1 1 Responding to the Challenge Code for Sustainable Homes May 1st 2008 Where we are now? N.K. Tovey ( 杜伟贤 ) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук Energy Science Director CRed Project HSBC Director of Low Carbon Innovation Recipient of James Watt Gold Medal 1

2 Introduction to Current Energy Issues The twin Challenges facing us Climate Change Energy Security Review of historic trends in Building Regulations and associated energy use in domestic buildings. In Part 2: The opportunities facing us Where we are now?

3 Carbon factors for each unit of fuel consumed at point of use. The following include the transmission/ distribution losses – e.g. electricity 8.5% –energy generated locally is effectively worth more than nationally supplied energy Gas ~ 0.19 kg/kWh Oil ~ kg/kWh Coal ~ 0.33 kg/kWh Electricity varies depending on mix of power stations. Was over 0.65 kg/kWh in 1990 but fell to 0.46 kg/kWh in 1999, but as since risen with closing of nuclear and less gas being burnt. Currently ~ 0.52 For identical situation oil boiler will cause emission of around 40% more CO 2 than for gas Issue of Fuel Choice

4 Climate Change Issues Carbon emissions in electricity generation will increase in next 5 years even if demand is held constant - Each unit generated by coal ~ 1000 g / kWh gas ~ 400 g/ kWh nuclear ~ 10 – 20 g/kWh Reducing demand for electricity in homes is important Need to reduce carbon emissions by 60% by 2050 The Hard Choices Facing Us Emissions from electricity generation will rise in short term even if we order new nuclear. Deployment of renewables is barely keeping pace with increased demand yet alone replacement of nuclear

5 Energy Security Issues Since 2004 UK has been importer of gas 70% of coal is now imported UK is no longer self sufficient in Energy Importance of Energy Conservation not merely energy efficiency, but overall reduction in energy use Still have major coal resources, but only viable with Carbon Capture and Sequestration because of high carbon factor Prospects of CCS? Hydrogen/Fuel Cells? Only really viable when electricity generation has been decarbonised CCS routinely available Increase in Renewable/Nuclear Generation CCS Unlikely except for demonstration schemes before The Hard Choices Facing Us

6 A Pathway to a Low Carbon Future 未来的低碳之路 1. 不要浪费能源 Awareness: Information Packs 3. 使用可再生能源 Renewable Energy 4. 抵消碳排放 Offsetting 2. 使用效率高的设备 Technical Solutions to conserve energy Low energy lighting/better insulation etc

7 Change since 1990 Electricity +24.2% Gas +21.4% Oil +31.8% Coal -87.0% Overall +15.3% Energy Consumption and CO 2 Emissions in Domestic Sector Energy Consumption Carbon Dioxide Emissions Change since 1990 CO 2 emissions +5.4% Carbon Intensity has improved by 8.6% - but absolute emissions are important

8 Energy Consumption: Comparison of Sectors The Domestic Sector is a critical area to tackle climate change

9 Throttle Valve Condenser Heat supplied to house Evaporator Heat extracted from outside Low Temperature Low Pressure High Temperature High Pressure Responding to the Challenge: Technical Solutions The Heat Pump Compressor A heat pump delivers 3, 4, or even 5 times as much heat as electricity put in. Working with thermodynamics not against it.

10 Example: Heat house with condensing gas boiler ~ 90% efficient For each unit (kWh) of heat provided. –1/0.9 = 1.11 units of gas must be supplied –Carbon associated with this ~ 0.21 kg –Direct electric heating ~ 0.52 kg Heat Pump with Coefficient of Performance of 4 –Carbon emission associated = 0.52/4 = 0.13 –A 38% saving over gas. –Note some people claim higher savings based on incorrect DEFRA carbon factor of 0.43 –Improved performance of heat pumps is possible with under floor heating Issue of Fuel Choice

11 First introduced as Part L in 1976 Basic Statement – largely following what was then common practice e.g. cavity walls brick cavity block with no insulation: - no insulation in floor, minimal insulation in loft. 1994: First attempt to address overall annual energy consumption, although elemental method of compliance was still permitted 2002: Carbon Index introduced 2006: Target Emission Rate and Dwelling Emission Rate introduced. Changes in the Heating Standards of Houses

12 How has the performance of a typical house changed over the years? Bungalow in South West Norwich built in mid 1950s

13 House constructed in mid 1950s Part L first introduced ~>50% reduction First attempt to address overall consumption. SAP introduced. Changing Energy Requirements of House In all years dimensions of house remain same – just insulation standards change As houses have long replacement times, legacy of former regulations will affect ability to reduce carbon emissions in future

14 House constructed in mid 1950s Changing Energy Requirements of House Existing house – current standard: gas boiler Improvements to existing properties are limited because of in built structural issues – e.g. No floor insulation in example shown. House designed to conform the Target Emission Rate (TER) as specified in Building Regulations 2006 and SAP As Existing but with oil boiler

15 House constructed in mid 1950s Changing Carbon Dioxide Emissions Code 5: Zero Carbon House for Heating/Hot Water and Lighting Code 6: Zero Carbon House overall but in reality is this achievable

16 The Behavioural Dimension Analysis of 114 houses in Norwich using Gas Heating Predicted consumption from SAP was within 1.9% of actual energy consumption for Space Heating/ Hot Water and Gas Cooking. Plot shows variation from predicted for each house Little variation with household size Consumption varies by up to a factor of 9 for any given household size. Education/Awareness is important. provide INFORMATION PACKS

17 The Behavioural Dimension Household size has little impact on electricity consumption. Consumption varies by up to a factor of 9 for any given household size. Allowing for Income still shows a range of 6 or more. Education/Awareness is important.

18 CO 2 / year tonnes tonnes tonnes tonnes > 10 tonnes Variations in Carbon Emissions in existing houses Analysis: courtesy of Karla Alcantar

19 Introduced over next few years to improve standards to ultimate “zero carbon house” But objectives of a low carbon future may be jeopardised if attention is not also paid to sustainable transport associated with new dwellings The Future: Code for Sustainable Homes Data for 1 household with 2 cars

20 Code for Sustainable Homes May 1st 2008 Responding to the Challenge N.K. Tovey ( 杜伟贤 ) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук Energy Science Director CRed Project HSBC Director of Low Carbon Innovation Recipient of James Watt Gold Medal 20

21 Improvements on the SAP 2005 standards as required by the different code levels can be met by: Improved Fabric performance Lower U-values Technical Solutions Solar Thermal Solar Photo-voltaic Heat Pumps Biomass Micro- CHP Low Energy Lighting (SAP 2005 already specifies 30%) Responding to the Challenge: Energy Service Companies may offer a solution for financing Issues of Carbon Trading

22 Improved Fabric / standard appliance Performance SAP 2005 standard reference Responding to the Challenge: ItemSAP referenceImproved Value 1 Improved Value 2 WindowsU-value = 2U-value = 1.4 WallsU-value = 0.35U-value = 0.25U-value = 0.1 FloorU-value = 0.25 RoofU-value = 0.16 Boiler efficiency 78%83% default90% SEDBUK

23 The Future: Code for Sustainable Homes CO 2 Emissions (kg)Reduction ASAP Reference BBoiler η = 83% (default) 23775% CBoiler η = 90% (SEDBUK) % Dη = 90%: Walls: U = % Eη = 90%: Walls: U = % Fη = 90%: Windows: U = % GC + D + F % HC + E + f % Improvements in Insulation and boiler performance Code 1 Code 2 H nearly makes code 3

24 Responding to the Challenge: Technical Solutions Solar Thermal Energy Basic System relying solely on solar energy

25 Responding to the Challenge: Technical Solutions Solar Thermal Energy indirect solar cylinder Solar tank with combi boiler

26 Normal hot water circuit Solar Circuit Solar Pump Responding to the Challenge: Technical Solutions Solar Thermal Energy Dual circuit solar cylinder

27 Annual Solar Gain 910 kWh Solar Collectors installed 27th January 2004 Responding to the Challenge: Technical Solutions Solar Thermal Energy

28 Responding to the Challenge: Technical Solutions Solar Thermal Energy

29 House in Lerwick, Shetland Isles with Solar Panels - less than 15,000 people live north of this in UK! It is all very well for South East, but what about the North? House on Westray, Orkney exploiting passive solar energy from end of February

30 CO 2 (kg)Reduction ASAP Reference BBoiler η = 90% (SEDBUK) % Cη = 90%: Solar Thermal – 2 panels dual cylinder % Dη = 90%: Solar Thermal – 2 panels separate cylinder % Eη = 90%: Solar Thermal – 3 panels separate cylinder % Fη = 90%: Solar Thermal – 4 panels separate cylinder % Gη = 90%: Solar Thermal – 5 panels separate cylinder % The Future: Code for Sustainable Homes Improvements using solar thermal energy Code 1 Code 2 Note: little extra benefit after 3 panels, but does depend on size of house

31 S Responding to the Challenge: Technical Solutions Solar PhotoVoltaic

32 CO 2 (kg)Reduction ASAP Reference BBoiler η = 90% (SEDBUK) % Cη = 90%: Solar PV 5 sqm % Dη = 90%: Solar PV 10 sqm % Eη = 90%: Solar PV 5 sqm + 2 panel solar thermal % Fη = 90%: Solar PV 7.4 sqm + 2 panel solar thermal % The Future: Code for Sustainable Homes Improvements using solar Photovoltaic Code 1 Code 2 Code 3 Note: 2 panels of solar thermal have same benefit as 5 sqm of PV

33 Responding to the Challenge: Technical Solutions The Heat Pump Any low grade source of heat may be used Coils buried in garden 1 – 1.5 m deep Bore holes Lakes/Rivers are ideal Air can be used but is not as good Best performance is achieved if the temperature source between outside source and inside sink is as small as possible. Under floor heating should always be considered when installing heat pumps in for new build houses – operating temperature is much lower than radiators. Attention must be paid to provision of hot water - performance degrades when heating hot water to 55 – 60 o C Consider boost using off peak electricity, or occasional “Hot Days”

34 CO 2 (kg)Reduction ASAP Reference BBoiler η = 90% (SEDBUK) % CGround to Water Heat Pump (Radiators) % DAir to Water Heat Pump (Radiators) % EGround to Air Heat Pump % FAir to Air Heat Pump % GGround to Water Heat Pump (Under floor) % HAir to Water Heat Pump (Under floor) % The Future: Code for Sustainable Homes Improvements using Heat Pumps Code 1 Code 2 Code 3 Code 4 Code 3

35 CO 2 (kg)Reduction ASAP Reference 25040% BBoiler η = 90% (SEDBUK) % CBiomass Boiler 67373% DBiomass Boiler with Solar Thermal 67073% EBiomass Boiler with 5m Photovoltaic 49680% FBiomass Boiler with 10m Photovoltaic 31887% G Biomass Boiler + 10m PV + improved insulation + 100% Low Energy lighting 14794% The Future: Code for Sustainable Buildings Improvements using Biomass options Note: Biomass with solar thermal are incompatible options Code 1 Code 2 Code 3 Code 4

36 Micro CHP Ways to Respond to the Challenge: Technical Solutions Micro CHP plant for homes are being trialled. Replace the normal boiler But there is a problem in summer as there is limited demand for heat – electrical generation will be limited. Backup generation is still needed unless integrated with solar photovoltaic? In community schemes explore opportunity for multiple unit provision of hot water in summer, but only single unit in winter.

37 CO 2 (kg)Reduction ASAP Reference 25040% BBoiler η = 90% (SEDBUK) % CWater to Air Heat Pump (under floor) % DAs C with improved insulation % EAs D with 100% Low Energy Lighting % FAs E with Solar Thermal % GAs E with 5 m Solar PV % HAs E with 10 M Solar PV 86465% The Future: Code for Sustainable Homes Various Combinations Code 1 Code 2 Code 3 Code 4

38 How can low carbon homes be provided at an affordable cost? Energy Service Companies (ESCos) Home costs same initial cost as traditional home Any additional costs for providing renewable energy, better insulation/controls are financed by ESCo Client pays ESCo for energy used at rate they would have done had the house been built to basic 2005 standards ESCo pays utility company at actual energy cost (because energy consumption is less) Difference in payments services ESCo investment When extra capital cost is paid off Client sees reduced energy bills ESCO has made its money Developer has not had to charge any more for property The Environment wins Responding to the Challenge:

39 Significant Improvements can be achieved Better Insulation Standards Heat Pumps Biomass Boilers Solar Thermal Solar PV The Future: Code for Sustainable Buildings: Conclusions But avoid incompatible options Too large a Solar thermal Array Biomass with solar thermal CHP with Solar Thermal Lao Tzu ( BC) Chinese Artist and Taoist philosopher "If you do not change direction, you may end up where you are heading." WEBSITE Cred-uk.org/ Follow Academic Links