Energy in Architecture and Urban Planning” – thus taking over the baton from the Athens Charter developed by Le Corbusier, who had advocated the division of functions in towns. It has already made an impact, culminating in the 2002 International Architects’ Conference in Berlin, with the motto: “Architecture as a Resource”. In 1998, we christened the fifth conference, held in Bonn, under the motto “Building a New Century!” At this time, a wide range of projects was in progress, which have opened up new designs using solar energy and focused attention on urban development as a whole. This could also be seen at the 2000 conference in Bonn, which was entitled “The City as a Solar Power Station!” At the moment we can see how much has been achieved since then in response to various stimuli, not least those created by this conference series. I hope that all of these stimuli will bear even more fruit as part of a snowball effect, as we do not actually have much more time. This is the main problem and I would like to conclude with a few remarks on this subject. Everyone now knows that today’s power supply system would not be in good shape, even if the climate problem did not exist. There are still many other energy problems, all of which can be overcome by switching to renewable energies, without any subsequent costs for society. We must be aware that we do not have much time. If, however, the other side repeatedly spreads the message that there are no alternatives to nuclear and fossil energies in the short and medium term, this leads to serious psychological tension. For what will people think if they believe both messages at the same time? They will reach the logical conclusion that the problem can no longer be resolved, which will lead to the spread of “new future” mentalities and new forms of nihilism. People can only commit themselves to a new way forward if they can understand it and are convinced that it actually exists. This is precisely the problem facing us today – that of contradicting the people who say that it really is not possible or would take a lot of time, although we no longer actually have this amount of time. Moreover, we can no longer avoid the most important issue – we must broaden our idea of energy and the traditional view of energy policy to include the focus on “Sun and Sense” or “Sense through Sun”.
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GÜSSING, a Model for Other Regions Self-sufficient energy supply based on regionally available renewable resources and sustainable regional development Peter Vadasz
4)
Introduction Güssing is the capital of a district with approximately 27,000 inhabitants, in South East Austria, close to the Hungarian border. In 1988, this region was still one of the poorest in Austria according to statistics. Due to the geographically unfavourable location near the border, major trade or industrial businesses did not exist at that time and the whole district lacked any form of transportation infrastructure, having no railroad or highway. This resulted in a scarcity of jobs, 70 % weekly commuters, and a high rate of migration to other regions. In addition, there was the problem of substantial capital outflow from the region caused by energy bought from outside (oil, power, fuels), while existing resources (e.g. 45 % forest land) remained largely unused. In 1990, experts developed a plan for the area to abandon the use of fossil energy completely. The area considered was 45 km2 at the start, consisting of 45% woodland, 44% open land and 11% urban area.The objective was to supply at first the town of Güssing, and subsequently the whole district, with regionally available renewable energy sources, providing the region with new forms of added value. The plan comprised the aspects heat generation, fuels, and electric power. First steps toward implementation consisted of targeted energy saving measures in Güssing. As a result of the energetic optimization of all buildings in the town center, expenditure on energy was reduced by almost 50%. Then, the realization of numerous demonstration energy plants in the town and the region helped to promote the implementation of the model step by step. Examples include the successful installation of a bio-diesel plant using rape oil, the realization of two small-scale biomass district heating systems for some parts of Güssing, and, finally, a district heating system based on wood fuel for the town of Güssing.
4) Mayor of Güssing, Austria
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0-energy Gussing Energy self-sufficiency was finally realized in 2001 when the biomass plant of Güssing was installed; it relies on a newly developed biomass-steam gasification technology. At present, Güssing produces more energy (heat, fuels, and electric power) from renewable resources than it consumes. This gave the region an added value of Euro 13 million (calculation based on 2005 figures) per year. The implementation of this innovative energy concept induced a sustainable regional development process, which transformed the formerly “dying region” within 15 years into a region with a high standard of living and excellent quality of life. In recent years, Güssing has been awarded honors as the “environmentally most friendly town” and “most innovative municipality” in Austria. One of the first infrastructure improvements, i.e. the installation of the district heating system Güssing (1996), already made the town on the border an interesting location for the establishment of businesses. A special scheme promoting the establishment of enterprises in the area brought 50 new enterprises with more than 1,000 direct and indirect jobs in the renewable energy sector for the region. Güssing, since then, has developed into an important location for parquetry production, hardwood drying, and environmental technologies. The realization of the biomass plant Güssing and the establishment of the RENET Austria (Renewable Energy Network Austria) competence network gave rise to the launching of numerous national and international “renewable energy” research projects in Güssing.
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Management The “European Center for Renewable Energy” (Europäisches Zentrum für Erneuerbare Energie EEE) coordinates all demonstration plants, projects, research emphases as well as programs for training and further education in this field. The manifold research activities here have also contributed to the attractiveness of the region and to the creation of additional high-quality jobs. Work within the “Energy Systems of Tomorrow” subprogram aims to further disseminate this successful model. The objective is to further develop the strategies and technologies tried out in the town of Güssing and to apply them in the whole district. By 2010, this area should also have attained a self-sufficient energy supply, and thus, numerous concomitant positive effects for the economy in the region.
Technology The flagship and most important innovation of the Güssing model is the biomass plant, which uses a special fluidized bed steam gasification technology. The process developed at the Vienna University of Technology (Univ. Prof. Dr. Hofbauer) offers some advantages compared to conventional combustion processes, especially in combined heat and power applications. For the realization of the project several partners cooperated within the competence network RENET: REPOTEC plant technology, Vienna University of Technology, EVN, and the Güssing district heating utility. The plant, which became operational in 2001, has a rated fuel capacity of 8 MW and produces 2,000 kWh electric power as well as 4,500 kWh heat for district heating at a feed rate of 2,300 kg wood per hour. The plant currently operates for 8,000 hours per year. The vital component of the plant is the fluidized bed gasifier and consists of two fluidized bed systems that are connected with each other. Biomass is gasified, together with steam, at a temperature of approx. 850°C in the gasifying zone. Using water vapour instead of air as gasifying medium results in a nitrogen-free, low-tar product gas with high calorific value. Part of the residual char is conveyed by the circulating bed material (sand), which also serves as heat storing medium, to the combustion zone and is burned there. The heat transferred to the bed material is needed to maintain the gasification reactions. The flue gas is then separated and the heat contained therein is used in the district heating system. The product gas has to be cooled down and cleaned for use in the downstream gas engine. Heat recovered in the cooling process is, again, used for the district heating system. A special technology permits the recycling of all residuals, which means that the gas cleaning process generates neither waste nor effluent. The gas engine converts chemical energy contained in the product gas into electricity. Again, waste heat from the engine is fed into the district heating system. This approach results in very high efficiencies: electric efficiency ranges between 25% and 28%, and overall efficiency (power and heat) is approx. 85%. On account of the favorable properties of the product gas (no nitrogen, high hydrogen content), there is a broad range of possible uses, such as the generation of fuel gas, synthetic gas, gasoline and diesel, methanol as well as hydrogen. 45
Figure 2 The biomass plant
Research The various research projects currently conducted in Güssing address topics such as the generation of hydrogen, fuel cells, the production of methane and fuels, cooling and district heating systems and aim to test and implement new technologies. The overall objective is to develop energy centers to meet the demand of the region and which are able to produce heat, electricity, gaseous and liquid energy carriers from a variety of energy-rich biogenic raw materials and residue matter using an approach called polygeneration. The quantities of the various resources produced will depend on the needs and the size of the respective region. Admittedly, the relative proportion of the various by-products cannot be changed infinitely, but modifications should be possible within certain limits. The experience gained in the biomass plant Güssing gave rise to a number of research projects, in cooperation with various Austrian and international partners in the fields of science and industry (e.g., Volkswagen, Daimler Chrysler, Volvo, EDF, and BP). Some of the projects have already been realized in Guessing, others are in the planning stages or on the verge of implementation. The strategy for the period between 2007 and 2013 is to implement the concept of “polygeneration”.
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Figure 3 The ‘methane’ plant
Land use and need An important factor in self-sufficient energy supply refers to the availability of the necessary land area for energy crops. Thus, the first part of the project aimed to ascertain, at the level of municipalities, whether the available land area is sufficient to cover energy demand. This provided for a quite accurate assessment of focal points of demand and an evaluation of potential sites. The sum of the land area balances at the level of individual municipalities will result in a land area balance for the whole region. In a next step, researchers analyzed the energy demand in the region and ascertained the capacity of renewable energy sources actually used today. The analysis of the energy saving potential and existing resources has also been conducted at the level of municipalities or parts of villages. These findings served to identify suitable technologies and to develop energy supply scenarios for the district; researchers also calculated the potential for CO2 reduction. In order to ensure an efficient supply of biomass, a special logistics concept has been developed, in analogy to the one for the town of Güssing.
0-energy region Research work done so far has shown that a self-sufficient energy supply for a region the size of the district of Güssing is actually feasible. At present, the overall energy demand of the district amounts to 564,777 MWh (2005); the plants existing today already cover as much as 34% (power), 49% (heat), and 47% (fuels), regardless of the demand for 47
renewable energy sources. Project participants modeled five different scenarios that permit 100% of the demand to be covered by energy from renewables alone. A look at potential resources and suitable conversion technologies shows that full use of the forest land would offer the largest land reserves. Depending on the scenario, the remaining land reserves would range between 13,000 ha and 14,000 ha; this means that, even with self-sufficient energy supply implemented, some 30% of the district’s surface area remains as reserve for additional demand in the future. A complete shift to renewable energy sources would reduce CO2 emissions in the region by some 85%, up to 15,530 tons per year. These findings were used in the follow-up project to identify potential sites and possible approaches toward implementation,to perform cost / benefit analyses, and to develop financing models. Implementation of the concept is expected to afford numerous synergies – as was the case in the town of Güssing – that can have a positive effect on the development of the region. Shifting energy supply from fossil to renewable energy sources could create added value on the order of Euro 39 million. Other objectives include an improvement of the situation on the job market, new opportunities for training and further education, and enhanced self-confidence of people in the region. New opportunities could arise in the fields of tourism, cultural activities and sports. These sustainable stimuli could create a model region and a role model for other areas, which might adopt such concepts as well.
Benefits and lessons learned: • • • • • • • • • • •
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Creating local jobs reduces commuting. Creating new jobs allows people to return to their villages. Local control of energy means more energy security. The project should be locally driven. leadership is important, with a local person appointed to manage the transition. Local ownership is important (preferably 100%). In Gussing 49% is owned by the municipal and 51% by local investors. This way everyone has an interest in the development. The order of resource use is as follows: first use available natural resources, like forests, crop waste and by-products, before adding others like growing energy crops. Liquid and gaseous fuels provide flexibility and create value. Everything needs to be measured. Plants need to be optimised, making them more affordable and more efficient. Logistiscs are important: sources and users need to be near each other. Another time, the district heating scheme could me much smaller: first build a gas distribution net and use the heating byproduct for near byconsumers. This is much cheaper, more efficient, and flexible.
Related sources: http://en.wikipedia.org/wiki/G%C3%BCssing http://www.gussing.at/frame.asp?Bereich=Wirtschaft http://www.oekoenergieland.at/konzept/modell-guessingdetails.html?start=1 http://www.eee-info.net/cms/EN/
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The Goal is PlusEnergy! Rolf Disch
5)
An energy-generating house fulfils a threefold objective: it will be supported exclusively by 100% renewable energy. It will be CO2-neutral. And, it reduces energy consumption so extensively that it will generate more energy than it will use. In addition to these are the selection of healthy building materials and a feasible market price. In order to test the operability of PlusEnergy, a long-term study at Bergische University in Wuppertal was conducted. The results were published in January 2009 in the Deutsche Bauzeitschrift (German Building Magazine). Firstly, an average home was defined from data collected on the Solar Settlement in Freiburg: 2.9 residents, 137 m2 (1,475 ft2) heated floor space, and a 49 m2 (527.5 ft2) solar panel installation with 6.3 kW peak power output. This home expends only 79 kWh/m2 per year, yet it annually produces 115 kWh/m2 per year. The surplus is thus 36 kWh/m2 of primary energy.
5 ) Architect, Freiburg Germany
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This is the way to achieve the world’s best energy value for buildings. It is, however, far more than a simple energy standard. PlusEnergy offers an architectural and ecological, social and economic concept incorporating many aspects and possibilities. Creating a PlusEnergy house design makes the individual home into a power plant: the PlusEnergy house produces more energy than its owners actually need. With this positive energy balance, it exceeds every previous standard. Because low-energy homes still consume too much energy, and even passive homes still emit CO2 into the atmosphere, the energy surplus of a PlusEnergy house sets a new standard. Passive building is not enough: ‘carbon neutral’, ‘emission free’ and ‘minimal energy homes’ must be outmatched – we need ‘solar activation’ for our homes! Long ago the PlusEnergy house was developed so that it could be built anywhere at a marketable price: from single homes to entire housing communities, for residential and commercial building, as hotels, schools, exhibition halls and nursing homes – for all imaginable goals. Today the PlusEnergy house is not only ecologically but also economically sound. As energy costs rise, the PlusEnergy house will continue to turn utility costs into excess income. The additional investment becomes financed through saving and selling energy. Cheaper building is more expensive!
How does it work? In order to achieve its annual median positive energy footprint, the building makes the best possible use – active and passive – from the only form of energy available in abundance, free of charge everyday, everywhere: solar energy. The house generates its own electricity and heat, uses them intelligently, and retains them in the building structure. The roof is made of the most extensive photo voltaic unit equipped with a solar thermal collector to heat tap water. The well-tested and well-proven use of the roof overhang provides protection from the high summer sun, while still allowing rays of the winter sun to penetrate into the home. High-grade and transparent, the south façade’s infrared-reflecting, triple-paned insulated glass retains warmth within the home. The entire skin of the building is insulated, thermal-bridge free, and is densely sealed. In addition, the ventilation system facilitates a permanent fresh air supply with nearly no heat loss. The activation of the building masses as a thermal reservoir is further strengthened by the addition of the Phase-Changing Material in the inner walls. As with commercial buildings, a vacuum-insulated façade is implemented. Should an additional heating unit be necessary, there are several options to do so with renewable energy. We employ advanced, clever solutions as necessary, i.e. high-tech heating systems. This makes the technical expenditure of our homes easy, robust, low-maintenance and user-friendly – because these are also economically successful.
Ecological building – healthy living Using natural materials is not only great for the environment; it is also good for the environments we build for ourselves. After all, central Europeans spend over 80% of their lives indoors. 52
Figure 1 Cross-section of a PlusEnergy house
For both living and working spaces, the PlusEnergy house avoids any kind of harmful substances. All of the building materials must be emission free. Together with modern ventilation systems – not energy-wasting air conditioning – the PlusEnergy-construction guarantees permanently fresh, healthy and well-climatized air. Light-flooded rooms are conducive to a cheerful atmosphere. The large-paned windows, so essential for PlusEnergy, also bring about a positive and comfortable balance within the home. Ecology is not about asceticism or giving up on our comforts; PlusEnergy means the luxury for all that is essential for a buoyant and reasonable, healthy and joyful lifestyle.
The solar settlement in Freiburg “The long-term goal is carbon-free homes,” reported the German government with their fifth energy research program – as if reality was not already beyond that. However, science is well beyond the next step, as proven by the 59 existing Energyplus houses in the Solar Settlement in Freiburg. The results of a long-term study at the Bergische University in Wuppertal were published in January 2009 in the Deutsche Bauzeitschrift (German Building Magazine). The Solar Settlement houses actually do generate a surplus – and indeed the average per square meter and year was 36 kWh. Included therein are all of the energy consumption values: heating and warm water, household and appliance power, rather than simple heat energy as is elsewhere the case.
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By way of comparison, existing buildings in Germany consume an average of 435 kWh, the minimum energy standard for new buildings (EnEV 2009) is 260 kWh, and even the passive house allows up to 120 kWh of consumption. Here we are talking about consumption alone. The PlusEnergy house covers its own consumption and generates another 36 kWh on top of that. How is it calculated? Professor Karsten Voss and engineer Mira Heinze explain this in their study. They act on the assumption from the average of all the Solar Settlement homes: three residents share 137 m2 floor space. Now imagine the exact same house built to the minimum energy building standard (EnEV). This would consume 185 kWh/m2 per year. However, one can only insulate a home so well – how the residents live and which electrical equipment they use also play a role. This is why an energy-saving household is estimated, as the Solar Settlement determined, to stay at 165 kWh/m2. Now the building is only within the passive house energy standard, consuming 98 kWh/m2. It also depends on where the energy used comes from. For instance, a mini-CHP in the home using wood pellets from the region is more efficient than an age-old heating system with Arabian petroleum. That is why there is a key multiplier for so-called ‘primary energy’. Through the district heat network with partial wood burning, in Freiburg we consume 79 kWh/m2 of primary energy. In addition to 79 kWh/m2 in consumption, the photovoltaic installation generates 115 kWh. This yields a final energy gain of 36 kWh. The total energy savings at the Solar Settlement, including the 59 Energyplus homes and the commercial and retail ‘Sun-Ship’ building, are equivalent to 200,000 L of oil or 500 tons of CO2 per year. Since the realization of the Solar Settlement, the home and housing community concepts have been further developed. With optimized components, PlusEnergy homes can now generate up to 200 kWh/m2 per year.
PlusEnergy as an investment Crisis? What crisis!?! There are only challenges: economic, social, and ecological. Challenge and response: sustainability is the answer to today’s crisis and the basic energy problems of our international economic system. Investments in PlusEnergy-projects have proven to be resistant to the current economic crisis, and they will also defy any energy crises. PlusEnergy-real estate investment funds have so far upheld or exceeded all of their prognoses and have satisfied well over 1,000 investors. Among our institutional investors, foundations, above all, have contributed not only towards a safe, high-yielding and clear-cut investment but also an ecologically ethical one.. A PlusEnergy house brings financial advantages to the owner as well as the tenants, and in the event it is owner-occupied, the benefits are double. Because the PlusEnergy house reduces energy consumption to a minimum and generates a surplus of up to 200 kWh of primary energy per m2 per year, a supplementary income is achieved instead of extra costs. The energy savings and the buyback price for the solar power bear the higher investment compared to a conventional new building. Even with the financing costs included, a PlusEnergy building will still uphold not only an energy plus but also a financial plus in the first year. 54
Figure 2. The new PlusEnergy development in Koeln-Ostheim.
Every community energy-productive! In the UN, EU and German Federal Parliament and all over, the provisions for environmental protection are being discussed, targets aimed for and programs launched. The changeover will happen locally, in cities and communities. Moreover, these communities have the potential to be at the forefront of the movement right now, to take the energy turnaround into their own local hands and thereby ensure their future sustainability. That is why all German communities - all 11,000 - were contacted. All German mayors were informed of the PlusEnergy opportunity. Over 300 of them have expressed an interest and several PlusEnergy housing estates are already in planning: Königsfeld, Schopfheim, Waissach, Nuremberg, Cologne… little and large communities in addition to developers have begun contracts with the PlusEnergy concept, in order to explore the PlusEnergy opportunity. A number of projects are already underway.
What can communities do? The community is an owner and a model at the same time. It can build and use PlusEnergy houses to show that they work. As property owners they can adequately allocate property. Residential city builders can become committed to the highest efficiency standards. Communities can develop a political master plan and enact it. Above all, the community should decide on a development plan. The first step to a PlusEnergy housing community is the master plan, which will be optimized with regard to urban development and energy. 55
A pilot project that convinces and enthuses always has a chance of being implemented. A large number of institutions, sponsors and foundations will gladly provide support, if they are only asked for it. Today, local and regional banks are aware of the major prospects of sustainable projects and PlusEnergy is the opportunity. Likewise, the market for ‘green money’ is expanding, even where other markets struggle. Institutional investors and private owners alike invest increasingly and profitably – ethically and ecologically. So help carry out a trend-setting public participation project. It will give citizens the chance to achieve sustainability and to invest in a local, green, real-estate investment fund – in their social security. This is how we do it and it has proven to be successful. Cities and communities need sustainable buildings. Wherever brand new housing communities or redensification buildings are planned, wherever attracts singles and young families, where multi-generation living projects with attractive living space for both young and old can be created, that is where we must think 30 to 50 years in advance. The decision to move to or from, invest or not invest lies with the plausible and sustainable vision of the community. Is it not an electrifying idea to add an example of such living quality to every community, and thus own something that anyone interested can really see and feel? That is how a PlusEnergy house embodies modernity, savoir-vivre and indeed luxury at its finest; in short, everything a location would like to show off in order to promote itself. New building standards demonstrate this: “We are thinking of future generations,” said Ernst Ulrich von Weizsäcker, an environmental activist, Emeritus Dean of the Environmental College of Santa Barbara, California and former president of the German Federal Environment Committee.
The Freiburg Charter Our office is currently working on the ‘Freiburg Charter’ – an ambitious catalogue of objectives and principles aimed at contributing locally to tackling the impact of climate change. The time is ripe for decisions, especially in community politics. Make these decisions for communal environmental protection with the Energyplus projects.
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Architecture of Conglomerates Lucien Kroll
6)
The situation, first (summary) The IPCC promised us various disasters within ten years and this was already declared three years ago which means that the point of no return is 2017. And, by the way, the ‘Kyoto/Copenhagen’ process failed miserably: we simply did not reduce our energy consumption and CO² production at all… That is clear now, but then what? As technology is not the solution but the culprit, we need to ask people to stop believing in it and, on the contrary, to favour the low-tech over the high-tech that destroyed the planet mostly during the ‘thirty glorious years’ which were in fact the worst years of humanity: we invented all the best means to destroy the planet and we adopted them all without hesitation… Cities and their transport are guilty for two thirds of pollution! We figure it will take a century to correct them in the world (insulation, amount of area, new ways of living together, production of energy, food, work, etc). We have certainly embarked upon many courageous actions, but painfully slowly, preferring to accumulate money in finances and luxury more than on repairing the planet. As it is technology that has led us to this ‘final solution’, let us choose another direction: let us try humanism to change mindsets and the public will. And let us try to learn to change by changing… Rational modern urban cities are all designed like American military camps, settled in no-man’s-lands to shelter merchandise and to let trucks and cars circulate everywhere whilst forgetting that people also live there. The big social schemes with prefabricated housing became ‘criminogenic’: they are the last trigger of the process. After the experiences of Pruitt and Igoe in Saint Louis, Missouri, il Corviale in Rome with its famous length of one kilometre, a recent significant event occurred in Paris; in these new quarters (Clichy-sousBois), the riots of the banlieues saw 10,000 cars and 250 public buildings burnt out in 20 days. They are professionals, that much is clear…
6) AUAI sprl, Architect, Brussels, Belgium;
[email protected].
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We must remember that even in economic science, there are TWO ways of making decisions: rationalism and incrementalism, which seems widely unknown (inhibition?). The first system was codified by Herbert Simon (he received a Nobel prize for that…): the General Problem Solving approach was a blind, deaf and rationalist system calculating naughty procedures totally ignoring the context: each step is definitive until the last task which logically remains theoretical and destructive of a holistic civilisation. The second has been defined by Charles Lindblom as “Disjointed incrementalism: the science of muddling through”. The basic definition is also ‘step by step’ but at each step looking to the consequences upon the context of the works done and trying to correct the action if needed. As the first context is clearly and visibly the inhabitant, minimum respect should be requested: does he possess a future or will he be extinguished soon? Therefore, spontaneously, incrementalism tries to save humanity and the planet. Simple, isn’t it? So, urgently, we need to be incrementalists and humanists. This implies the participation of all involved in properly organised meetings (not ‘by the way’ meetings) and think tanks, so as to discover and respect the complexity of the people. This will of course overthrow the current bases of architecture and urban design. The ‘project’ will nevermore be mechanical, abstract and technical but take place in disorder, with emotion, and a deep diversity of forms, techniques and expressions. Even architecture programs will nevermore be fixed at the beginning of the action, but will evolve over the course of the project with inhabitants and users playing a central role, and never stop. A question derives from the conflict between procedure and process: if an agglomeration is a gathering of objects in a place having in common just the short distance that separates them, then the conglomerate is a gathering of subjects linked by empathy and cooperation. The result will be unimaginable by all well-established architects: new ones will act more naturally. They will have to disorganise as much as possible, disassemble the homogeneity of their project in order to reach a complexity that allows the greatest urban diversity. In these uncertain times we are living in, this conglomerate attitude allows us to be so flexible that the whole program has to be utterly improvised as a real organisational technique. This will produce a bright new ‘natural landscape’ far away from our cities as store depositories and houses designed like machines. I have two naughty questions. The first is: in coming years, with the disasters facing us, what will the model of dwelling be? I guess it will be slowly invented by groups of participants who will face those quite unknown, not understandable, not predictable circumstances of living in the next period of disasters. Please let us not put this question to specialists, architects or engineers. They already answered this same question in the sixties, inventing the “machine to inhabit” (a definitive solution, said Walter Gropius) and creating them by the million. And we now organise huge works to demolish them by the hundreds of thousands… The other is also a hard question: what innocent materials will we be allowed to use for our dwellings tomorrow? I know crude (or baked?) earth, stones, chalk, animal or plant insulation, wood in large or tiny sections and some glass (still useful…). Faced with the huge world of building sciences and techniques that are all-polluting, we will not have the strength for improving them fast enough, but I bet we will witness an extraordinary explosion of low technologies and intelligent systems for recycling all the trash of one that becomes the raw material for the other. We will probably, all of us, become very poor and no longer able to afford a big house with ‘rich’ materials; it is an urgent quest to replace that waste by being abstemious and proud of it. This is a good program for ‘new’ architects that will reveal 58
differences like those between gothic cathedrals with their millions of working hours imbedded, and our present social houses where, stupidly, we spare work hours to spend more money on high-tech means and waste of natural resources... Concerning the inhabitants, as these are the ‘context’ of each other, I call ‘vicinitude’ the opposite of ‘urban solitude’. This should be the minimal necessary proximity, vicinity, contiguity, ‘nearness’, which impossible to provoke, but possible to achieve by inducing it using architectural forms and juridical purviews that merely suggest these relations. And then we wait patiently… If it is impossible to act positively or to impose it, it is only possible to forbid it… This is an unknown rule of postmodern urban design: the engineers will shiver… It firstly consists of avoiding definitively viewing architecture as a cold, calculated mechanism to be designed within closed, quite specialised teams which merely produces ‘self-contained’, frigid, egotistical schemes (that is modernity…). Or, on the contrary, observing the possible impacts on the user’s behaviour, socially, emotionally, equitably (that is post modernity…). Alas (or not?), this attitude is only attainable for architects who have already renounced their mechanical or even artistic certainties dating from the previous century. Technology applied to projects that are only technologically ‘green’ may reveal itself to be just as harmful as the old technology: common technology has a powerful distrust of sentimental behaviour even if it makes green city life endurable. Nowadays, we are seeing big environmental projects that seem to have been designed by George Orwell in 1984. There is an incompatibility between modern, educated, mighty architects and the new lowscale and empathic attitude of the necessary behaviour of new architects: it seems to be a future conflict between generations… In that sense, the military design of the last Olympic games in Beijing is a frightening, unbearable spectacle of late modernity. Institutional analyses may also help us to think about the significance of forms upon the behaviour of inhabitants, especially during these unbalanced years. From the 9/11 tragedy of the World Trade Centre we know that architecture has a powerful language: the towers spoke exclusively about world finances and the planet by money… Incidentally, in spite of the horror of the tragedy, we should congratulate the former mayor of N.Y.C., Rudolf Giuliani: without the WTC towers, his city recovered the magnificent landscape it showed before. The terrorists did clearly understand the ‘language of architecture’ (architects pretend that architecture has lost its language) in that this architecture screamed its financial world colonisation. Genuine deconstructivism (following the French philosophers invited by some American universities, with a sort of bulimia: Jacques Derrida, Jean-François Lyotard, Michel Foucault, René Girard, etc.), normally shows us the significance of our hidden egotism as architects (the personal unavowable motivations). However, some American architects have turned that philosophy into sellable merchandise. Let us remember that deceptive exhibition under the name of deconstructivism, organised by commercial architects in 1988 at the MOMA, New York. This was about a tricky complication of forms of their architecture without any sense that could modify the relation between their architecture and the context. Peter Eisenman, an intelligent leader of that movement destroyed his architecture (always cubic) in little cubes with an identical form. Indeed, he invented ‘parthenogenesis- architecture’.
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Order versus disorder Participation in the aforementioned approach, when honestly followed, produces an organic disorder that the architect may use to lead his project without being frustrated; quite the contrary. The warm discussions that precede the process, necessary to go further into the new questions provide him with a strange feeling of being useful… This follows the same processes as the spontaneous ancient cities that formed themselves slowly and organically. It is no imitation but a mere logical process answering to the same circumstances with the same actions but by other means. But with a terrible set of new necessities and contradictions that will appear brutally, we will see that it will not be a copy of the good old times… Do not invite ‘nature’ into the cities: nature will become a miserable spectacle (Guy Debord’s “Société du spectacle”). It is better to respect the indigenous groups of plants that invade possible living places as these will act as a counterpoint to the hard, built environment and the climbing plants will demonstrate this empathic association. Moreover, this is less expensive. This is not a criticism of wonderful, traditional, geometric parks but merely the consequence of a new way of seeing the ‘post-climate’ landscape. Also, care of the biomass should be constructive. We must guarantee a minimum rather than simply plant artificial rows of identical trees… Funnily enough, the three rules of classical theatre - ‘action, place, time’ - have been reinvented in urban design and architecture in recent modernity by those looking for an instrument of torture. The rules have been completely reversed to fit our new atmosphere. In urban design and architecture, action would be the reduction to a sole function (inhabit, circulate and recreation, as they believed…). (In fact it is the reverse: high quality welcoming pieces that do not fit or obey the majority by their use, aspect, scale, style, etc. Continual contradiction becomes necessary to make it habitable: homogeneity is the worst enemy of habitability.) As regards place, this has been consecrated to one ‘function’ with its accessories and without anything else that could be independent of the principal. There must be a single system to which everyone obeys, rather like an army with its uniforms. Time has been interpreted as an instant, never a duration: the total scheme seems to have been designed last night, without hesitation, without depth: annoying as an abstraction.
Antique conglomerates The Ospedale della Scala is the best example of a conglomerate: in my lectures people understand immediately what is meant! During centuries the process of conglomerate had slowly swallowed up an ancient path of goats climbing the hill to the Dome. As it was building on the buildings it also swallowed up the Chapel of Saint Catherina di Siena which lost it side facades; these became the inner wall of the new neighbours. Thus was created an urban ‘mass’ grouping all different uses and which was developed as a hospital in the Middle Ages. More recently, I visited the Castello di San Angelo in Rome which is the most touching example of our conglomerate: upon the foundations reminiscent of the Etruscans, each period has added its own layer until the summit, in function of the context and without ever deforming it.
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Participation There are various types of user participation. The most banal is consulting future inhabitants (or any person willing to help) in order for the architect to shock or refine his personal design. This is already a praiseworthy first step. When one seeks advice on the composition from other architects who pretend to be possible inhabitants it is a sharing, open and brotherly process but the architect still carefully retains his authority upon his own homogenous design. Finally, some architects try to ‘compose’ with a more ambitious attitude whereby each architect voluntarily keeps his own style perceivable in his personal part, thereby cooperating in a mosaic of unanimous differences that may be replaced by others without perturbing the wholeness. The role of the principal designer is to organise a scheme ‘as a work of collective art’ where the contradictions are positive, expressing first of all, the great diversity that makes a city habitable, evaluating, changing with new needs, without losing its ‘soul’. The role of the architect explodes: he is no more the solitary genius but one among others (non-architects). His new work could be seen as frustrating but in fact practical experience shows that it is curiously rewarding to play that role: his professional qualities are hugely necessary to translate and combine all needs. At first he feels that the members of the group hesitate, but suddenly they decide to trust him without saying anything, which he ‘feels’ warmly! After that moment he may be genial and quite personal: his art as a contribution to the group process becomes positive. He is responsible for the expression of the diversity of the dwellers: this is a new future for new architects. His designs are always ‘open’ in the sense used by Oskar Hansen, a Polish architect and also a great friend. For many years in Warsaw he taught his concept of “Open Form” and the attitude of architects that allows this permeability for natural evolution.
Free Jazz and participation A comparison with the improvisations of Free Jazz, which differs greatly from the ‘cadence’ in classical concertos, is useful here: the instrumentalist is free to improvise for only a certain time within the piece. In architecture or urban design it is a far more ‘mechanical’ responsibility. The first architect stays personally responsible for different safety questions. However, some major decisions already de-dramatise the solitude of architectural objects. Bjorn Alterhaug and John Pal Indenberg, two Jazz Norwegian musicologists, settle a parallel between Free Jazz and my own way to design, taking the Mémé as the model of that attitude, for the ancient cities were born as a long symphony with innumerable voices and without musical partition. This was the same for jazz groups around 1950-1960, including Ornette Coleman and others in New Orleans. There each musician knew the movement of the person in charge of the motto so well that he ‘instinctively’ guessed the changing themes and made the link. By doing so they expressed democracy and black liberation. In a sense, it is not very different from the random exercise we played to ‘compose’ the fronts of the Mémé; and the nine architects we chose for Ecolonia to juxtapose them randomly are not so different from the sentences written on the folded notice of the surrealists...
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The artist-bricklayers At la Mémé I proposed that the workers create freely. Initially, they could mix white cement blocks and dark grey ones in a wall of red bricks, exactly as they wanted. The first attempts were banal but then, tightening the rules I said, “Put them exactly from here to there, without it being a 45-degree slope”. Thus, standing on their scaffolding, they had to turn off the radio to think about the work: without precise drawings, the line came out to be too steep or too flat and they had to correct it with bricks, which made it a very nice job. They felt like they were autonomous or co-authors for a week. After that we proposed other exercises on a large recreation area of the school: let us make some ‘hills’, so wide and so high. These were marvels of intention: the pupils were always climbing them. The workers came back with their families to show what ‘they’ had done that week. We considered these works ‘popular art’ and asked for them to be given a sign of appreciation The university answered, “NO, we have our artists…”. And later they destroyed all the work without asking anybody if it had a value: each to their own personal culture…
Two examples Ecolonia We were contracted in 1989 to design a group of 101 houses in Alphen-aan-de de-Rijn (NL) which had to meet a strict list of environmental obligations set out by the Ministry of Housing. It became the first sustainable district in the Netherlands (and Europe). A remarkably friendly client was the Bouwfonds, a social housing company. I had to design an ‘eco-compatible’ layout and to organise the nine architects (but in fact to disorganise them). We chose nine at the outset in order to avoid any homogeneity. They were the best in the Netherlands but not well known: they were ecologists. Each of them had to keep their own ‘style’ and not come up with common architecture. They accepted and received a list of environmental obligations, written by the Ministry of Housing. I had to invent a method to escape from the artificial forms that the urban designers had fatally drawn and at that moment I had no inhabitants to question. So, I studied a series of ‘urban components’ – the actions or behaviours of the inhabitants (patterns). Next, I placed the components ‘randomly’, or rather following a spiral (an invisible form), and then I arranged the interfaces. The result was an image without any geometrical, visible intention, and then I redistributed the places for the blocks of the nine architects. They had to divide them into two or three parts and were free to discuss with their ‘new’ neighbours (the blocks by the other architects), even without me guiding. This is akin to the way a ‘spontaneous’ city formed itself over centuries. I tried to protect this precious disorder from the Technical Services of the municipality, which was a long battle. Ecology is contagious: what the inhabitants added to their personal lot was immediately in the same mood of differentiation of my own design. As an example, we had no budget to develop nice gardens, just a large lawn between the façade and the central pond that we placed in the centre of the land. So as soon as people came to live there, they worked hard to design and build their gardens, always after discussions with their neighbours and without any influence from the architects. Now, twenty years later, they are magnificent, shining and touching… 62
Admiraalsplein in Dordrecht This part of a neighbourhood is the most significant example I have of a conglomerate! The reasoning behind the construction was not at all an architectural classical project with “venustas, firmitas, utilitas”, but rather a salvation operation to save the neighbourhood from slow collapse (disorder: our client, the social promoter Woondrecht who owned these buildings, had decided that the best thing to do was to bring in new inhabitants to offset the flight of the Dutch inhabitants, too many immigrants coming, the danger of youth, etc.). Our promoter was sure that all the money we spent then would be beneficial within a few years, saving the whole neighbourhood. He held talks with the municipality of Dordrecht who gave him a good budget, “just to do it better”. There was neither program nor clear budget! We made a model occupying the area with something that could be buildings but without any readable form and we organised meetings with neighbourhood committees involving anyone willing to help. We worked with these proposals and slowly we saw a ‘possibility of building’ emerging: a certain volume in that place. Then, a large department store interested in the place turned up, and another, less expensive, and also thirty boutiques, and a group of doctors who ran a day care centre, and a community centre, and a Chinese restaurant, and two schools together. Then the doctors pulled out, followed by the community centre, the schools and so forth. With each event we changed our plans…. The program was decided following the events and the budgets could not be calculated during this process. During the studies they changed again and even during the works on the site. It was already a genuine conglomerate… The promoter was under the obligation not to begin work without fifty percent of the building sold, but even after a huge meeting to announce the building including a massive model, songs, a meal, drinks, publicity and so on there were no sales. However, suddenly, when the first building took form, nearly everything was sold: the possible clients had simply not believed that it was possible. There are no two identical apartments: the social mix we had promised to seek was automatically achieved by the huge differences in the apartments and other uses. Now, the second phase has the same characteristics but is a slab to transform: it contained identical, tiny apartments and we changed it into apartments that were all different, some smaller and some bigger. This is now finished and is becoming inhabited. Moreover, the community centre came back, the doctors will go into the third phase, the schools are interested again: there is no limit on time… This is a postmodern way of building - incrementalist and flexible; quite the contrary of a seemingly military, rational organisation. It is a conglomerate…
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A Life Cycle Tower for a Better Future Contributions of the Building Industry to a Sustainable Tomorrow Hubert Rhomberg
7)
Abstract Faced with ecological challenges and limited resources, the construction industry has to make its contributions for a sustainable tomorrow. As one of the industries with the heaviest impact on nature, this is the construction industry’s responsibility. One of the contributions could be a lifecycle oriented process of building combined with measures which enable buildings to use a fraction of the resources and energy currently used. The key lies in system integration and the linking of materials and technology as well as by implementing highly standardized industrial processes like prefabrication. These efforts lead to a high level of quality and a guarantee in price. The author illustrates this process with an eco-innovation – a timber-based high rise – to show what future contributions the construction industry could make, as well as how wood as a raw material will find its way back into urban architecture. The author underlines the importance of knowledge accumulation and sharing, the need for mandatory global policies and national guidelines regulating the usage of resources.
Introduction “Be fruitful and multiply, and fill the earth and subdue it”fill the world and subdue it”
8)
Do we have the right to subdue the world? Do we have the right to influence our biosphere? What are the outcomes of our imprudent actions over the last 100 years? Will we continue to overuse natural resources like ores, fossil fuels, water and even land surface, leading to erosion, water shortages, natural disasters—just because they are part of our life? Or will we respond to the alarming signals with a shift in our daily actions and future plans?
7) Hubert Rhomberg manages the family-owned Austrian Rhomberg Group, now in its fourth generation. He studied at the Technical University of Vienna, Austria and the University of St. Gallen, Switzerland 8) Genesis 1:28
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On the one hand, we are faced with an ecological crisis. On the other hand, we are threatened by such things as the financial crisis. Market failures, speculation, malfunctioning early warning systems, short term profit maximization have unsettled our trust in the stability of our global financial system. The result has been a demand for stronger regulations, and politicians and major governments have answered by committing financial aid to address a crisis caused by only one industry. The financial system may be restored by a few simple measures–this is, however, not the case for our ecosystem. Instead, every industry and every government will need to contribute to delivering a joined global framework. The chief challenge, however, is the lack of resources, if our current life-style remains the standard for satisfying our needs. It is therefore becoming obvious that we need to do more with less.
The truth about the building industry The building industry is responsible for • 25 to 40 % of energy consumption, • 30 to 40 % of greenhouse gas (GHG) emissions and • 30 to 40 % of solid waste generation. On average, the building industry is the largest single industrial employer, representing approximately 10 to 40 % of a country’s Gross Domestic Product (GDP), 10 % of countrylevel employment, and 74 % of employees in developing countries (UNEP, 2009a). Nevertheless, neither the Kyoto Protocol nor the Bali Roadmap exploits the GHG emissions reduction potential of buildings. This underscores the impact of the industry’s performance, and it is fair to state that this industry has the greatest potential for delivering cuts in resource usage at low costs, using available and mature technologies (UNEP, 2009b).
Input for a new approach “The human economy must be constrained to function within the limits of the environment and its resources and in such a way that it works with, rather than against, natural laws and processes” (Ekins et al. 2009:2). We must make pragmatic adjustments and devise proper measurements if we are to create a future sustainable human economy. For example, we must dematerialize our material welfare and how we provide our energy. Dematerialization stands for “the radical reduction in the use of all materials by humans, where materials comprise metals, non-metallic minerals, fossil fuels, water 9),the atmosphere, and renewable resources such as ecosystems, forests and fish and land-use”(Ekins et al. 2009: 2).
Measures Twenty years ago, Friedrich Schmidt-Bleek (1993) designed two measures for de-coupling economic activities from the use of natural resources. One is the “ecological rucksack”,
9) marine, fresh, renewable, non-renewable
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containing all the indirect effects of resource use, such as the materials taken from nature in order to produce a good or an infrastructure. In other words, the rucksack considers all materials - including those consumed for energy - from ‘the cradle to the point of sale’. Thus, the rucksack could be understood to be the ecological equivalent of the market price of a good or an infrastructure in Euros. The other measure is aimed at the owner or user of the good, showing the real expenditures from production, use and disposal of a good. This measure is called Material Input Per unit of Service (MIPS), and it includes all the mass and energy (and money) required to produce, use, repair, maintain and dispose of a good. MIPS is Schmidt-Bleek’s ecological answer, the ‘material footprint’ of every product, service, or utility generated. Schmidt-Bleek (1993) also suggested that market prices should be stated in t life-cycle-long costs for a unit of service generated (COPS). (This would, for instance, provide the actual cost of driving a car one kilometer, or using one square meter within a building. At the Wuppertal Institute, Schmidt-Bleek’s colleagues have detailed the ecological rucksack and MIPS and put them into practical use.
The whole is greater than the parts Reflecting on the materials currently could be a first step towards a shift in the building industry’s thinking: This could lead to a shift to raw-materials with a light ecological backpack or re-introducing venerable materials like wood. A second step could be a lifecycle-oriented building process (see Figure 1). Figure 1 shows that 80% of the total WHAT costs can be influenced at the planning phase 10).
Figure 1: Overview of ability to influence total costs during the construction phases. There are great effects and low costs at the start of a project, and increasing costs and decreasing effects thereafter (Bruck, Geissler and Lechner 2002). 10)
Basis: average useful life of 25 years for an office building
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In later phases (construction, use and re-use) the ability to make substantial costadjustments becomes more limited and it is difficult to generate an economically sustainable advantage. Hence, it is necessary to take all possible occurrences during the life-cycle of the building into account during the planning phase, in order to optimize the complete process. In the past, optimization of the building process was done for each phase separately, resulting in a number of measures tailored to the respective phase. But as Aristotle said “the whole is worth more than the parts” – and a more holistic approach is needed. The provision of energy is an expertise on its own. To promote renewable energy sources rather than using fossil resources, different technologies have been developed and supported by subsidies and governmental aid. Now we need to make the transition in terms of the characteristics of a building. In the near future, buildings will be able to produce energy instead of simply consuming it, which is a further step towards greater resource efficiency. A more holistic view of energy usage, both its consumption and production, is essential for architects, planners, investors and politicians. Furthermore, well-developed, simplified systems for building service engineering are needed, for example with iintegrated façade concepts that permit the generation of energy. The building industry is organized in trades; in other words, it is highly fragmented. The consequence is that construction is a long complex process. Buildings are conventionally developed as one-off prototypes, which results in long completion times and high designand construction-risks. System building methods optimize the design and construction process. Using a high degree of pre-fabricated components, system buildings lead to significant improvements in quality and price, and the costs may be estimated precisely.
A solution with multiple effects for a sustainable tomorrow
11)
Up to now, most buildings have been constructed in conventional reinforced concrete. Increasingly scarce resources, concerns over CO2 emissions, and the rising prices of steel, insulation and concrete have led to more interest for wood as a building material of the future. .
Faced with the threats of our eco-system, many actors have tried to set up strategies for a sustainable tomorrow. In the mid-1990s, the Austrian-based building company Rhomberg started to establish strategic goals for implementing sustainability guidelines during the construction process. To meet this challenge, Rhomberg set up two major research projects in cooperation with the Austrian Institute for Ecology and the Austrian Federal Ministry for Transport, Innovation and ) Technology: The Immo-Rate 12 project and the Building of Tomorrow Project: Sustainable Housing - Services creating individual and social advantages (Sandgrubenweg, Bregenz, Austria) 13 ). 11) The following facts, figures and measures are based upon the findings of the research project “LifeCycle Tower” supported by the “Building of Tomorrow“ research programme of the Austrian Federal Ministry of Transport, Innovation and Technology, 2010. 12) Immo-Rate: A Guide and Toolbox for rating innovative real estate projects. For further details, see http://www.ecology.at/immo_rate.htm [10 Aug 2010] 13) Building of Tomorrow – Project : Sustainable Housing - Services creating individual and social advantages: Building of Tomorrow is one of the Federal Ministry of Transport, Innovation and Technology’s research and technology programs. Starting from the low-energy solar building approach and the concept of the passive building, and incorporating ways of using environmentally friendly and
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The most recent research project Building for Tomorrow Plus: LifeCycle Tower was started by Rhomberg in cooperation with Hermann Kaufmann Architects, the Arup GmbH and the Wiehag GmbH with the aim to develop a sustainable construction system for multi-storey buildings which unifies economic, ecological and social aspects. Based on previous research projects and using new findings from additional project partners, the LifeCycle Tower project was successfully completed in spring 2010. The LifeCycle Tower represents a new way of system building by offering a modular timber system that meets all the requirements for fire resistance, acoustic performance and load capacity. Its components are consequently standardized and largely prefabricated, and the construction time as well as burden of emissions on the construction site is profoundly reduced.
Resource efficient - fewer emissions The LifeCycle Tower building is less dependent on raw materials than a traditional building. Compared to reinforced concrete, using timber for construction reduces CO2 emissions by more than 90% (Braune & Benter 2009). Beside the high quality which controlled prefabrication guarantees, the approach ensures cost security. Furthermore, prefabrication reduces planning as well as construction time by half compared to the classic concrete-steel high-rise. In addition, using wood, a sustainable material, as the main construction material is expected to gain top category certification from LEED, DGNB and ÖGNI. The Tower has been designed for economic and efficient use of energy and even generates its own energy. The complete concept is innovative in that it avoids energy consumption, even achieving energy gains.
High level but simple technology The vision was to construct a system-built high rise using prefabricated components. Member connections should be "dry", and concreting and screed work kept to a minimum. This led to the development of prefabricated components for the floors, facades and core of the 1000 m² per floor, centrally stiffened building. The system-built method has a grid that allows a wide range of different floor layouts. The result is flexibility of use and the ability to customize the basic building to suit local circumstances. The floors are of reinforced concrete and wood composite construction. The layer of wood is in the form of individual beams. Glued laminated timber (glulam) can be used instead of cross-laminated timber, while the reinforced concrete layer gives the required fire protection and sound insulation. This solution is ideal from the point of view of fire resistance. The reinforced concrete slab effectively separates the storeys into individual fire compartments and prevents the floor from burning through in the event of a fire (see figure 2).
renewable materials in construction, new designs with great promise for the future have been developed and implemented. The project “Sustainable Housing – Services creating individual and social advantages” offers contemporary sustainable solutions for residential buildings. These will be optimized and realized by interdisciplinary planning oriented to the life-cycle, services supporting the quality of life, and intelligent use of information and communication technologies. For further Details, see http://www.hausderzukunft.at/results.html/id3263 [10 Aug 2010]
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Figure 2: Interior perspective showing the deck system. (Copyright: Rhomberg Group)
The central core connects the floors and stiffens the building. Glued laminated timber reinforces the core walls. The walls are made up of vertical glulam loadbearing members or open panels of glulam posts and rails. The properties of the wood and type of connections provide better sound insulation than a monolithic reinforced concrete core. Having a stiffened core allows the greatest possible freedom for the design of the facade.
Multitasking façade The facade on the high rise is designed double, with the façade columns fully integrated into the prefabricated elements. The excellent insulation properties of the wood considerably simplify the task of integrating the supporting members into the plane of the facade. The prefabricated components are assembled storey by storey, with the deck elements simply placed on the facade elements. The transfer of the vertical loads is by pure compression, so the columns merely need to have locational restraints. The concept of combining the load bearing members and the building skin into one element and having prefabricated deck elements shortens the construction time. After the installation of a floor, the storey below is immediately available for fitting out. The technical building services are centrally located in the basement. The services are distributed up shafts in the core and within the floor construction, where they run parallel to the timber ribs. With this system, the structural material, the wood, is apparent throughout the interior of the building. Storey heights can be lower, as the load bearing members and the technical building services share the same space in the deck. This eliminates the need for a suspended ceiling. Floor boxes and cable ducts in the floor provide access for services, so there is no need for a double or voided floor construction, even in the offices.
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Fire protection and safety Obviously, good fire protection is particularly important in a building made of wood. The designers examined several different approaches. The fire resistance of the facade columns and the structural members in the deck modules were determined based on combustion tests. The system building method allows damaged facade elements to be replaced or the effects of fire on the timber ribs to be rectified. A building-wide sprinkler system prevents fires from spreading. The core is protected against fire by F90 quality board. The reinforced concrete floors between the storeys also form first-class fire breaks. The logical construction sequence in which one component is stacked onto the other ensures that there is always at least 10 cm of concrete between the storeys. Another advantage is weight: softwood from spruce or fir weighs about 450 kg/m3, which is considerably lighter than concrete, which weighs approximately 2400 kg/m3. Using wood for structural connections not only reduces the weight, but also increases the strength and flexibility of these non-rigid connections. This also guarantees a higher earthquake protection.
Conclusion We face serious environmental and economic challenges, which demand ecological innovations, aggressive global policies and tight national guidelines for all industries. These need to be mandatory, as voluntary guidelines do not have the power to induce the obvious and badly needed changes. The construction industry in particular, has to assume its responsibility. It is not enough to merely pay attention to CO2 emissions. We need to go further, for instance dematerializing products and implementing a lifecycle oriented construction process. Allembracing methods, such as MIPS, can offer a useful support to implement resourceefficient actions. Coupled with building standards - guaranteed by certifications like LEED, BREEAM, DGNB and OEGNI - a high standard of green buildings can be established. Besides the efforts of industries, new tax incentives and subsidies for energy efficiency investments need to be created. Additionally, the consumption of resources should be taxed according to their degree of scarcity. To enable a quick response from the construction industry, it is essential to develop a profound knowledge on green building, energy and resource efficiency, and the thermal integrity of buildings. To this end, further investments in education must be made. This includes energy-efficiency training for every stakeholder within the industry, as well as vocational programs. The know-how that has been acquired has to be shared through regional, national and international knowledge clusters and educational initiatives which could be led by construction companies. Likewise, a higher level of awareness needs to be achieved among the community at large. NGOs as well as governmental campaigns could support those efforts. This way, the pressure to change will be on each stakeholder. To sum up, the key towards a sustainable tomorrow is system integration and the linking of traditional materials with new technologies, finesse and sophistication, courage and trust in the future. The LifeCycle-Tower is a contribution and a first step towards building a better future, and it can provide food for thought for researchers as well as the building industry. 71
References Braune A. /Benter M. (2010): “CO2-Check für LifeCycle-Tower”, Stuttgart. Bruck M., Geissler S., Lechner R. (2002): Total Quality Planung und Bewertung (TQ-PB) von Gebäuden. Bundesministerium für Verkehr, Innovation und Technologie, Vienna. Ekins P., Meyer B., Schmidt-Bleek F., Schneider F. (2009): A Proposal for Global Resource Policy, [Online], Available: http://www.worldresourcesforum.org/files/file/gws-paper095-versionDavos.pdf [10 Aug 2010].
Goldman Sachs (2007): BRICs and Beyond, http://www2.goldmansachs.com/ideas/brics/BRICs-and-Beyond.html [10. August 2010]. Hails C. et al. (2008): WWF Living Planet Report 2008, [Online], Available: http://assets.panda.org/downloads/living_planet_report_2008.pdf [10 Aug 2008]. Schmidt-Bleek, F. (1998): MIPS - Material Input per Service-einheit, Berlin: Droemer Knaur. United Nations Environment Program Sustainable Building & Climate Initiative (UNEPSBCI), (2009a): Annual Report 2009, [Online], Available: http://www.unep.org/sbci/pdfs/SBCI_2008_2009_Public_Annual_Report.pdf [10 Aug 2010] United Nations Environment Program Sustainable Building & Climate Initiative (UNEPSBCI), (2009b): Buildings & Climate Change – industry call to action, [Online], Available: https://www.usgbc.org/ShowFile.aspx?DocumentID=6506 [10 Aug 2010]. World Business Council for Sustainable Development (WBCSD), (2010): Business & Development – Challenges and Opportunities in a rapidly changing world, [Online], Available: http://www.wbcsd.org/web/projects/BZrole/Vision2050-FullReport_Final.pdf [10 Aug 2010]. Zangerl M. (2010): “LifeCycle-Tower – Final Report”, „Building for Tomorrow“-ResearchProgramme of the Austrian Federal Ministry of Transport, Innovation and Technology, Bregenz.
Related Websites: Rhomberg Group: http://www.rhombergbau.at Factor 10 Institute: http://www.factor10-institute.org Immo-Rate: http://www.ecology.at/immo_rate.htm Building of Tomorrow: http://www.hausderzukunft.at/results.html/id3263
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Rapid GHG reductions in the built environment under extreme conditions Nils Larsson
14)
Abstract A considerable number of papers produced by IPCC and others have outlined the science behind climate change predictions, probable impacts, mitigation measures and possible adaptation. In this short paper, we attempt to identify some of the key links between climate change and the building sector and then to suggest some possible responses for rapid reduction of greenhouse gases under emergency conditions.
1
Greenhouse gases in climate change
The anthropogenic driver of climate change is the increasing concentration of greenhouse gases (GHG) in the atmosphere, chiefly CO2, but also including Methane, Sox and Nox gases. The World Resources Institute (WRI) estimates that buildings are directly responsible for 15.3 percent of global GHG emissions. To this a share of industrial emissions should be added for materials and for road transport. A very conservative estimate of building-related GHG share would therefore be in the range of 20 percent to 25 percent, and this would be higher in developed countries. A strategy for the diminution of GHGs must therefore include the building sector as main target for GHG reductions.
1.1
Trends in emissions and global temperature increases
The International Energy Agency has concluded that …“although opinion is mixed on what might be considered a sustainable, long-term level of annual CO2 emissions for the energy sector, a consensus on the need to limit the global temperature rise to 2 ºC is emerging. To limit to 50% the probability of a global temperature increase in excess of 2 ºC, the concentration of greenhouse gases in the atmosphere would need to be stabilized to a level around 450 ppm CO2-eq”( IEA World Energy Outlook 2009, executive summary, p.7).
14) International Initiative for a Sustainable Built Environment,
[email protected]
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Figure 1 Outline of probable climate change impacts, partly taken from IPPC 2007 AR-4 report i . 74
Is such a target likely to be achieved? Although the IEA is guardedly optimistic, trends in emissions seem to point in a different direction. In its 2008 Climate Science Issue Brief, the World Resources Institute cites recent research in the field: “Raupach et al. note that the growth rate of carbon dioxide emissions from fossil fuel consumption and industrial processes has grown from 1.1% per year over the 1990s to more than 3% per year from 2000 to 2004 … The authors find that declining trends in energy intensity of GDP and carbon intensity of energy are now being slowed and even reversed, and thus decarbonization trends are not as strong as previously.” The WRI editors comment that…”Scenarios of future climate-related damages (such as those of the IPCC), which to date have been based on more optimistic assumptions, may prove to be conservative descriptions of possible future damages.”
2
Global climate change impacts
One of the sobering aspects of the work done by the IPCC is their exposition of the time scales involved. IPCC demonstrates that CO2 emissions today have a positive feedback on global mean temperature that lasts for over 100 years, and the resulting sea level rise due to thermal expansion lasts well over a 1,000 years. Even if action to reduce GHGs is immediate, the effects of current emissions are still to come. Action is therefore needed, but in addition to the difficulty of obtaining political action, the slow rate of change in the building sector creates a special problem. The overall impact is also clearly identified by IPCC, and the following excerpts from the 2007 IPCC Report identify some major climate trends for the 21st century: IPCC also predicts that temperature increases will be most pronounced towards the end of the century, with the northern hemisphere the most exposed. The UK Met Office has issued a short pamphlet on the effects of climate change on housing in the UK 15), which is generally consistent with the IPCC predictions (UK Met Office 2009).
3
Material demand, scarcity and supply problems
Climate change is not the only challenge that will be faced by the building industry during the next century. Several of these factors will converge to make the life of developers, designers and builders especially difficult. Fuel costs and possible shortages will create problems for automobile owners, especially for those who want to emulate the North American pattern of living in outer suburbs with one car per adult occupant. There may be respite in the form of greatly increased fuel efficiencies or car-sharing, but there is no general solution save that of
15)
The Met Office website on 01 October, 2008 also stated: “Anyone who thinks global warming has stopped has their head in the sand…. The evidence is clear — the long-term trend in global temperatures is rising, and humans are largely responsible for this rise. Global warming does not mean that each year will be warmer than the last, natural phenomena will mean that some years will be much warmer and others cooler.…. In the last couple of years, the underlying warming is partially masked caused by a strong La Niña. Despite this, 11 of the last 13 years are the warmest ever recorded.”
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Figure 2 Consumption of selected raw materials, from University of Minnesota, 2005
increasing densities in such areas to a point where public transport becomes economical, something that will take decades. The building sector also faces competition for fossil fuels with, for example, natural gas being used for power generation and space heating, as well as for the production of fertilizers. As Figure 2 shows, 5 major industrialized countries consumed about half of the global consumption of Copper, Aluminium and Nickel, and for other materials such as Iron, Crude Steel, Zinc and Tin, the consumption levels of the same 5 countries represented between 2+ to 4+ times their proportion of the global population. During the last 5 years, priced for some of these key materials have risen sharply, and then fallen again. The rapid economic growth of Brazil, China, India, Indonesia, and Russia will increase the competition to extract more supplies, but it is apparent that we will reach a point within the next three decades when scarcity coupled with demand will raise prices to levels that would currently be considered clearly unsustainable. Obviously, projects will still be built, but it seems inevitable that they will be very costly and that they will have to serve purposes that are of an urgent nature.
4
Climate change combined with resource depletion
The climate and resource issues outlined above will result in major problems for investors, designers and operators of buildings in most regions. They will be complicated by the recession, which one hand makes it harder to find construction funding, while governments want to encourage construction employment on the other. Meanwhile, demographic changes will shift demand for types of dwelling units, which may alter the value of existing buildings to a considerable extent.
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4.1
Efficiency
Great strides are being made in improving the ecological performance of materials and mechanical systems are rapidly increasing in energy efficiency. Progress is also evident in the environmental performance of some new large buildings through changes in design practice, such as the adoption of Integrated Design Process protocols. However, performance improvements are mainly applicable to large and expensive new buildings, and more so in Europe than in North America or Asia. It should also be noted that new buildings in most regions represent only from 2% to 4% of the total building stock. Thus, high-performance exemplar projects represent only a very small portion of the total stock. Clearly, the stock of existing buildings should be the major focus of performance improvement efforts in the building sector. In the sub-sector of single-family houses (the most energy inefficient form of building) there has been considerable improvement in energy performance in North America over the last 15 years.
4.2
Consumption
Irrespective of efficiency gains in residential and non-residential buildings, the trend in developed countries to massively over-consume housing, and to develop it in a very lowdensity pattern, has required large quantities of materials for both infrastructure and buildings, with consequent embodied and operating GHG emissions. The urban development of Las Vegas from 1973 to 2000, mainly from single-family housing, provides a striking example in Fig. 3.
Figure 3
Aerial photos of urban development in Las Vegas in 1973 and 2000, from UNEP 2005
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A more general perspective is provided by the data below. Although data is for the USA, Canada follows a very similar path (Rees, 2009). • •
• • •
Between 1950 and 2004, the size of the average new house in the USA expanded by 135%, from about 93 m2 to 218 m2; One in five new houses now comes in at more than 465 m2. (The US National Association of Home Builders’ ‘showcase home’ for 2005 was 553 m2 or 15% bigger than the 2004 model. Forty-three per cent of new construction features 2.75 m ceilings compared with 15% in the 1980s. Meanwhile, between 1950 and 2003, average US household size fell from 3.7 to 2.6 people. This means that floor space per capita increased by over 230% from 25 m2 to 84 m2.
Such development patterns continue, and effectively wipe out efficiency gains. The problem is likely to worsen, with substantial urban growth forecast for regions such as Asia, Africa and Latin America, and with increasingly affluent populations striving for Western standards of accommodation. The sheer numbers, as shown below in fig 4, will make solutions based on efficiency alone unlikely to succeed.
Figure 4 UN World Population Prospects: The 2006 World Urbanization Prospects: 2007 Revision
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5
The dilemma
The overall situation is that, although impressive efficiency gains are being made in building and equipment performance, excess consumption is wiping out these gains. More troubling is that consumption is culturally determined, and cultural changes usually require a decade or more of substantial information and incentives. Some regions and countries, especially in Europe, have responded in a positive way, but major private sector emitters are not likely to respond to a sufficient degree, especially not within the very small narrow window of opportunity for mitigation that still exists. Add to this the need for substantial amounts of new construction in developing countries, and it is unlikely that global reductions in greenhouse gas emissions will be sufficient to result in levels below 450 ppm of GHG, which in turn will bring into play some of the more dire predictions of IPCC. We therefore face a possibility of massive disruption of agriculture and industry and living and working conditions, possibly by mid-century and certainly by the end of the century. Although we all want to look for a happy ending, we are not likely to avoid this fate unless there is a major paradigm shift, and such shifts usually require major external events to be considered. The Depression, WW2 and 9/11 are historical examples of such conditions. A major problem in motivating decision-makers to act is that the harbingers of climate change in North America and northern Europe have been, until now, relatively gradual and benign. This sequence may cause us to become numbed by a gradually escalating series of climate-related incidents and not act decisively until it is far too late. However, climate change may also be announced by a series of major and sudden natural disasters, an outcome that is certainly within the bounds of projections made by the IPCC. If such a series of sudden catastrophes were to have direct impacts on elites in developed countries, especially in the USA. or Canada, there would likely be a strong and immediate public demand for effective responses to mitigate the effects of the events. This would provide a real opportunity to simultaneously deal with the greenhouse gas emissions that cause climate change, if key people and organizations had realistic plans and were ready to act. Sudden climate disasters are not a pleasant prospect, but it is one of the few scenarios that offer the potential for resolute action. We have a duty to explore the possibility of catastrophic climate-induced events, what the consequences might be, and how they might best be dealt with.
6
Scenarios for the debut of climate change effects
Our assumption for the type of major events related to climate change that are likely to occur during the next decade include coastal storms with related storm surges, inland storms, flash floods, droughts and major forest fires.
6.1
Business-as-usual scenario
If a series of such events take place in first-world regions within the next decade, with extensive damage and multiple deaths, it is likely that the imminence of climate change will 79
finally be accepted by the majority of media and decision-makers. Based on the history of catastrophic events of other types, we can assume that the shock effect will open the minds of the public and elites to radical measures. But such openness will last only for a few weeks, and desperate leaders will grab whatever plans are available. The result could be hasty, ad-hoc and poorly considered action. We have unfortunate examples of this kind of reaction from the collapse of the USSR, the 9/11 event, SARS, the recent recession, and even the Gulf of Mexico oil spill of 2010. In the case of the forthcoming weather shocks from climate change effects, we may unfortunately face a similar situation, but the consequences may be even more serious. The immediate concern will be to care for injured populations and to carry out immediate repairs, and this is likely to push the need for adaptation and mitigation measures to the back burner. Governments might be led to announce that, in addition to urgent repair and re-building efforts, national emissions must be reduced by large amounts over a very short period (say 80% by 2025 instead of 2050), along with promises of massive fines if targets are not met. Reaching such performance requirements would be very difficult, because strategies for such a rapid and deep reductions would have to be invented on the fly. We can foresee that such actions might be achievable in, for example, in the automotive or the consumer goods sectors, but it will be much harder to do so in the building sector. The building industry is very large and complex, with a few large players and very many small ones on the production side, and with control even more dispersed on the demand side. Finally, buildings are almost all unique, so global approaches need local modifications. Given the scenario outlined above, a government might well push the construction and real estate sectors towards a rapid a drastic reduction in emissions, along with promises of massive fines if targets are not met. Achieving such goals will be very difficult, because very few countries have central departments with direct responsibility for the building industry. Also, the industry is very large and complex, with a few large players and very many small ones on the production side, and with control even more dispersed on the demand side. We can envision the results without too much speculation: • First, we would expect a surge in demand for man and materials to carry out urgent repair, re-building and re-location needs which would, within weeks, deplete the supply of skilled and firms in the affected region; • Manufacturers of building materials would be faced with urgent production requests, but would face greatly increased power costs, and might also have to cope with a disrupted labor force and plant conditions. Prices for materials and services of this type would therefore reach astronomical levels; • Owners or managers of existing commercial buildings would have to reduce operating hours to meet GHG reduction targets; • Residential tenants will face mandatory energy cuts; • The value of buildings with poor energy efficiency will plummet. Suburban building land values will also face massive drops because of controls on new building and stringent limits on private vehicle emissions, which will bring new construction in outer suburbs to a halt.
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•
Many standards for good design and operations, such as adequate lighting levels, indoor comfort conditions, and work to preserve heritage buildings will fall by the wayside, at least temporarily (say for 20 years); • Social tensions will rise to very high levels when those who want to pursue their normal paths (commercial building development, building your dream home) are faced with permit refusals, while climate refugees and families suffering from energy poverty are given priority; • And the need to deal with repair and remedial work will lead governments to say that they cannot afford more GHG mitigation measures; In view of such a series of effects, little effective reduction in emissions would be achieved.
6.2
A scenario for contingency planning
Some of these consequences can be avoided if quick and decisive action takes place, but such responses are likely to be effective only if action plans have been developed before the emergency occurs, and are ready for immediate implementation. Even though some government and many private-sector organizations have not been willing to take meaningful mitigation steps to date, they might be willing to prepare contingency plans for rapid reduction, as part of a due diligence process. Such plans must support very rapid reductions in GHG emissions over a short timeframe – something like 75% over 5 years – but varying with the sector and specific cases. To be available when the time comes, such plans must be voluntarily developed now by a variety of public- and private-sector organisations, so they will be ready when needed. A large number of contingency plans will need to be prepared by individual governments and private-sector organizations, to cover most key sectors of the emission-producing economy. Measures proposed do not include those that require lengthy planning or implementation times, such as the introduction of carbon taxes or risk assessment studies of existing urban areas and building stock with regard to possible climate change impact events, such as floods, wind storms, heat waves etc. 16) Such work is a necessity for postdisaster recovery. Excluding measures that require lengthy planning of implementation times, a selection of essential contingency plans would include plans for the rapid introduction of the following. 1)
2) 3)
A ban on the construction of new coal-fired generation power plants and the extension of existing plants, unless significant GHG sequestration is provided; Rapid reduction of peak loads in electrical networks through the rate structure and through load ceilings; Acceleration of feed-in tariff policies from decentralized renewable power sources;
16)
See for example Methods for risk assessment and mapping in Germany, preface to special issue of Natural Hazards Earth System Science 6, 721-733, 2006, and also Winter storm risk of residential structures - model development and application to German state of Baden-Würtemberg, P. Heneka, T. Hofherr, B, Ruck and C. Kottmeier, in Natural Hazards Earth System Science 6, 721-733, 2006.
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4) 5) 6)
7) 8) 9) 10)
11)
12)
13) 14)
15)
Measures to minimize short-term speculative price rises for construction materials; Back-up provision for power outages and other service interruptions (water, food and other supplies, communications etc.); Plans to ensure that facilities of critical importance, such as hospitals, public transportation systems, water and sewage treatment and pumping systems, remain provided with electrical power, heat, water and other vital services; Alternative locations for key facilities such as docks 17) and airports and of populations in areas vulnerable to flooding or fire 18); Programs for the rapid conversion of surplus office buildings to residential uses; Identification of empty non-primary dwellings for accommodation of climate refugees; A freeze on new construction in un-serviced or low-density areas or potential flood areas, and a zero operating GHG emissions requirement for new construction that is permitted; Rapid reduction in operating emissions of public buildings, private office, hotel and multi-unit residential buildings, through implementation of “shovel-ready” retrofit plans and better operating practices, all while minimising disruption or reduction in service levels to occupants; Rapid reduction of peak loads and emissions in manufacturing plants and service-sector facilities, by means of changes in industrial processes, operating hours or other relevant means; Prohibition of the sale of appliances and equipment that do not meet certain operating efficiency criteria (e.g. "A" label in Europe); Crash training programs for regulators, renovation contractors, simulation specialists and others needed to upgrade performance in new and existing buildings; Urgent performance improvement measures for existing dwellings.
It is clear that the content of GHG rapid reduction plans proposed above would be a sensitive matter in some cases, where the leakage of information under current conditions might pose political difficulties because of limitations on personal freedom of action, or harm standings in a highly competitive market. It is therefore suggested that participating organizations would not be compelled to share their plans with any outside organization, but only to report that they have completed a plan that satisfies the content criteria established in the project. The main emphasis here is to ensure that workable and humane plans are available for rapid implementation when circumstances demand it. There are certain characteristics that such plans would have to be based on if they are to be effective.
17)
The U.S. military is well aware of the dangers that many of its coastal bases are facing; see National Security and the Threat of Climate Change, CNA Corporation, 2007 18) The dismal efforts at relocation and rebuilding in New Orleans are a reminder of how extensive and well coordinated the required efforts will have to be if they are to be successful
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• • •
• • •
7
Measures proposed will have to be able to be very quickly implemented; beginning within weeks rather than months; The scope of proposed action will have to be defined (e.g. all or part of a property portfolio, certain segments of a customer base etc.); Estimates of speed and amount of net reduction in GHGs emissions will have to be provided, projected on a year-by-year basis over a 5-year time frame; Plans will have to identify measures to minimize negative social disruption or other secondary impacts; Identify main obstacles or sources of likely opposition and suggest coping strategies; Complementary action required by governments, other regulatory authorities or financial institutions to facilitate implementation of the plan should be identified.
Conclusions
Some governments, especially in Europe, have launched ambitious plans to reduce GHGs, but it is not yet clear whether their voters will agree with the changes in lifestyle that will be necessary to meet these targets. Excessive consumption will not easily be reduced, and is likely to lead us into global temperature increases that will be considerably greater than the desired target of 2 ºC; It will probably require one or more climate-induced disasters of major proportions to shock governments and their populations into real action, especially in North America. When that happens, there will be an immediate demand for contingency plans to reduce GHGs in a very rapid way and to implement urgent measures for climate change adaptation. In view of on-going government inaction, it is most logical for national and local governments, as well as private organizations to develop such plans and keep them ready. The alternative is to do nothing now, but to be forced to accept hastily developed and unsound plans when an emergency is declared.
References IEA World Energy Outlook 2009, Executive Summary, pg. 7 IPCC AR4 Working Group 1, Summary for Policymakers, 2007, p. 8. Note that Virtually certain are events with a 99% probability of occurrence while Very likely are events with 95% probability of occurrence. Rees, William E. (2009) The ecological crisis and self-delusion: implications for the building sector, in Building Research & Information, 37: 3, 300 — 311 UK Met Office April 2009, Effects on Housing WRI Issue Brief, Climate Science 2007, World Resources Institute, September 2008
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The Energy Transition Model Bringing rationale to the emotional discussion on our energy future John Kerkhoven
19)
Abundant fossil energy cannot be taken for granted anymore Our economy and welfare are built upon the abundant availability of fossil energy sources. Unfortunately, we can no longer, because of possible scarcity, and should no longer, because of possible climate change, rely on these energy sources in the near future. Driven by the belief that that our society must now move towards a more sustainable future, we, together with many public and private partners, have invested in the transition away from dependence on fossil fuels. This knowledge has been made publicly available to anyone interested, in the form of an online tool and a database containing over one thousand recent reports on the energy situation in Europe. The model is fully integrated in our website and the reports can be found through the search function on our website: www.energytransitionmodel.com
Fig.1: The Energy Transition Model as a framework for discussing our energy future rationally. (picture by Arend van Dam
19) Dr. Ir. John Kerkhoven is Managing Director, Quintel Intelligence; www.energytransitionmodel.com
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Fig. 2: Homepage of the Energy Transition Model at www.energytransitionmodel.com
Figure 3: Partners of the Energy Transition Model in the Netherlands
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Fig.4: Policy measures that can be taken in the Energy Transition Model. CO2 measures as an example.
The Energy Transition Model: a tool for communication, education and policy-making As from the end of 2007, we have been developing an easily accessible and free of charge energy transition tool, which is now being used by numerous politicians, energy company boards, company strategy departments and students. We have called this the Energy Transition Model (ETM). We have demonstrated that this model can structure the complex emotional discussion about our energy future, and help increase our understanding of what lies ahead of us. The Energy Transition Model is a model validated by our partners that takes current economic reality and corroborated physical and chemical relations into account. In other words, we use the current costs of a new coal power plant or a modern offshore wind turbine. It also contains the conversion rates from coal to electricity and heat in such a plant, as well as the CO2 emissions. Efficiencies of other energy technologies like electric cars or gas-fired heat pumps are also part of the model. The model helps the user to utilize these figures as a starting point. Of course there are also many things that we do not know for sure. For example, the future price of coal is unknown. Hence, the model allows users to tap in their own forecasted coal price and adjust the sliders in the model to perform a sensitivity analysis on any aspect 87
of the energy system. The model will instantly show the consequences of the choices made. Although the model can be used individually, it is also commonly being used for group discussions of various forms. The Energy Transition Model allows everybody to implement his or her vision on the world. At the same time, in return the model will show the direct consequences of the choices made. One of the most important conclusions that can be drawn from the model is that demand-side measures are nearly always cheaper and more effective than supply-side measures in the near future. It turns out that it is even possible to take steps that are cheaper (at today’s prices) than many measures currently contemplated, while reducing CO2 emissions and imports for primary energy and improving sustainability. All of these measures are possible using currently available technology.
Growing incentives to start an energy transition The incentive to become less dependent on ever scarcer energy resources and/or to protect our trade balance is high. Although an economic crisis may slow development down, there is a high likelihood that easily accessible oil will become scarce within fifteen years. Conventional gas production in the Netherlands will decrease in that period by 75% and as a consequence energy imports will have to rise in a period in which prices of primary energy sources could also rise. The urgency to protect our climate also seems to be ever greater. Policymakers in the US and Europe, for example, are discussing scenarios for 80% CO2 reduction in a period of forty years. In order to meet such targets, the term ‘energy transition’ should actually be replaced by ‘energy revolution’. The task ahead is immense.
Five actions toward a sustainable energy future The Energy Transition Model shows which scenarios are possible to meet these targets for the period 2010-2050. The optimization module (not publicly available) of the Energy Transition Model comes up with transition paths that are affordable, doable and able to meet the CO2 reduction targets in a slowly growing economy. From this analysis and many hundreds of sessions with policymakers to discuss the energy future, we conclude that:
1 Buildings need to become at least energy-neutral and possibly gridindependent Energy-Neutral and Energy Grid-Independent buildings are possible and sensible (NB: the author is currently building his own grid-independent house at a 10% higher cost than an otherwise conventional house). It is quite obvious that in northwest Europe, current heating technology should be replaced by more efficient forms of heating (electric heat pumps, gas fired heat pumps, micro-CHPs and so on), in combination with increasing levels of insulation. 88
Fig. 5: Example of 2050 scenario for household energy demand with 80% CO2 reduction for the Netherlands (limited energy efficiency increase, slowly growing economy and 100% increase in fossil fuel prices, CO2 price at 50 Euro per tonne. Use of current state-of-the-art technology.)
In this scenario the transition path goes via gas technologies (as these can be implemented easily in existing houses) to electric technologies in 2050. In the Netherlands, for example, phasing out traditional heating and replacing it by any of the previously mentioned technologies would save more energy than the electricity used by all Dutch households put together. Improved housing insulation would make this equation even better.
2 Energy use in transport, especially passenger transport could be slashed Energy used in personal car transport could easily be reduced by half in a relatively short period, while still accommodating slowly growing mobility. Figure 6 shows how the introduction of electric and compressed green/natural gas-powered cars can achieve this in a period of four decades, assuming moderate improvements of internal combustion engines.
Fig. 6: Example of 2050 scenario for transport energy demand with 80% CO2 reduction for the Netherlands (limited energy efficiency increase, slowly growing economy and 100% increase in fossil fuel prices, CO2 price at 50 Euro per tonne. Use of current state-of-the-art technology.)
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3
Towards biomass-based industry
As oil demand in the developing world is set to increase strongly in the future, oil prices may be expected to rise in the mid- to long-term future. To bolster innovation and provide a longterm hedge against rising oil prices, industry should be encouraged to experiment more with biomass as an alternative feedstock to oil. So the production of plastics, for example, should shift over time from using oil as the base product to biomass. Naturally, the amount of land needed to produce higher levels of biomass in our energy system would increase drastically. Figure 7 shows the use of biomass in heat and electricity production for industry in the 80% reduction scenario.
Fig. 7: Example of 2050 scenario for Industry energy demand with 80% CO2 reduction for the Netherlands (limited energy efficiency increase, slowly growing economy and 100% increase in fossil fuel prices, CO2 price at 50 Euro per tonne. Use of current state-of-the-art technology.)
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Towards a new diet
Although this is not (yet) a module in the Energy Transition Model, the ideas on mass biomass production are also consistent. If we are to make biomass available, we need to reconsider the majority proportion of farm land used for feeding cattle. The more our population is willing to eat a vegan diet, the more land becomes available for extra food, nature or biomass production. According to some predictions, as much as 70% farm land globally could potentially become available. As a by-product, it is also expected that the health of the population would improve. This would clearly be not just an energy revolution but a revolution in eating habits, especially in western societies.
5
Oil and Gas as fossil transition fuels
During the energy transition, fossil fuels will be unavoidable. In Dutch society, a transition path via gas and natural oil makes the most sense. Gas is regionally available, relatively cheap and cleaner than its alternatives. Natural gas and mineral oil still play large roles in the 80% CO2 reduction scenarios for 2050 found by our optimization module. Without exception, coal is almost completely phased out. 90
Fig.8: Example of 2009 situation (left) and 2050 scenario for primary energy use with 80% CO2 reduction for the Netherlands (limited energy efficiency increase, slowly growing economy and 100% increase in fossil fuel prices, CO2 price at 50 Euro per tonne. Use of current state-of-the-art technology.)
Transition via CO2 capturing and storage (CCS) The Energy Transition Model allows various CCS-enabled plants to be built, including the infrastructure to store the CO2 underground. However, it is difficult to create conditions in the optimization module of the model whereby CCS makes sense. Measures on the demand side with a similar CO2-reducing effect are almost always cheaper and more sustainable.
Fig. 9: Example of 2050 scenario cost comparison of electricity power plants (limited energy efficiency increase, slowly growing economy and 100% increase in fossil fuel prices, CO2 price at 50 Euro per tonne. Use of current state-of-the-art technology.)
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Many people believe that CO2 prices will rise, coal prices could stay low, wind prices are more or less stable and solar PV prices will slowly decline. In such a scenario, the CCSenabled plant would not be able to compete on cost with solar or wind alternatives by as early as the 2020–2030 timeframe. Given that the first commercial large-scale CCS plants are planned for 2020, this seems a rather uncertain route.
Giving every European a tool to investigate the energy future It is our intention to make the Energy Transition Model progressively available for all European countries (test models are currently available for several countries other than the Netherlands). In the Netherlands the model also operates at the level of a province or a city. New versions to be launched this year will include possibilities to build energy-neutral and/or grid-independent houses. In addition, the implications of any scenario for electricity grids are fully modelled and now available for the Netherlands. We warmly welcome support from companies and institutions, either in the form of partnering/sponsoring and/or data collection, in our mission to help every European (from policymakers to students) understand the options for our energy future.
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Part III Papers
From Space Habitats to Zero Emission Buildings Space Borne ZEB Enabling Technologies Julien S. Bourrelle
20)
, Arild Gustavsen
21)
, Bjørn Petter Jelle
22)
Abstract Zero Emission Buildings (ZEBs) strive to minimize net emissions from the building stock by substantially reducing energy demand and promoting local energy production from renewables. Improvements towards achieving ZEBs may come from technologies not yet implemented in the building sector but existing in other fields. Adapting technological solutions to buildings may be a quick and efficient way to attain the ZEB status. For half a century, space engineers strove to develop habitats which would enable life to survive in the inhospitable environment of outer space. Some of the supporting technologies were adopted for use on Earth and have already found their commercial place in the building sector, e.g. photovoltaic systems. Other technologies, specific materials and general concepts in the design of space habitats are still to be adapted for use in buildings. This paper starts by looking to space habitats as ZEBs, which reveals interesting variables for consideration in the development of a framework for a robust definition of ZEBs. The International Space Station (ISS) and the Biosphere 2 Project are discussed as case study examples of mostly material-closed but energy-opened buildings. A selection of materials used in outer space that may provide high energy savings in the building sector concludes the study.
1
Introduction
The global community aims to reduce net greenhouse gas (GHG) emissions, notably by a reduction in primary energy use. Existing buildings are responsible for over 40% of the total primary energy used in our societies (IEA 2008). There is a global potential to reduce approximately 29% of the projected baseline emissions by 2020 cost-effectively in the 20) Department of Architectural Design, History and Technology, Norwegian University of Science and Technology (NTNU), Alfred Getz vei 3, NO-7491 Trondheim, Norway;
[email protected] 21) Department of Architectural Design, History and Technology, Norwegian University of Science and Technology (NTNU), Alfred Getz vei 3, NO-7491 Trondheim, Norway; 22) Department of Materials and Structures, SINTEF Building and Infrastructure, Høgskoleringen 7B, NO-7465 Trondheim, Norway; Department of Civil and Transport Engineering, Norwegian University of Science and Technology (NTNU), Høgskoleringen 7A, NO-7491 Trondheim, Norway.
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residential and commercial sectors (Levine et al., 2007). Furthermore, the Intergovernmental Panel on Climate Change (IPCC), in its Fourth Assessment Report, identifies the reduction in energy consumed by or embodied in buildings as one of the three measures to reduce GHG emissions cost-effectively in the building sector. Energy savings may derive from optimising the use of buildings and by better understanding the different factors influencing energy consumption. Energy will be the main focus of this paper, while the final objective for ZEBs should be understood to be a reduction of GHG emissions. This paper will look at the extensive research done in the space sector involving space habitats and regard them as zero emission- and zero energy buildings. To the best knowledge of the authors, space habitats have not yet been looked at in this way. Such a premise exposes the many aspects that may be important to consider when developing a robust framework for the definition of ZEBs. Such a framework is essential for governing bodies when establishing or expanding the norms that guide the industry and ultimately reduce our dependence on energy and mitigate GHG emissions. Furthermore, significant reduction in energy consumption may be accomplished by integrating new technological solutions within the building envelope. Solutions derived from Life Support Systems (LSSs) of space stations and space-derived materials will be presented. LSS solutions mostly apply to indoor climate, whereas material solutions may mostly improve the thermal characteristics of buildings by influencing the radiative heat transfer and, to a lesser extent, the building's thermal mass. Also, some materials may be useful for energy production and storage.
2
Method
This paper regards space habitats as ZEBs. Based on engineering design publications relating to both space habitats and their test facilities, general concepts are derived and compared with some of the work of the International Energy Agency IEA SHC Task 40 / ECBCS Annex 52 Towards Net Zero Energy Solar Buildings (Voss and Riley, 2008). The second part of this paper is based on a literature review and analysis of different space technologies that may provide energy saving potential for buildings. Notably, the spinoff databases of both the National Aeronautics and Space Administration (NASA) Innovative Partnership Program and the European Space Agency (ESA) Technology Transfer Programme were carefully investigated.
3 Space habitats as zero emission and zero energy buildings Space habitats provide protection and life support to astronauts. They exhibit a certain level of material closure, but are energy-opened systems, i.e. admitting the inflow and outflow of energy to and from the system, mostly in the form of solar radiation. Generally, they are divided into three types depending on the mission duration. Short missions last between a few days to one or two weeks and are typical for the space shuttle. Medium duration missions last from several weeks to several months and are typical on board the
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Figure 1. International Space Station Life Support System Diagram. (Credit: NASA)
International Space Station (ISS) and the defunct MIR station. In space stations today, food is brought from Earth while the water used for all activities (with the exception of oxygen generation) is recycled and fed back into the system (see fig. 1). Solid waste and waste from the air filtration system are not recycled and exit the station. Long duration manned space missions have been extensively studied for future missions to Mars or permanent settlements on the Moon. Various concepts were studied, most of them relying on materialclosed bioregenerative life support systems where food, water and air would be recycled indefinitely. The best known Earth-based prototype for a long duration mission was built in the 1990s as The Biosphere 2 Project (Allen, 2008). These very advanced habitats may be a useful source of knowledge for the development of ZEBs. Space habitats may be considered net zero energy buildings based on the available definitions of such buildings, (Torcellini et al., 2006; Marszal and Heiselberg, 2009) and in particular on the preliminary definition adopted by the European Parliament:
“A net zero energy building means a building where, as a result of the very high level of energy efficiency of the building, the overall annual primary energy consumption is equal to or less than the energy production from renewable energy sources on site.” (European Parliament, 2010)
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Space habitats may resemble off-grid buildings on Earth, operating solely based on the energy theycan harvest from renewables. All components of space habitats are optimised to a much greater extent than normal building components on Earth since energy use needs to be kept to a strict minimum both for cost reasons and due to the technical difficulties in radiating back excess heat. Space habitats are perhaps the most efficient “buildings” so far constructed and thus fit perfectly the proposed zero energy building definitions. Furthermore, both the ISS and Biosphere 2 can be considered, to a certain extent, to be working prototypes of ZEBs. The ISS has continuously been staffed for more than nine years and relies on solar radiation as its only energy source. Biosphere 2 has been operated non-stop in closed-mode for a period of two years while sustaining a crew of eight and maintaining all biomes in relative equilibrium. The level of closure within Biosphere 2 was much higher than in the ISS. While the ISS vents out CO2 and H2 (see fig.1) and sends back to Earth detritus and by-products of atmosphere filtration, the Biosphere 2 was created on the basis of a sustainable closed system where waste cannot be allowed to build up and must be recycled. Both the ISS and Biosphere 2 are very interesting case studies for the design of ZEBs; they may be used to identify possible technological improvements that could be adapted for the creation of more energy efficient and more sustainable buildings on Earth.
3.1
The Biosphere 2 Project
Biosphere 2 (fig. 2) was, for the most part, a novel combination of known technologies that were adapted to a particular application (Maccallum, 2004) in a way that ZEB designers may now be inspired by. Twenty years ago, a group of specialists were able to create a building with an air tightness some 1000 times the commercial building standard (Zabel, et al., 1999) where a crew of eight lived during two years, isolated from the outside world. Various engineering challenges needed to be overcome both in the design and operation of such a building (Dempster, 1999; Allen and Nelson, 1999) Biosphere 2 was designed to operate with the aim of supplying the crew of “Biospherians” with food, an atmosphere with safe levels of trace gases, complete recycling of wastes and water and minimal air leakage. Some of these challenges are related to ZEBs while others relate to even more advanced sustainable buildings. In other words, Biosphere 2 is an “eye-opener” on the different variables that may one day be looked at for the engineering of sustainable buildings. An impressive list of publications derived from this project ranging from engineering to social interaction aspects.
Figure 2 The Biosphere 2 Project
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3.2 Towards a framework for the definition of ZEBs: Defining the boundaries The material-closed nature of space habitats highlights interesting aspects to be considered when defining the boundaries for ZEB emission or energy calculations. Defining boundaries for ZEBs is a central part in the development of a robust definition framework for these types of buildings. Within a material-closed system, waste and by-products need to be recycled or usedup, or they otherwise build up and intoxicate the habitat. Biosphere 2 highlights the importance of the energy consumed by activities which are usually not taken into consideration within the energy balance of buildings. It may be very relevant to include some of these activities which actually derive from the building's operations but that usually take place off the building site and so are ignored in energy calculations. For example, the production of waste is a direct consequence of activities taking place within a building. However, waste management is usually not taken into consideration when computing the energy balance. The same logic applies for the inflow of potable water and food, and the outflow of wastewater. In light of this, we may ask ourselves: Why are electricity and combustibles usually the only energy carriers taken into consideration in ZEB energy calculations? If we do not consider consumables and building related activities within energy calculations, we are creating an incentive for the user to off-site activities in order to attain ZEB status. An analogy may be made with the use of a dishwasher. The dishwasher needs electricity to clean dishes, which is taken into consideration within the building's energy balance. In order to achieve ZEB status, a user may decide to use only disposable dishes, getting rid of the need for a dishwasher and thus reducing his electricity consumption, helping the building achieve ZEB status. In such a case, the achievement comes at a great environmental cost as the calculation method encourages the use of disposable dishes which do not enter into the overall energy balance. This analogy is one of many that illustrate the importance of studying energy carriers in order to robustly define sustainable buildings. Taking inspiration from more advanced buildings while defining boundaries for ZEBs may help prevent the increase of off-site energy consumption. The study of highly material-closed life support systems may provide a broader view on such aspects and help draw the line on what should or not be included within the definition of ZEBs. While wastewater treatment and water purification are usually done off-building site, they relate to the activities taking place within the building. Water flows in and out of the building in a way very similar to electricity and thermal energy from district heating systems. Thus, water treatment could arguably be included in the building energy balance. Space infrastructures highlight the importance of wastewater treatment and provision of potable water but also provide energy efficient sustainable technologies to tackle these issues. LSSs include efficient sewage methods to recycle water and reuse nutriments from wastewater. Some of these technologies have already been adapted to large scale use. 23) 23)
NASA (1980) A New Image for the Water Hyacinth. Spinoff Database - NASA Stennis Space Center; NASA (1988) Wastewater Treatment: The Natural way. Spinoff Database NASA Stennis Space Center;
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4
Solutions derived from space technology
The harsh environment of space drove specialised research for more than half a century. The provision of high quality indoor climate in restrained spaces links the design of enclosed space habitats to the design of increasingly closed buildings. Technological solutions for LSSs and the thermal balance of spacecrafts may find useful application in the design of efficient buildings. For example, several high performance materials were studied to cope with the special thermal environment of spacecrafts which might have interesting applications in buildings. Conductive and convective heat transfer are relevant within spacecrafts themselves, whereas the close vacuum of outer space has the effect of virtually eliminating all medium-based heat transfer to and from the spacecraft, thus relevant research on radiative heat transfer is being carried out in the space field.
4.1
Life Support System (LSS) and indoor climate
LSSs deal with providing a living environment for astronauts. They provide a clear and breathable atmosphere, water and food. The design for ZEBs calls for a substantial increase in closure, an objective that makes LSSs relevant to building design. Increasing air tightness reduces heat loss to the surroundings while at the same time reducing the interaction between the indoor and outdoor atmospheres. Such isolation of the indoor environment raises concerns as to indoor air quality and climate. Adequate ventilation may prevent poor indoor air quality, but it, in turn, results in heat loss to the surroundings. Heat loss may be significant, especially in small buildings, were heat recovery systems are not always easy to implement. Incorporating air revitalisation technologies in such buildings may help reduce energy consumption. Indoor climate solutions for restrained spaces were intensively studied in closed ecological or biological systems and within space habitats (Allen and Nelson, 1999; Dempster, 1999; Zabel et al, 1999; Allen et al., 2003; Pynter 1997). Morowitz et al. (2005) presented aspects of closure as a scientific concept, classifying different systems based on their level of closure and studying the impact on the indoor environment. From that classification, two types of closure are within the scope of this article and with possible application in buildings: (1) the closure which exists within Controlled Environmental Life Support Systems (CELSS), as developed by various space agencies to support human spaceflights; and (2) mini-biospheric systems with a complexity of internal ecosystems, also designed in relation to space exploration. CELSSs will allow for a certain level of openness, especially for food and air revitalisation whereas bioregenerative LSSs will work as mostly closed systems where all pollutants and wastes are degraded, transformed and fed back into the system itself. Solutions for the control of Volatile Organic Compounds (VOCs), toxic trace gases from outgassing of building components, CO2 build-up and removal of particulates and microorganisms may find their place in small scale and increasingly closed buildings. Such solutions from both types of closure may be relevant to ZEBs, though from a conceptual point of view the closure within CELSS is most similar to ZEBs. Also, bioregenerative technology may be appealing for applications in buildings as they help
NASA (1991a) Sewage Treatment. Spinoff Database -NASA Stennis Space Center; NASA (1991b) Water Conditioner. Spinoff Database - NASA Johnson Space Center.
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provide a high quality indoor atmosphere while being pleasant for the inhabitants as a cobenefit (Wolverton, 1988) . The Sabatier reactor is another of many technological solutions for closed living environments, notably studied for in-situ resource utilization on Mars (Holladay, 2007) The Sabatier reaction (Eq. 1) has been studied for space use and may find interesting applications in other fields if adapted appropriately.
CO2 + 4H2
CH4 + 2H2O
(1)
CH4 + 2O2
CO2 + 2H2O
(2)
Both the Sabatier reaction and the combustion of methane (Eq. 2) are highly exothermic. Buildings on Earth may benefit from these reactions if adapted correctly. For example, a small scale Sabatier reactor could be used to remove CO2 from the indoor environment of buildings on Earth. The Sabatier reactor could be used directly as a heat source for the building while the methane produced by the reaction is stored and used as fuel for a space or water heating system. If renewably-generated hydrogen is available, this system could be used to both assure acceptable levels of carbon dioxide within the building and act as a sustainable central heating system unit (Hoekman et al., 2007;Brooks et al, 2007). The CO2 produced from the combustion of methane would not count towards the emission calculation of a theoretical ZEB as it originally derives from human respiration.
4.2
Materials derived from space technology
As explained earlier, the thermal balance of spacecrafts in outer space is virtually driven by radiation alone. In order to keep spacecrafts and their payload within their operating temperature range, much research has been done on radiative heat transfer, notably investigations into different types of coatings and multi-layer insulation. Also, in order to buffer rapid heat gains or losses, and passively keep temperature within certain limits before heat can be radiated back, different types of Phase Change Materials (PCMs) with a low mass to thermal mass ratio were developed. Other high performance thermal insulators, such as aerogels, also underwent various studies in the space field. The simplest way to control radiative heat transfer to a surface is to apply coatings which may take the form of simple-to-apply paints to more sophisticated conversion coatings. When such simple methods are insufficient, Multi-Layer Insulation (MLI) may help prevent great heat gains or losses. When material transparency is desirable, mostly for human spaceflights, chromic materials are used to regulate the flow of heat. Three types of chromic materials are relevant here: electro-, thermo- and photochromic materials. PCMs make it possible to store thermal energy directly as latent heat of fusion. The information available on PCMs is enormous (Zalba et al., 2003) and it is outside the scope of this paper to go into detail about these materials. We limit ourselves to point out space applications that may foster new ideas for integration within buildings. PCMs have mostly 101
been used in space by the USA for Low Earth Orbit (LEO) spacecrafts to cope with the rapid change in thermal energy input due to the cyclic Sun-facing and Earth-shadow position. They increase the thermal mass of spacecraft without influencing significantly the actual spacecraft mass. Also, they have been used as alternatives to batteries as an energy storage medium. Other materials of great interest to the building industry include aerogels and photovoltaics (PVs). Due to their low density, fine mesostructure and transparency, aerogels were first used in the space field to dissipate kinetic energy of hypervelocity particles and to capture them intact (Tsou, 1994) Recent research proposes using aerogels as insulators for liquid hydrogen launch vehicle tanks (Fesmire and Sass, 2008) and more generally as cryogenic thermal insulation systems (Fesmire, 2006). Aerogels are very promising high performance thermal insulation materials with a possible widespread use in the building industry (Beatens et al., 2010). Aerogels developed for space applications are to resist extreme conditions not encountered on Earth. The research carried out at the Jet Propulsion Laboratory or at the NASA Kennedy Space Center may, for example, be very relevant in discovering new ways of solving some of the remaining problems for the adoption of aerogel as the de facto insulation material for buildings. Finally, photovoltaic technologies underwent intensive research in the 1950s and 1960s for their high potential as electrical energy producers in outer space. The technological advancement permitted their integration into commercial products in the 1970s. Today still, solar cell technologies are continually being improved in the space sector and findings are being adapted and transferred for commercial use on Earth.
5
Conclusion
This work presented space technologies as a potential source of solutions for the design of sustainable buildings on Earth. Rather than exploring any particular technology in detail, it aims to serve as an eye-opener, setting up the basis for further investigations into the space field by building specialists. It identifies potential cross-disciplinary technological solutions for the building sector by (1) identifying space habitats as ZEBs and by (2) pointing out relevant space technologies. Notably, this work revealed interesting variables to be taken into consideration when defining the boundaries for ZEBs, and solutions for indoor climate problems and the thermal balance of buildings. By providing references in the space field, it will hopefully help sustainable building specialists to foster innovative ideas for the design of ZEBs.
Acknowledgements This work was supported by the Research Council of Norway, NTNU, SINTEF and carried out within The Research Centre on Zero Emission Buildings. The authors would like to thank Rolf Jacobson for his valuable inputs in reviewing this article.
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Nasa Innovative Partnerships Program. http://www.nasa.gov/offices/ipp/home/index.html. European Space Agency Technology Transfer Programme. Available from: www.esa.int/ttp Biosphere 2 Publications. Available from: http://www.biospheres.com/publications.html.
References Allen, J. (2008) Me and the Biospheres: A Memoir by the Inventor of Biosphere 2, Synergetic Press. Allen, J., and Nelson M. (1999) Overview and Design Biospherics and Biosphere 2, mission one (1991-1993). Ecological Engineering, 13, 15-29. Allen J., Nelson, M., and Alling, A. (2003) The legacy of biosphere 2 for the study of biospherics and closed ecological systems. Advances in Space Research, 31, pp. 1629-1639.; Beatens, R, Jelle, B.P., Gustavsen, A., and Grynning, S. (2010) Aerogel insulation for building applications: A State-of-the-Art Review. Submitted to Energy and Buildings. Brooks, K.P., Hu, ShuJ. H., and Kee, R.J. (2007) Methanation of carbon dioxide by hydrogen reduction using the Sabatier process in microchannel reactors. Chemical Engineering Science, 62, 1161-1170. Dempster, W.F. (1999) Biosphere 2 engineering design. Ecological Engineering, 13, 31-42 European Parliament (2010) Energy performance of buildings (recast) I (2010/C 184 E/65) Official Journal of the European Union, C184E. Fesmire, J.E. (2006) Aerogel insulation systems for space launch applications. Cryogenics, 46, 111-117. Fesmire, J. E. and Sass, J.P. (2008) Aerogel insulation applications for liquid hydrogen launch vehicle tanks. Cryogenics, 48, 223-231. Hoekman, S.K., Broch, A., Robbins, C., and Purcell, R. (2010) CO2 recycling by reaction with renewably-generated hydrogen. International Journal of Greenhouse Gas Control, 4, 44-50; Holladay, J.D., Brooks, K.P., Wegeng, R., Hu, J., Sanders, J., and Baird, S. (2007) Microreactor development for Martian in situ propellant production. Catalysis Today, 120, 35-44. International Energy Agency (2008), Promoting Energy Efficiency Investments - Case Studies in the Residential Sector, Paris, France, IEA Publications. Levine, M., Ürge Vorsatz, D., Blok, K., Geng, L., Harvey, D., Lang, S., Levermore, G., Mehlwana, A.M., Mirasgedis, S., Novikova, A., Rilling, J., and Yoshino, H. (2007) Residential and commercial buildings. In Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds)], Cambridge, United Kingdom and New York, NY, USA, Cambridge University Press. Maccallum, R., Poynter, J., and Bearden D., (2004) Lessons Learned From Biosphere 2: When Viewed as a Ground Simulation/Analog for Long-Duration Human Space Exploration and Settlement. International Conference On Environmental Systems. Colorado Springs, CO, USA. Marszal, A. and Heiselberg, D.P. (2009) A literature review on ZEB definitions - Draft report for discussion. Aalborg, Denmark, Aalborg University. 103
Morowitz, H., Allen, J.P., Nelson, M., and Allinga, A. (2005) Closure as a scientific concept and its application to ecosystem ecology and the science of the biosphere. Advances in Space Research, 36, 1305-1311. Pynter J. D. B. (1997) Biosphere 2: A Closed Bioregenerative Life Support System, An Analog for Long Duration Space Mission. Plant Production in Closed Ecosystems. Kluwer Academic Publishers. Torcellini, P. Pless, S., and Deru, M. (2006) Zero Energy Buildings: A Critical Look at the Definition. ACEEE Summer Study Pacific Grove, California; and Tsou, P. (1994) Silica Aerogel Captures Cosmic Dust Intact. Jet propulsion Laboratory. Voss, K., and Riley, M. (2009) IEA Joint Project: Towards Net Zero Energy Solar Buildings (NZEBs). Published by IEA Solar Heating & Cooling Programme - Task 40 and IEA Energy Conservation in Buildings and Community Systems Programme - Annex 52 Joint Project. Wolverton, B.C. (1988), Foliage plants for improving indoor air quality. National Foliage Foundation Interiorscape Seminar. Hollywood, FL, NASA Stennins Space Center. Zabel, B., Hawes, P., Stuart, H., Marino, B.D.V., (1999) Construction and engineering of a created environment: Overview of the Biosphere 2 closed system. Ecological Engineering, 13, 43-63. Zalba, B., Marín, J.M., Cabeza, L.F., and Mehling, H. (2003) Review on thermal energy storage with phase change: materials, heat transfer analysis and applications. Applied Thermal Engineering, 23, 251-283.
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Towards a Definition of Zero Impact Buildings Shady Attia 24) and André De Herde
25)
Abstract There have been several attempts to define zero impact or near zero impact buildings. Most of these are based on measuring performance or on metric benchmarks regarding the quantity or quality of the various resources employed during a building’s life cycle. However, the problem underlying these efforts is that the resources are measured independent of each other, leading to restrictive overall design approaches. Most existing definitions focus on breaking even with a single resource, such as energy, water or materials, during the building’s life cycle. In fact, the building community needs to set a collective definition for what constitutes a zero ecological impact building, conflating all the resources involved. In this paper, we discuss this deficiency and suggest a shift in thinking necessary to define zero impact buildings. The resulting definition allows us to examine broader criteria including land management, carbon neutrality, energy neutrality, water efficiency and material neutrality. This paper reviews existing definitions or perspectives on zero impact buildings in order to redefine a more comprehensive definition of zero impact.
1
Introduction
The Brundtland Report (1987) and the Intergovernmental Panel on Climate Change (IPCC) Report both agreed in describing the current environmental imbalance as one where in: “the human demand on the planet is exceeding the planet's regenerative capacity.” (Solomon, 2007, pp.996). In order to correct this imbalance, current generations have taken on the challenge of better resource conservation and management. Many scholars and committees have analysed how to close the energy cycle of buildings, or for that matter how to close the land, water or material cycles of buildings (ASHRAE, 2008; IEA, 2009; Nadav, 2008; David, 2010; Raymond, 1998; Rovers, 2009). However, these endeavours rate the different resource flows and cycles separately. At the other end of the spectrum, sustainability indicators such as eco-footprint analysis and life-cycle analysis are too broad, too complex and require the input of variables (food, waste, occupant behaviour and transportation) that are beyond building design practice (EEA, 2008).
24) Architecture et Climat, Université Catholique de Louvain, Louvain La Neuve, Belgium
[email protected]; 25 ) Architecture et Climat, Université Catholique de Louvain, Louvain La Neuve, Belgium;
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In fact, we cannot achieve zero impact buildings (ZIBs) without setting a comprehensive definition of ZIBs. A definition that includes all resource cycles during a building’s life will reveal where the potential lies for maximum impact of environmental decisions on the overall life cycle of buildings. We need a definition that is based on metrics and benchmarks and that therefore can lead and guide the design process. It must also be based on a universal benchmarking standard and provide a framework that allows comparison, analysis and a perspective on opportunities that optimize the use of resources. This paper aims to examine and refine this issue, particularly by comparing existing definitions and reviewing them in light of a more comprehensive ZIB definition. Our goal is to provide a defensible and realistic definition of innovative ZIBs that cater to the cradle to cradle (C2C) philosophy (McDonough and Braungart, 2002). The need for clarity has become increasingly important as the ZIB concept has become more widespread. Yet without a universally accepted definition of what zero impact entails, the issue has become confused. Without consistent parameters to determine ZIB compliance there is no way to achieve our sustainable objectives. Without the performance indicators or metrics, the end result is predictable: buildings will continue to be produced on the basis of the same practice that has produced our existing built environment.
2
Existing definitions and perspectives
The following section explores the different resources contributing to the life cycle of a building, in what way these resources are viewed as zero impact, and how this compares to a more comprehensive definition of ZIBs. We should note that determining if a building is truly zero impact is a complex task. Definitions by default are constricting because they are static, while the reality is that buildings and cycles are dynamic.
2.1
Land use
According to the European Union Directive (2005), land is the scarcest resource on earth, making land development a fundamental component in effective sustainable building practice. Worldwide over 50% of the human population is urban. Environmental damage caused by urban sprawl and building construction is severe and we are developing land at a speed that the earth cannot compensate. Buildings affect ecosystems in a variety of ways and they increasingly overtake agricultural lands and wetlands or bodies of water and compromise existing wildlife. Most contemporary cities must deal with surface runoff, surface temperatures, and urban heat island effects, all problems related to intensive land use. When discussing land resource definitions two aspects have to be taken into consideration. The first is quantitative, involving the degree of density – or the ratio of available building land to the building footprint. The second is qualitative and considers the adaptation of site facilities to the building’s context, including the management of site water, heat island effects, habitats and pollution. However, land use policies are still an open area of research at present and lack definition as to the role of land use in achieving zero impact. Current research is more concerned with the classification of existing urban land use, land coverage, spatial structures, including the housing density, the mean housing and plot sizes, and the spatial aggregation of built up areas (Herold and Menz, 2000; Frohn, 1995). 106
Yet ZIB designers require strategies and performance indicators for sustainable land use that guide decision making and the design process that leads to zero impact buildings (Dunster et al., 2008). Designers are looking for ways to integrate buildings into the biotic and abiotic surrounding context, and to conserve material and land resources through optimized use of land including long-term retrofit plans.
2.2
Energy
Energy is the building resource that has gained the most attention within the built environment research community. There are several approaches to achieving zero impact from this perspective: energy metrics (kWh or MJ), boundary balance (net zero) and balance period (monthly, seasonally or yearly). Research has also stated the importance of comparing design data to the monitored data and to quantifying on-site production against on-site consumption. There are also discussions on the energy quality (primary), type (solar, wind, CHP) and storage in relation to grids and transmission. In trying to achieve zero impact through energy reduction, many practitioners have aimed for a net zero energy goal per site, meaning the import into the building must equal the export. However, a zero impact building should mean that a building’s energy efficiency is maximized, therefore taking into account the grid generation and transmission losses, utility emission rates, and utility cost structures.
2.3
Material
Building materials are another limited resource within a building’s life cycle. In contrast to energy and water, materials circulate within a near closed-loop system (Rovers, 2009; Rovers, 2008; Bryan and Trusty, 2008). The regeneration period of most materials used in current building construction is extremely long since they were millions of years in the making. The only renewable building materials are organic materials including wood and bamboo. Unfortunately, little research is being conducted to ascertain the viability and sustainability of using renewable organic materials. There are several tools available that aim to assess the environmental impact of building materials, including Ecobau, Green Guide, EcoBat and EcoInvent. However, most existing strategies follow the cradle to grave approach, with no regard for the existing building stock. The soundest methodology for material use in buildings is described by Rovers (2009). In this definition building designers borrow materials as a credit, which they materialize temporarily in the building stock, and are re-used or further refined in future buildings.
2.4
Water
Water is a key resource that lubricates the building sector as much as oil does. Buildings require water during construction and during occupancy. In fact, water efficiency is like energy efficiency (Sharma, 2009). Water efficiency is a key metric in evaluating building sustainability. As yet, there is no procedure that makes zero water consumption in buildings possible. Nor is there a metric that encompasses the demand for water, seasonal 107
fluctuations, variation across geographies and the potential for harvesting water. There are sufficient methods, programs, and regulation controlling the use of water fixtures and devices in buildings (Arpke and Hutzler, 2005). However, the major problem with these approaches is that they consider water as a revenue-neutral resource. It is therefore important to formulate a definition that not only takes the water life cycle within buildings into account, but also the energy costs and carbon emissions associated with obtaining water. Any water usage metric should consider the energy impact of water usage as a whole.
3
The problem of existing definitions
Thus far the role of land use, energy, materials and water in achieving zero impact has been reviewed from a conceptual perspective (USGBC, 2010; Lippiatt and Helgeson, 2009; ASTM 2005). The common procedure is to define the parameters of the definition of a ZIB by choosing a metric and setting a boundary limit. To a large extent most of these definitions aim to reach a balance. However, there are major problems with this. This section discusses the major faults of existing definitions from a technical standpoint along with an examination of the relevant characteristics of the zero impact building philosophy. The primary problem that has weakened previous attempts to define a zero impact use of resources is the tendency of researchers to deal with every resource separately, regardless of the total CO2 emissions. In fact, sustainable building design should aim to optimize the use of all resources. More importantly, each and every resource used in the building has a history of energy consumption behind it: the energy of manufacturing, transporting and processing the resource. Therefore, in order to truly achieve zero impact, we need to be willing to see and deal with all the resource’s phases and to pursue a more integrated approach that takes this into account. Additionally, it would be beneficial to create a CO2 index for every resource so that we have a consistent understanding of the resource’s impact within the building process. Secondly, the existing parameters derive from the notion of neutralizing the resource consumption and define this as zero impact. In fact, the “break even” approach is very limiting. Restricting the boundaries to ‘zero' or ‘net zero' is misguided because it discourages the potential to research how buildings can in fact generate a resource. A comprehensive definition of ZIBs would emphasize the viability of harnessing renewable resources. The ‘zero' goal limits innovation and creativity in achieving long-term sustainable building practices. If energy generated on site or water collected on site prove to be abundant resources, why then should we limit our objectives to zero? Thirdly, most definitions focus on linking resource consumption efficiency to building area regardless of occupancy size. In fact, taking into consideration the needs of occupants is equally as important as building area in achieving consumption efficiency. In the energy field, Switzerland is considering a resource efficiency measurement per capita. The Swiss 2000-Watt Society proposes defining energy consumption relative to the number of occupants (Morrow and Smith-Morrow, 2008). Similarly, the United Kingdom is proposing a Personal Carbon Allowance (PCA). The PCA concept is based on setting tradable domestic quotas at around 5 tonnes of CO2 per capita per year. Fourthly, most perspectives neglect context as a factor of influence. Researchers have worked to define universal parameters that do not always correspond with local context or 108
seasonal variations. ZIBs should be defined as context-sensitive, thereby allowing for diversity and flexibility in buildings relative to their context. In brief, existing definitions for ZIB are theoretical and require more refinement to reflect the reality. Up to now, most definitions have not been comprehensive enough to tackle the zero impact objectives. There is a certain urgency to set a definition for zero impact buildings, one that considers energy, water, materials and land simultaneously. Also any definition should seek simplicity and consistency in order to facilitate comparison and provide effective design guidelines. The four resources should have standardized metrics and benchmarks that are debated and agreed upon. A conceptual shift in how to effectively approach ZIB objectives is therefore necessary. This requires a further discussion of the core subject in this research: the zero impact approach (Herold and Menz, 2000).
4
Towards an assimilated definition
From the discussion above we can conclude that there are three important criteria that should converge in a zero impact definition. Firstly, the definition must be based on holistic building design integrating land, energy, material and water. Secondly, the definition must incorporate maximizing on the viability of harnessing renewable resources, particularly in the case of energy and water. Thirdly, the definition must promote a closed-loop use of resources, where land and materials are up cycled either for re-use or given back to nature. This brings us back to the core issue behind this paper: how to define ZIBs from a cradle to cradle perspective and attain a consistency and precision of definition that allows performance comparison and achieves a sustainable built environment in a feasible manner. Whilst addressing the problems previously discussed, with an emphasis on the four essential resources (namely: land, energy, water and materials), a new definition is as follows: A zero impact building seeks the highest efficiency in the management of combined resources and a maximum generation of renewable resources. The building’s resource management emphasizes the viability of harnessing renewable resources including energy and water and achieves a closed-loop of overall material and land use.
The following units are suggested as universal metrics for communicating the resource management efficiency among all stakeholders involved in the building industry. The suggested metrics conform with other international units as closely as is compatible with self-consistency comprehensive, and, in large part, already employed in practice. 1. 2. 3. 4.
Land: area (m2) / footprint (m2) per capita Energy: carbon emissions (CO2) / area (m2) per year per capita Water: water (litre) / carbon emissions (CO2) / capita per year 2 or water (litre) / carbon emissions (CO2) / area (m ) per year Material: materials (ton) / carbon emissions (CO2) / area (m2) / capita and abiotic depletion potential / kg antimony equivalent 109
5
Discussion
The purpose of constructing a combined definition is to create a common framework that can be built upon. Exposing the definition to a wider audience will allow new ideas and tighter constructions to be added. The definition is only the beginning of a further process of definition, which the building design community must pursue. The definition of what makes a zero impact building fits into C2C perspective. Our goal here is not to advocate a fixed, onesize-fits-all approach to defining ZIBs, but to propose a consistent long-term approach. We believe that definitions for ZIBs could be successful concepts if they integrate all aspects of building design and construction practice and are supported by transparent evaluation methodologies. An assimilated ZIB definition recognizes synchronous cycles in resources during the building life cycle. Land, energy, water and materials are interconnected in various ways in ZIBs. Therefore, a proper definition should focus on an overall balance, diverting resources where appropriate and giving them back to nature so that buildings are in equilibrium with their resources. Any zero impact metric should measure the carbon impact of energy consumption as a whole. The usage of each of the resources reviewed is understood in a specific way and makes a specific and unique contribution in relation to carbon emissions. Designers should embrace the proposed standardized metrics and calculation methods as a means towards integrated design. Researchers should also build on existing knowledge and link their findings to back into the definition of zero impact buildings. It would be futile to assert that the proposed collective definition of ZIBs should take precedence over all others since the C2C philosophy is already so influential and broad in scope. There is also an emerging trend to create ecologically positive building footprints where the building design is very efficient and through suitable technologies energy and water become positive resources. There is a need to create buildings that imitate nature so that the footprint is ecological, healthy and beneficial in general and not only on the level of energy consumption. For example, buildings that support life or generate purified air, distilled water and energy or improve on the microclimate. Our role as human beings is to contribute to the health of the planet and this we must pursue with vigour. Finally, a ZIB’s life cycle and performance should be better monitored and documented in databases so that these can help us understand how buildings perform over their lifetime. Vast volumes of information can help establish real-world efficiency benchmarks per resource.
6
Conclusion
The four metric definitions described in this paper promote a sustainable design model leading to zero impact buildings. The value of these definitions lie in their use as a metric for designing ZIBs, particularly in regards to land, energy, materials and water. We must understand that the various resources are merely individual components in the approach to zero impact buildings. These metrics are intended to facilitate zero impact designs so that the management of resources becomes measurable. Combined, they provide a framework that can guide design decisions not only in terms of carbon emissions but also in terms of the impact within other life cycles relevant to land, materials and water. In this way, we avoid cradle to grave processes and supplant them with cradle to cradle metrics. 110
References Arpke, A. and Hutzler, N. (2005) “Operational Life-Cycle Assessment and Life-Cycle Cost Analysis for Water Use in Multi-occupant Buildings,” in Journal of Architectural Engineering, September, vol. 11, no. 3, pp. 99-109. ASHRAE (2008). Vision 2020, Producing Net Zero Energy Buildings. Atlanta, USA ASTM International (2005). “Standard Practice for Measuring Life-Cycle Costs of Buildings and Building Systems,” ASTM Designation E917-05, West Conshohocken, PA. Brundtland, G., (1987). Brundtland Commission Report. United Nations World Commission on Environment and Development Bryan, H. and Trusty, W. (2008). Developing an Operational and Material CO2 calculation protocol for buildings. SB 2008 Melbourne, Australia. CBE (2008). Getting to Zero. Berkeley, University of California; EnergyIQ (2010). “Action-oriented energy benchmarking for non-residential buildings,” LBNL, accessed March 2010: http://energyiq.lbl.gov/ and http://energybenchmarking.lbl.gov/EnergyIQ.html David, B. (2010). “Moving Toward Water Use Metrics and Benchmarks,” Water Smart Innovations Conference, October 6-8, Las Vegas, USA. Dunster, B., Simmons C., and Gilbert B. (2008). The ZED book. Oxon: Taylor & Francis. EU-Directive (2005). Thematic Strategy on the sustainable use of natural resources, COM, p. 670. European Environment Agency, (2008). The Ecological Footprint. Copenhagen. Frohn, R. (1995). Improved landscape metrics for environmental monitoring and assessment. PhD dissertation, University of California Santa Barbara. Herold M. and Menz G. (2000). “Landscape Metric Signatures (LMS) to improve Urban Land Use Information derived from Remotely Sensed Data,” in Computers & Geosciences, vol. 26, no. 4, pp. 451-468; IEA (2009). Towards Net Zero Energy Solar Buildings. Montreal, Canada. Kilkis, S. (2007). “A new metric for net-zero carbon buildings,” in Energy Sustainability, California; Lippiatt, B. and Helgeson, F. (2009). “Multidisciplinary life cycle metrics and tools for green buildings,” in Integrated Environmental Assessment and Management, vol. 5, no. 3, pp. 390-398; Marszal, A. and Heiselberg, P. (2009). “Zero Energy Building (ZEB) definitions - A literature review,” in D.o.C. Engineering. Aalborg University; McDonough, W. and Braungart, M. (2002). Cradle to Cradle. North Point Press. Morrow, K. and Smith-Morrow, J. (2008) “Switzerland and the 2000-Watt Society,” in Sustainability Magazine. Nadav, M. (2008) “Counting Carbon: Understanding Carbon Footprints of Buildings,” in Environmental Building News, July. Raymond, J. (1998) “Emerging trends in building environmental assessment methods,” in Building Research & Information, January, vol. 26, no. 1, pp. 3-16. Rovers, R. (2008). “A resource management model for the built environment.” Http://www.sustainablebuilding.info/post-crash/files/Closed%20Cycles-IofV-paperrovers-010108.pdf Rovers, R. (2009) “Material-neutral building: Closed Cycle accounting for building construction,” SASBE, TU-Delft. 111
Sharma, R. et al. (2009). "Water efficiency management in datacenters: Metrics and methodology," in IEEE International Symposium on Sustainable Systems and Technology, pp.1-6. Solomon, S., et al. (2007) Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, pp. 996. Torcellini, P., Pless, S., and Deru, M. (2006). “Zero Energy Buildings: A Critical Look at the Definition,” ACEEE, California; USGBC (2010). “LEED: Leadership in Energy and Environmental Design,” U.S. Green Building Council Web http://www.usgbc.org;
112
Field Study of Retrofit Solutions for Residential Housing Davide Calì, Tanja Osterhage and Dirk Mueller
26
)
Abstract The complete refurbishment of nine buildings, each containing ten apartments of 72 m² is presented, and preliminary results are shown. The buildings have a different retrofit scenario in terms of insulation, heat production and delivery, domestic hot water production and airhandling systems. Following the energy saving ordinance for buildings in Germany of the year 2007 (EnEV, 2007), each building has been evaluated. A monthly energy balance based on weather data from the German test reference year has been calculated for a one year period. The results show that depending on the refurbishment solution, the retrofit can reduce the energy demand up to 93%, and increases thermal comfort. Within the next three years, the buildings will be monitored in high time resolution. Physical models of the buildings and the components are under developement using the modeling language Modelica, and will be validated through measured data. Once validated, the models will be used, for example, to elaborate regulation strategies for the plants and to create new virtual refurbishment versions in the direction of a zero-impact building.
1
Introduction
Human activities in buildings account for 40% of the primary energy used in OECS countries (IEA, 2008) In the year 2006 the residential sector accounted for 25.9 % of the final energy consumption in the EU [0]. Since space heating and cooling is the most significant component of household energy demand [0], this is one of the sectors with highest energy saving potential. Building refurbishment can be one of the cheapest ways to reduce both primary energy consumption and greenhouse gas. A large number of buildings constructed in the second half of the twentieth century consume a big amount of energy due to low insulation standards and heating systems that are inefficient and outdated.
26) All three authors: Institute for Energy Efficient Buildings and Indoor Climate, E.ON Energy Research Center, RWTH Aachen University;
[email protected]
113
Figure 1 . East façade of the first block, before refurbishment
In this contribution, he complete refurbishment of nine buildings is presented: the buildings, located in Karlsruhe, Germany, are built in three blocks and the flats are disposed on five floors. The 52 m long principal façade of each block (Figure 1), is east-oriented. The retrofit solutions are here analyzed and compared in order to better understand the importance of buildings’ retrofits in terms of primary energy saving per year and square meters. In parallel the aim is to comprehend which retrofit solution is more effective, in terms of primary energy saving. The buildings and buildings’ performances are compared through the specific heat demand per year and square meter of floor space qh and the specific primary energy demand of the buildings per year and square meter floor space qP. Those parameters are calculated following the energy saving ordinance for buildings in Germany of the year 2007 (EnEV, 2007; DIN V 4701-10, 2003), using the procedure of the monthly energy balance, and with weather data from the test reference year for the location Karlsruhe.
N
Block 1,Heilbronnerstaße 27(a), 29(b), 31(c).
c b a
c b a
c b a
Block 2, Heilbronnerstaße 33(a), 35(b), 37(c). Block 3, Mannheimerstaße 43(a), 45(b), 47(c).
Figure 2 Blocks orientation, “a” are the first buildings, “b” the second, “c” the third. 114
LIVING ROOM 19.7 m²
SECOND BEDROOM 14.4 m²
SECOND BEDROOM 14.4 m²
LIVING ROOM 19.7 m²
N Left Flat
CORRIDOR FIRST BEDROOM 16.3 m²
FIRST BEDROOM 16.3 m²
STAIRS BATH 4.6 m²
Right Flat
CORRIDOR
KITC. 8.3 m²
KITC. 8.3 m²
BATH 4.6 m²
Windows Wall between first and second Building
Figure 3 Qualitative layout of one floor of the first buildings of each block. KITC. is the Kitchen.. The total floor space of each building is 721m²; the envelope-surface is 1,097m² for the a- and c-buildings, 959m² for the b-buildings.
2
The buildings before the refurbishment
2.1
Buildings’ description
The buildings are built in three identical parallel blocks (Figure 2), each having 30 apartments. To realize an effective comparison of the different refurbishment’s measurements, the three blocks are refurbished with increasing heat insulation standards. In each of the three buildings of each block several innovations are adopted in terms of technical plants: each block have technical plants with increasing energy efficiency. Each building contains ten apartments; each of them has a kitchen, a bathroom, a living room, two sleeping rooms and a small central corridor, for a total floor space of 72 m²) (Figure 3)..
2.2
The buildings before the retrofit
The buildings were built in 1955, originally without insulation and with single glass windows. The heat was provided by a cackle stove installed in each living room, domestic hot water (DHW) was supplied by electrical or gas circulatory type water heater. In a later time the buildings had been lightly refurbished. Before the complete refurbishment presented in this work, the buildings were in the following condition: • double glass windows with an overall heat transfer coefficient U equal to 3.1 W/(m²K), (those windows had been installed during a previous refurbishment process in the eighties), • only the south and the north façades were insulated with 4 cm insulation with λ=0.04 W/(m²K), the U-values for the external walls were between 1.22 and 0.55 W/(m²K), 115
the ceiling of the last floor, under the pitched roof space, had a U-value of 2.58W/(m²K), • the floor between basement and ground floor had a U-value of 1.93 W/(m²K), • the walls between the flats and the stairs had a U-value of 1.25 W/(m²K).
250 200
194.1
183.4
193.8
150 100 50 0 a
b
c
qP in kWh/(m²floor spacea)
qh in kWh/(m²floor spacea)
The qh and the qP have been calculated, and the results are shown in Figure: the b-buildings have a minor energy demand because of the minor external envelope surface (see Figure 2). The a- and c-buildings have a small difference in terms of qh: this is produced by small geometric variations of the buildings (windows orientation). The heating system, as well as the DHW plant, is equal for each building: as consequence, qh and qP are proportional (in equation 1 the correlation between qP and qh is described; eP is a parameter indicating the quality of the heating plant as primary-energy/heat- DHW- and ventilation-energy-demand ratio, qHW is the DHW energy demand, for the EnEV calculation qHW is assumed to be 12.5 kWh/(m²a) (DIN V 4701-10, 2003)).
400
352.3
334.0
351.9
a
b
c
300 200 100 0
Figure 4. Left: the specific heat demand of the buildings, per year and m²floor space. Right: the specific primary energy demand of the buildings, per year and m²floor space.
qP = eP • (qh + q HW ) , 3
(1)
The refurbished buildings
The first block has the simplest refurbishment solutions (both in terms of thermal insulation and plant) and for this reason will be considered as reference case: this is also the standard retrofit realized by the company which owns the three blocks for other buildings in the city of Karlsruhe. The retrofit of the second block, if compared to the first block refurbishment, postulates the use of more insulation and a more advanced plant technology, which are easy to find on the market, anyway. The most advanced refurbishment’s solutions 116
Figure5.. Refurbishment solutions: the white text on dark background is related to the thermal insulation, the dark text on the gray background is related to the technical plant solutions.
are realized for the third block: with the use of vacuum panels together with high efficiency heat pumps and waste heat recovery units this block is designed to reach the lowest primary energy demand. In Figuree 5 the refurbishment solution are described. WHRU indicate waste heat recovery units, the number in percent next to WHRU is the efficiency of the heat exchange process. The thermal conductivity λ of the insulation is indicated by a number in each box, for example 035 means λ = 0.035 W/(mK).
Heat and primary energy demand of the first block The first block has already been completely refurbished and is now inhabited: qh and qP have been calculated and are portrayed in Figure 6 The qh is lower in the middle building because of the minor external envelope surface and also for this case, the difference between the a- and the c-building is brought by minimal geometrical differences of the buildings. All the three buildings are supplied by district heating and have exactly the same technical plant; however, the connection to the district heating is built in the c-building, which means for this building a smaller amount of heat losses through the hot water pipes installed 117
38.9
36.0
Heilb. 27
Heilb. 29
39.5
Heilb. 31
qP in kWh/(m²floor spacea)
qh in kWh/(m²floor spacea)
50 40 30 20 10 0
60 50 40 30 20 10 0
55.6
52.7
54.6
Heilb. 27
Heilb. 29
Heilb. 31
Figure 6. Left: the specific heat demand of the buildings, per year and m²floor primary energy demand of the buildings, per year and m²floor space.
. Right: the specific
space
in the cellar, compared to the a- and the b-building. For this reason, even though the abuilding has a lower heat energy demand than the c-building, the primary energy demand for the c-building is lower (the eP of the c-building is smaller than the one of the a-building).
Heat and primary energy demand of the second block
50 40 30 20 10 0
36.9
34.8 26.4
Heilb. 33
Heilb. 35
Heilb. 37
qP in kWh/(m²floor spacea)
qh in kWh/(m²floor spacea)
The second block has already been refurbished and has been inhabited since February 2010. The qh and the qP have been calculated and are portrayed in Figure Figure 7. The lower heat energy demand of the b-building, compared to the one of the a- and the c-building, is not only caused by a minor external surface of the b-building, but also by the use of passive house standard windows. Though the a-building has lower heat transmission losses than the c-building (for geometrical reasons), it has a major qh: this is explained by the art of the installed ventilation plant which comports higher ventilation losses for the abuilding. Although the qh of the b-building is much lower than the one of the other buildings for this block, the primary energy demand of the three buildings is almost equal: as seen in equation 1 the qP is directly influenced by the eP. The a-building has a lower eP (compared to the b-building) because of innovative waste heat recovery units installed directly on the windows of each sleeping room and of each living room. In the c-building the lower eP (compared to the b-building) is brought by a thermo solar plant (tube collectors) for the DHW production: the solar DHW production plays a fundamental role in the direction of zero energy buildings. 60 50 40 30 20 10 0
44.7
45.0
45.5
Heilb. 33
Heilb. 35
Heilb. 37
Figure 7. . Left: the specific heat demand of the buildings, per year and m² floor space. Right: the specific primary energy demand of the buildings, per year and m² floor space.
118
Heat and primary energy demand of the third block
50 40 30
29.9
28.5
34.1
20 10 0 Man. 43 Man. 45 Man. 47
qP in kWh/(m²floor spacea)
qh in kWh/(m²floor spacea)
The third block presents the most advanced refurbishment solutions available today on the market, both in terms of insulation and technical plants. The complete block will be ready by the end of 2010. An interesting comparison has to be done between the b-buildings of the second and the third block: the U-values of the walls and windows are practically equal (the advantage in the use of vacuum panels is in the thickness of the insulation, 16cm for the second block, 8cm for the “sandwich-built” insulation with 4cm vacuum panels and 4cm standard insulation 035), nevertheless the qh of the b-building in the second block is better than that in the third block: this is explained by the art of the installed ventilation plant which comports higher ventilation losses for the b-building of the third block. Looking at Figure 7 and Figure 8 and comparing the qh of the a-buildings, the role of the passive house standard windows emerges: the transmission and ventilation losses are for the two entrances the same, but the a-building of the third block has a 19% lower heating demand. When looking at Figure 8, it emerges that the CO2 tubes heat pumps (installed in the aand the b-building) ensure better energy performances than the air heat pump (installed in the c-building). The eP of this block is anyway clearly influenced by the use of waste heat recovery units with heat exchange efficiency up to 90 %; the positive effect of the high efficiency WHRU is evident looking at the qP of the buildings of the third block. 60 50 40 30 20 10 0
25.0
21.2
Man. 43 Man. 45 Man. 47
Figure 8. Left: the specific heat demand of the buildings, per year and m²floor primary energy demand of the buildings, per year and m²floor space.
4
32.6
. Right: the specific
space
Result evaluation
In order to portrait the thermal transmission losses of the three blocks before and after the refurbishment, the HT' (specific heat losses per square meter envelopment and per Kelvin) are shown in Figure 9 the intent to create three blocks with three thermal insulation classes has been reached. One of the objectives of this work is to outline the possible savings in terms of primary energy in the field of buildings’ refurbishment: in Figure 10 are shown the qP of each building in kWh/(m²a) before and after refurbishment, and, in percent, the amount of primary energy saving brought through the relative refurbishment solution. The second objective of this work is to evaluate which of the refurbishment measures can be more effective: the qP of each refurbished building and, in percent, the amount of primary energy saving brought through the relative refurbishment solution compared to the standard refurbishment of the first block are shown in Figure 11. 119
HT' in W/(m²EnvelopmentK)
1.5
1.40
1.2 0.9 0.6
0.35
0.31
0.3
0.28
0.0 Before Retrofit
Block 1 Block 2 Block 3 refurbished refurbished refurbished
Figure 9 HT’of the three blocks before and after refurbishment: specific heat losses per square meter envelopment and per Kelvin.
After Retrofit
qP in kWh/(m²Floor spacea)
First Block
Second Block
400 352.5 334.5 352.4 350 87.3% 86.5% 87.1% 300 84.2% 84.2% 84.5% 250 200 150 100 55.6 52.7 54.6 44.7 45.0 45.5 50 0 a b c Heilb. Heilb. Heilb. Heilb. Heilb. Heilb. 27 29 31 33 35 37
Third Block 92.9% 93.7%
100%
90.7%
90% 80%
25.0 21.2 32.6
70% 60%
Primary Energy Saving
Before Retrofit
Man. Man. Man. 43 45 47
Figure 10.. Primary Energy demand per square meter of floor space and year, of the buildings before and after refurbishment. In percent, the primary energy saving of the retrofit solutions, compared to the primary energy demand of the buildings before the retrofit.
qP in kWh/(m²Floor spacea)
Third Block 55.0%
350
64%
59.8%
300
40.2%
250 200
32%
150 100 50 0
48%
19.6%
55.6
14.6%
52.7
54.6 44.7
45.0
16.6%
16% 45.5
25.0
21.2
32.6 0%
Heilb. 27Heilb. 29Heilb. 31Heilb. 33Heilb. 35Heilb. 37 Man. 43 Man. 45 Man. 47 Figure 11. Primary Energy demand per square meter of floor space and year of the block after refurbishment. In percent, the primary energy saving of the retrofit solutions, compared to the primary energy demand of the buildings of the first block.
120
Primary Energy Saving
Second Block
First Block 400
qP in kWh/(m²Floor spacea)
400 350 300 250 200 150 100 50 0
Before Retrofit 352.5 354.2
a
334.5 343.0
b
After Retrofit 352.4 356.4
c
44.7 41.5
45.0 45.0
45.5 42.6
Heilb. 33
Heilb. 35
Heilb. 37
qP without detailed TB calculation, BR qP with detailed TB calculation, BR qP without detailed TB calculation, AR qP with detailed TB calculation, AR Figure 12 . Primary Energy demand per square meter of floor space and year, of the second block, before refurbishment, BR, and after refurbishment, AR: The results with and without the use of the detailed thermal bridges (TB) calculation is compared.
5
Discussion and future perspectives
A well planned refurbishment for residential buildings can bring savings in terms of Primary energy up to 93.7%. Already a “standard refurbishment” with 14 cm insulation, λ=0.035 W/(m²K), with connection to the district heating, guaranty energy saving of about 84%. Between the second and the third block, the most influential factor for the energy saving of the third block, is the use of high efficiency heat recovery devices. Although the results here presented are obtained using the most detailed calculation analysis prospected by EnEV 2007, the results could still be improved with a detailed evaluation of thermal bridges following the finite element method. A detailed evaluation of thermal bridges has been done for the not refurbished buildings, and for the second block, refurbished: the results, directly compared to the results without the detailed thermal bridges calculation, are shown in Figure 12. If the detailed thermal bridges calculation is executed and taken into account, the primary energy saving between the not refurbished buildings and the second block is clearly bigger. To answer the question: “how to get a zero-energy building?” the amount of surface of Photovoltaic panels (Mono-crystalline) that should be installed on the roof to bring the primary energy balance and the CO2 balance of the buildings of the third block to zero has been calculated. This calculation has been done only for the third block, since this is the block with the most performing combination of heating and insulation systems. The two sides of the roof are inclined of 30° and are in direction east and west. A monthly solar energy balance has been calculated with the solar radiation data of the climate region 12 (Karlsruhe). For the a-entrance 48 m² photovoltaic panels are required, for the b-entrance 40 m², for the c-entrance 64 m². A CO2 balance (using conversion factors between final energy 121
and CO2 given by the IWU (2009) and a primary energy balance for this block has been executed (see Figure 13): the total energy saved by the own production of the photovoltaic system of each entrance per year has been divided through the floor space of each entrance, and multiplied with the primary energy factor for electricity (EnEV 2007), in order to make it comparable with the primary energy demand per square meter and year of the entrances.
CO2 in t/a
6.0
50.0
Primary Energy kWh/(m²floor spacea) DHW
3.0
1.9
1.5
25.0
0.8
0.0
0.0
-3.0
-25.0
11.0
9.1
5.0
VES HES
-4.2
-6.0
-25.0
PV
-50.0
Block 3, Entrance a
CO2 in t/a
6.0
50.0 3.0
1.9
1.0
Primary Energy kWh/(m²floor spacea) DHW
0.7
25.0
11.0
0.0
6.1
4.1
VES
0.0 -3.0
HES -3.6
-6.0
3.0
CO2 in t/a
50.0
3.2 1.0
1.3
25.0
0.0
-9.0
PV
Primary Energy kWh/(m²floor spacea) DHW
18.7 6.1
7.8
VES
0.0
-3.0 -6.0
-21.2
-50.0
Block 3, Entrance b
6.0
-25.0
HES -25.0 -5.5
-50.0
-32.6
PV
Block 3, Entrance c”
Figure 13 CO2 and Primary Energy balances for the third block, entrances a, b and c. DHW stays for Domestic hot water, VES for Ventilation engineering system, HES for Heating engineering system, PV for Photovoltaic system. Both the CO2 and the primary energy balance go to zero since the building are all using only electricity (for the heat pumps) as energy carrier.
122
The results here presented are related only to a static calculation. Perspectives in terms of exergy flows are also not shown: an exergy comparison could offer different perspectives because of the difference between “primary energy efficiency factor” and “exergetic efficiency factor” (LowEx, 2006). For this reason, simulation of the buildings and of the buildings’ components using the modeling language Modelica will be run and exergy-flows will be taken into account and evaluated. The simulations will also work as a tool used to elaborate new control strategies for the buildings’ technical plant. To validate the models, a complete monitoring of the buildings started in February 2010: both parameters related to comfort conditions (air temperature and humidity in the rooms, CO2 and Volatile Organic Compounds sensors, etc.) and to the technical plant (air changes per hour, supply and return temperatures of radiators and floor and ceiling heating systems, water flows through heating devices, opening-windows sensors, temperature sensor in the stratified storage, etc.) as well as weather conditions and soil temperatures, will be monitored at high time resolution. This monitoring phase will also be useful to evaluate how far those buildings are from a zero energy building. Once validated, the models will be used, for example, to elaborate regulation strategies for the plants and to create new virtual refurbishment versions: the possibility to create virtual zero energy buildings will be explored. A cost/benefits analysis will also be executed.
Acknowledgment We appreciate the financial support by BMWi (German Federal Ministry of Economics and technologies), promotional reference 0327400G.
References EnEV 2007, Energie Einsparverordnung, Energy saving ordinance for buildings, 2007. IEA, Energy efficiency policy recommendation, 2008, International Energy Agency, IEA. EEA, Final energy consumption by sectors, 2009, European Environment Agency, EEA. EEA, Energy and Environment Report, EEA, 2008. Energetisch Bewertung heiz- und raumlufttechnischer Anlagen, Teil 10: Heizung, trinkwassererwärmung, Lüftung, DIN V 4701-10, 08.2003. Thermal protection and energy economy in buildings . Part 6: Calculation of annual heat and annual energy use Kumulierter Energieaufwand und CO2-Emissionsfaktoren verschiedener Energieträger und –versorgungen, 2009, IWU, Institut Wohnen und Unwelt LowEx Tagungsband Hamburg 2006 Symposium zum Verbundvorhaben des Bundesministeriums für Wirtschaft und Technologie
123
Applications of Appropriate Renewable Energy Technologies in Chinese Rural Houses in QinghaiTibetan Plateau Wang Yan, Zhang Peng, Ju Xiaolei, Zhang Yabin
27)
Abstract This paper presents a demonstration project concerning the rebuilding design idea for a rural dwelling located in Tibet Autonomous Region (TAR), Qinghai-Tibetan plateau. It develops 0-impact approaches to improve the energy diversity, efficiency and to reduce the CO2 emission for rural dwellings. Renewable energy technologies are integrated and applied including solar chamber, solar kang (bed) with cobblestones as heat storage, heat storage by phase change material (PCM) and solar air heater. All the approaches and technologies adapt well to the local climate while following the principles for developing in this region and integrating with local traditional architectural style. Via the application of these technologies, the level of renewable energy utilization is largely improved and the local people’s dream of having a safer, warmer and larger house comes true.
1
Introduction “The urgent problem for us is the heating in winter. There are three rooms in my house but only one dung stove can be used for space heating. We long for a better living, but we can not afford the expensive costs“. A farmer in Qinghai-Tibetan plateau., 50 years ago.
Qinghai-Tibetan Plateau covers most parts of the Tibet Autonomous Region (TAR) and Qinghai Province in China, which is one of the most mysterious, fascinating places in China (Fig.1). The residents have a strong faith and keep simple folk customs. However, due to the restriction of geography and climate, most of the people live in vast rural areas with poor infrastructure. Local residents earn their living by raising livestock and planting crops (Fig 2). China has made great efforts to the development of TAR by improving the energy diversity, efficiency and reducing the CO2 emission. Based on the national developing
27) All four authors: China National Engineering Research Center for Human Settlements, China Architecture Design and Research Group
125
Fig.1 Qinghai-Tibetan plateau (photo Z. Yan, 2008)
Fig. 2 Traditional agriculture (photo Z. Lei, 2008)
strategies, this paper introduces a 0-impact approach in a demonstration project with minimum impact to environment but maximum heritage of traditional culture and life style. The research is funded by China National "Eleventh Five-Year" S&T Plan.
2
0-impact strategies
In order to achieve the targets of 0-impact, the following four strategies should be complied in the project:
2.1
Traditional culture and life style sustained
Tibetan culture has been deeply influenced by Indian Buddhism, and has absorbed Han and Nepalese culture, so housing form and living custom in this region are significantly different from others in China. Thus, the traditional architectural style and Tibetan custom must be taken into consideration to keep the Tibetan traditional culture and life style sustained.
2.2
Environmental friendly and ecological sounded
Over the years, TAR is always one of the best regions where the original ecological environment have been well maintained in the world with majestic mountains, clean rivers, diverse animals and lush plants. It is the real "Shangri-La." Therefore to protect the fragile ecosystem and keep it balanced, the impact on the ecological environment should be limited from the beginning of building construction till the daily operation in this region.
2.3
Affordability and accessibility oriented
Due to the current condition of mono-income, low-grade energy, insufficient energy supply, and inefficient heating equipment, low-cost and easy-handle technologies have to be adopted to reduce energy costs for living and maintain the life quality by the utilization of local renewable resources.
126
Fig.3 Full view of the site studied (photo by Li Chungang, 2008)
2.4
Promotion and propaganda approached
The purpose of residential building demonstration project in TAR is not only to improve single family’s life and income, but also to make more residents to participate in house building and arouse them to focus on life improvement through personal experience in adopting appropriate technologies. Thus, the technologies chosen should become easyavailable, easy-handle, dependable, convenient-maintained, and can be promoted in local residential building construction.
3
Description of the demonstration project
3.1
Location
The site of this project is located in the nature reserve of Mount Qomolangma, north of the Himalayas, with an elevation 4119m, only 50km away from the Mount Qomolangma. The geographical and climate parameters of this project are illustrated in Table 1. The full view of the village is shown in Figure 3.
3.2
Current situation and requirement
The local dwelling is always built by residents themselves with traditional materials and primordial construction ways. Consequently the consummate building function and comfortable indoor environment are seldom considered during the process of construction. It is difficult to improve the standard of dwelling for local residents without professional designing and financing support.
Table 1 Brief introduction of the site
[1]
*)
Altitude
>4000m
Annual maximum average temperature
12℃ (Jul)
Annual minimum average temperature
-7.4℃ (Jan)
Annual average wind velocity
5.8m/s
Solar irradiation and hours *) above the Huanghai Sea level, China
≥7500MJ/sqm•a, 3393 hr/a
127
Fig.4 (left) House owner and old dwelling (photo by Z. Yan, 2008) Fig.5 (rigtht) Traditional architecture style (photo by Z. Lei, 2008)
In order to change the situation and to support the improvement of local residents living, a representative low-income family is chosen to rebuild a new dwelling on the former site (Fig. 4). The family members are all Tibetan Buddhists. Their old dwelling is 40 sqm with poor indoor environment, out of repair walls/windows/doors. The room temperature could be minus in winter. Due to lack of storage space and livestock breeding room, the Yak and its fodder are deposited in the courtyard. It presents the most popular status of local dwellings. To provide a house with better living conditions, the following aspects should be considered: • Maintain the Tibetan architectural style and space for religious worship; • Enlarge the indoor functional space for the needs of living and working; • Improve the indoor living conditions; • Increase the utilization of clean energy, especially solar energy; • Provide opportunity of multi-income by updating housing facilities.
4
Technologies applied and integrated
4.1 Building design – layout function and passive design oriented The building design emphasizes the heritage of local history and culture. After satisfying the basic subsistence need, it also upgrades the extension ability of dwelling function. Traditional Tibet architectural style i.e. the door lintel, window lintel and dense rafter under parapet are well conserved. Facade colors are selected via the traditional template. For instance, the snuff color footstone means dignity, white wall represents chastity and luck, black parapet and window frame stands for stateliness and awe, and red foursquare wall on the roof indicates brightness and relaxation (Zongwei, 2004), as seen in Fig.5. Traditional subsistence mode is kept. • Unattached courtyard is designed to dry the crop and breed livestock; • Family hall for worshipping Buddha is designed to fulfill the religion need; • Living room is surrounded by bedroom, kitchen, and forage depot to form the hierarchy pattern which is accordant with local traditional architecture style (Fig.6). 128
Fig.6 Layout design
Reception function for tourists is extended. Large numbers of mountain climbers as tourists pass by every year for it is only 50 km away from the base camp of Mount Qomolangma • The interior living area is largely improved from 40 sqm to 100 sqm. • Bedroom and living room are laid in southeast part while accessory space (depot, kitchen, etc) is put in the north part of the dwelling so as to resist the strong wind from northwest and southwest direction in winter. • The master and guest bedrooms are separated by living room to ensure the privacy and security.
4.2 Material mix-used and recycled, conformation optimized and seismic structure oriented Selection of a local material with low-cost, good thermal performance and profitable for the environment is the core of the demonstration project. The walls adopt locally popular used clay bricks, and the roof consists of good thermal performed wood and earth. All the materials can be recycled after years and have no harm to the environment. The building envelope and heat transfer coefficient are shown in table 2.
Table2 Building envelope and coherent heat transfer coefficients*
Living area 100 sqm
External wall 400mm Clay block K=0.6W/(sqm•℃)
Roof Veneer covered with 150mm earth K=0.5W/(sqm•℃)
External window Double glazed insulating with plastic steel frame K=2.7 W/(sqm•℃)。
* parameters by design. 129
Fig.7
4.3
Illustration and completed solar chamber (photo by Zeng Yan, 2009)
Energy system optimized
The construction site has the most abundant solar energy in the world. Therefore the building should be fully integrated with solar technology to increase energy consumption for daily life and tourism services, otherwise to make no harm to the environment. Both passive and active solar technology means have been explored in the project.
Solar chamber The solar chamber is arranged in the south with the function of capturing thermal energy from sunshine and storing it in the back wall (Yuanzhe 1993) (some with heat storage material). The solar chamber, bedroom and living room are linked by manual control window or door, so that the storage heat can be transmitted simultaneously in the daytime and keep indoor warm by closing windows and doors in the nighttime of winter. On the contrary, manual control windows in the upper and lower part of the solar chamber are used to ventilate the air in summer to prevent overheat, see Fig. 7.
Thermal stored skylight with PCM The phased change material (PCM) is attached on the manual control window sash of the bedroom roof. The PCM will absorb and store the thermal energy by transforming into liquid during daytime and release the heat backwardly during the night (Zhu Qing 2005) see Fig.8.
Fig.8 Illustration and completed thermal stored skylight with PCM, ((photo
130
by Xiao Wei, 2009)
Fig.9 Illustration and completed Chinese solar kang (bed) (photo by Xiao Wei, 2009)
Chinese solar kang (bed) with thermal storage cobblestone Kang (bed) is the traditional heating tool in rural area of Chinese cold climate zone. The solar kang is combined with a cavity under it where cobblestones absorb heat from the sunshine. Meanwhile adjustable baffles with insulation and glisten materials outside the cavity are open to receive sunshine in the daytime and close to keep warm in the night time. When air temperature drops the cobblestones will start to release the heat to the kang board during the night, seen in Fig.9.
Solar air panel The solar air panel as space heater is installed in the south façade of the dwelling (Fig.10). The heating, ventilating and cooling principles are as follows. • There are two holes open to outdoor and anther two open to indoor. • The outdoor holes will be close in winter. • The indoor holes will be open generally in summer to make good ventilation. • Differ ways to open and close the holes may improve the ventilation and indoor climate.
Fig.10
Illustration and completed solar air panel (photo by Zeng Yan, 2009)
131
( a) Winter
( b) Summer
Fig.11 Indoor temperature comparison 11a: Winter; 11b: Summer
5
Evaluation
In order to evaluate the technologies used in the project a durative monitoring and a valuation of the performance of old and new-built dwellings have been in process by environment simulation software. Key indicators for evaluation including indoor thermal environment changes, energy consumption for heating, CO2 emission as well as technical cost will be monitored and evaluated.
5.1
Indoor thermal environment improved
As shown in Fig.11a, the thermal environment of old dwelling in winter is so uncomfortable that indoor average temperature is only 5.1℃. Even the main spaces such as living room and bedrooms could only reach to less than 8℃. After rebuilding, the situation is improved obviously that the average temperature rises from 5.1℃ to 9.0℃ while those of the living room and bedrooms are above 10℃. The comparison of summer condition shows little difference between old and new dwelling (Fig.11b). It ranges from 15℃ to 18℃. Correspondingly heating in winter is more important than cooling in summer. The frequency distribution of temperature is another factor for estimating thermal environment. Fig.12a shows that the annual temperature is divided into low temperature interval (T<14℃), middle temperature interval (14℃
28℃), it is an obvious sign of improved indoor thermal environment that low temperature duration decreases 18.5% and the middle temperature increases 11.3%, the range of indoor temperature from winter to summer is much narrower than the old dwelling (for old -2~32℃, for new 4~30℃), seen in Fig.12b. Monitoring and analysis of temperature shows that the indoor thermal environment improved obviously.
5.2
Energy efficiency increased and CO2 emission reduced
Because of the cool weather in summer, seldom energy is used for cooling in this region. The energy consumption of building concentrates in heating season from September to April. By using environment simulation software, the evaluation result of the difference 132
1800
7000 6000
1600
11.3%
before after
hours number
1200
18.5%
3000
1000 800 600
2000 1000
heating o <14 C
o
400
cooling
comfortable
o
>28 C
o
14 C~28 C
200
0
0 -2/0
low temperature
middle temperature
2/4
6/8
high temperature
10/12
14/16
18/20
22/24
26/28
30/32
temperature
Fig.12 Annual Indoor temperature distribution. 12(a)(left Comparison of temperature distribution hours; 12 (b) right Temperature frequency distribution
between old and new dwelling (Fig.13) shows that heat load decreases from 90W/sqm to 63 W/sqm, nearly 30% down. By alternative use of solar energy the annual fossil energy consumption reduces from 3.24 tce to 1.85 tce with 42.9% CO2 emission reduction equivalent (Fig.14). The effect of energy saving and CO2 emission reduction is remarkable.
5.3
Cost of construction affordable
2
fossil energy consumption(tce/a)
80
60
40
20
0
3.0
6.00
2.5
5.00
2.0
4.00
1.5
3.00
1.0
2.00
0.5
1.00
0.0
after
before
Fig.13 Comparison of heating load
before
after
Fig.14 Heating energy and CO2 emission
133
CO2 emission (tce/a)
Cost has a significant impact on the prospects of spreading the relevant technologies. As shown in Table 3, the total cost of this project is 76650 RMB, 11650 RMB higher than normal local dwelling, in which the expenditure of high-performance glass and heat storage material accounts for 75% of the cost increases. The unit cost of the new dwelling is 766.5 RMB/sqm, 18% higher than normal one (650 RMB/sqm). With the reduction of material cost, the expenditure for construction should decrease gradually in the future.
heat load(W/m )
hours number
4000
before after
1400
5000
According to the incentive policy in TAR (Bi Hua 2008), the government and the enterprises support about 30% of total cost by each respectively, the other 40% will be covered by tax free loan in the following 3 years. Thus the local families can be affordable for the total cost.
Table 3 Total cost of the case dwelling (in RMB*)
foundation and structure
65000
solar chamber
4200
solar kang (bed)
950
thermal stored skylight with PCM 4500
solar air panel
2000
total cost
76650
unit cost (RMB/sqm)
766.5
st
* 1 Euro =8.4 RMB approximately (Exchange rate, June 1 , 2010)
6
Conclusion and discussion
Technologies applied in the case dwelling design and construction are meaningful to the rural dwelling construction in Qinghai-Tibetan plateau. Firstly, the low-cost, effective technical means with combined use of clean renewable energy and conventional energy are applied for the improvement of common family’s lives. Secondly, the cooperation mechanism between professionals, house owners as well as enterprises can help local people to know, to accept and handle the technical means when they move into the new dwellings. Consequently the new type dwelling is not only a comfortable living space, but also offers house owners the opportunity to rent out rooms to tourists. However, there are still questions to be discussed: • The prototype of this demonstration project could or could not has the adaptability to the local development with propaganda to the other parts of TAR. Further field studies will be continued and long term monitoring should not be stopped.
Figure 15 (a) Before rebuilding (photo by Li Chungang, 2008)
134
Figure 15(b) After rebuilding (photo by Zeng Yan, 2009
•
• •
How to develop a design toolkit for energy self-maintained individual dwelling with reasonable database. Can a user friendly toolkit for the pre-schematic design evaluation be developed soon? How to calculate solar gain by monitoring temperature distribution hours and temperature frequency distribution. How to monitor and collect data of solar gain by instruments or by alternative means for solar chamber.
Acknowledgement The research in this paper is funded by China National "Eleventh Five-Year" S&T plan with project number of 2006BAJ04A01, 2006BAJ04A05. Thanks to the contribution from Prof. He Jianqing, Prof. Zeng Yan and Mr. Lu Yongfei, China National Engineering Research Center for Human Settlements; Mr. Zhang Lei, Mr. Zhang Ke and Mr. Li Chungang, Beijing Alwaysone Century Physical Culture Co., Ltd; Dr. Xiao Wei, Tsinghua University.
References Bi Hua (2008) The process of New Socialist Countryside Construction in Tibet Autonomous Region—housing project.[J] China Tibetology Developing strategy research group of Chinese renewable energy. Developing research series of Chinese renewable energy — Solar energy volume, [M] China Electric Power Press, 2004 Yuanzhe, Li (1993) Passive solar house design and construction, Tsinghua University Press Zhu Qing，Liu Zhaohui, et al., (2005) Utilization of phase change material in building envelope, [N] China Construction Zongwei. Xu (2004), Guideline of Traditional Architecture in Tibetan Autonomous Region, [M] China Architecture & Building Press 135
Planning 0-Energy Cities Using Local Energy Sources Wouter Leduc
28)
Abstract The world is urbanizing rapidly and the demand for urban resources is increasing. Cities depend heavily on foreign fossil energy sources. Incoming resources are used inefficiently only part of the energy input is used and the rest is wasted. To reduce dependency and increase self-sufficiency, cities must search for local and renewable energy sources. Cities are a reservoir of untapped energy sources. Cities can support themselves to achieve 0energy status and to become independent. Cities have unused space available to capture incoming energy. Although several technologies are available, they are not widely implemented. Therefore, further effort should focus on planning and implementing these technologies. In addition, urban planning should support resources management. The proposed method, based on the Urban Harvest concept and exergy principle, towards planning 0-energy cities, consists of five steps. It gives an overview of urban energy demand and potential supply, and describes how supply and demand can be coupled effectively.
1
Introduction
For centuries, cities have been seen as both consumers and waste producers, but not as having their own resource potential. Cities depend heavily on external inputs and have next to no connections with the location of their sources. Evidence of this lies in their ecological footprints: cities largely overshoot their bio-capacities (Doughty and Hammond, 2004). Resources come in and waste goes out. Steel (2008) illustrates the concept of a “hungry city” and links it to what may be termed a fossil fuel-focused energy system. Accelerating urbanization, increasing scarcity of resources and climate change are all pressing us to manage and design our cities sustainably, moving towards closing cycles, minimization of impacts and strategic management of resources. In research already conducted, Leduc and
28) RiBuilT, Research Institute Built Environment of Tomorrow, Hogeschool Zuyd Heerlen, and Landscape Architecture Chairgroup, Wageningen University and Research Centre. [email protected]
137
Rovers (2008) and Agudelo et al. (2009) have argued that cities offer ample possibilities to harvest local resources and thus become less dependent. Therefore, interaction between urban planning and resource management is crucial. This paper proposes a method based on the Urban Harvest concept and exergy principle to overhaul urban energy planning in order to achieve 0-energy cities. The 5-step method, tested on Kerkrade-West (Southern Netherlands), gives an overview of urban energy demand and potential supply, and describes how to couple supply and demand effectively.
2
Theoretical background
Urban Metabolism The concept of urban metabolism provides a holistic framework for analyzing a city’s input– output relationships with its surrounding biophysical environment. Cities are seen as organisms, “using the metaphor of biological metabolism, i.e. the chemical process within an organism involving intake of resources, their transformation into more or less complex forms, and the subsequent excretion of wastes” to describe urban processes (McDonald and Patterson, 2007, p.180). In recent decades, “urban metabolism has been used as a framework for providing valuable information about energy efficiency, material cycling, waste management and infrastructure in urban systems” (Kennedy et al., 2007). Urban metabolism is a way to quantify the overall flux of resources in a specific region or city. Nowadays cities show linear metabolism: non-renewable resources are imported, inefficiently captured and transformed, and used. After use, waste is exported and valuable resources lost (fig. 1a). In order to move towards 0-energy cities, cities must evolve to circular metabolism – closed-cycle resource management (Rovers, 2008). Circular metabolism implies that incoming, renewable resources are captured and transformed for efficient and effective use within the city, and waste is minimized by applying recycling and cascading (fig. 1b).To close cycles, function and resource flows within the built environment should be optimized.
Urban Harvest, sustainable resource management and urban planning The Urban Harvest (UH) concept, based on the urban metabolism concept (fig.1b), developed as a strategy to investigate all possible options for harvesting local resources and (re)using emissions and wastes within the city. UH deals with capturing any renewable primary and secondary resource within an urban system and its aims for (re-)use, and is thus closed-cycle resource management (Rovers, 2007, 2008). One major principle underlying UH is exergy. Exergy, or quality of energy, refers to the second law of thermodynamics (Wall, 1977; Dincer and Rosen, 2005). By way of example we may take a ‘waste’-flow: an outgoing flow which remains after activity completion. In an open system, remaining qualities will be wasted. In a closed-cycle approach, this outgoing flow is not seen as waste but as flow with lower quality. Flows with lower quality can be useful to perform an activity requiring lower quality, and cities can be seen as reservoirs of both renewable and residual un-used energy qualities, or exergy.
138
Harvesting of water, wind and energy
Non-renewable energy, water, materials
Emissions to soil, water and air
Reused and recycled waste materials, gases and liquids
b. Urban Harvest a.
Sources-and-sinks
Figure. 1 Linear vs. circular urban metabolism (Agudelo-Vera et al., forthcoming)
However, in order to harvest and convert local resources within a city, we need to know when and where resources are available (Leduc et al., 2009). If resources with remaining un-used qualities are not available at the right time and place, or cannot be converted or stored, they are lost. Four parameters: quantity, quality, location and time characteristics, link the field of resource management to urban planning. Integrating these four parameters in urban planning is necessary if we are to achieve 0-energy cities. Urban planning must include urban circular metabolism objectives, and should also explore infrastructure patterns and networks. Cities could exploit their mixture of urban functions and structures, all in close proximity, by optimally exchanging residual and renewable resources (Van Kann and de Roo, 2009; Van Kann and Leduc, 2008). Infrastructure integrates the four parameters, but to use infrastructure effectively, urban planning should develop synergies between clusters of spatial functions within appropriate distances (Leduc and Van Kann, 2010).
3
Method
The UH-concept uses the Urban-Tissue as a functional unit: a quick scan visualizing urban land-use distribution, resources demand and supply potential (Leduc and Rovers, 2008 ). Urban-Tissue is a standard unit - 1 hectare - which makes identification of several urban flows possible and is a means to express typologies of built environment (Rovers, 2007). Formula 1 describes the major parameters within the UH-concept:
Urban Maximum Technical Harvest = Potential Urban Harvest x Øtech x Øurban (1)
139
Potential UH is the maximum amount of source available or collectable within the boundaries of Urban-Tissue. However, to calculate how much of this maximum potential can be captured and converted within the city – Urban Maximum Technical Harvest (Urban Max Tech Harvest) – some reduction applies: Øtech relates to technical efficiency restrictions, and Øurban relates to urban characteristics and typology restrictions (Rovers, 2007; Agudelo et al., 2009). The proposed method builds on the description of Dutch Urban Average Tissue, UrbAT-NL (see Rovers, 2007; Leduc and Rovers, 2008). The method to develop the specific urban energy tissue (see also Agudelo et al., 2009) consists of five steps (fig. 2): 1. Urban land-use distribution: Inventory of urban functions and surfaces; 2. Demand inventory: Hierarchical quality identification and quantification of urban energy use; 3. Demand minimization strategies and supply inventory: Inventory of measures to limit urban demand; hierarchical quality identification and quantification of urban energy sources, renewable and residual; calculation of technical feasibility; 4. Couple supply – demand: Try to ensure that quality of energy is as high as required for use but no higher, by using principles of multisourcing and cascading; use decision tree (fig. 3) to define if resource can be applied locally; 5. Optimize supply – demand: Apply recycling principles; identify, localize and connect clusters and install networks; optimize storage and exchange with other systems; calculation of Urban Max Tech Harvest by scenario development. The specific urban energy tissue, EN-UrbAT, is developed to support the accounting, coupling, and planning of urban energy demand and potential supply.
1. Land use distribution
Initial demand ID
2. Demand inventory
Figure 2
140
Minimization
measures Demand Inventory (Quantity, quality, location and time
3. Demand minimization strategies and supply inventory
Minimization
Supply
+
+
Demand
4. Couple supply – Demand
Application of UH-concept in cities
measures Cascade measures Recycling measures Demand Multisource 5. Optimize supplydemand
Decision tree – Existing BE
Decision point
RESOURCE potential
Urban Harvest (UH)
IN-system
Couple Supply & Demand
export to other system YES
Storage
NO
Demand
NO
Skip redevelopment; Look for other location; If location doesn’t have potential, better
YES Exergy by biodiversity
Potential (energy quality) used for other purpose
NO
Capture
YES
To location were certain quality is missing, or no local potential
Conversion Max. implementation
Fulfill other demand
Quality + Quantity
Matching? QQTP
NO
Adapt development accordingly Make optimal use of local potential
Later use
NO
Storage
NO
YES
export to other system
Time + Place OK?
YES
Cascading qualities
Fulfill ENERGY demand
Remaining re-used
UH, coupling, limit unused qualities, capture remaining, results in: Closing cycles of system Remaining not usable in-system Capture
MINIMIZE YES
Figure 3
NO Entropy
Decision tree – existing built-up area
141
Figure 4 Indication of spatial function in Kerkrade-West. The black line indicates the administrative borders of district
3
Results
The author developed the EN-UrbAT and tested the UH-concept at Kerkrade-West, a district in the Kerkrade municipality in the south of The Netherlands. Kerkrade is located in a former coal-mining region, which has shaped the characteristics of the municipality. Kerkrade-West has a surface area of about 1000 hectares with almost 16,000 inhabitants, various building densities, a mix of spatial functions, and also agricultural, forest and water areas. Kerkrade142
A
B
D
U
I
S
U
- Offices
I
M
- Shops
N
Locht - Industry
Houses
100m
Roads V
E S
Business
T
Recreation Gaia-park
S
Lake & green
Dentgenbach Cranenweyer
Spekholzerheide-business
Houses
S
A C
Agriculture
A N Business
T
Willem-Sophia Figure 5
Abstraction of land-use distribution, Urban-Tissue Kerkrade-West, in 1 ha (100 m by 100 m)
West was once an energy supplier through coal mining, but is now an energy demander and dependent on external resource supplies. The first step of the method shows urban land-use distribution with an inventory of urban functions (see figure 4 and figure 5), a quick-scan of urban land-use distribution downscaled to one hectare. Tables 1 to 3 show land-use distribution and urban function specifications. Most of the urban area in Kerkrade-West is built up with houses, business, retail, schools, etc. This is followed by a large agricultural and green area (t. 1). The specification for the total business area (t. 3) shows that most surfaces are for warehouses, with some heavy industry and large-scale shops. In the Spekholzerheide business park there is: machinery industry, medical appliances production industry, chemical film production industry and brick producing industry. In Dentgenbach business park there is: an aluminum smelter, a large bakery, four chemical industries producing synthetic fibers and pharmaceutical products, two paper/cardboard industries, two synthetic material processing industries, and rubber processing industry. 143
Table 1: Land-use distribution, statistical data, ha (CBS 2003, 2008)
Total 1006
Land 987
Water Urban Semi built-up** 100
Built-up* 426
Recreation 120
Non-urban (agri & forest)
traffic 61
19
279
*: area for houses, business, retail, hotels & restaurants, education, care **: mainly vacant land and wreck storage Table 2: Number of houses, total and specified, and estimated surfaces with other urban functions (Municipality Kerkrade, 2003; CBS 2008)
Houses, total number 7215
Detached 866 Surfaces, ha 3.2 14.0 3.0
Schools Care Hotel & catering industry Retail Offices
Semi-detached 1443
Row 3968
Apartments 938
13.0 4.0
Table 3: Estimated business area specification, in ha (Parkstad Limburg, 2003)
Business area De Locht Rodaboulevard* Spekholzerheide+ Willem-Sophia** Dentgenbach
Offices
1.1
Large-scale Shopping 11.3 1.9
Hotel & catering industry
Warehouses
Industry
11.3 0.6 25.4 23.2 85.3
8.2 25.1
*: soccer stadium is in this area, total area (stadium + parking) is 9 ha +: also waste collection point and storage, 8.5 ha **: also quarry, 9.9 ha Table 4: Energy demand quantities of several energy qualities for studied urban functions per year
Function Houses Schools Care Hotel & Catering industry Retail Offices
Elec, MWh 24,300 880 760 3700 15,000 520
Public lighting
670
Business area
435,000
Transport fuel, liter
144
17,000,000
Heat/gas, GJ 481,000 11,250 6800 26,500 54,000 1100 2,072,000
Other fuel, GJ
3300
The second step is the inventory of current urban energy demand, categorized according to type of energy demand - quality, and amount of energy demand - quantity. Table 4 shows the results for four energy qualities studied: electricity, heat, other fuel and transport fuel. Business areas account for the largest demand for different specified energy qualities, and heavy industry accounts for the largest contribution. Furthermore, houses represent a substantial energy demand, as does retail within the district. Another large consumer is transport and traffic. Table 5 shows the specification for industrial heat demand and possible sources. In this case temperature indicates quality, with higher temperatures denoting higher quality. The third step constitutes an inventory of measures to cap urban energy demand, and to identify the quality and quantity of available urban energy sources. Firstly, urban demand can be limited by improving process efficiency or adjusting the performance of processes. See table 6 for an overview of possibilities for two studied scenarios (see also step 5): Scenario-moderate (Sc-mod) and Scenario-max (Sc-max). Secondly, the author studied the potentials of local renewable and residual resources: solar and wind energy; road potential; biogas and hydrogen; hydropower; and biofuel production, from algae. Table 7 and figure 6 give an overview of maximum technical feasible amounts according to energy quality and quantity.
WIND SCENARIOS Existing Power = 5 MW Potential Extra Power = 77,5 MW
11 km km
2
New: 1 WT = 2,5 MW
Existing: 1 WT = 2,5 MW
New, in existing business area 1 WT = 1,5 MW
2
0,5 km2
Figure 6
2 km 11km
Proposal for wind turbine location
145
Table 5: Heat demanded, differing temperatures and possible urban sources
Industry
Demanded temp., ºC
Brick production Aluminum smelter Synthetic materials
1200 600-700 95-240
Source
Delivered temp., ºC
Biogas, hydrogen Steam industry Cooling-water industry
600-1800 100-300 40-100
Table 6: Estimated reduction potential, fossil, for studied efficiency, and function change measures
Measures, changes
Electricity, MWh
Heat, GJ
Other, GJ
Transport fuel, l
Passive house standard a
Sc-mod
1800
157,000
Sc-max
3600
314,000
Adjustments b business area
Sc-mod
5000
20,000
Sc-max
180,000
410,000
Transport + mobility c
Sc-mod
-9150*
8,500,000
Sc-max
-18,300*
17,000,000
Public lighting Full-service e laundry shop
d
Sc-mod
330
Sc-max
330
Sc-mod
700
Sc-max
1400
3300
a
: passive house standard applied on existing housing stock, not full passive standard reachable; Sc-mod: 50 % of houses, Sc-max: 100 % of houses;
b
: see t. 3 for specification; Sc-mod: 50 % of shopping and office area is virtual, resulting in 30 % lower energy demand; Sc-max: IDEM Sc-mod + changes in heavy industry (some remain, some deleted and changed to warehouse, new industry Æ only when renewable energy and materials)
c
: split into cars, vans, trucks; small distances (>5 km): no motor transport allowed, car sharing (12 %), car and van kilometers electric, truck kilometers: 50 % electric, 50 % biofuel (see t.6); Sc-mod: 50 % electric and biofuel potential applied, Sc-max: full electric and biofuel potential applied; d
: use of more efficient materials and less lights, maximum reduction of 50 %; already for Scmod;
e
: replace 10 individual household laundry machines/dryers with 1 full-service laundry shop (larger laundry machines/dryers); Sc-mod: applied for 25 % of houses, Sc-max: applied for 50 % of houses; *: additional electricity demand due to changes to electric mobility and transport
146
In step 4, the decision tree (fig. 3) is used to couple available potential, via multi-sourcing and cascading, with local energy demand. This decision tree indicates crucial decision points. To fulfill a certain demand there should be a local potential, such as incoming sun, and an energy demand. If there is not, the potential can be captured and stored for later use, or exported for use in another system. If there is resource potential it is possible to capture and convert the harvest potential and couple the received quality and quantity with demand, of the same value, at a given place and time. Furthermore, we may also try to cap the use of higher-valued sources for lower-valued demand. For example, PV-cells can be used to capture sun and either have it converted to electricity for direct use or fed into the grid and stored for later use. When demand is fulfilled we collect the remaining quality and cascade it within the system, curtailing the waste of un-used qualities, for instance, use outgoing, heated ventilation air to pre-heat incoming ventilation air, thereby lowering the demand for heat energy. The remaining quality energy should be captured if it cannot be re-used in the system and exported to another system where it can be useful. Wasting (no-capture) should be minimized so as to keep quality loss down. In step 5 the author used two scenarios: Sc-mod and Sc-max (step 3, t. 6-7) to calculate the Urban Max Tech Harvest of Kerkrade-West. These scenarios are used to link the quality and quantity of energy demanded to the potential energy supply. Figures 7a-c show the scenario-results, where the vertical dimension represents demand (downwards) and supply (upwards). Table 8 gives an overview of demand vs. supply. By using the decision tree, based on the exergy principle, remaining qualities are captured and converted to be re-used, for instance capturing heat from industrial exhaust air and delivering it to the heat network to supply other industries or other urban functions. In order to apply cascading, recycling optimally, and thus to use remaining qualities, it is important to localize clusters and identify missing links, and also to connect these. For instance, we may cluster several industrial facilities to one system or even expand the system to other urban functions close by such as houses, shops, offices, greenhouses. Another possibility is to offer potential for a specific new industry or function to fill in gap, such as industry that functions on lower temperature heat or greenhouses that need CO2 and heat.
147
Table 7: Estimated renewable potential, energy qualities and quantities Technology/application PV on roofs, vacant land, floating, railway cover a Solar boilers on house roofs
b
Electricity
Heat
Transport fuel
MWh
GJ
l
Sc-mod
134,000
Sc-max
223,000
Sc-mod
126,000
Sc-max Wind turbines on vacant, low density land
c
Heat-producing road technology d Hydropower, outlet lake
e
252,000
Sc-mod
171,000
Sc-max
405,000
Sc-mod
80,400
Sc-max
165,500
Sc-mod
200
Sc-max
200
Biogas from green household waste and f black water
Sc-mod
Hydrogen production via electrolysis (wind turbines) g
Sc-mod
Not included
Sc-max
1,500,000
Biofuel production, algae ponds
h
15,000
Sc-max
27,300
Sc-mod
1,020,000
Sc-max
2,040,000
a
2
: estimated industrial building roof area = 41.6 ha, house roofs = 15 ha (25 m /house) + 1.9 ha (20 m2/apartments), PV-field on vacant industrial land = 11 ha, stadium roof = 2.2 ha, floating on lake = 6 rd ha, railway cover: railway area = 15 ha, assumed 2/3 available; Sc-mod: PV-efficiency = 15 % (for NL = 150 kWh/m2), Sc-max: PV-efficiency = 25 %; b
2
: estimated surface per house = 3 m = 35 GJ heat/house; 500 houses already equipped with solar boiler; Sc-mod: half of remaining houses get solar boiler (yield of existing added); Sc-max: all of remaining houses get solar boiler (yield of existing added);
c
: 2 wind turbines (WT) of 2.5 MW each already existing, added 5 WT of 1.5 MW & 28 WT of 2.5 MW 3 (see fig. 5); formula: Eyear = b*V *A (b = measure for total returns, NL average = 3.7); Sc-mod: average wind speed = 6 m/s; Sc-max: wind speed = 8 m/s; d
rd
: see de Bondt and Jansen, 2004; total road area = 37 ha; Sc-mod: 1/3 of road available for heat rd production; Sc-max: 2/3 of road (25ha) available, incomplete surface due to fewer future asphalt roads; e
3
: rainwater run-off to lake to increase discharge; 1,400,000 m rain; exchange rate: water discharge of 1 m3/s = 35 kW power Æ 100 MWh produced; doubled by adding treated grey water run-off from houses; Sc-mod & Sc-max: max. potential; f
: local collection of green household waste and black water from houses and local conversion into biogas (added to grid); Sc-mod: half of potential possible; Sc-max: full potential reached; g
: hydrogen production via electrolysis, extra electricity delivered by WT (included in WT-estimations); Sc-max: 1 MJ = 1/12 m3 H2, 1 m3 H2 demands 2.5 kWh electricity (and 0.5 l water), improved process (normally 5 kWh and 1 l); h : for trucks assuming that 50 % of fuel (or km) can be electric, remaining 50 % must be produced via 2
biofuel; assumed BTU for diesel: 36,500 BTU/l; assumed algae production: 1 m algae pond produces 5,000,000 BTU; Sc-mod: 50 % of remaining truck fuel via algae; Sc-max: 100 % of remaining truck fuel via algae.
148
Business Gaia Stadium
Lake + green
Houses
2 4
3
Agriculture 1
Vacant
Roads
Business
Figure 6a Electricity demand (left) and supply, sc-mod (middle) & sc-max (right); business area demand in 1 bar, houses represents all other demand; houses 1 is reduction due to passive house, full-service laundry and public lighting changes; houses 2 is PV-option; wind turbines on vacant land (3); 4, represents business area function changes.
2 1
4 3 5
Figure 6b Heat demand (left) and supply, sc-mod (middle) & sc-max (right); business area demand in 1 bar, houses represents all other demand; houses 1 is reduction due to passive house standard; houses 2 is solar boiler option; road heat potential (3); 4, represents business area function changes; hydrogen produced with wind turbines (5)
1
2
Figure 6C Fuel demand (left) and supply, sc-mod (1) & sc-max (2); road represents demand; agricultural area represents biofuel production
149
Table 8: Overview of demand and potential supply, Sc-max, for Kerkrade-West
Demand
Type/measure
Base
Total
Elec, MWh
Heat, GJ
480.800
Other fuel, GJ
2.652.000
Transport fuel, l
3300
17.000.000
Renewable energy generation Renewable potential, existing + added
PV
223.000
Solar boilers
252.000
Road technology
165.500
a
Wind turbines
405.000
Hydropower
200
Biogas Hydrogen production
27.300 -306.000
1.500.000
Further energy reduction Function change and efficiency improvement measures
Passive house standard
3600
314.000
Adjustments business area
180.000
410.000
Public lighting
330
Transport + mobility
-18.300
Full-service laundry
1400
Remaining a
: technology also generates cold, 52.000 GJ;
150
0
3300
17.000.000
0
0
0
4
Discussion and conclusion
Applying the UH-concept and exergy principle means harvesting, capturing and converting all available renewable and residual urban potential within the urban area to minimize external inputs and outputs. Results show that it is possible to supply urban energy demand with local potential by integrating quality, quantity, location and time characteristics of the energy flows. To achieve the full 0-energy option, the author proposes some major adjustments in industry. This would result in less heavy industry and could entail fewer jobs. If planners take local potentials into account, industry may change from energy-dependent to energy-neutral or even energy-producing, for example by cascading residual heat. Furthermore, a city should not only maximize energy flows but planning should also focus on where materials come from. This increased focus on local potential and characteristics will increase production, leading to more jobs. 0-energy cities can only be achieved by harvesting maximum potentials. This implies that significant adjustments and measures must be implemented, which will have an impact on the urban environment. Therefore, urban planning needs to adapt and include UH into planning, in order to facilitate capturing and harvesting the available energy potential. UH assists in coupling urban supply and demand more effectively and in achieving urban circular metabolism and thus more optimal urban systems. The proposed method shows the importance of taking an inventory of the urban landuse distribution. It further analyzes energy demand and potential supply, to couple supply and demand in an optimal way towards 0-energy cities. The decision tree is a tool to support the decision-making process, by evaluating multiple scenarios based on the local context. The encountered difficulties should be seen as challenges rather than threats. Such difficulties offer possibilities for innovative ideas. Further, including this method based on the UH-concept towards 0-energy cities in planning practice means that planners should also look outside administrative borders because synergies might well emerge just across the border. Although the author tested this method on an existing built-up area, it is also feasible to expand the method to new-to-built urban districts in which planners do not face restrictions imposed by existing conditions. This would mean that planning can directly apply the UHconcept towards 0-energy cities. In order to achieve 0-energy cities, the proposed measures maximize urban energy potential. However, if we are to obtain optimal urban systems, the focus must be broader than merely on energy. Urban planning must factor in other urban flows such as materials and water. And in order to optimize cities, urban planning should aim for an integrated urban system, focusing on harvesting all urban flows and finding a way to combine flows to achieve 0-energy, 0-material and 0-water cities. The proposed method to study urban energy demand and supply and couple them, based on UH and exergy, shows how urban planning can evolve and how optimal urban systems can be developed towards 0-energy cities.
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Acknowledgement The author is a researcher on the SREX-project, the Dutch abbreviation for Synergy between Regional Planning and Exergy (www.exergieplanning.nl), which is supported by NL Agency, a department of the Dutch Ministry of Economic Affairs. I wish to thank my colleagues Claudia Agudelo, Ferry Van Kann and Leo Gommans for their help and contributions to this final result.
References Agudelo, C., Mels, A., & Rovers, R. (2009). Urban Water Tissue: Analysing the Urban Water Harvest Potential. In A. Dobbelsteen, van den, M. Dorst, & A. Timmeren, van (Eds.), Smart Building in a Changing Climate (pp. 63- 78). Amsterdam: Techne Press. Agudelo-Vera, C.M., Leduc, W.R.W.A., Mels, A.R., & Rijnaarts, H.H.M. (Forthcoming). Harvesting urban resources towards more resilient cities. CBS, Centraal Bureau voor de Statistiek (2003). Grondgebied 2003 Wijk K-0 KerkradeWest. Voorburg, Heerlen, Kerkrade: CBS, Gemeentelijke Basisadministratie Kerkrade, Vestigingenregister Parkstad Limburg. CBS, Centraal Bureau voor de Statistiek (2008). Gemeente Op Maat 2006 – Kerkrade. Voorburg: CBS. de Bondt, A.H., & Jansen, R. (2004). Energy from asphalt - Road Energy Systems®. Scharwoude: Ooms Avenhorn Holding b.v. Dincer, I., & Rosen, M.A. (2005). ‘Thermodynamic aspects of renewables and sustainable development’, Renewable and Sustainable Energy Reviews, 9, 169-189. Doughty, M.R.C., & Hammond, G.P. (2004). ‘Sustainability and the built environment at and beyond the city scale’, Building and Environment, 39, 1223–1233. Gemeente Kerkrade (2003). Woonsituatie 2003 Wijk K-0 Kerkrade-West. Gemeente Kerkrade: Burgeronderzoek – 18-jarigen en ouder. Kennedy, C., Cuddihy, J., Engel-Yan, J. (2007). ‘The changing metabolism of cities’, Journal of Industrial Ecology, 11, 43-59. Leduc, W., & Rovers, R. (2008). Urban Tissue: the representation of the Urban Energy Potential. In: Proceedings of the 25th Conference on Passive and Low Energy Architecture: Towards Zero Energy Building. Dublin, Ireland 22-24 October 2008. Leduc, W., Agudelo, C., Rovers, R., Mels, A. (2009). Expanding the exergy concept to the urban water cycle. In: Proceedings of the 3rd International Conference on Smart and Sustainable Built Environments: Building smartly in a changing climate. Delft, The Netherlands 15-19 June 2009. Leduc, W.R.W.A., & Van Kann, F.M.G. (2010). Urban Harvesting as planning approach towards productive urban regions. In: Proceedings of the 42nd Scupad Congress: Bringing Production Back to the City. Salzburg, Austria 6-9 May 2010. McDonald, G.W., & Patterson, M.G. (2007). ‘Bridging the divide in urban sustainability: From human exemptionalism to the new ecological paradigm’, Urban ecosystems, 10, 169192. Parkstad Limburg (2003). Vestigingenregister – Bedrijfsvestigingen 2003 Wijk K-0 KerkradeWest. Heerlen: Parkstad Limburg. 152
Rovers, R. (2007). Urban Harvest and the hidden building resources. In: Proceedings of the CIB World Building Congress: Construction for Development. Cape Town, South-Africa 21-25 May 2007. Rovers, R. (2009). ‘Post Carbon - or Post crash - managing the Orbanism’, World Transport Policy and Practice, 14, 7-17. Steel, C. (2008). Hungry city: how food shapes our lives. London: Chatto & Windus. Van Kann, F.M.G., & Leduc, W.R.W.A. (2008). Synergy between Regional Planning and Energy as a Contribution to a Carbon Neutral Society: Energy Cascading as a new Principle for mixed Land-use. In: Proceedings of the 40th Scupad Congress: Planning for the Carbon Neutral World. Salzburg, Austria 15-18 May 2008. Van Kann, F.M.G., & de Roo, G. (2009). Scaling of Multi-functional Structures as a Spatial Argument for Low-Exergy Planning. In: Proceedings of the 3rd International Conference on Smart and Sustainable Built Environments: Building smartly in a changing climate. Delft, The Netherlands 15-19 June 2009. Wall, G. (1977). Exergy – a useful concept within resource accounting. Göteborg: Chalmers University of Technology, and University of Göteborg.
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Towards 0-Impact Industrial Sites a 0-impact tool Katleen De Flander Abstract The aim of the Sustainable Industrial Sites (SIS) project (INTERREG IV-A Euregio MaasRijn) is to create a clear reference frame within the Euregio and beyond for ‘sustainable’ industrial sites (see www.sustainableindustrialsites.eu). Therefore, a tool is being developed that uses 0-impact as the main structuring element. For each module of the SIS-Tool, a set of indicators measures how far a site is from target 0. The SIS-Tool is a tool with a low threshold that can be used by developers to perform a free quick scan to get a first indication of where they are, what can be improved and how they can set an ambition level to work towards.
1
Introduction
The execution of sustainable measures on a building level has increasingly become a logical step in the building process. Governments have become more engaged and supportive, information and advice is plentiful and the scale is manageable. However, at higher scale levels, be it a neighborhood, city or in this case an industrial site, the whole matter becomes more complex.
Because nearly one third of the world’s energy consumption and 36% of its carbon dioxide (CO2) emissions are attributable to manufacturing industries (Gielen Dolf et al, 2008), governments are also now focusing increasingly on industrial sites as they will need to comply with the EU 20-20-20 targets by 2020. However, one significant issue regarding the manufacturing industry (which accounts for a large proportion of industrial site occupation) is that the development and widespread use of new materials and processes is a protracted effort that is limited by capital stock turnover, norms and standards for new materials, as well as acceptance by the market. Therefore, such changes must be implemented in the coming decade if they are to have a substantial impact by 2050 (Gielen Dolf et al, 2008). Growing numbers of public and market parties 29) are talking about ‘their’ sustainable industrial sites. But what exactly is a sustainable industrial site? As for CO2-neutral or
29)
industrial site developers are either public, for instance municipalities or regional governments, or private developers
155
carbon-neutral cities, the question we must ask is: what are we talking about here? Is it a well-defined mission, or is it just marketing? (Rovers, R., Rovers V., 2008). ‘Sustainability’ is an often used and misused term. Without clear definitions and clearly set boundaries for the system concerned, such language is empty and worthless. In Flanders, a new law that includes CO2-neutrality as a requirement for receiving public subsidies for the development of a new industrial site has pushed many parties to start thinking about sustainability. Unfortunately, in this case only energy is addressed and the definition of CO2-neutrality only includes electricity. Notwithstanding, the upside is that the first step has been made and some industrial site developers, which in Belgium are often municipalities, now want to go a step further and gain a ‘green’ image. Indeed, this is how the development of the SIS-Tool started. Questions such as: How do we make a ‘sustainable’ industrial site? What can we ask from the companies that want to settle here? How far can we go without scaring businesses away?, are all in the minds of many developers aiming at an attractive green image. The last question is particularly important for municipalities and local regions as industrial sites are an important part of their local economies. However, competition between adjacent municipalities trying to attract new economic power makes them less willing to set environmental demands on sought-after business owners. Ideally, agreements over larger regions (and cross-border) would be made in order to eradicate the competition effect, although we are still far from achieving this. A further reason why it is often difficult to implement environmental measures at the industry or company level is that building owners are rarely the same as building users. Environmental measures do not yet equal a higher rental price per m2, so why would building owners make the higher initial investments if they will not feel the benefits of their actions? Although things are slowly changing, for instance with the EPB Directive on buildings’ energy performance, this is seldom a decisive factor for tenants who attribute greater value to location, size and services.
2 2.1
The SIS-Tool Objectives and 0-impact approach
The aim of the Sustainable Industrial Sites (SIS) project (INTERREG IV-A Euregio MaasRijn) is to create a clear reference frame within the Euregio and beyond for ‘sustainable’ industrial sites. Since looking at energy alone is not enough, several modules are developed to deal with the various aspects of sustainability. More about this follows later in this paper. The tool offers the possibility to measure, plan by means of setting ambition levels and draw inspiration from existing examples (Figure 1). The central approach of the SIS-Tool is not ‘to-do-a-bit-better-than-now’ but to set the clear target of 0, for energy, materials, water, mobility and so forth. 0 becomes the structuring element and everything is measured in terms of how far a site is from the 0 target.
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Figure 1: Measure - Plan - Execute cycle for continuous improvement towards a sustainable industrial site. Source: Author for SIS-project ; Graphic Design: Visuell, Aachen
2.2
Quantitative vs qualitative
A review of the factors that influence the sustainability of an industrial site immediately reveals that they can be split into two categories: measurable and unmeasurable. We have chosen to keep these two categories separate and not attempt to quantify albeit highly important social or legal aspects, for instance, as this would lead to subjectivity. The qualitative aspects have been molded into a roadmap for developers in the form of a Metroplan (Figure 2), guiding them in the consecutive phases of a site development through the different aspects of sustainability. The qualitative aspects were laid out by and according to the JERTS (Legal-Economical-Spatial-Technical-Social) management system from the MRB research group of Ghent University (Van Eetvelde G. et al). The quantitative aspects selected by the SIS-team are as follows: • Energy - developed by the Centre of Sustainable Building Flanders with input from VITO (Flemish institute for technological research), • Water - developed by Hydroscan (Leuven), • Materials building - developed by Matriciel (Louvain-la-Neuve) • Materials output - developed by the Centre of Sustainable Building Flanders with input from OVAM (Public Waste Agency of Flanders) • Mobility home-work, professional, freight - developed by ICEDD (Namur) • Biodiversity - developed by JNC-AWP International (Nivelles) These aspects form the various modules of the SIS-Tool in its pilot phase. Other modules may be added at a later date.
157
Figure 2: Roadmap for developers showing the qualitative aspects of a sustainable industrial site in the form of a Metroplan laid out by and according to the JERTS (Legal-Economical-Spatial-TechnicalSocial) management system from the MRB research group of Ghent University. Source: Author for SISproject; Graphic Design: Visuell, Aachen
2.3
Practical delimitations of the SIS-Tool
The SIS-Tool does not aim to be an all-inclusive instrument as this would take years to develop each module. Nevertheless, scientists were either hired or consulted for the development of each module. The SIS-Tool aims to be a tool with a low threshold that can be used by developers to perform a free quick scan so as to get a first indication of where they are, what could be improved and how they can set an ambition level to work towards. The tool will be programmed online generating immediate results. After deciding on where to focus their work, a more detailed analysis can be requested, for which other existing tools could be used. One major obstacle when developing indicators for industrial sites is the huge disparity in the size and nature of the sites and the companies that constitute them. It is precisely because of these great differences (ranging from harbors to SME sites), that it is difficult to calculate indicators in terms of m2, m3 or number of employees, as would be the case for housing or office buildings. 158
Figure 3: Dashboard model with the differing module meters. Source: Author for SIS-project; Graphic Design: Visuell, Aachen
2.4
Dashboard model
As mentioned above, the aspects that form the different modules of the SIS-Tool are energy, water, materials, mobility and biodiversity. Rather than adding up these modules to produce one result, they are visible alongside each other on the ‘company’ dashboard and the ‘industrial site’ dashboard (which is the sum of all of the companies and the public part of the industrial site), thereby giving a clear overview of total performance (Figure 3). This modularity means that not all modules have to be analyzed at once; one or several can be selected and they can also be spread over time. In the future, the dashboard can be extended to include new modules if desired. For each module, the SIS-Tool uses a set of indicators to measure how far the site is from target 0 at any given moment. In other words, the tool measures a distance-to-target-0 (DDT) of 25%, 50%, 75% or more. These percentage distances make up the differing ‘ambition’ levels: level 4 (=target = 0-impact), level 3 (<25% DDT), level 2 (<50% DTT), level 1 (<75% DTT) and level 0 (>75% DTT). In addition to indicating the current performance status of the industrial site, they can also be used to set an ambition level. The indicator formulas are fed by a simple quantitative question data list for each module which requires input from the companies and the site developer or administrator. Error notifications will be built in if impossible numbers are filled out in these data lists, although it is impossible to verify all answers. Should the tool be required in the future to grant subsidies or for competition purpose and so forth, a control mechanism will need to be developed. This, however, is beyond the scope of the SIS project. Since this is a modular system, the tool allows a different ambition level to be set for each module. The developer can also choose to leave some freedom of focus to the companies, for instance: level 3 for 1 module of choice and level 2 for 2 modules of choice. 159
Figure 4: Visual representation of the different ambition levels; Source: Author for SIS-project; Graphic Design: Visuell, Aachen
A ‘play mode’ is included in each module to show what happens to the level when the survey values are changed and to see how much the values have to be adapted to trigger a level increase. The reason behind this is that it is impossible to write general recommendations on how to increase the ambition level of an industrial site for a given indicator, again because of the great differences in size and character. As can be seen in figure 4, level 4 represents the 0-impact target where by harvesting and closing cycles for all in- and outputs, the system becomes closed within its system borders. Level 0 is how things often work at the present time with in- and outputs merely 160
flowing in a linear fashion through the system. Levels 1 to 3 make up the levels in between, as explained above.
2.5
Defining target 0 for each module
For each module, 0 must be defined separately. Each module has one or several indicators. The indicator value gives a score from 0-100%, which is actually the inverted value of the distance-to-target-0. (Table 1). This is best illustrated by reference to a few practical examples of how the indicators are defined: Table 1: Indicator values; Source: Author for SIS-project
level 0
level 1
level 2
level 3
Indicator value
0%
25%
50%
75%
level 4= 0-impact 100%
Distance-totarget-0
100%
75%
50%
25%
0%
Example 1: water module (Hydroscan, 2009) Indicator 1: water use This indicator assesses whether the most optimal water sources are used according to the principal that the use of tap water, surface water and above all ground water must be discouraged as much as possible. The use of rain water, rough water (water of lower quality than tap water provided by another company) and reclaimed water from an in-house water treatment installation are valued as sustainable.
For certain sanitary uses (showers, sinks, kitchen and so on), tap water is recommended for hygienic reasons. Therefore, for half of sanitary water use tap water is permitted without a negative assessment. The production of certain consumer products (food products, care products, medicines, etc.) demands the use of high quality high water. Therefore is the use of tap water, surface water or ground water allowed for the volume of fluids that stays behind in these products. ambition level 4 can be reached when no tap water, ground water or surface water (other than for manufacturing products that demand this) is used, except for a limited part for half of sanitary water use. This is the target 0-impact. ambition level 3 can be reached when less than 25% of water use (except half of sanitary water use and for manufacturing products that demand this) is from tap water, ground water or surface water; if ground water is used, this can account for no more than 10% of water use ambition level 2 can be reached when less than 50% of water use (except half of sanitary water use and for manufacturing products that demand this) is from tap water, ground water or surface water; if ground water is used, this can account for no more than 20% of water use 161
ambition level 1 can be reached when less than 75% of water use (except half of sanitary water use and for manufacturing products that demand this) is from tap water, ground water or surface water; if ground water is used, this can account for no more than 30% of water use
Example 2: mobility home-work module (developed by ICEDD, Namur) For this module at this time it is not entirely realistic to define target 0 as 0-emissions. We cannot expect all employees to cycle or walk to the industrial site. Therefore, in this case target 0 is defined as follows: 40% of employees travel on public transport 10% by soft transport (bike, on foot) 20% by car-sharing 30% by car / motorbike
(current average in Wallonia = 8.8%) (current average in Wallonia = 4.7%) (current average in Wallonia = 4.8%) (current average in Wallonia = 77.5%)
The pilot tests of the project will reveal if this definition of target 0 is extensive enough or if it needs modification. The target 0 definition can also be adjusted over time, for instance when electric cars are more common.
3
Concluding remarks
The SIS-Tool was born of a need to define a ‘Sustainable Industrial Site’. By using 0-impact as a target, it will become clear that there is often a long way to go to reach this. However, as a structuring element, target 0 makes it possible to compare, benchmark and plan for the future. The tool will give not only municipalities and other public or private industrial site developers but also governments the opportunity to take action and set quantitative restrictions, whether they be voluntary or mandatory. After programming the modules online, a first set of industrial sites will be tested with this performance tool. The outcome of these pilots will clarify if the 0-targets are defined well, where the tool needs to be adjusted and if it gives the expected result. After this pilot phase, the SIS tool will be publicly available on the website: www.sis-tool.eu and via the general SIS-project website: www.sustainableindustrialsites.eu. The tool may also provide valuable information about the companies taking part in the test. Companies can also use the tool to carry out a self-scan without participating in a complete site.
4
References
Gielen, Dolf (IEA, France) et al, 2008 ‘Reducing Industrial Energy Use and CO2 Emissions: The Role of Materials Science’, MRS Bulletin, Volume 33, April 2008, pp471-477 Hydroscan, 2009 ‘Report for SIS-Project - Module water’ (unpublished, for content see www.sis-tool.eu online after the test phase of the SIS-project)
162
Rovers, R., Rovers V., 2008 ‘0-energy or Carbon neutral? Systems and Definitions’ Discussion paper, unpublished, see www.sustainablebuilding.info SIS-Project website: www.sustainableindustrialsites.eu and future SIS-Tool website: www.sis-tool.eu Van Eetvelde G. et al, ‘Groeiboeken duurzame bedrijventerreinen’, Vanden Broele, www.dbt.ugent.be
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Urban Morphology and the Quest for Zero Carbon Cities Serge Salat
30)
and Caroline Nowacki
31)
Abstract Ever-increasing environmental constraints demand a profound change in natural resource consumption. Technical solutions now make it possible to increase a building’s energy efficiency, reducing its negative ecological effects. However, these solutions must be integrated into a more comprehensive urban planning process, steering urban forms and human behaviour towards more efficient models. Our paper reveals that zero carbon cities can emerge from in-depth analysis of spatial structures and urban forms. Research at the CSTB Urban Morphology Laboratory describes the morphology of cities using geometrical parameters, such as street lengths and building heights, to obtain indicators that tell us something about energy efficiency as well as social, architectural and economic aspects. This approach allows us to compare the performance of cities across the world in order to characterize different urban issues which could help decision-makers in choosing between different opportunities in the development of their cities.
1
Introduction
Our paper highlights the role of urban morphology in the search for zero carbon cities. Our Urban Morphology Lab proposes a model of urban development that presents the assets and defaults of different urban typologies and concludes that dense cities comprised of medium-size courtyard blocks allow the saving of at least half the energy consumption and carbon emissions that are common today. Furthermore, by using a method that links form with flow, double energy savings can be achieved. Such results can be very useful in organizing tomorrow’s cities. Our research is guided by the conviction that decision-makers and local authorities should be aware of the structural challenges they will be confronted with when tackling energy issues. To this end, we will present some key tools and illustrate them by providing the reader with various examples. 30
) Serge Salat, Director of the Urban Morphology Lab, CSTB, Paris; [email protected] ) Caroline Nowacki, Research Projects Coordinator, Urban Morphology Lab, CSTB [email protected]
31
165
2
The importance of urban morphology at an urban scale
2.1 Transportation energy and the importance of density in the energy performance of cities Density is a key factor in the energy performance of cities both through energy spent on transportation and through urban typology. Transportation energy is linked to density by a simple law. The Newman-Kenworthy curve shows that the amount of transportation energy used is an inverse function of demographic density: E=k/D. This law implies that the amount of energy spent in a metropolitan region is the squared size of the region. In other words, a metropolitan region whose span is 5 times larger than another one will tend to use 25 times more energy. An important parameter used by the lab is the urban density ratio which is the total number of built square meters divided by the entire surface of the site including public spaces and roads. In traditional European urban areas a building footprint can be as high as 65% of its site while in sprawling American cities or modernist urban areas it may be lower than 10%. In Le Corbusier’s modernist utopian city of 3 million inhabitants, much ground was left empty for the enjoyment of city parks. Sadly, in reality the space between buildings has been allocated to giant highways and turnpikes and huge parking lots. In most parts of Paris the urban density, that is the ratio between total floor space in square meters (including every storey of every building) and the square meters of the area, is around 4 to 5. In Shanghai or Guangzhou the urban density is, in fact, four times lower since the scale of the whole city allows for greater square meters of open space. Now, the level of motorization in Shanghai is extremely low (5.9%) but due to improvements in living conditions and the sprawling expansion of the city, it may in the future reach the same level as in Los Angeles (80%). On the basis of the tremendous size of the urban region alone, the transportation energy per inhabitant in Shanghai will likely be 5 to 10 times higher than in the dense cores of European cities. Already an 8 to 16 fold difference in car-use energy can be observed between some dense Asian cities such as Hong Kong, Seoul, and Tokyo, and the sprawling west-coast cities of America such as Los Angeles.
Figure 1 Relationship between transport and land use. The Newman-kenworthy curve shows a strong link between demographic density and transportation energy needs
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2.2
Urban typology and density
The different levels of density are statistically associated with different urban block typologies. As explained below, urban density does not equal verticality. In fact modern vertical urban forms are 4 to 5 times less dense than traditional European urban blocks. The explanation is very simple. In Paris, 65% of the ground is built with 7-storey buildings. If we divide the occupied ground space by 6.5 so that it equals the 10% of occupied ground space in Pudong, we need to multiply the number of floors by 6.5 in order to get the same density, and this leads to building towers of 45 floors. We have checked these results by analyzing numerous Chinese urban fabrics. To describe the relationship between density and urban form, we will rely on the work done by Agma in Density and urban forms in the metropolis of Marseille. In this book, density is measured at the scale of the building block using the FAR (floor area ratio). Detached houses are the least dense urban form. The density of a traditional village is identical or even higher than some tower blocks, which are high but scattered. Again we see that density does not correspond to verticality. The traditional courtyard of 4 to 7 floors is the urban form with the higher density. Tower blocks are generally 4 times denser than detached houses, and traditional courtyards are 4 times denser than high rises. This means the difference in densification between detached houses and traditional courtyards is 16fold! Statistically, densities are associated with specific typologies of form. To achieve higher density, the most appropriate urban form is clearly the collection of traditional courtyards, like Haussmann’s 19th century courtyard blocks in France, and not the modernist high-rise in an open setting.
Figure 2 Six types of urban forms. From left to right: scattered detached houses (FAR=0,04); detached houses (FAR=0,25); traditional village (FAR=1,5); terraces (FAR=1 to 1.2); courtyards 4 to 7 floors high (FAR=5); slab and tower blocks (FAR=1,25). Source: "Densités et formes urbaines dans la métropole Marseillaise," Urbanism Agency of the of the City of Marseille.
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These variations on urban forms with densities rising to a factor of 16 have sizeable 32 ) consequences in energy consumption. Jean Pierre Traisnel studied the energy consumption of three typologies found in the Paris region, looking at heat and other building functions as well as travel by the inhabitants. The first typology corresponds to the centre of Paris made of dense, traditional, medium-size courtyard blocks. They date back to the 19th century and are not well insulated, yet their heating consumption is not very high because the envelope does not have many windows (which are higher thermal bridges). The second typology is a 1960s tower block with a large surface area of windows. Here the area of heat loss is greater and its location in the suburbs means less public transportation (as opposed to the higher density of transportation zones in the city centre) though an increased energy use for the everyday transportation taking people to amenity/activity zones spread out in the suburbs. The third typology is grouped pavilions built recently in a suburb of Paris, where there is very little public transportation. Though these houses have been built recently and benefit from a much higher insulation in its walls and roof compared to the two other typologies, its heating needs are basically 30% to 40% greater than insulated collective housing. The new pavilions use as much heat as the buildings of the past which are not well-insulated. The first typology allows for the creation of a dense urban fabric, with a mix of activities and good connections by public transport. This is why transportation transfers account only for 25% of the total energy consumption by their inhabitants, versus 50% for the pavilions and tower blocks. Total energy consumption for a new construction in the centre of Paris is 800 MJ/km2 per year versus 1300 MJ/km2 for a new pavilion (+60%) and more than 2000 MJ/km2 for an old pavilion. Unless by reducing individual transfers, which is not possible due to the form and organization of the suburbs, it is impossible for pavilions to be as energy efficient as courtyard blocks in the town centre: they would need to have 0 loss through the envelope. Carbon emissions due to transfers in the suburbs are 2 to 3 times higher than emissions for heating in the suburbs. Moreover they are twice as high as the emissions of the centre of Paris. The emission rate in new high-rise suburbs is 40% higher than in central Paris. When considering energy consumption for buildings only, it is 20% higher in the suburbs in comparison with Paris. This shows that new technologies cannot be the solution alone since inhabitants of very well-insulated pavilion create twice as much carbon emissions as inhabitants of a renovated old building in central Paris.
3
Toward a parameterization of the morphological factor
The second part of our article is dedicated to the presentation of the parameters and indicators associated with the morphological factors. This information should be used to create efficient urban designs. There are four main sets of morphological parameters influencing the energy efficiency of an urban area. • Building mass organization (built-up area, FAR, contiguity, building height, compactness…) • Openness to the sky (occlusivity, solar admittance) • Passive volume (i.e. the volume less than 6 meters from the envelope) • Street networks 32
Traisnel, J.P. “Habitat et développement durable,” in Les cahiers du CLIP,” April 2001, pp. 37-59
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3.1 A measurement of parameters describing the interaction of the city’s fabric with its environment By selecting various samples of urban fabric in a particular city, calculating their morphological parameters, and associating these with their respective energy consumption, it has been possible to determine the energy-efficiency of different urban textures, the most relevant parameters, and their respective impacts. Further analysis of the fabric of a city’s street network provides a measure of the connectivity and diversity of route choices in the area. Various characteristics can be calculated such as: density of streets, density of intersections, distance between intersections, and the average number of connections between two points (cyclomatic number). These results indicate an area’s degree of connectivity and accessibility, and can then be used as indicators for traffic flows and congestion, and the resultant fuel-usage and pollution effects. The results can be used to inform more energy-efficient urban development by: identifying the most/least efficient urban areas in the city and thus areas requiring high priority; assessing the urban growth potential of selected sites and identifying areas for low-impact development; assessing the energy performance of development proposals; and guiding the design of future urban developments. The benefits of such an analysis to a city’s urban planning policies and strategies are great, since the energy performance of the current design guidelines can then be evaluated, the information can assist in the calculation of a set of sustainability indicators for the city, and action can be taken to make the guidelines more ‘energy-efficient’.
Figure 3 200 x 200 meters urban sites. Kyoto low-rise areas of 2 to 5 floors have the same density as Shanghai areas of 10 to 25 floors, while Guangzhou recent developments need to multiply the building height height by 10, and to reach 30 floors to multiply only by 2,5 the density of low-rise Kyoto.
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3.2
The urban fabric in Asian, Chinese and European cities
Paris, Kyoto, and the ancient fabrics of Guangzhou and Shanghai, have very similar parametric profiles. Hong Kong is different (2 times denser than Paris in built form and 10 times higher in building height with severe problems of solar admittance, stagnation of pollutants and urban heat effects, that demonstrate the limits of high-density through very tall buildings). Some high-rise districts in Shanghai and Hong Kong with more than 45 floors, have similar or lower urban densities than 7-storey neighborhoods in the historic centre of Paris. This was predictable for geometric reasons and because of land use, but it still remains a very striking finding: very tall high-rises are in reality medium or low density despite their perception as imposing and dense. This has significant effects on the sustainability and adaptability of this type of vertical urban fabric.
3.3 Building mass and street grids: the effect of a fine urban grain (a tight collection of small buildings) versus a loosely-connected urban grid (largescale buildings in a larger setting) The street patterns of the studied cities are also very different. We have used comparative graphs to assess the efficiency of street networks. An important parameter is the cyclomatic number, the number of different paths between 2 points in a network. This number is high in Paris, Hong Kong, Kyoto, Tokyo and the ancient parts of Chinese cities, although this is divided by 15 in the new Chinese developments. The average distance between intersections is more than 3 times higher in Guangzhou CBD than in Paris, while the density of intersections is 10 times lower in Guangzhou than in Kyoto.
Figure 4 200 x 200 metres urban sites. Three very different patterns of street grids.
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A clear range of urban patterns reveals itself in this parameter. At the lower end, Kyoto and Tokyo have a very finely grained street pattern with an average distance between intersections of 50 m and very high levels of connectivity (cyclomatic numbers higher than 90 and going up to 150). The street pattern in Tokyo is organic and follows the topography, while in Kyoto the square shapes of the neighborhoods (chô) are a 1200 year-old heritage, planned in 794 when the city was called Heiankyô, and inspired by the Tang dynasty Chinese capital of Chang’an. Nevertheless the mathematical analysis of the street grid reveals the same underlying structure in both Kyoto and Tokyo, planned almost 1000 years later. Both are typical pedestrian cities in Asia, influenced by Chinese culture. The middle ground can be found in 19th century European cities, with striking similarities between Paris, Hong Kong and the centre of Melbourne, all planned by Europeans. The average distance between intersections is usually 150 m and the cyclomatic numbers range from 60 to 90. These cities were planned as pedestrian cities and provided with good public transportation. Finally, at the opposite end are contemporary Chinese developments with huge distances between intersections (between 500 m and 600 m) and very weak levels of connectivity, with cyclomatic numbers around 6 (thus 15 times weaker than in Europe). These street patterns are typical of car-oriented cities.
3.4 Traditional medium-rise and connected urban blocks are more energy efficient than isolated high-rise buildings isolated from a continuous urban tissue Our analyses have shown that for both lighting and thermal comfort energy (the parameters of compactness and passive volume) as well as for transportation energy, the compact, lowrise urban blocks of traditional European cities are more efficient than recent low density, high-rise Chinese developments by at least a factor of 4. The only reason why Chinese cities do not spend 4 times more energy than European cities is the low level of motorization in China and the relatively low level of thermal comfort. However, with an increase in motorization and in the criteria of comfort, the car-oriented large-scale and looselyconnected patterns of contemporary Chinese urban fabrics have the potential to lead to an explosion in energy demand. Therefore, improving the design of the fabric of Chinese cities and steering them in the direction of more compact transit-oriented development, is key to the future sustainability of Chinese cities.
4
Conclusion
An understanding of urban morphology has a large part to play in the achievement of zero carbon cities. Our work shows that the morphological factor can be evaluated by different parameters such as building mass organization, openness to the sky, passive volume and street networks. Relevant indicators such as compactness, solar admittance and contiguity can be used to define these key factors. This information is valuable to decision-makers and can help them to shape cities on the basis of effective and intelligent urban forms, both at fabric level and at the wider urban scale. Urban morphology proves itself to be one of the four decisive factors influencing the carbon emission of cities, alongside the widely-discussed influence of building technology, 171
energy systems, and consumer’s behavior. We believe that urban morphology should play a leading part in the quest for zero carbon cities, as urban forms are the starting point and thus greatly influence the choice of one technology over another, as well as influencing inhabitants’ behaviors. For example, a compact and high density city is likely to favor the use of a public transportation network. Defining the urban morphology allows us to explore the maximum efficiency of new technologies, for example by choosing a form that increases the building’s receptiveness to daylight. The quest for zero carbon cities should therefore take urban morphology into account to fully exploit the opportunities and energy savings needed.
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The Urban Harvest Plus approach to 0-impact on built environments, case study Kerkrade West Ronald Rovers, Herwin Sap, Wouter Leduc, Vera Rovers Gommans 34 ), Ferry van Kann 35 )
33 )
, Leo
Abstract The need to restructure our society into a sustainable society has been recognised by many. However, a clearly defined methodology to guide such an objective is usually lacking. At the Research Institute for the Built Environment of Tomorrow (RiBuilT) a proposed method has been summarised as “the Concept of O”: O for a circular approach to resource management and 0 (zero) for 0-impact on resource use, 0-energy, 0-materials, 0-water, 0-land use and 0-air pollution. This paper looks at applying this approach to existing urban environments.
1
Introduction
Cities are among the most vulnerable systems in the world. Today more then 50% of the global population live in cities and depend on provisions and supplies from distant sources. The systems have become very complex and a small change in resource supply can cause great distress in urban environments (Atkinson, 2008). In fact, cities have no back-up whatsoever to cope with the crises that may lie ahead of us. Resources of all kinds can become scarce and yet they are interdependent: if oil runs out, the shipping of food will be obstructed. If biofuels are sown and harvested, renewable materials (as an alternative to the high energy consumption of steel and cement) will be under pressure. In fact there is a direct correlation between the provision of energy, food and materials to urban areas. This will only increase when in the future, as is widely recognised, society will have to shift towards more organic and renewable resources. A sustainable city in the future “enables all its citizens to meet their own needs and to enhance their well-being without damaging the natural world or endangering the living conditions of other people, now or in the future.” (Girardet, 2000)
33) Rovers, Sap, Leduc, Rovers: Research Institute for the Built Environment of Tomorrow [RiBuilT], Zuyd University, Heerlen, the Netherlands 34) Technical University of Delft [TUD], the Netherlands 35) Rijks Universiteit Groningen [RUG], the Netherlands
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The search for a sustainable city has already generated opinions (Frey, 2004) and actions, like several climate-neutral city initiatives. In the United Kingdom and the Netherlands a formal government program is ongoing (Rovers, 2008). To evaluate the vulnerability of a city for stress in its resource provisions, the Urban Harvest method was developed (Rovers, 2007). This method calculates the viability of an urban environment: its ability to negotiate the difference between resource demand and the potential to produce its own resources within the urban system. It explores the transition from consumptive cities to productive built environments. This approach is a starting point in evaluating the potential for transition of existing urban environments, and the potential for expanding the method to see if it can also lead to the reduction of resource consumption to zero; that is to say, self-sufficiency wherein everything needed is produced within its own boundaries, leading to a closed cycle. This will reveal not only direct potential, but also additional measures needed to reduce demand, like change in functions within a system and strong reduction in demand for existing functions. The analysis is use-based, and will not only explore technological improvements, but alternative use allocations as well. For example, it’s no use improving laundry machines if a laundry shop can provide the service more effectively by reducing overall energy use and material production and raise comfort at the same time. The strategy discussed was developed partially on the basis of the findings by a research program which explores the 36 use of exergy principles in spatial planning. SREX ) is a long-term Dutch research program advancing a step-by-step strategy in analysing urban areas to create a conceptual redevelopment plan. The strategy researched here, called Urban Harvest Plus (UH+), is based on the four principles of closing resource cycles:
• • • •
close the cycle reduce the volume in the cycle reduce the speed of use of resources in the cycle limit the energy that drives the cycle
A step-by-step approach was then developed for each resource to optimise its use, and a maximisation phase was analysed to deal with conflicts such as resources claiming the same surface areas in their optimisation. Exergy analysis in the field of urban planning (SREX 2010 research) shows that in order to maintain the highest quality in a system (small or large), the use of an external source is the most profitable. However, enlarging the system size to a global scale reveals that this is attainable only through solar power since in all other cases neighbouring systems are decreased in quality. The optimisation of such an urban environment system would lead to a solar radiation based balance. Since converting solar radiation into useful resources for human application is always related to access to radiation, this has consequences in terms of square meter space. Analyses of closed cycles have shown that they can only exist infinitely if renewable resources are applied in the cycle; that is, renewable in the sense that they are re36) SREX. Research program financed by the Dutch government exploring the exergy principle in spatial planning. See http://www.exergieplanning.nl
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established or regenerated within the time of use. Also, renewable material resources are mostly organic and solar radiation based. The same is true of food, which leads to the conclusion that a system can only be optimised when solar radiation is used for all sources together: food, materials and energy. To harvest only energy from solar radiation would be a sub-optimisation and neglects the claims materials and food make on a system, since these also require access to radiation in square meters. The Urban Harvest Plus method therefore optimises an urban environment by looking into all these resources simultaneously and calculating the potential to provide them in the square meters within the area.
2
The 5 step UH+ method
The method is as follows: The premises is that an existing urban area probably consumes more than it generates within the system’s borders. The aim is to create an equal balance (zero measurement) of consumption and (possibly small scale) production. From this point on the UH+ process can be applied in five steps:
Fig. 1. The 5-step process illustrated in a flow chart
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The five steps of the UH+ process: 1. 2. 3. 4.
5.
Calculate maximum potential productivity for each resource; Explore functional changes that reduce need and demand (alternative services, dematerialisation); Apply maximum reduction measures for functions staying the same (renovation for low-energy standards, etc.); Optimise each resource separately, combining the remaining demand with potential production, for example by matching qualities (e.g. temperature cascading) and double land use, etc. This leads to an optimised plan for each resource. However, there can be overlaps in claims, which leads to the next step; Maximisation process for all resources together.
The end balance should be zero or reveal the required imports and exports still needed but that could not be solved within the system.
3
Maximisation, principles and rules
Step 5 requires some explanation. This is a crucial step. When the demand and production potential for each resource are optimised, the plans for each resource are drawn together to maximise on combining need and potential for resources. In both the optimisation of a single resource and the maximisation of combined resources, it is clear that a set of principles and rules is needed to help make choices regarding priority resources and necessary land use. The method defines a set of principles to facilitate decision making. Rules are defined as practical interpretations of the principles. In this process an initial list of both rules and principles was developed and tested. One of the most interesting findings was that in order to rank the importance of different resources, it was necessary to define priorities in the survival of humans. The basic necessities of survival, as it turns out, are the most useful principles. Following on from that, energy is the least important in that ranking (external input of energy). Securing air, water, food and material has a higher priority in times of crisis; without air we have only minutes to live, without water we have days, without food we have months, without materials we have years and (without technological) energy decades.
4
Pilot study: Kerkrade-West
The town of Kerkrade West, an area of around 7000 houses, 16,000 people and 980 hectares, was taken for this pilot study. The town includes an industrial district, a shopping mall, a recreational area, housing in a village setting and agricultural land. The actual flow of resources through the area was analysed as was the process of transferring the area’s resources into a closed cycle. This was based on the hypothesis that in 20XX fossil fuels would be abandoned and the main part of the resource flow would be produced within the area, either from primary sources such as agriculture or through secondary sources by recycling. Water would be locally harvested and treated. 176
NATURE Survival of nature/bio‐ecology is at the heart of any approach CYCLES The closing and maintenance of cycles is a basic principle Closing cycles today includes reducing the volume and speed of use of resources in the cycle, and limiting the energy driving that cycle. QUALITY A maximum exergetic performance is the benchmark Exergy, a measure for the quality of energy, also applies to mass. The combined (and sustained) quality, or minimal decrease of it, determines the best solution, with solar radiation as the only quality adding source. SYSTEMS Only systems with defined borders can take part in a CC approach; this is a basic requirement. Exchange between systems can only take place when both are evaluated according to principles 1 and 2. HUMANS Basic human needs ranked in order of importance to survival, is the guiding principle in choices regarding resource cycles. There is a preferred order in the resources necessary to humans in built‐up environments: air‐water‐food‐materials‐ (technological) energy.
This phase of research did not consider social or demographic changes in the coming decades, so the end situation involves approximately the same amount of people and needs. In an upcoming phase of the project the findings will be compared with and tested against the predicted changes in the area, exploring different scenarios and which choices might be socially acceptable or economically feasible. Changes accepted on the basis of social or economical reasons will, of course, influence the timeframe in which the region could become self-sufficient. The outcome of the research shows that the cycles can only be closed if all possible options are cultivated and there are some changes within society itself. This pertains not to the level of welfare, but involves a different social organisation. It has been shown necessary to shift to a more serviced society whereby certain functions are serviced communally rather than individually. 177
Food - scale level In terms of food production, it has been found that the scale of a small built-up area is too small to supply the current pattern of food consumption. Since food was only one of the resources in the study, the issue of scale was resolved by supplementing the study with an area the size of the province of Limburg. On this level the region can provide its own food on a vegetarian basis (so this will require a change in society). With this basis for the case study, the land currently in use for agriculture would consequently remain land reserved for food production. This reduces the remaining available space or surface area for other resources. (Recent research shows that potentially more food could be produced on a small surface area, however this has not been addressed here.)
Water The study showed that it was possible to close the water cycle within the area. This relies heavily on harvesting rainwater as a primary input for all processes, including use as drinking water. Where possible it would be put into direct usage (such as toilet flushing). To level out seasonal differences a second storage basin could be created in the urban area. The area benefits from a 40 meter altitude difference, so this could also be used to generate energy. The basin could be used as energy storage as well, to meet demand. Since the objective is 0-impact, the (rain)water leaving the area would have to be as clean as when it came in, necessitating a large array of helophyte cleaning areas. Yellow and black water can be treated and cleansed separately or jointly and used to generate biogas or for food composting and materials production.
Energy In a 0-impact situation energy would be completely based on renewables: mainly solar and wind energy, plus some hydropower, and the use of a mine water source (these are former coal mines filled up with water that has reached a useful subsurface temperature). The (strongly) reduced demand for heat however, would be met mainly by solar heat collectors and the mine water source. Since high temperatures will remain an integral part of industrial processes, a hydrogen scheme could be developed. This requires additional electricity, by wind, solar power and hydropower. All possible options would have to be exploited to meet demand, leading to an additional 28 wind turbines of 2 MW each and all roof surfaces used for photovoltaic panels (PVs). In this scenario, the demand has been significantly reduced. Buildings and houses are renovated to passive house (low energy) standards. Some uses have been adapted, for example there are no more laundry machines but laundry shops. Public lighting employs LED systems. Mobility is reduced by distant working schemes and internet shopping. Car sharing schemes are implemented and all mobility would be based on electricity (and partly hydrogen).
Materials Most crucial and space-demanding for a 0-impact scenario are the materials. All remaining square meters have to be used or cleared for the production of enough organic materials to meet yearly demand and to supply the planned renovation of the buildings. This is supplemented by 100% re-use of all other materials becoming available in the area. 178
Figure 3. The materials situation before and after transition.
Biomass as a source for energy is therefore not an option in the area because of its large land-use. New bricks can be produced from local soil, freed by land excavations, bearing in mind of course the additional need for high (brick-baking) temperatures that would be based on renewable resources and the hydrogen scheme.
Even then, a strong reduction in demand is required. There is hardly room for new construction, so new square meters will have to be found in the reduction of shops and office space and their refurbishment for new uses. Roads would be halved in the area, leaving only one-way traffic. This would open up space for new agricultural areas, reduce maintenance needs and supply a lot of secondary materials to harvest. What the study did not resolve was the need for steel, or metals in general. New research has to be carried out to see how this could be solved, possibly via new technologies (bio-based materials). Maximisation A maximisation phase was carried out after the separate resource plans were determined. Some resources claimed the same surface areas while others required more area. Passive house renovations (alterations for low-energy) require the production of additional materials. A scheme to evaluate the balance is necessary, with the principles and rules guiding the decisions on spatial claims. This leads to an even balance for all resources within the area.
Change in character Ultimately, the area would emerge with a new look, at street level as well as from an areal perspective. Hard surface areas in public space are reduced, mainly as a result of residues and the use of free space for helophytes and the cultivation of crops. Houses have new ‘passive-house-style’ architecture, with roofs adding to production potentials by PVs and glass houses. Cars in the street will have become rare due to central parking lots and car sharing. In certain districts there are regular service modules” for cleaning water, laundry 179
shops, car sharing, second-hand businesses and a lively, productive landscape all around. Every square meter has its role in a resource cycle, though can also be combined with a recreational use. The lake is partly used as an ’off-shore PV plant’ (floating panels in the lake) and soccer fields have moved to industry roofs to free up land for agriculture.
Summary of Rules ‐ Only renewable resources will be used to close cycles in a system. Non‐renewable will be depleted sooner or later (or ‘lost in dilution’) ‐ What goes into a cycle for human use, has to be regenerated within the time span of its use. In other words: renewables are only renewable if they are regenerated (replanted, re‐captured, etc.) ‐ Mass must remain mass Waste does not exist, there is only energy and mass in different forms, times and locations. ‐ Solar access ‐ square meters ‐ timeframe. This is the determining factor in comparing efficient conversions. It all comes down to land use for a specific period to produce useful resources to humans from solar radiation, whether this be drinking water, food, mass or energy. ‐ Using internal system qualities takes priority over external system qualities to meet demand. The potential to generate useful resources within a system is the crux of a closed cycle approach. ‐ Demands are to be met with the most direct and nearest available options. ‐ Since resource use is mostly related to providing services for humans, it is at the level of usage that optimisations have to be addressed. ‐ In decisions regarding physical space and time allocated to a specific resource, water takes priority over food, food takes priority over mass, mass takes priority over (technological)
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Next: Phase 2
We now have a clear picture of the (reduced) demand and the potential of an urban environment to attain a sustainable scenario in which it can cope with crises and function in a balanced way with the consumption of resources. However, stating the potential does not yet make it happen. A transition plan is required to implement measures over a period of 20 or 30 years. Models for this transition period have been researched in many books and studies (Kemp et al, 2007). In practice this means that the (clinical) resource plan has to reflect peoples wishes and needs. Only if it does so will plans be adopted and the ultimate target of 0-impact be reached. In this case study we have not dealt with an even more intriguing development: the shrinking of the region’s population. A natural initial assumption is that a shrinking population would reduce the demand for resources, and in fact create a new opportunity within the system: re-using resources from empty buildings as building parts in other projects. In this light, we hope to develop a model with a standardised approach to growth and shrinkage (or negative growth).
6
Conclusions
It is possible to increase the viability of an urban area to a level that can cope with all crises, making it “post-carbon” instead of “post-crash” (i.e. adapting voluntarily rather than by force due to system crashes) (Rovers, 2009). And it is possible to establish a truly self-sufficient area, even whilst maintaining most of the current level of welfare. Adaptations in lifestyle however are needed: transportation will change (both in type and use) and shopping and office work will change (“the city is the office”) (Harrison, 2001). People will be more involved in the area due to the development of co-ownership and jointly managed services, like energy management, water management, and other services. Roofs will change in character and ownership. It must be stated that this is still a limited research. Not all data were obtained, national averages or educated guesses had to be used in some instances, and the study did not examine goods (televisions, furniture, etc.) going through the area. This will require another study. The study did reveal that one aspect absolutely determines the potential of urban area transformations: the square meters. The principle conclusion in the Urban Harvest Plus method is that every square meter in the system area must be evaluated: whether it is the roof area, road surface, dis-used land or soccer pitch, the central question is how each and every square meter can contribute to a balanced use of resources or reduce the demand for them. In a follow-up paper within the SREX research program, how the universal value of a square meter (or the exergetic value of space) can be reappraised to create a sustainable and balanced approach to our built environment will be explored further.
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References Atkinson, Adrian. (2008) Cities after oil—3, Collapse and the fate of cities, City, Vol. 12(1) Frey, Hildebrand W. (2001) The Search for a Sustainable City, paper presented at Plea2004 Eindhoven, The Netherlands, 19-22 September 2004 Harrison, A. (2001) Accommodating the new economy: the SANE Space environment model in Journal of Corporate Real Estate Vol. 4 (3) Herbert, Girardet. (2000) Cities People, Planet, Liverpool, UK, Schumacher Lectures April 2000 Kemp R, Loorbach D, and Rotmans J. (2007) Transition Management as a Model for Managing Processes of Co-Evolution towards Sustainable Development, in International Journal of Sustainable Development & World Ecology, p78 - 91 Rovers, Vera. (2008) Carbon neutral cities in the Netherlands, Scupad conference Salzburg 2008 Rovers, Ronald. (2007) Urban Harvest, and the Hidden Building Resources, Paper CIB2007-474 –CIB 2007, www.cibworld.nl Rovers Ronald. (2009) Post Carbon - or Post crash – managing the Orbanism, in World Transport Policy & Practice, Vol. 14 (4), page 7-17 SREX : Long term research program financed by Dutch Governement, exploring the exergy principle for Spatial planning. Universities of Groningen, Delft , Wageningen and Heerlen, reports. http://www.exergieplanning.nl/
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Prefabricated timber as a means of achieving zero carbon Gavin White
37)
Abstract This paper examines the definition of zero carbon and outlines why embodied carbon should be considered as an integral part of that definition. Currently about 20% of a building’s carbon footprint is associated with embodied carbon, and the relative importance of this is to increase. By focusing on a case study of the Open Academy, Norwich, a building engineered by Ramboll UK, this paper shows that it is possible to create a zero carbon building out of cross laminated timber panels that is economical to build and architecturally appealing.
1
Why all the fuss about zero carbon?
The zero carbon issue really boils down to an attempt to halt climate change. It is widely accepted that CO2 emissions are the main contributor to climate change, whereby greenhouse gases, of which CO2 accounts for nearly 80%, absorb infrared radiation and disrupt the balance of energy flowing into and out of the earth’s atmosphere. Since 50% of the UK’s greenhouse gas emissions come from running buildings, and 10% from producing building materials, ‘zero carbon’ is a hot topic in construction. In Great Britain for example, the Government has stated that all (new) building types should be zero carbon by 2019 38). Zero carbon, in this context, is defined as solely relating to operational carbon i.e. the carbon emitted from the use of a building. Embodied carbon, that is the carbon associated with extracting and processing construction materials, is specifically excluded from the governmental aim. The reason given for this is that there is insufficient reliable data to be able to set targets in relation to embodied carbon 39). As structural engineers however, we typically only consider operational carbon when it interfaces with what we do. For example, when designing an exposed concrete soffit, an 37) Ramboll, UK 38) As set out in the Strategy for Sustainable Construction, June 2008. 39) “We do not believe a full consideration of embodied carbon is practical or realistic in the short-tomedium term. Evidence on the lifetime carbon costs of particular technologies is weak, and varies considerably depending on where and how they are manufactured.” Paragraph 3.12, Building a Greener Future: policy statement, DCLG.
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engineer should consider that it could be used to assist with night-time cooling. Otherwise, as structural engineers, our primary responsibility is in relation to embodied carbon i.e. the carbon associated with the materials we use.
2
Zero carbon – operational or embodied?
If zero carbon is defined as simply pertaining to operational carbon, then we can maintain the argument that zero carbon is achievable. However, we must not ignore the fact that about 20% of a building’s carbon footprint is associated with embodied carbon (Figure 2). 40 This is likely to rise to 40% with new legislation such as that coming into force in the UK ) , which requires a reduction in operational carbon emissions. The relative importance of embodied carbon within a building’s frame is therefore set to increase. Equally, there is an argument for reducing the carbon emitted by buildings today, rather than waiting for a carbon offset to be delivered in the future by better operational carbon efficiency. As engineers we should recognise that actual carbon savings made now have a greater impact on climate change today than savings we hope to make in the future. As sustainable engineers, we should therefore understand the concept of zero carbon as applying to both operational and embodied carbon.
3
A Zero carbon reality check
3.1
How much carbon are we really talking about?
To put the issue of embodied carbon into context, let’s consider the output of an average structural engineer at Ramboll UK. Each engineer is responsible for approximately 1,750m2 internal area of building construction each year. If these structures use steel or concrete frames, this means that each engineer is responsible for embodied carbon emissions of 41 approximately 350t of CO2 ). This is a significant figure. To put it in perspective, an 42 average person in the UK has a carbon footprint of around 10t per annum ) . In this context, the appeal of timber as a sustainable material becomes apparent. Even ignoring the sequestration of carbon (the fact that as timber grows it absorbs and stores CO2), timber has a substantially smaller carbon footprint. The same 1,750m2 of timberframed building construction would contain approximately half the embodied carbon of a steel or concrete frame. Furthermore, if we do allow for the sequestration of carbon we can argue that the same gross internal area of timber frame building stores around 650t of CO2 i.e. a net potential reduction of 300t of carbon emissions to be applied to a construction project. Therefore the
construction project, instead of being indebted by 350t of CO2, as it would be with a steel or concrete frame, starts with 300t CO2 ‘in the bank’.
40) Changes to the Building Regulations: Part L 41) Based on the Inventory of Carbon and Energy, University of Bath and Ramboll Carbon Calculator software. 42) This figure rises to 20t CO2 per annum if the carbon associated with imports is taken into account – Sustainability without the hot air – Professor MacKay.
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Figure 2 Graph showing the increasing importance of embodied carbon
4
Timber construction materials – benefits/costs
4.1
Sequestration of carbon
Timber is generally viewed as one of the best materials for sustainable construction projects. However, whilst the sequestration of CO2 cannot be denied, we do have to consider that timber will ultimately decay and the CO2 (or worse methane) will be released. That being said, as structural engineers we well know that as long as a building is looked after, it might well stand for in excess of 200 years. Furthermore, we can control to some extent how the CO2 is released. The demolished timber frame could be burnt to produce energy which would otherwise have to be generated by other carbon intensive means. In addition, with the current trend towards reclaiming materials it is feasible to foresee the reuse of construction materials, including timber. There can be a temptation therefore, to tick the sustainability box simply by proposing the use of timber in a project whether or not it is appropriate to that design element. For example, in designing a large open plan office space an engineer should assess whether timber could efficiently take the structural load. Is it good design to use double the amount of timber (vs. concrete or steel) simply to improve your sustainability credentials? Is it really better from a zero carbon perspective? Ultimately, structural engineers should not focus on simple choices such as concrete vs. timber. Instead, a more holistic approach should be adopted. Questions that should be 185
asked include, what does a building need and how hard can I make the materials work to achieve this? In essence what is the overall lowest carbon option? 43 In the UK at least, timber is also viewed as a relatively expensive material ). As engineers we must be mindful of the client’s budget, and also the fact that winning new business is often about providing an economical solution. When bidding for work there is little point in specifying timber throughout a design if it renders the package of works financially unattractive. A zero carbon design is one thing, a design that will be built is another. Ultimately, as engineers we should be looking at a ‘lowest embodied carbon’ scale, whereby, all things being equal, we specify materials in order of their sustainability credentials.
4.2
Timber is flexible
Traditionally timber frames have been associated with rectilinear buildings. Indeed, one of the principle criticisms of timber use in construction is that it limits creative options in design. However, the Open Academy case study below illustrates that with appropriate thought, timber can be as flexible in design as steel or concrete.
4.3
Prefabricated timber panels
One of the less well recognised benefits of timber use in construction is in prefabrication (figure 3). By using cross laminated timber panels, on site wastage can be dramatically reduced, with an associated cost saving for the client. This reduction in waste is significant in reducing the carbon footprint of a building as, on average, about 20% of construction materials on every new building ends up in a skip.
Figure 3
Typical cross-laminated timber panel
43) Not least because, in the absence of a local supplier, UK construction projects have suffered foreign currency fluctuations on imports of cross-laminated timber.
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Figure 4
Open Academy, Norwich, UK during Ficonstruction
5
Striving for a real zero carbon building
5.1
Case study – Open Academy, Norwich, UK
The Open Academy in Norwich, UK, is a £20m new school building. The building has three storeys and houses classrooms, a theatre and a sports hall. The total floor area is over 9,500m2, at the centre of which is a glulam tied arch roof that forms an atrium. What is special about the Open Academy is that the entire superstructure of this sizeable development is constructed out of cross-laminated timber panels. The finished development represents the UK’s largest solid timber panel building. The Open Academy illustrates that timber design (as opposed to a traditional steel or concrete frame) can be both a sustainable and financially viable proposal:
•
Carbon neutrality - The principle benefit of using timber is that it has the lowest embodied carbon of any construction material. The carbon footprint of the Open Academy, by being constructed out of cross-laminated timber, is at least half that of a comparable steel or concrete structure. Furthermore, construction of the Open Academy used some 3,500m3 of timber, which is thought to store around 3,000t of CO2. If we take account of this carbon store, the carbon footprint is not halved, indeed it is negative, thereby offsetting the building’s operational carbon for a period of 10 years 44). The building is therefore ‘carbon neutral’ for 10 years.
44) The operational energy consumption of the Open Academy is predicted to be around 30kgCO2/m2/year. Therefore, the yearly CO2 consumption of the building will be 9500 x 30 = 285tCO2/year. Equating the CO2 stored within the timber in the building to the operational energy gives 2900t CO2 / 285tCO2 per year = 10.2 years. Hence, it is possible to express the carbon stored within the structure as a period of years that the school is able to operate as a ‘carbon neutral’ school.
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Figure 5: Open Academy, Norwich circulation space
•
Air tightness – this is a key factor in the drive to reduce operational carbon because heat (i.e. carbon) escapes through gaps in the building fabric. UK Building regulations require an air tightness of 10m3/(h.m2) 45), but the Open Academy achieved 3 with the cross-laminated timber system with no additional measures to the normal fixing details.
•
Foundations – timber panel construction is a relatively light weight form of building compared to steel or concrete. This generates a carbon saving, because less material is required to support the building loads. A corollary of this will be a cost saving for the client.
•
Construction Waste – The Open Academy has shown that it is possible to have virtually no waste on site from the structural frame erection. This highly unusual situation is derived from the use of pre-fabricated timber in construction. The total waste produced during the superstructure erection phase has been less than the volume of two standard sized UK skips. Further still, this minimal timber waste has been passed to a timber merchant for recycling.
•
Programme – In construction it is well known that time is money. The use of cross-laminated timber in the superstructure for the Open Academy has halved the superstructure construction period. It was built in just 18 weeks. A time lapse presentation of the quick construction technique this framing solution allows can be seen at http://www.open-academy.org.uk/building-the-academy
45) A performance level of 10 m3/(h.m2) at 50 pascals represents a reasonable upper limit for air permeability
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Figure 6: Open Academy, Norwich – Atrium roof
The use of cross-laminated timber also virtually eliminates the need for secondary steelwork as the timber panels also form the cladding substrate for the walls. This will also reduce programme length considerably. The overall shorter programme should also reduce the operational carbon of the build itself – i.e. the CO2 emissions generated by the contractor. The timber panel system itself also enables construction firms to achieve early weather-tightness, as the panels themselves form the weather-tight structure. There is no need to add further weather-tight measures. A direct benefit of the early weather-tight date is that following trades e.g. plaster work, can start earlier in the programme than under traditional structures. These efficiency gains should translate into cost reductions due to the shorter program length. Furthermore, due to the precision cut nature of the cross-laminated timber panels (typically 1-2mm tolerance), it is also possible to pre-order the windows as the exact opening size can be guaranteed. This not only reduces the program length, it also facilitates an earlier weather-tight date. •
Scaffolding – the use of timber in design can provide benefits that a structural engineer might not immediately consider. The use of cross-laminated timber panels in the Open Academy has afforded significant cost savings by avoiding the need for scaffolding for the 3 storey building. This has been achieved by the choice of cladding system and clever integration of the edge protection to the slab with the panels before they are lifted into place.
•
Architectural creativity –The curved façade of the Open Academy was created using facetted panels and the classroom layout was optimised to make efficient use of the timber cross-laminated timber system. This shows that criticisms of restricted architectural creativity in timber buildings are unfounded. 189
Following the work on the Open Academy, and data gathered as part of the research for the Open Academy design, a Ramboll team has created a Carbon Calculator that enables us to estimate the embodied carbon figures for different designs. By considering structural capacities of different materials we can then compare the embodied carbon of different building layouts and frame types. We can then advise clients of the carbon impact of different solutions, including timber frames.
Figure 7
Extract from the Carbon Calculator
6
Conclusion
This paper shows that it is possible to create a zero carbon building out of cross laminated timber panels, which is economical to build and architecturally appealing. Cross laminated timber panels can be used in large scale structural engineering projects to provide the following benefits; carbon neutrality, reduced construction waste, minimal strip foundations and programme savings whilst still delivering the building that the client requires.
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Photo Catalytic Degradation as a Tool for the Reduction of Ambient Air Pollution Cyriel Mentink, Toon Peters, Paul Donners, Jan Theelen, Wouter Snippe, Martijn Janssen, Jacob Pijnenburg, Paul Borm 46) Abstract Air pollution is a major problem in most large cities all over the world. Reducing the amount of pollutants is one approach to reduce exposure due to local imissions. The purpose of this study was to test the efficacy of the Smartscreen™ –a porous sound screen coated with a photo catalytic coating- for its potential to reduce particulate matter and NOx in a laboratory environment. Pollutant levels were monitored at the start and end of a tunnel equipped with and without the SmartScreen™. A 30% reduction could be seen in the amount of particulate matter (PM10 and PM2.5) but only a slight decrease was observed in NOx levels. However, most of these results on particle levels could be ascribed to changes in air velocity and direction.
1
Introduction
Most cities in industrialized countries have to cope with poor air quality due to increased traffic burden. Major airborne pollutants like particulate matter, ozone and NOx have an enormous impact on quality of life, morbidity and mortality of the population of these cities. Removing or reducing the source of these pollutants, mostly traffic, is the most efficient method in reducing these negative health effects but this is not always feasible or desirable. Reducing the amount of pollutants is a second approach to reduce exposure due to local imissions. In this respect, the Smartscreen™ was designed as an efficient and easy-to-apply tool to reduce particulate matter (PM) en NOx. The Smartscreen™ is a porous screen coated with a photo catalytic layer (TiO2) which can be fitted to most modular sound screens used today. In this way, both noise and air
46) Cyriel Mentink,Toon Peters, Martijn Janssen, Paul Born: Centre of Expertise in Life Sciences, Zuyd University, Heerlen, The Netherlands; Paul Donners: DGMR, Sittard, The Netherlands; Ballast Nedam NV, Nieuwegein, The Netherlands;Jacob Pijnenburg, Dept. of Environmental Enforcement & Monitoring, Province of Limburg, Heerlen, The Netherlands
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Figure 1. 3D impression of the Smartscreen™ (left) and detailed view of the porous mats (right)
pollution can be dealt with. This porous screen mimics the physical process which vegetation uses to filter particulate matter from the air. In recent years, many studies have been performed to investigate the mechanism of this filtration. The efficacy of this filtration depends on both biological and physical processes. Porosity of the vegetation ensures a reduction in air velocity, thereby causing coagulation of smaller particles into larger agglomerates which are deposited on the screen (Beckett, 2000a; Beckett, 2000b; Woodruff, 1954). Resuspension of deposited PM is a major problem and may also occur on the Smartscreen™. In order to reduce resuspension, the Smartscreen™ is wetted during its use (Wesseling, 2004; Nowak, 1994). TiO2 is a photo catalytic semiconductor which can react with a various number of organic and inorganic materials. Under the influence of UV light of sufficient energy, TiO2 initiates a redox reaction which can break down the NOx present in the air. Many research has been done on the general mechanism of the catalytic properties of TiO2 (Diebold, 2003; Rodriguez, 2001; Beeldens, 2006). In order to expand the working range of TiO2, TiO2 has been doped with metals and non-metals, preparing oxygen-deprived TiO2 and coupling TiO2 with narrow band-gap semiconductors. This all results in TiO2 which can function in the visible light region and thus under artificial (non-UV) light conditions (Maggos, 2007; Fujishima, 2008). In this study, the Smartscreen™ was tested in a pilot laboratory setting for its efficacy to reduce both PM and NOx.
2
Materials and methods
The porous part consisted of a varying number of polyamide mats (Enkamat 7020, Colbond, Arnhem. The Netherlands) coated with photocatalytic active TiO2 (S5-300A, Millenium Inorganic Chemicals, Rueil Malmaison, France) by dipcoating. Coating was checked by electron microscopy (JSM-840A, JEOL Europe BV, Nieuw-Vennep, The Netherlands). 192
Figure 2. Schematic representation of the pilot laboratory setting. Ventilator and exhaust inlet are situated at I. Porous parts of the Smartscreen™ are placed at H between the two revolving parts of the test rig. Upper part: top view, Lower part: side view A: 50 cm B: 90 cm
C: 160 cm D: 205 cm
E: 70 cm F: 30 cm
G: 60 cm H: 20 cm
I: 50 cm J: 20 cm
Particle size of the TiO2 was checked using a Nanosight (Nanosight LM20, Nanosight Ltd., Wiltshire, UK) and the presence of nanoparticles in the air during dipcoating was tested with a CPC counter (Condensation Particle Counter, Model 3022A, TSI GmbH, Aachen, Germany). The porous part of the Smartscreen™ was tested in a pilot laboratory setting (figure 2), consisting of a 4.1 m long tunnel, constructed of HDPE, divided in two parts in which the exhaust of a Mercedes truck type 1013 was used as input at a flow rate of 4.73 m/s at base concentrations of PM10, and PM2,5 levels of respectively 328 and 299 µg/m3. Polyamide mats were wetted to keep resuspension as low as possible. In order to ensure that enough UV light reached the porous part of the Smartscreen™, the tunnel was equipped with two quartz windows mounted with a UV lamp (Osram ultra-vitalux ,ULTRA-VITALUX 300W 230V E27 FS1, OSRAM Benelux BV, Capelle a/d Ijssel, The Netherlands). Pollutant levels were monitored at the beginning and the end of the tunnel equipped with or without a varying number of the polyamide mats at six different points. Measuring points were evenly distributed on a horizontal line at 100 cm from the mats (three before and three behind). PM levels were measured using a Grimm 1.107 (Grimm Aerosol Technik GmbH & Co. KG, Ainring, Germany), NOx levels using an online monitor (42 W Thermo Electron, Breda, The Netherlands) and air velocity and pressure were measured using a Testo 400 meter with L-pitot tube (Testo BV, Almere, The Netherlands). 193
3
Results
3.1
TiO2 coating
As can be seen from the SEM pictures (figure 3), dipcoating of the polyamide mast was successful even after rinsing with water (sample 4b). However, leaching of the TiO2 was visible in the rinsing fluid but this was not investigated any further. In this respect, NOX measurements were only performed with dry TiO2 coated mats. Coating on the mats appeared to be very brittle and it is not known how much TiO2 was lost during the measurements. Average size of the TiO2 was 60 nm and no particles were detected during the dipcoating process.
Figure 3. SEM pictures of TiO2 coated polyamide mats. Sample 1b direct after dipcoating, 2b after 15 minutes washing, 3b after 30 minutes washing and 4b after 60 minutes washing.
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3.2
Air velocity and pressure profile
The results show that inserting an object (mat) in the airstream induces a change in both the air velocity and pressure. A reduction of 2 m/s can be seen both in front and behind the mats. The effect is more pronounced for the dry mats than for the wet mats. (Figures 4 and 5 below)
3.3
PM measurements
It is shown that upon introduction of two dry mats or one wet mat a 30% reduction in PM10 and PM2.5 levels could be seen (figure 6 and 7 on next page). Introducing an extra mat did not have an additional effect on these results. No difference could be seen between PM10 and PM2.5.
3.4
NOx measurements
NOx levels showed a slight decrease after the introduction of one mat, but an increase with respect to starting levels after the introduction of extra mats. Data of NO and NO2 showed a similar pattern. (see figure 8 on next pages)
Figure 4. Air velocity and pressure profile with a varying number of dry mats
Figure 5. Air velocity and pressure with a varying number of wet mats
195
Figure 6. PM10 (left) and PM2.5 (right) levels with varying number of dry nylon mats
Figure 7. PM10 (left) and PM2.5 (right) levels with varying number of wet nylon mats
Figure 8. NOx measurements with a varying number of TiO2 coated mats
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4
Discussion
It should be emphasized that this was a pilot set-up to test the efficacy of the porous part of the Smartscreen™. Although much insight on the behavior of the test rig was obtained during the experiment, it is not a validated instrument for quantification. In order to obtain a laminar flow, the test channel should be round and according to the ISO 10780 (“Stationary source emissions- Measurement of velocity and volume flow rate of gas streams in ducts”) measurements should be performed at a point as far away as possible from an obstruction. Due to the use of quartz glass, a round channel could not be used and the desired length of the tunnel could not be reached due to practical issues. Next to this, the test rig consisted of two parts which can rotate easily, thereby changing the overall shape of the tunnel and affecting the air velocity and agglomeration of PM. A diesel engine was used as a typical source of PM and NOx but appeared to fluctuate during stationary operation. Performing all measurements simultaneously (before and behind the mat) might could resolve this problem. Dipcoating of the polyamide mats appeared to result in a functional coating but TiO2 leaching could be seen upon washing. Taken together with the brittleness of the coating, this method is not suitable for coating of larger areas. Incorporation of TiO2 within the polyamide of the mats might overcome these problems. The photo catalytic activity of TiO2 was not tested, but recent research showed that doping TiO2 with additives not only expands the working range of the coating into the visible light region but can also increase its overall activity. No nanoparticles were detected during the coating process which is vital for the health of the workers handling nanosized materials. It was clearly shown that introduction of an obstacle in the air stream induced a 30% decrease in PM10 and PM2.5 levels. This coincided with a marked change in both air speed and pressure. Changing the air speed and pressure would make the smaller particles agglomerate to larger ones which can subsequently be deposited on the screen. Extrapolation to a real-life situation using computer fluid dynamics (CFD) calculations, showed that a 10% reduction could be achieved 10 meters behind the Smartscreen™ with a diminishing effect upon increasing distance. NOx levels showed a small decrease with the introduction of one mat but an increase to almost normal levels of NOx upon introduction of multiple mats. Using a high energy UV light could induce the formation of ozone and result in the formation of NO and NO2. Together with a non-validated TiO2 coating, it is not possible to quantify the reduction of NOx levels. The Smartscreen™ appears to be an attractive solution for reducing air And the results demonstrate a tendency towards reduction of particulate matter. Extrapolation to a real-life situation with CFD calculations showed that most of the results obtained are probably due to changes in air flow and pressure. Field tests with similar solutions in the innovation platform air quality (IPL) of the Dutch government showed similar results (Innovatie Platform luchtkwaliteit, 2009) It was also shown that a traditional sound screen had a similar effect, questioning the additional effect of specialized sound screens. However, using TiO2 and porous structures in a more enclosed environment like a street canyon or a tunnel could have a more profound effect (Fujishima, 2008).
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Acknowledgements Parts of this publication were published as a contractor report as part of the IPL program.
References Beckett K.P., Freer-Smith P.H., Taylor G.(2000a). “The capture of particulate pollution by trees at five contesting urban sites”, Journal of Arboriculture 24: 209-230. Beckett K.P., Freer-Smith P.H., Taylor G.(2000b). “Effective tree species for local air quality management”, Journal of Arboriculture 26: 12-19. Beeldens A. (2006). “An Environmental Friendly Solution for Air Purification and SelfCleaning Effect – The Application of TiO2 as Photocatalyst in Concrete” (thema 11.7 “New Materials and Techniques”). Conferentie Transport Research Arena (TRA). Diebold, U. (2003). “The surface science of titanium dioxide” Surface Science Reports 48: 53-229. Fujishima A., Zhang X., Tryk D.A. (2008). “TiO2 photocatalysis and related surface phenomena” Surface Science Reports 63: 515-582. Innovatie Platform luchtkwaliteit 2009, “Invloed TiO2 coatings op de luchtkwaliteit; Eindrapport onderzoek naar de werking van TiO2 coatings op geluidsschermen ter vermindering van NO2 concentraties in de lucht langs snelwegen”, available at: www.ipluchtkwaliteit.nl/data/Eindrapport%20titaandioxide%20IPL%204a%20sept%202 009.pdf Maggos Th., Bartzis J.G., Liakou M., Gobin C. (2007). “Photocatalytic degradation of NOx gases using TiO2-containing paint: A real scale study, Journal of Hazardous materials” 146:, 668-673. Nowak, D.J. (1994). “Air pollution removal by Chicago's urban forest”, In: McPherson, E.G., Nowak, D.J., Rowntree, R.A. (eds). Chicago's Urban Forest Ecosystem: Results of the Chicago Urban Forest Climate Project. USDA Forest Service, Northeastern Forest Experiment Station. General Technical Report NE 186. Rodriguez, J.A. (2001).”Chemistry of NO2 on Oxide Surfaces: Formation of NO3 on TiO2 (110) and NO2↔O Vacancy Interactions” J. Am. Chem. Soc. 123: 9597-9605. Wesseling, J.P., Duyzer J., Tonneijck A.E.G., van Dijk C.J. (2004). “Effecten van groenelementen op NO2 en PM10 concentraties in de buitenlucht” TNO Milieu, Energie en Procesinnovatie, Apeldoorn. Woodruff, N.P. (1954). “Shelterbelts and surface barrier effects on wind velocities, evaporation, house heating, snowdrifting” Technical Bulletin 77: 5-27.
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Zero-Impact Water Use in the Built Environment M.M. Nederlof and J. Frijns
47)
Abstract Zero-impact water use in the built environment entails far more than merely saving drinking water. In this paper, the zero-impact goal is embodied in the concepts of ‘sustainability’ and ‘cradle-to-cradle’, and takes the whole urban water cycle into account. Several impacts are identified, ranging from energy consumption to waste production. In terms of sustainability, zero-impact water use implies reducing use of fossil fuels, waste production and scarce mineral spillages. Insofar as cradle-to-cradle is concerned, the targets may be more challenging: complete reuse of waste materials as a high quality source (‘waste is food’), production of renewable energy on site and development of various concepts adapted to local conditions (‘celebrate diversity’). However, the main challenge seems to be the unraveling of the biological cycle (including water) and the technological cycle (including manmade products such as heavy metals, pesticides and pharmaceuticals). Reuse of sewage sludge as a fertilizer for agriculture, for instance, has become impossible as a consequence of mixing these cycles. In the built environment the key challenge is also to connect water and energy flows. Warm water conservation measures, for example, will become an important factor in energy performance improvement in housing design and construction.
1
Introduction
In the Netherlands, as in most Western European countries, drinking water and sanitation meet very high quality standards. The quality of Dutch drinking water is regulated by the Dutch Water Act which is even more stringent than European Drinking Water Quality Standards. As a result, consumer confidence is very high. Wastewater is efficiently collected and treated in wastewater treatment plants to reduce the contaminant burden on surface water. In most cases, the receiving surface water meets the water quality criteria laid down in the European Water Framework Directive. With the exception of a few Legionella incidents, there are no longer waterborne diseases caused by contaminated drinking water.
47) KWR Watercycle Research Institute, Nieuwegein, the [email protected]
Netherlands,
www.kwrwater.nl;
199
Contaminants Minerals
Source
Drinking water
Energy Chemicals
Value for consumer
Consumption
Energy Faeces, urine Rain water
Energy, Nutrients, Contaminants
Waste water
Discharge
Energy Chemicals
Figure 1 Schematic picture of energy, contaminant, nutrient and waste streams in the urban water cycle.
Water supply companies also claim to be ‘environmentally friendly’ by minimizing energy consumption, chemical use and waste production. This paper deals with the question of whether the domestic water cycle has a (negative) impact on the environment and if so, what the possible measures are to create a zero-impact urban water cycle (see figure 1). Possible impacts of the present urban water cycle can be found in the following fields: • water use in the water cycle; • presence of contaminants; • wastewater and other waste materials; • nutrients and minerals; • distribution of contaminants; • energy use, CO2 emissions; • consumption of chemicals.
1.1
Water use
In the Netherlands, 127.5 liters of drinking water are used per person per day. This primarily goes on flushing the toilet, bathing and washing clothes (table 1). Only 2 liters are directly consumed by drinking, either directly or indirectly via cooking in water. In most cases the resulting domestic wastewater is mixed with rain water to produce a final wastewater stream of 300 l per person per day. In order to supply all citizens with enough high quality drinking water, 676 million m3 of groundwater and 490 million m3 of surface water are extracted in the Netherlands as a source to produce 1,140 million m3 of drinking water per year.
200
Applications Bath Shower Sink Toilet Washing clothes, hand Idem, machine Washing dishes, hand Idem, machine Cooking Coffee, tea, drinking Rest Total Table 1
Consumption in l per person per day 2.5 49.8 5.3 37.1 1.7 15.5 3.8 3.0 1.7 1.8 5.3 127.5
Domestic drinking water consumption (Source: Vewin, 2010)
The extraction of water as such has hardly any impact on the environment, except for those cases where groundwater tables become too low (drought in vulnerable areas). In such cases there is an imbalance between the amount of rain feeding the aquifer and the water extracted for drinking water.
1.2
Contaminants
Contaminants show up at two places in the water cycle. Firstly, drinking water sources may contain contaminants, including organic micropollutants (e.g. pesticides) and pharmaceuticals (Halling-Sørensen et al., 1998; Ter Laak et al., 2010). Secondly, numerous contaminants are added to (waste) water during consumption. In fact, water is mainly used as a carrier to dispose of contaminants. The former is not an impact of the water cycle on the environment but rather an impact of the environment on drinking water production. As a result, sophisticated technologies are needed to remove these contaminants in drinking water production. Examples are advanced oxidation and membrane filtration with energy consumption in the range of 0.3-0.5 kWh/m3 for produced drinking water. The contaminants that are added to wastewater before disposal have a negative impact on the receiving surface water quality. Limiting the discussion to manmade anthropogenic compounds alone, residues of pharmaceuticals, paint, oil, heavy metals and so forth, are disposed of to surface water. These components are partly removed by wastewater treatment plants, which are mainly designed to remove COD, N and P.
1.3
Wastewater and other waste materials
Some of the chemicals introduced or already present in the source end up as waste. A major issue is whether these waste streams can be used as a resource for other processes. Caustic soda, for instance, as a result of the softening process becomes calcium carbonate pellets that can be used in steel production. The total production of softening pellets is 66 201
kton/year (Reststoffen Unie, 2008). Due to the presence of toxic compounds, coagulation sludge must be disposed of as ‘chemical waste’. For the same reason, wastewater sludge cannot be used as a fertilizer, but is incinerated for cement production or used as fuel for energy plants. In total, 350,000 kton (after dewatering 1500 kton) of sludge is produced by wastewater treatment plants (WWTPs) in the Netherlands, of which 80% is incinerated due to strict regulations for fertilizers. As such, wastewater does not necessarily have a negative impact on the environment as long as contaminants are effectively removed. Besides toxic components, N and P are important parameters to prevent eutrophication of the surface water.
1.4
Nutrients and minerals
In fact, nutrients like N and above all P have a twofold environmental impact. Firstly, they may cause water quality problems to surface water when wastewater treatment is not sufficiently effective. An excess of nutrients leads to eutrophication of surface water (algae blooms). Secondly, nutrient resources are depleted - for instance, P originating from mines is used as fertilizer (18 kton P per year; Vergouwen, 2009) which eventually ends up in domestic wastewater (14 kton P in wastewater per year, 12 kton P per year ending up in wastewater sludge), resulting in an ongoing mining of limited resources. It has been estimated that there is only enough P available to last another one hundred years (Vergouwen, 2009).
1.5
Energy consumption
For the various steps in the water cycle, energy is required. It is needed to produce and distribute drinking water and to collect and treat wastewater. The respective amounts concerned are 570 MWh/y and 545 MWh/y + 29 Mm3/y gas. The total volumes of drinking water distributed and wastewater produced are 1,093 million m3 and 2,068 million m3 respectively. Energy consumption per m3 is equal: 0.5 kWh/m3 for both drinking water and wastewater. This results in a CO2e footprint for the water cycle of 1700 kton/year (Frijns et al., 2008). It is interesting to note that the energy required to heat water for bathing, washing machines and so forth is far more than that required for drinking water production and wastewater treatment put together (1,200 kWh/per person per year versus 62 kWh/pppy for the water cycle; Sukkar et al., 2009). It has been calculated that a 6% reduction in warm water use, or a 10% recovery of heat from domestic water would offset the total energy use of the water cycle (Frijns et al., 2009).Taking the shower as an example, it is possible to conclude that water consumption is coupled to energy consumption. Thus, a water-saving shower device is at the same time, and more importantly, an energy-saving device.
1.6
Chemical consumption
Various chemicals are used during drinking water production and wastewater treatment. Examples are: caustic soda for pellet softening, coagulants for surface water treatment, ferric chloride for P-binding in wastewater treatment and organic polymers for sludge treatment. Although their consumption as such has little direct 202
impact on the environment, the energy required to produce such chemicals might be significant. For instance, to produce caustic soda 3kWh/kg energy is required (www.eurochlor.org); assuming a hardness reduction of 1.5 mmol/l, this means an 3 extra energy consumption of 0.1 kWh/m for produced drinking water. This is five times the direct energy consumption of the softening process mainly used for pumps (Frijns et al., 2009). The energy consumption for softening is presumably offset by a 20% reduction in gas use for heating water in households.
2
Critical impacts of the present water cycle
In a nutshell, environmental impacts are often described in terms of sustainability with various tools to quantify sustainability and, more recently, in terms of cradle-tocradle. In both approaches ‘responsibility for future generations’ is taken as a starting point. 2.1
Sustainability (resources, energy and waste products)
Frequently, sustainability is further considered in terms of the three P’s: People, Planet and Profit. Limiting sustainability to the Planet aspect, if we acknowledge that alternative technical solutions should be affordable (Profit) and acceptable (People), the concept of sustainability can be made operational by defining a number of sub-criteria: energy consumption, use of non-renewable resources, waste streams and claims on space in the direct vicinity of treatment facilities. Taking sustainability literally means identifying those resources that are used in such a consumptive way that at some time in the future the water cycle will stop working because of a lack thereof. With reference to the possible impacts set out above, the following aspects are identified: • use of fossil energy (either directly or indirectly via chemical production); • chemical waste resulting from drinking water and/or wastewater treatment; • spilling of scarce minerals such as phosphorus. It was concluded in LCA(Life Cycle Analysis) studies by KWR that material use for assets has a negligible environmental impact as long as the assets have a long useful life (e.g. piping for 80 years) and provided that they are not classified as chemical waste at the end of their useful life. Claims on space such as limiting fertilizer and biocide use in an area where groundwater is extracted are not critical in the sense that they promote environmentallyfriendly agriculture.
2.2
C2C: the technological and biological cycles
Cradle-to-cradle is underpinned by three leading principles (Braungart and McDonough, 2002): a) waste is food, b) use renewable energy sources powered by the sun, and c) celebrate diversity. One criticism put forward in the cradle-to-cradle concept is that recycling in sustainability definitions is eventually ‘down cycling’ to a lower quality of the initial 203
resource. Keeping quality high is one of the main challenges in the C2C concept. An example of this would be that softening pellets are not just recycled but ‘upcycled’ to high value applications. Another important principle is the distinction between the ‘biological cycle’ and the ‘technical cycle’. Water belongs to the biological cycle; indeed, as such the hydrological cycle is very much C2C because water does not disappear (it is recycled again and again and does not lose its quality), and it is powered by the sun. The technical cycle contains manmade products using finite resources which can be made C2C by using the materials over and over. A famous example of this is the C2C chair that can be stripped down to its basic components, from which a new chair can be made. In fact, water as such is not the issue in our countries, in contrast to more arid areas (such as Southern Europe). Applying the C2C concept to the domestic water cycle, the critical impacts are: • the mixing of the biological and technical cycles, resulting in resources being lost: sludge cannot be used as a fertilizer, manmade chemicals are thrown away without reuse possibilities; • the use of non-renewable energy sources, where unlike sustainability the assumption is that energy consumption might increase as long as this energy is renewable; • lack of diversity as a result of the relatively large scale on which drinking water and wastewater treatment plants are designed, the advantage of which is generally believed to be the ‘economies of scale’ principle.
3
Technical ways to a zero-impact water cycle
3.1
Making the water cycle more sustainable
Cutting fossil fuel use The simplest way to reduce consumption of fossil fuels is to buy ‘green energy’ from an energy supply company. In the Dutch benchmark between water supply companies this option is rewarded with a positive environment score. A second step could be to reduce energy consumption as much as possible. For drinking water treatment this means optimizing water treatment steps with regard to energy consumption. In particular, advanced treatment techniques to remove organic micropollutants such as advanced oxidation methods and membrane filtration significantly increase energy consumption per m3 of produced drinking water. Another example of an energy-consuming technique is reverse osmosis for seawater desalination (about 2 kWh/m3). With regard to wastewater treatment, energy consumption can be reduced by optimizing the aeration of wastewater in aerobic wastewater treatment. Energy can even be produced by applying anaerobic processes producing methane. More importantly, energy consumption related to drinking water use in buildings could be slashed. The energy used to heat water for showering (530 kWh per person per year; Sukkar et al., 2010), for instance, could be cut by about 50% by installing a heat exchanger. With a return on investment of 2-8 years, such a device seems to be economically worthwhile.
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Reduction of chemical waste Both drinking water production and wastewater treatment inevitably result in the production of waste. In drinking water treatment, waste can be reduced by using clean sources. With surface water treatment, waste can be reduced by optimizing treatment steps such as coagulation. The choice of the coagulant (iron or aluminum) largely determines whether the resulting sludge is classified as chemical waste or not. Different types of waste are produced according to the type of technology used. Membrane filtration results in a concentrated brine stream which must be disposed of. Although this stream may be reduced by increasing the recovery of the membrane filtration installation, the salt load will remain the same. Rapid sand filtration results in (iron containing) backwash water, which can be reduced by treating the backwash water with membrane filtration. Although such reduction efforts will lessen the amount of waste, the overall energy consumption will increase.
Reduction of scarce mineral spillages While disposing of wastewater effluent to the surface water, the water cycle may in fact be closed. However, the minerals still present in the effluent are also disposed of. This applies especially to phosphorus which comes from phosphorus mines. This mineral then becomes part of our food via artificial fertilizers. Our food will be digested, resulting in feces and urine containing phosphorus. In wastewater treatment most of the COD is removed but with P this only occurs to a limited extent. New European regulations will tighten the P standard for receiving surface waters. Even when P is included in sludge, its use as a fertilizer is not permitted. There are several options for phosphorus recovery from wastewater (Vergouwen, 2009; de Graaf, 2010). The first is struvite precipitation from urine and/or blackwater after a fermentation step (which produces biogas) or recovering P from the ash after incineration (the Thermphos process). In the DESAR project (decentralized sanitation and reuse), blackwater from a vacuum toilet is first fermented to produce biogas and then P is precipitated as struvite (Vergouwen, 2009). In conventional wastewater treatment P can also be partly recovered.
3.2
Making the water cycle more C2C
Following the three main C2C principles, several measures can be taken to make the water cycle more C2C-proof.
Waste is food The primary and most challenging idea in the cradle–to-cradle concept is that no waste is produced, only resources. In principle, these resources should retain their quality so that they can be used over and over again. For drinking water treatment this would mean that coagulation sludge should be treated in such a way that the coagulant is retained. Since this is practically impossible because of chemical reactions, other types of water treatment should be preferred. One possible alternative for coagulation could be ceramic membrane filtration for which no or only a small dosage of coagulant is necessary. Alternatively, preventive measures should be taken such that no toxic compounds are present in the source and thus neither in the sludge. Although numerous incentives are being brought in to improve source water quality (European Water Framework Directive), in the coming decades toxic compounds will still be present in drinking water sources. 205
Membrane concentrate could be a useful resource by removing salts and using the remaining water. Insofar as wastewater treatment is concerned, the challenge would be to use the nutrients present in the wastewater for fertilizer. Wastewater treatment should be redesigned in such a way that a fertilizer product is produced with both an optimal nutrient ratio (N,P,C) and an absence of toxic compounds. This entails completely removing toxic compounds in wastewater treatment combined with preventive measures to avoid unnecessary spills of oil and paint, for example. One of the main challenges will be to separate organic contaminants (e.g. pharmaceuticals) from the organic waste fraction, where the question is at which point in the urban water cycle such an intervention is most efficient.
Use solar-powered renewable energy When renewable energy is used to recover scarce resources time and time again, in principle resources may be used abundantly. Brackish groundwater and sea water are in plentiful supply in many countries. The main problem is the amount of energy required to produce drinking water from these sources. One example that obeys the abundance principle is the C2C islands project (Ameland in the Netherlands and some other European islands), which aim to become independent from the mainland by producing their own renewable energy by wind and/or solar power. Wastewater itself can also be used as an energy source. The biodegradable fraction can be converted to methane in an anaerobic process. When all of the COD (chemical oxygen demand) is used from the wastewater, assuming an 80% recovery of organic matter to biogas, 9400 TJ energy could theoretically be produced. This is far more than the energy required for wastewater treatment. Wastewater treatment plants could therefore become net energy producers (Frijns et al, 2009). This idea of the ‘energy factory’ fits in very well with the C2C concept. It has been calculated that by introducing anaerobic fermentation of wastewater sludge in combination with combined heat power generation (CHP), 70% of the required electrical energy could already be produced on site (Sukkar et al, 2009).
Celebrate diversity Depending on local differences, be they cultural, determined by presence of resources or availability of financial resources, differing solutions might be optimal for each situation. In arid areas where water is a scarce resource, reuse of wastewater for drinking water might be necessary. Examples of this can be found in Singapore and Namibia. In cities near an ocean or sea, sea water desalination might be applied, provided that renewable energy is used. Decentralized systems (such as the DESAR concept) may be used to efficiently remove pharmaceuticals from urine and/or blackwater (de Graaf, 2010). Finally, perhaps we need to rethink the whole system. This means evaluating the uses of drinking water and the required quality for each different function. Naturally, we need drinking water to drink, but to flush the toilet and for many other applications such high quality is not necessary. Different sources could be used for different applications, such as rain water or brackish water for flushing the toilet. We might even consider options that need no water at all (washing clothes with CO2 or ozone, for instance).
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4
Discussion
The distinction between sustainability and cradle-to-cradle is not as clear-cut as presented in this paper; both concepts focus on the interest of future generations. Sustainability seems mainly to entail reducing energy, resources and waste streams. In the short term, while using the existing infrastructure of the water cycle, this is a good thing to do and in practice many (technical) possibilities are emerging. In the long run, however, a paradigm shift is necessary: we must rethink the system including re-evaluating functions and the required quality of water. By factoring in the C2C concept we can change our mindset to thinking in terms of possibilities rather than restrictions. It is clear that the availability and affordability of renewable energy is a critical factor in future water cycle designs. The concepts of sustainability and cradle-to-cradle can be used to define ‘zero-impact water use’ in the built environment. In the Netherlands and surrounding countries, water consumption as such is not the crux of the matter. Critical impact factors of the domestic water cycle at present are: • energy consumption, especially for water heating; • introduction of toxic compounds to wastewater; • scarce resource spillages, especially phosphorus. Fortunately, there are several technical possibilities to improve the domestic water cycle in terms of sustainability and/or cradle-to-cradle. Examples of these have been discussed in this paper. As long as renewable energy sources are not abundantly available, (renewable) energy should be used wisely.
5
Recommendations
In order to create a zero-impact water cycle, the water sector and related research institutes should work together with at least the building and energy sectors. There can be no zeroimpact water use without zero-energy buildings. The relative contribution of energy needed in houses for warm water heating is likely to increase with the Dutch policy to further cut the Energy Performance Coefficient for new houses. Houses are already being built with only 750 m3 natural gas use per year, which means that warm water now accounts for about 50% of domestic gas use. Warm water conservation measures are therefore an increasingly important factor in energy performance improvement in housing design and construction. Moreover, the urban metabolism concept facilitates the integration of different cycles (water, energy, nutrients) in the built environment. Future city planners must consider water, energy and nutrient flows together rather than separately, and will have to design with flexibility for future changes. Using the sustainability and C2C concepts, non-sustainability factors in the present water cycle can be identified and common goals could be defined. Such common goals can be built upon to come up with new concepts in the water cycle. However, much work is still required to make these new concepts a reality. In the transition phase, tools in the field from transition management may be used. Two critical aspects in further developing and implementing sustainable concepts are acceptability and affordability for the consumer. 207
Here, the other P’s: People and Profit, are essential. Finally, pilot studies and frequent evaluations will prevent the sector from taking an unrealistic, mistaken direction.
References Braungart, M. and W. McDonough (2002). Cradle to Cradle, remaking the way we make things. New York: North Point Press. Frijns, J., Mulder, M. and J. Roorda (2008). ‘Op weg naar een klimaatneutrale waterketen’, WaterKIP (Stowa and KWR), Stowa Report 2008-17. Utrecht, the Netherlands: Stowa. (in Dutch) Frijns, J., Hofman, J. and A. van Wezel (2009). ‘Water as energy carrier: climate mitigation and renewable options in the water sector’, Proceedings IWA Water & Energy Conference, 29-31 October, Copenhagen, Denmark. Graaf, M.S. de (2010). Resource Recovery from black water. Wageningen University. Halling-Sørensen, B., Nors Nielsen, S., Lanzky, P.F., Ingerslev, F., Holten Lützhøft, H.C. and S.E. Jørgensen (1998). ‘Occurrence, fate and effects of pharmaceutical substances in the Environment – A review’, Chemosphere 36:2, pp357-393. Pamminger, F. and S. Kenway (2008). ‘Urban Metabolism, improving the sustainability of urban water systems’, Journal of the Australian Water Association, 2008, p45-46. Sukkar, R., Kluck, J., Blom, J. and J. Averesch (2009). ‘Mastercase energie in de waterketen’, Stowa Report 2009-46. Utrecht: Stowa, the Netherlands (in Dutch). Ter Laak, T., Van der Aa, M., Houtman, C., Stoks, P and A. Van Wezel (2010). Temporal and spatial trends of pharmaceuticals in the Rhine. Nieuwegein, the Netherlands: Association of River Waterworks, RIWA. Vergouwen, A.A. (2009). ‘Fosfaat, van leegloop naar kringloop’, Stowa Report 2009-40. Utrecht, the Netherlands: Stowa (in Dutch). Vewin (2010). Drinkwaterstatistieken, de watercyclus van bron tot kraan. Rijswijk, the Netherlands: Vewin (in Dutch). Reststoffenunie (2008). Annual Report. Nieuwegein, the Netherlands: Reststoffenunie (in Dutch).
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Tilburg: A Road Map for Becoming a Zero-Carbon City in 2045 Erik Alsema, Jappe Goud, Geurt Donze
48 )
, Martin Roders
49 )
Abstract The city of Tilburg wants to become a zero-carbon city by the year 2045. To this end, various policy options have been investigated and a road map to achieve this has been drawn up. This paper firstly discusses how the policy target of net zero carbon can be clearly defined. Among other issues, this definition concerns the choice about which options for CO2 mitigation will or will not be allowed. Secondly, scenarios have been developed for achieving a net zero-carbon building stock for the three housing associations in Tilburg. Starting from a full assessment of the present CO2 emissions of the building stock, these scenarios investigate the possibilities to improve the existing housing stock, taking into account autonomous portfolio developments as well as intensified improvement programmes. Furthermore, the contributions from new-built low-energy houses are considered as well as the potential for generating renewable energy on or for the total housing stock. This approach shows that it is possible to bring about net zero carbon for housing. Lastly, a list of key action points are provided for cities that wish to devise a zerocarbon action plan.
1
Introduction
The city of Tilburg and its Social Housing Organizations (SHO) take climate change seriously. It is for this reason that the municipality has drawn up a declaration which was signed by the four SHOs of Tilburg in addition to more than 40 other local businesses at the beginning of 2009. The goal of the declaration is to become a zero-carbon or climate-neutral city by the year 2045. Although this target is still several decades away, action needs to be taken now in order to achieve it. The assignment of the declaration ties in closely with the energy-saving policies of the SHOs, which in 2002 joined forces on this issue, regarding three consecutive ‘energy covenants’. During the recent covenant (2006-2010) the SHOs mapped the energy performance of the existing building stock. All dwellings were given an energy label. A logical phase after 48) W/E Consultants Sustainable Building, Utrecht, the Netherlands 49) Tilburgse Woonstichting, Tilburg, the Netherlands
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this inventory is to create a long-term perspective for adapting the building stock. The climate declaration came just in time to provide the overall goal for such a long-term plan. However, the main question for the SHOs was whether it is possible to achieve zero-carbon in their buildings by 2045. Therefore, the Tilburg SHOs together with the municipality of Tilburg commissioned W/E Consultants to investigate this and to devise a road map to achieve the goal of zero-carbon building stock. The road map produced by W/E showed that this target can indeed be attained. The year 2010, which is the last year of the third energy treaty, will be used to explore the possibilities of establishing a fourth covenant, in which SHOs and the municipality agree on what concrete measures will be taken to make their building stock zero-carbon. The guidelines provided by the zero-carbon road map will serve as the foundation for the agreement.
2
Project definition
In this paper we consider two questions concerning zero-carbon planning. We shall focus here on carbon emissions from the housing stock owned by the three housing associations in Tilburg. The first issue concerns precisely defining the zero-carbon target: what are the system boundaries and what exact means will be allowed in order to accomplish this target. For example, should all emission reductions be made within the city borders or can reductions also be ‘imported’ from outside the city? This discussion should result in an unambiguous and transparent definition of the local policy target for 2045. The second question we address is how the housing stock in Tilburg can make the transition towards zero carbon. How much can or should be achieved by reducing the energy demand from existing houses, what targets should be set for the energy performance of new dwellings and what role can renewable energy play in this development? Together with W/E Consultants, the three housing associations in Tilburg have drawn up a common road map to set out priorities for their own housing stock. We shall discuss the research that was conducted in designing this road map.
3
Defining the zero-carbon policy target
A recent report set out a definition framework for zero-energy and zero-carbon building projects (Alsema et al, 2009). This framework identifies three aspects of the definition, namely: 1) the goal, 2) the scope and 3) the means. Our study also includes the project boundary, which encloses the buildings themselves, and the ‘system boundary’, which encloses not only the project but also all energy conversion processes that are necessary for operating the buildings (i.e. electric power plants). As is the norm, ‘net zero carbon’ is defined as: “zero emission when summed over a full year”. It is important to note that these emissions are to be measured on the system boundary and not on the project boundary. (For a further explanation of these concepts see Alsema et al, 2009.) Although for the Tilburg case the overall goal was already set by the municipal climate plan, the specific target for the housing corporations was more detailed, in line with the 210
aforementioned framework. It was decided that the goal for 2045 would be zero carbon for the operational phase of the buildings only; that is, without considering the carbon emissions embodied in the building materials. Household energy consumption is to be included in the carbon accounting with the restriction that the housing associations could not take any final responsibility for these emissions. Not surprisingly, the scope was defined as all the housing complexes owned by the 50 associations ). Some discussion was needed to establish precisely the means that are allowed in reaching the zero-carbon target (see Table 1). It was decided that ‘external energy saving’ - that is, energy saving occurring outside the project boundary (i.e. heat supply from CHP to a district heating system), can be included in the zero carbon goal. External renewable generation, such as certified green electricity that is purchased by the associations or households, can also be accepted in the zero carbon accounting. Carbon compensation schemes, nuclear power and carbon capture, on the other hand, were not marked as allowable measures. Naturally, net zero carbon does not mean that there will also be zero impact. There are several other negative effects from buildings with regard to the environment and other matters. However, Life Cycle Assessments have shown that many environmental impacts are ultimately related to fossil energy mining and combustion (Huijbregts et al, 2006). Therefore, the quest for zero-carbon emissions will have positive effects on more environmental issues than merely climate change. Table 1: Overview of the target definition for Net Zero Carbon for the Tilburg social housing study Target: Year:
Net Zero Carbon (during operation phase) 2045
Scope:
Houses of 3 corporations in Tilburg
Means: Energy saving – Project
Yes
Energy saving– External
Yes
Renewable generation – Project
Yes
Renewable generation– External
Yes
CO2-compensation – Project
No
CO2-compensation – External
No
Nuclear – Project
No
Nuclear – External
No
CO2-capture and storage – Project
No
CO2-capture and storage – External
No
50) The office buildings owned by the associations were not included in the road map study.
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4
Road map for a zero-carbon building stock
In order to devise a road map for a zero-carbon building stock for the Tilburg housing associations (Alsema et al, 2010), we developed a new stock model which focuses on CO2 emissions and CO2 reductions. The model starts from the present composition of the building stock in terms of building age and energy performance. The latter data are based on the energy performance audits for the EPBD obligation (see Figure 3). Our model then considers developments in the building stock, taking into account yearly rates of building sales, demolition and new construction. In line with existing practice, the new construction rate is taken to be equal to the selling rate. Building improvement is also an important parameter in the model, especially as regards improvements in the building’s energy performance. Both an annual improvement rate and an improvement factor, specified as the achieved reduction in the primary energy demand of the building, may be specified for each building type (i.e. construction year and label class) and for each 10-year period until 2050. For new buildings (90 m2 gfa), the energy performance requirements from the Building Code have been considered, with the foreseen reduction towards a net zero-energy standard by 2030 and further improvements beyond that time (see Table 2). The introduction of renewable energy sources for use by the buildings and the building inhabitants was also described in this model. We distinguish between two types of renewable options which are treated differently by the model. Firstly, there are a number of renewable options like solar hot water boilers and heat pumps which cannot be easily evaluated in terms of generated energy but which are considered in our model as heat demand reduction measures; their contribution is already incorporated in the demand data of table 2. Secondly, there are options like PV, wind turbines, sustainable heat supply (for instance from biomass) and the purchase of green electricity which we have accounted separately from the buildings’ energy demand (even though some installations, like PV, will probably be placed on those buildings). The latter renewable options are expressed as CO2 emission reductions, which are finally accounted on the level of the building stock where they should offset the remaining CO2 emissions from the buildings.
Table 2: Requirements for new houses in terms of primary energy consumption (building-related only), with indicative values for the Energy Performance Coefficient and CO2 emission.
Construction period 2010-2020 2020-2030 2030-2040 2040-2050
E-consumption primary (GJ/house/yr) 18 11 9 9
EPC*
CO2 emission (kg/house/yr)
0,50 0,30 0,25 0,25
1040 630 510 510
* EPC is the Dutch Energy Performance Coefficient; EPC values are indicative only and excl. PV; because PV is not accounted here, it seems as if no “net zero energy” situation is reached for houses after 2030.
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CO emi ssi on (t on/ yr ) CO 2 emission (ton/yr) 2
30000
Present label
G
25000
F 20000
E D
15000
C
10000
B A
5000
0 1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
Const r uct i on per i od Construction period
Figure 3: Yearly greenhouse gas emissions from the building stock for the year 2009, broken down by construction period and by energy label class. Total stock comprises some 28,000 houses.
This model has been used to assess a number of scenarios for emissions development from existing and new housing stock and for renewable energy generation until 2050. Figure 4 shows the development of emissions from the buildings in what is termed the ‘Reference Scenario’, which is based on an extrapolation of existing policy targets for the Dutch social housing sector until 2020 (‘Aedes-covenant’). As is evident, the emissions from the existing housing stock, most especially those built before 1970, will continue to dominate emissions for several decades. New buildings, on the other hand, make only a relatively small contribution. The Reference Scenario also assumes modest growth of renewable sources. Figure 5 shows both the CO2 emissions from buildings and the emission reductions from the renewable options. As we can observe, the top line of the buildings’ emissions (in red) and the second solid line from the top (in green) of the emission reductions do not cross before 2050, implying that no zero-carbon situation is reached within this scenario. Yearly building-related CO2 em ission 100 90 80 New built
70
2000-2010
60
1990-2000
50
1980-1990
40
1970-1980
30
<1970
20 10 0 2010
2020
2030
2040
2050
Figure 4: Development of the GHG emission ( in kton/yr) from the building stock in the Reference Scenario, with a breakdown by construction period ("New built" = construction after 2010). Emissions from domestic energy consumption (i.e. household appliances) are not included here.
213
CO2 emission/reduction (kton/yr)
CO2-em issions and -reductions for building stock (Reference Scenario)
100 80 60 40 20 0 2010
2020
2030
2040
2050
existing buildings
existing + new buildings
w ind
w ind+PV
w ind+PV+SH
Wind+PV+SH+GrPw r
Figure 5: Development of CO2 emissions by buildings and emission reductions by renewable energy generation in the Reference Scenario (SH= Sustainable Heat supply, GrPwr = Green Power supply).
CO2 emission/reduction (kton/yr)
CO2-emissions and -reductions for building stock (Solar Scenario)
100 80 60 40 20 0 2010
2020
2030
2040
2050
existing buildings
existing + new buildings
w ind
w ind+PV
w ind+PV+SH
Wind+PV+SH+GrPw r
Figure 6: Development of CO2 emissions by buildings and emission reductions in the Solar Scenario (SH= Sustainable Heat supply, GrPwr = Green Power supply).
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CO2 emission/reduction (kton/yr)
100
CO2-em issions and -reductions for building stock (Intensive Improvement Scenario)
80 60 40 20 0 2010
2020
2030
2040
existing buildings
existing + new buildings
w ind
w ind+PV
w ind+PV+SH
Wind+PV+SH+GrPw r
2050
Figure 7: Development of CO2 emissions by buildings and emission in the Intensive Improvement Scenario (SH= Sustainable Heat supply, GrPwr = Green Power supply).
In the Solar Scenario of Figure 6, however, which assumes strong growth in renewable installations and green power purchases, a zero-carbon situation is reached around 2040, showing that the zero-carbon policy target can indeed be achieved. Our financial analyses reveal a drawback of this approach - namely that it may require three times more investment in the coming decade than the Reference Scenario. A third scenario (Figure 7), which assumes a more intensive programme of building improvement, combines a number of attractive features such as lower investments than the Solar Scenario, a faster emission reduction from buildings and the prospect of a zero-carbon situation around 2050. It is important to note here that a faster pathway of emission reduction has advantages from a climate policy perspective (i.e. lower cumulative emissions to the atmosphere), which are overlooked when focusing solely on the zero-carbon achievement for a certain year. Based on our analyses we have recommended a road map for the Tilburg housing associations which emphasizes building improvements first and brings in renewable options somewhat later. The total investment costs in the first ten years for this scenario are estimated to be less than 130 M€, with a gross return on investment of at least 4%. We have concluded that this last approach has advantages from three perspectives: for the investor, for the climate policy and for building inhabitants. 215
Conclusions This paper puts forward a new approach for cities and housing associations that want to make a transition to being net zero carbon or net zero energy. A number of steps have been set out to define the target clearly and to devise a road map in order to reach it: • Define the scope, target year and allowed means for your climate policy ambition • Assess your starting situation in terms of building types, energy performance data, CO2 emissions and renewable generation • Asses the potential for exploiting renewable energy resources within your community; • Investigate the prospects for becoming net zero carbon (or energy) by means of scenario studies for building stock development, building improvement and renewable energy exploitation; • Based on the scenario results, select the approach that best fits your ambitions, investment budgets and other building portfolio objectives; • Make this approach into a 5-year action plan which identifies key action points, budgets and targets; • Evaluate progress after five years and update your action plan for a new period. For the Tilburg case we have used this approach to demonstrate that it is realistically possible to make the transition to zero-carbon housing, and to describe which concrete steps should be taken in the short term to work towards this goal. The approach and tools that have been described allow housing associations and other real estate owners to integrate energy performance and CO2 emissions into their portfolio management strategy for the housing stock. Thus, climate policy goals can become an integral part of the overall strategic planning of the organisation. With their proactive approach, the municipality of Tilburg and the three Tilburg housing associations are leading players in the Netherlands where climate policy is concerned.
References Alsema, E.A., Hoiting, H., Roth, E. (2009) Firm Ambitions, Clear Language, A framework for establishing targets and means for climate, energy and CO2 neutral building projects (in Dutch). Utrecht: W/E Consultants commissioned by PEGO/SenterNovem. http://www.senternovem.nl/energieneutraalbouwen/publicaties/stevige_ambities_klare_ taal_definitiestudie_.asp Alsema, E.A., Goud, J., Donze, G.J., Roth, E. (2010) Road map for a net zero carbon social housing stock in Tilburg (in Dutch). Utrecht: W/E Consultants commissioned by Tiwos, TBV, WonenBreburg, and Municipality of Tilburg. Huijbregts, M.A.J. et al. (2006), Is Cumulative Fossil Energy Demand a Useful Indicator for the Environmental Performance of Products?, Environmental Science & Technology, Vol. 40, No. 3, p. 641-648.
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Afterword Where do we go from here? We have delved into many issues in this book and seen examples of successful projects and strategies, as well as gaps in knowledge and understanding of implementing 0-options in a complicated world. How do we now proceed to set this transition in motion, to provide the knowledge and insights, tools and strategies to make this work? The knowledge printed herein and presented at the conference will be evaluated and published, at the SB11 Global Conference Sustainable Building in Helsinki 2011 and elsewhere. We will continue working on this subject, both as RiBuilT and in international networks like the working groups of the iiSBE, CIB and IEA. A 2012 conference is in the planning, to focus solely on implementing 0-options in existing building and neighbourhoods. One conclusion can be drawn already: people, those with a drive, those with leadership qualities, can make an enormous difference. Mayor Peter Vadasz is one such person who has shown that it is possible if you just set a target and go for it. We have seen this before, for instance in Jaime Lerner, the former mayor of Curitiba which is now a recognised sustainable city. As he has advised repeatedly, we must simply start rather than hang around waiting for all the answers. Naturally, mistakes will be made, but if all we do is wait for the answers, nothing will happen. Some of the projects described in this book are proof of this. Let it be a lesson for us all: let us get going, learn on the job, and seek help from experts and anybody else who can give directions. Let us implement and transform our built environment into a closed loop, before it transforms us. And let us start today. The editors
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