Sustainability: Building the future today

Transcription

1 Sustainability: Building the future today By: J.A.M. Baken, General Manager Ecofys BV 1 C.A.M. Stap, Managing Director Energy in the Built Environment, Ecofys BV 1. Introduction There is little need to explain that there is a worldwide necessity for sustainable buildings. From a technological point of view we are already capable of building houses and offices with a very high-energy performance (in terms of energy efficiency, generation and usage of sustainable energy). However, current building practice shows that often we do not produce the quality we are capable of (and economical issues are not always to blame). There are many relations between the building construction and its energy supply. In this paper we will make clear that an optimal building can hardly be realized when considering the building installations as add ons instead of integral elements of the whole. To make the energy supply an holistic element of the building design requires a vision on various aspects. In this paper we discuss many ideas that may contribute to the realization of high quality sustainable buildings. Firstly we focus on the role of the authorities, who define, with their policy, the boundary conditions for sustainable building. Next we look at the stakeholders in the building process. With some examples of building projects in The Netherlands we will illustrate that the future can be built today. 2. Policy The most important goal concerning energy in the built environment is to increase the energy performance whilst complying with health and safety aspects. A high-energy performance is defined by a low usage of fossil fuels, or low CO2-emissions per unit of volume. 1 Ecofys has a clear mission: a sustainable energy supply for everyone. This is the goal that everyone in our company believes in and strives for. In a company that is a leader in renewable energy and energy efficiency, knowledge and innovation are key elements in turning the ideas of today into the viable solutions of tomorrow. An experienced market leader Established in 1984, Ecofys specialises in energy saving and renewable energy solutions. As part of the Econcern group ( we offer research and consultancy services as well as product development. Besides Ecofys, the companies Ecostream, Evelop and Ecoventures also belong to the Econcern holding. Over the years we have conducted extensive research and completed projects for many energy companies, housing associations, building companies, (inter)national and local authorities, and energy consumers around the world. With more than 150 employees in six countries, we are one of the largest consultancies in sustainable energy and climate policy. Broad expertise Ecofys offers a wide range of high quality services, based on our extensive knowledge of renewable energy and energy saving solutions. Areas of expertise include solar energy, wind energy, biomass, hydrogen technology, energy supply and climate policies. Our experts are organised around different markets. Technical, financial, legal and planning disciplines are combined to develop balanced and cost-effective solutions. Innovative and forward thinking Ecofys is always at the forefront of climate and energy market developments. Because of our activities in strategic research and our contributions to international and local policy development we lead the way in applying these advancements in our projects. We also continue to develop new products of our own, or in partnership with other organisations. 133

2 Authorities should stimulate the market to develop buildings with a high-energy performance. Hence, policy makers have to be focused on the objectives instead of the means (we are in favour of regulation aimed at a certain energy performance without enforcing specific options). Figure 1 The Netherlands has chosen to implement a system based on a standard for the energy performance of buildings. This system gives both the policy makers and the building industry a significant amount of flexibility. The market forces determine what kind of measures will be developed to meet the regulation. The Energy Performance value (EPC) is a measure for the expected building related energy use of a house (space heating, ventilation, cooling and hot water supply), subject to standardized occupant behaviour. An EPC value of 1 corresponds to an annual energy demand for a typical Dutch terraced house of approximately 1000 m3 of natural GJ. A lower EP-value indicates an expected smaller energy use. The graph shows the development of the Energy Performance Standard (in Dutch: EPN) for houses in The Netherlands. The EPN was introduced in 1995, but it is possible to calculate the EPC for the previous years (see also figure 1). The two oil crises in 1973 and 1979 were the reason for the Dutch government to start regulating the insulation of buildings. The thickness of insulation was increased, step by step, from 0 to 8 cm s and later, in 1990, requirements for double-glazing were also introduced. A second important improvement was the introduction of condensing boilers for space heating. At the introduction of the EPN in 1995, the design had to comply with an EPC of 1.4 maximum. In two stages the required EPC has now been lowered to 1.0 in Figure 2 Figure 2 shows that the developments were above the expectation of renowned energy research institutes. Not too many years ago the progressive decrease of the EPC was believed to be unrealistic because of economic barriers. On the other hand, demonstration projects were carried out to show that from a technological point of view low EPCs could already be realized in an early stage. Currently the majority of both the Dutch politicians and those in the building industry believe the unexpected fall of prices of sustainable technologies is due to the strict energy performance legislation. Therefore, a new EPC level of 0.8 has been announced for Even an EPC of zero is being predicted. Various energy concepts making use of heat pumps and solar energy etc. are possible, reducing the net use of fossil fuels over the years to zero (figure 3). PANDA Houses WWF have worked with several large project developers to build very energy efficient houses in 5 locations in the Netherlands (Nieuwegein, Tilburg, Nijkerk, Almere en Apeldoorn). The project was very successful and has been continued in 2002 with 'solar houses'. The most important features of the project are that the houses are realised without any subsidies and that they have only made use of proven techniques and measures. These houses are therefore built within the existing commercial construction and financing methods. Figure 3 134

3 3. Vision As for all things that humans create, a vision is necessary to design an optimal building. Certainly, the principal and the architect should develop this vision in the earliest stage of the development process, thus allowing synergy between the energy supply and the building. Apart from being an element in an urban environment and determining the structure and atmosphere of a district or a city, a building is foremost the containment of a number of user functions, facilitating its occupants and contributing to their well-being. Therefore, the energy supply needs to be an integral component of the building and will be of influence on investment costs as well as exploitation costs of the building. For this reason the architect of a building must be aware of the implications of the building design on the energy demand and the indoor climate. An optimal energy supply system can only be achieved when taking the energy aspects into account in the earliest stage of development of a building. With regard to buildings we distinguish various aspects that make up a vision: - The time-dimension and life cycle approach - The Trias Energetica - Client orientation and stakeholder analysis - The learning curve 3.1 The time dimension Time dimension All construction activities of today will be part of tomorrow's future. Looking at very old maps of city centers we will often recognize the street plan that still exists and even some of the buildings that are still in use. This shows that the choices we make during design of towns, buildings or infrastructure will influence the possibilities for a sustainable energy future. How can we design a sustainable energy infrastructure in new areas that will be prepared for the future? This is a complex question because the whole energy chain consists of different components influencing each other. Also new clean and sustainable technologies are being developed and will be commercially available in the near future. In the table below the different levels of the built environment are given together with the expected lifetime and aspects that need to be taken care of. Level lifetime in years Influence on lifetime energy consumption Aspects affecting the energy use Urban plan Solar design Space for new infrastructure Density Building design Low energy demand for indoor climate (e.g. insulation, air tightness etc) Possibilities for integrated sustainable energy (e.g. PV, Solar hot water) Energy infrastructure Affects the choice for in-house conversion (e.g. natural gas, heat distribution). Affects the choice for future introduction of renewable energy (e.g. biogas, H2) Distributed energy production Source (e.g. natural gas, oil, earth heat). Efficiency (e.g. cogeneration) Building installations Efficiency, capacity Synergy with building envelope Equipment Choice affects highly the electricity usage 135

4 Normally, buildings will have a lifetime of at least 50 years. It is likely that within the life cycle the installations will be exchanged or retrofitted. The design should facilitate changes to energy supply system. Infrastructure In order to create a truly sustainable energy supply system clean energy carriers should be used, to eliminate many small sources of CO2-emissions. The most common CO2-free energy carriers for the built environment are electricity and heat (hot and cold water). In the near future hydrogen has the potential to become a viable option. Electricity is a versatile energy carrier with many possibilities. Especially looking at the decreasing need for heat for space heating, due to the improved insulation, heat recovery from ventilation air etc., the idea of an all-electric energy supply system for houses and offices is a realistic alternative for the near future. On the other hand it is also a relatively expensive form of energy. The production of electricity always results in the simultaneous generation of heat. We can make use of this phenomenon by cogeneration of heat and power (CHP). Cogeneration can be realized on the level of: - A district (large scale district heating and/or cooling by combined cycle units) - One large building (large office buildings, flats or a series of terraced houses) - One house(micro CHP) Energy chain The energy supply for the built environment consists of four elements: central sources/production; energy carriers; local sources and conversion; and end use. The demand for electricity and heat can be met by a number of energy carriers. Currently these are restricted to natural gas, district heat and electricity. In a sustainable future other carriers could play an important role, e.g. biofuels, synthetic (natural) gas or hydrogen. Central Production Carrier / infrastructure Local Conversion End use Energy functions Energy Energy functions functions Several possibilities are available for the central or local production of energy. The CO2-emission in the energy chain is largely dependant of the fuel source for production. Electricity from coal will emit more than twice the amount of CO2/kWh compared to a natural gas electricity plant. Renewable sources such as PV, wind or hydro will reduce the CO2 emission to zero. Mainly there are two ways to reduce CO2 emissions in the chain: 1) reducing the energy demand and 2) lowering the CO2 content of the energy carriers. Important programs to reduce the energy demand in the built environment are based on a passive design and making use of insulation, heat recovery, efficient boilers etc. Mainly this is meant for lowering the heat demand in houses and offices. More and more we see electricity having a growing part of the total energy demand. Cooling and lighting are the main applications responsible for this. Therefore programs in Europe more and more focus on energy efficiency improvement in these areas. Lowering the CO2 content of the energy carriers in the energy chain will of course help to lower the CO2 emission in the whole chain. For the long term it is expected that new carriers as mentioned above will play an important role. Another possibility is the CO2 capture and storing. Some experimental projects are currently delivering the first results and it is expected that CO2 mitigation could play an important role in the middle term future. 136

5 When using heat inside buildings we want to work with low temperatures. This enables us to use all kind of generation methods (solar heat, heat pumps etc.) with relatively high efficiencies. Heating and cooling can be done with centralized as well as with decentralized systems. District heating and district cooling can be very interesting options depending on the energy supply chain, the type of buildings (building density) etc. Networks can also serve as collective sources for decentralized heat pumps. At the moment there is a trend towards decentralized energy supply systems, also called distributed power generation. This trend is based on various developments: - Liberalization of energy markets Liberalization makes the network accessible for small producers - Increasing need for autarkic systems The fear for terrorism and the fear of failure of the function of the market (black outs) feed the need to become self-supporting - Technological developments The introduction of low cost photovoltaic systems, micro CHP-units etc. make decentralized power generation more attractive. 3.2 Life cycle approach With respect to energy we need to realize that the building design influences the energy consumption during the entire lifetime of a building and that this energy consumption can be quite significant. For a house, the building related energy demand (depending on the climate zone) is in the range of 40 GJ/year. With a lifetime of 50 years this results in an energy use of 2000 GJ or some 350 barrels of oil. Still, feasible energy saving measures are often not implemented because of economical constraints. Normally, the beneficiary party will be the occupant and not the initially investing project developer or housing association. New ways of organizing the energy supply could offer a solution for this problem. Actually, the occupants of a building are not interested in electricity or hot water, they want light, a nice indoor climate etc. Energy service companies (ESCO s) can provide services that fulfil the needs of the end-users in a more direct way. Outsourcing of the energy supply to ESCO s can result in optimization of the life cycle costs. We see a trend where installers get involved in the early stages of the building process to guarantee performances for a fixed price for comfort, safety, ICT and energy management in a building. We also notice a trend of building companies leasing buildings to the occupants. This is also a formula that stimulates the market to use a life cycle approach. 3.3 Trias Energetica Any amount of energy that can be reduced will not have to be produced. So, the first priority should be to avoid waste of energy. Orientation of the building, positioning of the rooms with specific functions, insulation, etc. are good examples of measures that are very economical and can save a great deal of energy. The remaining energy demand should be met by renewable energy as much as possible. Only if necessary the remainder of the energy demand should be supplied by efficient use of fossil fuels. 137

6 1 reduce the energy demand by rational use of energy 2 use renewable energy 3 utilize fossil fuels with maximum efficiency 3.4 Client orientation There are many stakeholders in the building process (NB: in many cases the occupants who have in fact the largest interests are not present during the actual building process!). The interests of the various stakeholders depend on the specific situation (ownership, organization of the energy supply, etc.). The parties involved in the building process should be aware of the interests of all others involved. Stakeholder Principal/ Project developer Architect Authorities/Municipality Consultant Construction firm Owner/Occupant Energy company Supplier Occupant Interests Profit Name and Fame Compliance with regulation Innovation Turn over / Profit Comfort Client relations Turn over Comfort 3.5 Learning curve New legislation is one of the driving forces for a continuous development of new sustainable technologies all over the world. Before these technologies become commercially available, they will follow a learning curve through stages such as prototype, experiment, demonstration and best practice. Putting the new technologies into practice will improve reliability, create markets and lower prices. Figure 4: first zero energy street Large scale introduction of new technologies will not take place if reliability and price are not fully optimised. Therefore, ambitious new developments could make use of a dynamic development scheme: experimental and demonstration technologies will have a limited role in the first phase of a development, for example only 2% respectively 18% of the total building volume. Hence, these technologies will be improved, lessons will be learned and prices will go down. This will smoothen the path for large-scale application of this technology in the next phase of the development. This is shown in the following picture. Figure 5: learning by doing The integrative approach: a recipe for sustainable building Can we afford sustainable building? We think the question should be: Can we afford not to make our buildings sustainable? Already we experience the negative effects of the human energy use. Together with the oil prices we may expect that in general energy prices will rise steeply within the next years. It is obvious that not all available options for energy conservation and for renewable energy are feasible yet. However, by using an integrated approach many costs can be reduced or avoided. 138

7 One example is the integration of photovoltaic solar panels in the envelope of buildings, replacing other construction materials. Figure 6: Integration of PV From the societal point of view we should optimize the life cycle costs and not just focus on the investment costs. Especially in a large market like China, the scale-effects will have a large impact on the price of new technology and materials. To summarize the above mentioned ideas, a number of essential steps should be taken to create an integrative approach to sustainable building: Figure 7 : vision: a necessity for integrated approach DESIGN PHASE 1. Create a vision on the integration of energy supply in the building design; always consider the energy supply system as an integrated element of the building(design). 2. Make sure all disciplines are represented in the design team and use methods that allow/facilitate cooperation between the disciplines. 3. Make sure to get a clear picture of the required user functions of the building (for this a stakeholder analyses can be quite useful). 4. Analyse the relation between the building and its environment; building orientation, available infra structure, organization of the energy supply are important elements. 5. Keep future options open where possible. 6. Use the Trias Energetica as a leading guideline for your design. 7. Translate your vision into a concrete terms of requirements. 8. Use a life cycle approach to evaluate the feasibility of investments (make sure to involve the exploitation costs in the analyses). PROCUREMENT AND CONSTRUCTION PHASE 1. Ensure continuity in the building process; results from the design phase should be used in the procurement and construction phases. 2. Use clearly defined procedures to assure the quality during the construction phase. EXPLOITATION PHASE 1. Make guidelines for the users of the building and for service and maintenance companies to ensure that the installations are used correctly. Literature 1. Gilijamse, W.J.A., lectural speech at Saxion University, March 19,