Energy efficiency in the refurbishment of high-rise residential buildings

Transcription

1 2,123 Energy efficiency in the refurbishment of high-rise residential buildings Pedro Guertler Association for the Conservation of Energy Westgate House 2a Prebend Street London N1 8PT United Kingdom Winton Smith Association for the Conservation of Energy Keywords High-rise residential buildings, EU25, Candidate Countries, refurbishment Abstract A wide range of projects have been and are being carried out in Europe which assess the costs, benefits and effectiveness of investment in residential energy efficiency refurbishment. In the context of pressing and frequently conflicting environmental, economic and social policy objectives, energy efficiency investment is repeatedly found to be a cost-effective and reconcilable component of energy policies. High rise residential buildings are a particularly salient issue in this regard as their poor energy efficiency is regarded as a moderate to major problem by 19 out of 27 housing ministries who responded to a Europe-wide survey. Yet no previous research exists on the Europe-wide picture of the potential for energy efficiency improvement in high-rise buildings. Taking into account the present EU (25) plus Bulgaria, Romania and Turkey, this paper identifies significant scope for increased energy efficiency in high-rise buildings. The cost-effectiveness of energy savings and avoided CO 2 emissions is assessed, and it transpires that the most cost-effective energy savings can be made in the old EU Member States, whilst the most cost-effective CO 2 savings are achievable in the New Member and Accession States. The paper concludes that investment in improving the energy efficiency of the high-rise residential stock should be made, acknowledging that approaches to prioritising this investment still need to be refined. Introduction This paper was inspired by a project investigating the scope for increased energy efficiency in high-rise buildings and discussing the benefits investment in energy efficiency in these buildings might provide. The project considered the geographical area of the present EU (25 Member States) plus Bulgaria, Romania and Turkey. High-rise buildings in Europe were defined at the 3 rd Housing Ministers Conference in Genval, Belgium in 2002 as having more than four storeys. The approaches of housing policy to high-rise buildings arguably apply equally to multifamily buildings, but the definition was agreed upon as a separate category because it placed a firm emphasis on the housing problems of the new European Member States, as high-rise buildings according to this definition are far more prevalent in these countries. Data on the high-rise residential housing stock have been drawn from a variety of European sources, but originate mainly from a survey completed last year of European housing ministries, commissioned by the 3 rd Housing Ministers Conference, and from EuroACE members. Most approximately 50% of the high-rise stock was built from the 1950s to the 1980s, very often to poor energy efficiency and other construction standards. On average according to the survey, one in six dwellings in the 28 European countries covered is in high-rise buildings 36 million dwellings in total (PRC Bouwcentrum International, 2004). In some of the new Member States, up to 50% of the population live in high-rise buildings, most of which are in urgent need of general refurbishment. Refurbishment involves comprehensive building renovation and the repair of all defects. This paper intends to dem- ECEEE 2005 SUMMER STUDY WHAT WORKS & WHO DELIVERS? 423

2 2,123 GUERTLER, SMITH PANEL 2. MAKING BUILDINGS MORE ENERGY EFFICIENT Table 1. Categorisation of countries. < heating degree days (HDDs) HDDs EU15 countries EU10 countries AS3 countries France, Greece, Italy, Portugal, Spain (base region/building A) Belgium, Ireland, Luxembourg, Netherlands, United Kingdom (base region/building D) > HDDs Austria, Denmark, Finland, Germany, Sweden (base region/building G) Cyprus, Malta (base region/building B) Czech Republic, Hungary, Slovakia, Slovenia (base region/building E) Estonia, Latvia, Lithuania, Poland (base region/building H) Turkey (base region/building C) Bulgaria, Romania (base region/building F) - onstrate the benefits of and promote attention to the integration of energy efficiency improvements into the refurbishment cycle of high-rise residential buildings. Where in Europe should resources to save energy and CO 2 in the high-rise residential stock be targeted? Is the answer the same for energy savings and CO 2 savings? If not, how can priorities be set? Methodology Energy efficiency, or RUE 1, measures in the refurbishment of high-rise buildings considered in this paper have been identified from the approach taken by the so-called Trias Energica (Lysen 1996). This approach, applied to the buildings sector, prioritises actions taken to reduce energy demand and resulting CO 2 emissions. First, steps must be taken to reduce fabric energy losses. The second priority is to increase the use of renewable energy sources in meeting building energy demand, and the third and final priority is to otherwise ensure a more efficient use of fossil fuels. This project only considers RUE measures, hence focusing on priorities one and three: Improving the thermal properties of the building fabric that is floors, roofs, walls and windows/doors, and improving the efficiency of heat generation and distribution in/for the building more efficient boilers, implementation of balancing valves, pipe insulation, implementing or improving heating controls and so on. In order to model the potential for energy efficiency and the cost-effectiveness of investment in RUE measures, the 28 countries considered have been categorised according to both climate and socio-economic regions. Table 1 illustrates how this has been carried out. EU15 countries are European Union countries that were members before 1st May 2004, EU10 countries are those that have joined the EU since, and AS3 countries are accession states. The heating degree days (HDDs) are a reflection of a country s heating demand or climate. States in the < group are warmer climate countries, countries in the category experience more moderate climates, and those in the > bracket have colder climates. The categorisation results in eight base regions, which have allowed the definition of eight reference high-rise buildings or base buildings, each broadly representative of the high-rise stock in its region. Each base building was constructed employing typical energetic values derived from information about the predominant construction types in each country according to the survey of Housing Ministries, and informed by expert opinion from EuroACE member companies. buildings characteristics reflect the values of the individual countries buildings they represent, weighted according to the distribution of high-rise buildings across those countries. Two quantitative assessments have been carried out. First is the assessment of the effect on heating demand of integrating best available technology (BAT) energy efficiency improvements into the refurbishment of each base building, each of which is considered to be fully refurbishable in terms of the building fabric 2, and partially refurbishable in terms of the heating system 3. Cooling demand has not been included in the scope of this paper. d on expert opinion from EuroACE members and other European sources, only the energy-related costs of each measure have been considered 4. In other words, only the cost additional to the cost of a comprehensive building refurbishment; in the case of external wall insulation, for example, the cost of scaffolding and rendering (renewal) has not been included. Heating demand before and after renovation has been calculated according to the basic principles of the European norm EN832. Measures and processes not considered quantitatively, for reasons of scope and lack of adequate data, but which have an important role to play in refurbishment projects are solar shading, as stated above the effect of building fabric measures on cooling demand, pipe insulation, combined heat and power generation and lighting. The second quantitative assessment is the calculation of the sum total of potential CO 2 emissions, based on the responses by European Housing Ministries to the survey commissioned by VROM 5 on behalf the Genval conference (PRC Bouwcentrum 2004). 1. rational use of energy 2. Wall, roof and floor insulation, and window replacement. 3. Balancing valves, thermostatic radiator valves in the case of district heating connection and additionally boiler replacement in the case of building-based central heating. 4. See Guertler & Smith (2005) for a comparison with total refurbishment costs. 5. Netherlands Ministry of Housing, Spatial Planning and the Environment 424 ECEEE 2005 SUMMER STUDY WHAT WORKS & WHO DELIVERS?

3 PANEL 2. MAKING BUILDINGS MORE ENERGY EFFICIENT 2,123 GUERTLER, SMITH kwh/m2a heating demand after refurbishment heating measures window replacement floor insulation roof insulation wall insulation Ba se Ba se Ba se Ba se Ba se Ba se Ba se Ba se Figure 1. Heating demand reductions [plus heating demand after refurbishment], in kwh per m 2 of heated space per year, of selected measures included in refurbishment of base buildings. Results Figure 1 outlines the heating demand reductions achievable in each base building on the basis of the approach laid out in the section above. The heating demand after refurbishment is shown by the uppermost rectangles of each column 6. It can be seen that the savings vary considerably between warmer (buildings A to C) and colder countries. The reductions in heating demand achievable are between 60 and 75 per cent. Naturally, the costs of including these measures in refurbishment vary considerably as a result of different labour costs in the base regions. Given a five per cent discount rate and average household energy prices over the next 30 years, Figure 2 illustrates the net financial cost of the energy efficiency improvements and the cost of CO 2 mitigation. Negative values for the net annualised cost/benefit of energy saved (in Euro cent per kwh) are a net benefit. Assuming the investment cost is annualised 7 as would be the case if householders take out a loan to finance the investment energy efficient refurbishment yields a net financial benefit for each kwh heating energy saved over the lifetime of the measures for all base buildings apart from C. High net financial benefit is achievable in the EU15 base buildings (A, D and G), with marginal net benefits in the others. In high-rise building A, representative of warm climate EU15 countries, the large net benefit is caused by a combination of high heating energy prices (electricity being the main fuel), relatively low investment cost and a poor initial energy efficiency standard. For base buildings D and G moderate and cold climate EU15 countries the net benefit per kwh saved is primarily due to high energy prices, but also a result of fairly poor initial standards for base building D and the cold climate of base region G respectively. For buildings C, E, F and H, representing the countries of Eastern Europe and Turkey, the main cause of the smaller net financial benefit despite low investment costs is the very low heating energy price in each of these base regions; indeed, in the many cases of district heating supply, heat is paid for at a flat-rate. Energy prices have been uniformly assumed to rise by 1.5% in real terms over the lifetime of the measures. However, it can be argued that, given the eventual liberalisation of the energy markets and the removal of state subsidies, this rate is likely to be exceeded in the latter group of base regions, investment in which may then yield larger net financial gain. Guertler & Smith (2005) have carried out assessments of a 3% rather than 1.5% annual increase in heating energy prices in EU10 and AS3 countries. In contrast to energy savings, the most cost-effective CO 2 savings (as illustrated by the fourth column set in Figure 2) are achievable in base buildings C, E, F and H precisely the buildings with the least cost-effective energy savings. This is because reductions in energy expenditure enjoyed by households have not been taken into account to calculate the cost-effectiveness of CO 2 savings, only the cost of refurbishment has which is lowest for buildings C, E, F and H. The reasoning for not taking household energy expenditure reductions into account is that CO 2 mitigation is not in the first instance of interest to households, but to governments in the form of a contribution to emissions reduction objectives. If anything, governments reduced subsidy of energy 6. This implies that the total in each column is equal to the heating demand before refurbishment. 7. I.e. paid for over the economic lifetime of the measures implemented (30 years for building fabric and 20 years for heating measures), at a 5 per cent discount / interest rate. ECEEE 2005 SUMMER STUDY WHAT WORKS & WHO DELIVERS? 425

4 2,123 GUERTLER, SMITH PANEL 2. MAKING BUILDINGS MORE ENERGY EFFICIENT average 30 year heating fuel price [ cent/kwh] 5.00 gross annualised cost of energy saved (energy-related) [ cent/kwh] net annualised cost of energy saved (energy-related) [ cent/kwh] cost of CO2 mitigation [ cent/kgco2] cent 0.00 building A building B building C building D building E building F building G building H Figure 2. Energy prices, cost of energy and CO 2 saved ( any government action that concerns primarily the energy sector that lowers the cost of energy production, raises the price received by energy producers or lowers the price paid by energy consumers (IEA 2001)) should be balanced against the cost of CO 2 mitigation. However, data on this, the societal cost of energy, is inadequate to weigh up this benefit reliably. In any case, what is likely is that energy subsidies in new Member States and Accession States are high compared to the original EU15, where energy market liberalisation has progressed further. Taking these into account would reinforce the pattern of higher cost-effectiveness of CO 2 mitigation in base regions C, E, F and H. If the investment cost is financed via the right amount of grant or subsidy rather than loans, then more cost-effective energy and CO 2 savings are achievable in all of the base building H, 9.33 building A, 9.98 buildings because the cost of borrowing faced by householders can (at least partially) be avoided. Crucially, whichever methods of financing the requisite investment are considered, the investment cost needs additionally to be balanced against wider benefits such as deferred or avoided investment in energy supply infrastructure (Guertler & Smith 2005), the possibility of job creation (Wade et al 2000) and the improvements in comfort and health to which energy efficiency in the refurbishment of high-rise residential buildings can contribute. With respect to overall CO 2 emissions from the European high-rise stock, there is scope for substantial reductions. Figure 3 illustrates the annual CO 2 savings possible from the high-rise stock according to the European Housing Ministries respondent to the VROM-commissioned survey, based on their estimates of economic energy saving potential. The highest energy saving potential is in Eastern Europe; 39% in base region E and 34% base region H. Europe-wide, the energy saving potential is 28%, implying a reduction of Europe s total final energy demand of 1.5%, and a corresponding approximate emissions reduction of 35 MtCO 2 around 20% of the EU s Kyoto commitment to building G, 6.71 building F, 1.10 building E, 4.02 building B, 0.06 building C, 2.37 building D, 1.60 Figure 3. CO 2 savings potential [MtCO 2 ] according to European Housing Ministries Conclusions Where in Europe should resources to save energy and CO 2 in the high-rise residential stock be targeted? The answer is not simple for three main reasons. First, and broadly speaking, energy savings are most cost-effective in EU15 countries on the one hand, whilst on the other the most costeffective CO 2 mitigation is achievable in EU10 and AS3 countries. Second, wider benefits such as comfort and wellbeing improvements as well as wider costs for example the creation of adequate legislative frameworks for im- 426 ECEEE 2005 SUMMER STUDY WHAT WORKS & WHO DELIVERS?

5 PANEL 2. MAKING BUILDINGS MORE ENERGY EFFICIENT 2,123 GUERTLER, SMITH plementing refurbishments in the context of multi-tenured buildings of improving energy efficiency in high-rise buildings need to be taken into account, which will also vary nationally and regionally. Third and finally, energy efficiency improvement can support multiple objectives (i.e. the direct and wider benefits), and the allocation of resources for high-rise refurbishment needs to be targeted according to how these objectives are prioritised. From the European Union s perspective the first priority amongst the outcomes of high-rise refurbishment may be to reduce CO 2 emissions, to contribute to the European Union s umbrella Kyoto Protocol target. In this case resources should be preferentially allocated towards base regions C, E, F and H, the new Member States in Eastern Europe and the Accession States, where the most cost-effective CO 2 mitigation can be achieved. If the first priority were to save energy, to contribute to European energy security objectives, then resources should be preferentially allocated towards base regions A, D and G (EU15 countries) where the most cost-effective energy savings by a large margin are achievable. Given the changes happening in the European energy market including liberalisation in the new Member States by July 2007, the likely associated reduction of energy subsidies and increase in consumer energy prices (and household incomes) against a backdrop of increasingly costly fossil energy and the diffusion of RES 8 technologies there is no easy nor complete answer to the question posed above. More work needs to be done to assess in more detail the costs and benefits of energy efficiency in the refurbishment of high-rise residential buildings. The approaches taken will vary widely regionally as well as right down to the individual community and high-rise buildings in question. However, the approach taken in this paper does hope by offering some partial yet clear answers to the above question to contribute to this refinement process. Acknowledgements The authors would like to thank the European Alliance for Energy Efficiency in Buildings and the International Energy Agency, who both co-funded the project that inspired this paper and poster. References Guertler P and Smith W (2005): Energy Efficiency in the Refurbishment of High-Rise Residential Buildings. Association for the Conservation of Energy, London International Energy Agency (2001) Energy Subsidy Reform and Sustainable Development: Challenges for Policymakers. Last accessed on at / sustain_report.pdf Lysen, E H (1996): The Trias Energica: Solar Energy Strategies for Developing Countries. In Proceedings of the Eurosun Conference, Freiburg Sep 1996 PRC Bouwcentrum International (2004): Sustainable Refurbishment of High-Rise Residential Buildings and Restructuring of Surrounding Areas. Netherlands Ministry of Housing, Spatial Planning and the Environment, Den Haag Wade, J, Wiltshire, V and Scrase, I (2000): National and Local Employment Impacts of Energy Efficiency Investment Programmes. Final report of SAVE contract XVII/4.1031/D/97-032, DG TREN, Brussels 8. renewable energy sources ECEEE 2005 SUMMER STUDY WHAT WORKS & WHO DELIVERS? 427