1. Dr Rajat Gupta, Department of Architecture, rgupta@brookes.ac.uk Local Renewables 2007, Freiburg 13-15 June 2007 DECoRuM® tool to track energy use and carbon emissions from residential buildings

2. Contents Overview of DECoRuM DECoRuM: estimating baseline energy and CO 2 emissions DECoRuM: predicting CO 2 emission reductions and cost-benefits Application of DECoRuM to a case study in Oxford Extrapolation to UK housing stock. Benefits and applications of DECoRuM. Background to the study

3. Background to the study

4. Buildings are a large part of the problem: decade on decade they use more energy UK carbon emissions in 2000: 150 MtC For industrialised countries such as UK, b uildings account for almost 50% of energy use and related CO 2 emissions that are driving climate change. Derived from DTI Energy Report 2000 Buildings 75 Million Tonnes (50%) 35 Million tonnes Industry 40 Million tonnes Transport Non-Domestic 35 Million tonnes Domestic 40 Million tonnes Existing domestic sector and CO 2 emissions

6. UK Kyoto commitment: First steps down a long road… Cut greenhouse gas emissions by 12.5% on 1990 levels, averaged over 2008-12. UK domestic goal: 20% cut in CO 2 by 2010 on 1990 levels Tougher targets ahead: In 2000, Royal Commission on Environmental Pollution called for 60% cut by 2050 and 80% by 2100 relative to 1998 levels. UK CO 2 emission reduction targets The Institute for Public Policy Research (IPPR) is demanding a 40% reduction in CO 2 emissions by 2020 and 90% by 2050 to avoid ‘dangerous climate change’.

8. It is within this context that the DECoRuM model has been developed!

9. Overview of DECoRuM

10. DECoRuM: a next generation domestic energy model Capability to estimate baseline CO 2 emissions from individual dwellings using a locally-relevant approach, and well-established methodologies to ensure credibility. A mapping tool for representing domestic CO 2 emissions and reductions. This enables it to evaluate the potential for domestic CO 2 emission reductions from a whole range of measures on both the demand and supply sides of energy. An additional and unique feature of assessing the cost-benefits of individual CO 2 reduction measures and putting a financial cost to CO 2 emission reduction. Aggregates these to an urban scale – street, district or city level. DECoRuM provides local authorities and energy advisers with a tool to address the barrier of counting and reducing emissions locally.

11. Core methodologies used in DECoRuM Underlying physically-based energy models: BREDEM –12 linked to SAP 2001. Cost-benefit analysis approach

12. Outputs from DECoRuM

13. DECoRuM: estimating baseline energy and CO 2 emissions

14. Framework for baseline predictions DECoRuM baseline energy model estimates energy consumption and CO 2 emissions of individual dwellings as the basic component for calculation, and then aggregates these to an urban scale.

15. 95 input parameters for BREDEM-12 (SAP) calculation related to: - Site definition - Type of dwelling - Building fabric - Ventilation - Heating system - Hot water heating - Mechanical ventilation - Cooking - Lighting - Occupancy Techniques for data reduction: urban energy modelling 50 input data parameters common for all dwellings 5 input data parameters derived from built form 18 input data parameters derived from dwelling age 22 input data parameters collected for every dwelling Data reduction techniques in DECoRuM BREDEM-12 reference tables English House Condition Survey 2001 Standard dwelling configurations report Home energy survey forms Standard dwelling configurations report BREDEM-12 reference tables English House Condition Survey 2001 UK Building regulations Home energy survey forms Local authority records GIS urban map Walk-by surveys Sources of information 5 input parameters for every dwelling to estimate the solar potential Digital aerial image GIS urban map +

16. Data Reduction in DECoRuM Data to be collected by walk-by survey: 10 parameters (10% of total)

17. DECoRuM: predicting CO 2 emission reductions and cost-benefits

18. DECoRuM: 30 CO 2 reduction strategies Analysing CO 2 emission reductions rather than energy reduction is that it brings both demand and supply side measures into the same CO 2 equation

20. DECoRuM: cost-benefit methodology Helps to compare the cost of eliminating a tonne of CO 2 by using energy efficiency measures with low carbon technologies and solar energy systems .

21. Application of DECoRuM to a case study in Oxford

22. Oxford case study (318 dwellings) Aerial image of the case study area in North Oxford, UK This case study area was chosen because: Naturally fell within 2 enumeration districts. Number of dwellings in case study area was 318, comparable to other studies by researchers. Householders environmentally aware as realised from a survey done as part of the Oxford Solar Initiative project.

23. Oxford case study (318 dwellings) All the built forms and age groups of dwellings defined in DECoRuM, EHCS and OHCS, are present in the case study area.

24. Oxford case study: DECoRuM baseline energy & CO 2 model © Rajat Gupta, Oxford Brookes University, Oxford, UK.

25. Thematic map showing estimate of total annual energy consumption in the case study dwellings

26. Thematic map showing SAP ratings for dwellings in the case study

27. Thematic map of dwellings in the case study showing annual fuel costs

28. Oxford case study: Results from DECoRuM baseline energy model Mean energy use for a dwelling is 368kWh/m 2 /year CO 2 emissions are 80 kgCO 2 /m 2 /year. Average SAP rating was estimated as 45 Carbon Index: 3.4 Average annual fuel (running) cost per year per dwelling: £892

29. Results from DECoRuM baseline model: by built form and age groups Distribution of SAP rating, carbon index and running cost by age-band in case study area Breakdown of energy use, CO 2 emissions, running costs, SAP rating and carbon index as per built forms of dwellings in the case study

30. DECoRuM CO 2 reduction model: estimating solar potential 87% of the dwellings in the case study were suitable for installing either a SHW or a PV system or both.

31. Cost-effectiveness of various CO 2 reduction measures versus potential CO 2 savings in the Oxford case study area (Low capital cost scenario)

32. Potential for CO 2 emission reductions above 60% SHW and solar PV systems, individually installed cost £335 and £644/tonne of CO 2 saved in a low capital cost scenario. When applied in combination in package 3, the cost drops to £44 /tonne CO 2 saved. Emissions trading scheme: £15/tonne CO 2 Carbon capture and storage: £30-60/tonne CO 2 UK social cost of cutting a tonne of CO 2 : £19/tonne CO 2

33. Potential for CO 2 emission reductions from UK housing stock

34. DECoRuM: Key drivers Home Energy Conservation Act 30% improvement in energy efficiency in the domestic sector by 2007 relative to 1997 levels ~ 20% reduction in CO 2 emissions. Decent Homes Standard All social housing and vulnerable households in the private sector to be made decent by 2010: efficient heating and effective insulation. Fuel poverty To end fuel poverty by 2010 amongst vulnerable households. Home Information pack: EU Building Energy Directive Home Condition Report containing SAP energy rating and measures for improving energy efficiency. By 2007.

36. RIBA President’s medal for outstanding research 2006

37. DECoRuM is a next generation tool which is able to realistically count, cost and reduce CO 2 emissions locally. It extends the analysis for CO 2 emission reduction from buildings to make cities more sustainable to help avoid the worst impacts of climate change for the survival of the mankind itself. www.decorum-model.org.uk/