1. Norwich Business School Low Carbon Conversion and Nuclear Power Energy Conservation and Management in Buildings Renewable Energy 1 NBSLM03E (2010) Low Carbon Technologies and Solutions: Sections 10 - 13 N.K. Tovey ( 杜伟贤 ) M.A, PhD, CEng, MICE, CEnv

2. Norwich Business School 2 10. Energy Conservation in Buildings: The Basics 11. Heat Loss Calculations 12. Energy Management 13. Carbon Emission Factors 2 Lecture 2 NBSLM03E (2010) Low Carbon Technologies and Solutions N.K. Tovey ( 杜伟贤 ) M.A, PhD, CEng, MICE, CEnv

3. Norwich Business School 3 Intrinsic Energy Use provision of comfortable thermal environment Functional Energy Use energy use associated with specific activities in building at time. Intrinsic Energy Use (mostly associated with heating) will vary little with different uses (apart from specifics e.g. warehouses, sports complexes etc). Functional Energy Use will vary depending on use – e.g. office (high computer use), laboratory (equipment), supermarket, hotel etc. In a poorly insulated building, functional energy use over life time will be low as a percentage In a well insulated building, functional energy can be the dominant use – representing over 50% in the ZICER Building at UEA. Energy Conservation in Buildings: The Basics

4. Norwich Business School 4 Heat Loss / Heat Gain Three forms of heat transfer Conduction Radiation Convection For buildings - conductive losses are main issue to address in heat loss/heat gain. Q d A T1T1 T2T2 T1T1 T2T2 Temperature Profile Heat Flow is proportional to temperature difference Energy Conservation in Buildings: The Basics

5. Norwich Business School 5 Construction of Typical UK Walls: Solid Walls – most houses built pre-war. Brick plaster In addition to resistance of brick and plaster there is: Internal surface resistance External surface resistance Energy Conservation in Buildings: The Basics

6. Norwich Business School 6 Construction of Typical UK Walls: Solid Walls – most houses built pre-war. Brick U-value is amount of heat transferred per sqm for a unit temperature difference between inside and out. It is the reciprocal of aggregate resistance. R = r brick + r plaster + r int + r ext But resistance = as A = 1.0 k for brick ~ 1.0 W m -1 o C -1 r brick = 0.22 / 1.0 = 0.22 m 2 o C W -1 For plaster k = 0.7 W m -1 o C -1 so r plaster = 0.013/0.7 = 0.02 m 2 o C W -1 Total resistance = 0.22 + 0.02 + 0.123 + 0.055 = 0.418 m2 oC W-1 So U- value = 1 / 0.418 = 2.39 W m -2 o C -1 13 mm 220 mm Energy Conservation in Buildings: The Basics

7. Norwich Business School 7 Construction of Typical UK Walls: post war Brick cavity plaster Cavities provide an extra air-space and hence extra resistance to heat flow. Energy Conservation in Buildings: The Basics

8. Norwich Business School 8 Construction of Typical UK Walls: post war Brick cavity plaster 110 mm Components of resistance Internal surface Plaster Brick Cavity Brick External Surface r internal = 0.123 r plaster = 0.013 / 0.7 = 0. 02 r brick = 0.11 / 1 = 0.11 r cavity = 0. 18 r brick = 0.11 / 1 = 0.11 r external = 0.055 Total resistance = 0.123 + +0.02 + 0.11 + 0.18 + 0.11 + 0.055 = 0.598 m 2 o C W -1 U – value = 1 / 0.598 = 1.67 W m -2 o C -1. Or 70% of solid wall. Energy Conservation in Buildings: The Basics

9. Norwich Business School 9 Construction of Typical UK Walls: post ~ 1960 Brick cavity 110 mm Components of resistance Internal surface Plaster Block Cavity Brick External Surface r brick = 0.11 / 1 = 0.11 r block = 0.11 / 0.14 = 0.76 r plaster = 0.013 / 0.7 = 0. 02 r external = 0.055 r internal = 0.123 r cavity = 0. 18 Total resistance = 0.123 + +0.02 + 0.76 + 0.18 + 0.11 + 0.055 = 1.248 m 2 o C W -1 U – value = 1 / 1.248 = 0.8 W m -2 o C -1. Or 50% of brick / cavity / brick wall. Block plaster Energy Conservation in Buildings: The Basics

10. Norwich Business School 10 Construction of Typical UK Walls: post ~ 1960 Brick Cavity insulation 110 mm Components of resistance Internal surface Plaster Block Cavity insulation Brick External Surface r brick = 0.11 / 1 = 0.11 r block = 0.11 / 0.14 = 0.76 r plaster = 0.013 / 0.7 = 0. 02 r external = 0.055 r internal = 0.123 r cavity insulation = 0.05/0.04 = 1.25 Total resistance = 0.123 + +0.02 + 0.76 + 1.25 + 0.11 + 0.055 = 2.318 m 2 o C W -1 U – value = 1 / 2.318 = 0.43 W m -2 o C -1. Or 50% of uninsulated brick / cavity / block wall. Brick / cavity / brick wall with insulation has U – Value = 0.59 W m -2 o C -1 Block plaster 50 mm Energy Conservation in Buildings: The Basics

11. Norwich Business School 11 U – values for non-standard constructions can be estimated in a similar way U – values are tabulated for standard components U – value single glazing ~ 5.0 – 5.7 W m -2 o C -1 U – value double glazing ~ 2.5 – 2.86 W m -2 o C -1 Floors – typically 1.0 unless there is insulation. Roofs – depends on thickness of insulation Uninsulated post war ~ 2.0 W m -2 o C -1 25 mm - 0.89 W m -2 o C -1 50 mm - 0.57 W m -2 o C -1 100 mm - 0.34 W m -2 o C -1 150 mm - 0.25 W m -2 o C -1 200 mm - 0.18 W m -2 o C -1 250 mm - 0.15 W m -2 o C -1 There are diminishing returns after first ~ 100mm and other conservation strategies become more sensible both economically and in carbon savings. Energy Conservation in Buildings: The Basics

12. Norwich Business School 12 Ventilation in poorly insulated buildings may be only 25 – 30% of losses In well insulated buildings may be > 80% of total heat losses. >> ventilation heat recovery – e.g. ZICER. Ventilation occurs Through door/window opening Through crack around windows / doors / floors Through fabric itself Through vents, chimneys etc. Adequate ventilation is required for health Covered by specifying a particular number of air-changes per hour (ach) i.e. whole volume is changed in an hour. In a typical house 1 – 1.5 ach In a crowded lecture room may need 3 – 4 ach Energy Conservation in Buildings: The Basics

13. Norwich Business School 13 Ventilation: equivalent parameter to U-value i.e. Proportional to temperature difference Volume * ach * specific heat of air / 3600 W m -2 0 C -1 Specific heat: quantity of energy required to raise temperature of unit mass (volume) of material by 1 degree. For air, specific heat ~ 1300 J m -3 Ventilation heat loss rate = volume * ach * 1300/3600 = 0.361 * ach * volume Energy Conservation in Buildings: The Basics

14. Norwich Business School 14 10. Energy Conservation in Buildings: The Basics 11. Heat Loss Calculations 12. Energy Management 13. Carbon Emission Factors 14 Lecture 2 NBSLM03E (2010) Low Carbon Technologies and Solutions N.K. Tovey ( 杜伟贤 ) M.A, PhD, CEng, MICE, CEnv

15. Norwich Business School 15 Five components to heat loss / gain parameter Losses through Floor Roof Windows Walls Ventilation 20: Heat Loss / Heat Gain Calculations Ventilation: Volume * 0.361 * ach Fabric Components: Area * U - value Total Heat Loss / Heat Gain Rate (H) H = ΣArea * U–value of fabric components + Volume * 0.361 * ach Heat lost from a building in a cool climate (or heat gained in warm climate) must be replaced (removed) by the heating (cooling) appliance – e..g boiler (air-conditioner) Heat to be replaced (removed) = H * temperature difference (inside – outside) Heat Loss / Heat Gain Calculations

16. Norwich Business School 16 Design considerations: Heating/Cooling Capacity depends on internal and external temperatures. What should design temperature be? – Internally – comfortable temperature – thermostat setting. – Externally ? In internal temperature is set too high, sufficent heating will not be supplied in extreme conditions. But extra cost is often implied. Design External temperature in UK for heating –1 o C In more extreme parts -3 0 C is sometimes selected Heavy weight buildings do store heat to allow for some carry over to colder conditions. Heating appliances usually come in standard sizes – size to next size above requirement. Heat Loss / Heat Gain Calculations

17. Norwich Business School 17 Design considerations: Hot water heating is often provided by same source Provides an extra buffer for peak heating demand. Heating / Cooling must be designed to cope with peak design demand. Annual Energy Consumption Incidental gains arise from Body heat Lighting Hot water use Appliance use Solar gain Decrease / Increase overall annual heating (cooling) energy consumption – typically by several degrees. Heat Loss / Heat Gain Calculations

18. Norwich Business School 18 If incidental gains from all sources amount to 2250 watts, and the heat loss rate is 500 W C -1. Free temperature rise from incidental gains = 2250 / 500 = 4.5 o C If thermostat is set at 20 o C, No heating is needed until internal temperature falls below 20 – 4.5 = 15.5 o C. 15.5 o C is the neutral/base/or balance temperature. In UK and USA and used internationally the balance temperature for heating is on average 15.5 o C (60 o F). Each building is different and for accurate analysis, corrections must be applied. To allow rapid assessment of annual energy consumption  Heating Degree Days (HDD)……Cooling Degree Days (CDD) There appears to be no standard for the base temperature for Cooling Degree Days but UKCIP02 uses 22 o C Heat Loss / Heat Gain Calculations

19. Norwich Business School 19 Degree Days are an indirect measure of how cold or how warm a given period is. Used for estimating annual energy consumption. Heating Degree Days For every 1 o C MEAN temperature on a particular day is below base temperature we add 1. For 10 o C we add 15.5 -10 = 5.5 For -1 o C we add 15.5 – (-1) = 16.5 For -10 o C we add 15.5 – (-10) = 26.5 For days when MEAN temperatures above base temperature we do not add anything. Total Degree Days over a period is sum of all individual days Gives approximate estimate – see shaded box in hand out for more accurate method. Monthly Degree Days are published at www.vesma.com Heat Loss / Heat Gain Calculations

20. Norwich Business School 20 Annual Degree Days – East Anglia 20 year average 1959 – 1978 - 2430 20 year average 1979 – 1988 - 2351 20 year average 1988 - 2007 - 2182 20 year averageJanFebMarAprMayJunJulAugSepOctNovDec 1979 - 19983743362912281457236 69157266341 1988 - 200733730327221212865333162143258338 Example: 1 Heat Loss Rate (coefficient) is 450 W o C -1 What is estimated energy consumption for heating in January to March based on latest 20 year data = 450 * ( 337 + 303 + 272) * 86400 = 35.46 GJ Or 450 * (337 + 303 +272) * 24 / 1000 = 9850 kWh 86400 is seconds in a day 24 is hours in a day Heat Loss / Heat Gain Calculations

21. Norwich Business School 21 120 132 144 156 168 180 192 204 216 228 240 Hours Boiler Output for a house during early January 1985. 20 15 10 5 0 -5 -10 Temperature o C 10 9 8 7 6 5 4 3 2 1 0 Boiler Output (kW) Heat Loss / Heat Gain Calculations

22. Norwich Business School 22 If no heating is provided and mean external temperature is 20 o C Internal temperature has a much lower amplitude and lags by several hours Can be used in effective management Heat Loss / Heat Gain Calculations

23. Norwich Business School 23 In morning period, boiler is full on during period, but throttles back during evening period Heat Loss / Heat Gain Calculations

24. Norwich Business School 24 With time switching – larger boiler is required to get temperature to acceptable levels Heat Loss / Heat Gain Calculations

25. Norwich Business School 25 Large building in tropical country has 12000 sqm of single glazing Electricity consumption is as shown If Cooling Degree Days are 3000, and coefficient of performance of air-conditioner is 2.5, what is annual energy consumption? Gradient of cooling line is 75 kW / o C Annual consumption is 75 * 3000 * 24 = 5400 MWh If carbon factor is 800 kg /MWh Carbon emitted = 5400 * 800 / 1000 = 4320 tonnes Cooling demand Appliance / Base Load demand Heat Loss / Heat Gain Calculations

26. Norwich Business School 26 Gradient of line = 75 kW o C -1 actual heat gain rate = 75 *2.5 = 225 kW o C -1 must allow for COP of air-conditioner Installing double glazing reduces heat gain rate by: 12000 * ( 5 - 2.5) = 30 kW o C -1 U – values before and after double glazing Saving in electricity with be 30 /2.5 = 12 kW o C -1 Saving in electricity consumed = 12 *3000 * 24 = 864 MWh carbon saving = 864*800 / 1000 = 691.2 tonnes Heat Loss / Heat Gain Calculations

27. Norwich Business School 27 Annual electricity saved = 864 MWh - Annual carbon saved = 691.2 tonnes Marginal cost is 740 Paise/Unit - 9.328p per unit at Exchange Rate on 07April 2008 Total saving in monetary terms would be 864 * 1000 * 0.09328 = £80,594 per year With a life time of 30 years say, this represents a saving of £2.4 million A total of 25920 MWh saved and 20700 tonnes of carbon dioxide. If ‘K’ glass (low emissivity glass were installed) savings would be around 50% larger Data for India Heat Loss / Heat Gain Calculations

28. Norwich Business School 28 New house designed with heat loss rate of 0.2 kW o C -1 Two options Oil boiler - oil costs 45p/litre: calorific value 37 MJ/litre Heat Pump – electricity costs 4.5 per kWh Examine most cost effective option. Heat pump data as shown in graph. TemperatureCOP 6.53 12.54.0 164.2 83.2 Capital costs: Oil Boiler £2000, Heat Pump £4000 Heat Loss / Heat Gain Calculations

29. Norwich Business School External Temperature ( o C) COP from graph Number of days Difference from balance temperature Heat Requirement (kWh) Requirement after allowing for COP (kWh) (1)(2)(3)(4)(5)(6)(7) Jan - Mar6.5390938881296 Apr - Jun12.549131310.4327.6 Jul - Sept164.292 NoHeating needed Oct - Dec83.2927.533121035 Total energy requirement8510.4 Boiler efficiency90% Energy input boiler option as oil 9456 Total effective electrical input via heat pump 2658.6 Col (5) = 15.5 – col (2) Col (6) = 0.2 * col (5) * col (4) * 24 Col (7) = col (6) / col (3) Oil required 9456 kWh = 34042 MJ So 34042 / 37 = 920 litres are needed Cost of oil = 920 * 0.45 = £414 Cost of electricity for heat pump = 2658.5 * 0.045 = £119.64 and an annual saving of £294.36 Analysis is best done in tabular form Heat Loss Rate for house Heat Loss / Heat Gain Calculations

30. Norwich Business School Annual saving in energy costs = £294.36 At 5% discount rate, cummulative discount factor over 10 years is 8.721735 So the discounted savings over life of project = 8.721735 * 294.36 = £2567.36 This is greater than the capital cost difference of £2000 (i.e (£4000 - £2000), there will be a net saving of £567.36 over the project life and the heat pump scheme is the more attractive financially. Heat Loss / Heat Gain Calculations

31. Norwich Business School 31 10. Energy Conservation in Buildings: The Basics 11. Heat Loss Calculations 12. Energy Management 13. Carbon Emission Factors 31 Lecture 2 NBSLM03E (2010) Low Carbon Technologies and Solutions N.K. Tovey ( 杜伟贤 ) M.A, PhD, CEng, MICE, CEnv

32. Norwich Business School Energy Management: Electricity Consumption in a medium sized regional office of a large company Electricity Consumption improves in late 2004 Implementation of conservation measures - Low Energy Lighting phased over autumn Sudden jump in consumption Nearly double early 2005 level 33% higher than historic level Cost increase ~ £10000 - £12000 pa CO 2 increase ~ 100 tonne per annum Appears to be associated with malfunction of air conditioner 32

33. Norwich Business School Electricity Consumption kWh/m 2 ) Local Authority Offices NorwichGreat Yarmouth Kings Lynn Naturally ventilated Air- conditioned Good Practice 5497 289125140 Typical85178 Electricity kWh/m 2 kWh/employee Great Yarmouth125.34695 Kings Lynn140.03226 Norwich289.43817 33 Energy Management: Electricity Consumption of several offices of a large company

34. Norwich Business School ElectricityCarbon Dioxide kWh/sqm kWh/ employee kg/sqm tonnes/ employee Great Yarmouth125.3469589.23.34 Kings Lynn140.032261052.43 Norwich289.43817188.22.48 Annual Household consumption of Electricity in Norwich 3720 kWh Energy Management: Electricity Consumption and Carbon Dioxide Emissions of several offices of a large company 34

35. Norwich Business School 35 Basic analysis – Aim: Assess overall energy performance of building Normalise to a standard time period Assess variation with external temperature Prediction – Aim set targets for energy consumption following improvements Issues to address Convert all units to GJ or kWh for GJ multiply heat loss rate by Degree Days and number of seconds in a day (86400). for kWh multiply heat loss rate by Degree Days and number of hours in a day (24). Energy Management: Assessing Annual Consumption

36. Norwich Business School 36 Degree day method – Quicker – Oil & coal heating difficult – general estimates of consumption Mean temperature method – More accurate – Plot mean consumption against mean external temperature Energy Management: Assessing Annual Heating Requirements

37. Norwich Business School 37 Two component parts – Temperature related – Independent of temperature Hot water & cooking if by gas Total Energy = W + H*degree days*86400 W energy for hot water + cooking (gas) H is heat loss rate for the home – Two unknowns W & H, – Know degree days & energy consumption in two different periods of year – Estimate heat loss & steady energy requirement Assessing Annual Heating Requirements: Degree Day Method

38. Norwich Business School 38 Energy consumption 2 successive quarters: 31.76 & 18.80 GJ Corresponding degree days: 1100 and 500 Total Energy consumed = W + H * degree days*86400 1100 * H * 86400 + W = 31.76 ………..(1) 500 * H * 86400 + W = 18.80 ………..(2) Simultaneous equations (subtract 2 from 1) H = (31.76 – 18.80) * 10 9 = 250 Watts (1100-500)*86400 Substitute for H in either equation to get W W = 31.76 * 10 9 - 1100 * 250 * 86400 = 8 * 10 9 = 8GJ H - heat loss W - hot water Annual Heating Requirements: Degree Day Method - example

39. Norwich Business School 39 Once H & W have been calculated Performance for subsequent quarters can be estimated If degree days for 3 rd quarter = 400 – Consumption predicted to be – 400 * 250 * 86400 + 8 * 10 9 = 16.64 GJ H W If actual consumption is 17.5 GJ then energy has been wasted Annual Heating Requirements: Degree Day Method - example

40. Norwich Business School There is a fair amount of scatter about trend line Lines drawn at 1.5 standard deviations above an below trend line Some consumption data points lie outside the band and should be classified as “Reporting Incidents” With time tighter deviation lines can be drawn Analysis of Energy Consumption Data in a Building – Degree Day Method 40

41. Norwich Business School 41 Electricity consumption varies during year. Base load for appliances and refrigeration Variable lighting Load depending on number of hours required for lighting Intercept is base load (A) Gradient is Lighting Load Parameter L Appliances and Refrigeration Lighting Installing Low Energy Lighting will decrease gradient by a factor 5 Installing more efficient appliances will reduce base load Installing both measures will reduce both L and A Analysis of Lighting in a Building not heated by electricity

42. Norwich Business School 42 Plot the mean consumption over a specific period against mean external temperature Generally more accurate than Monthly Degree Day Method as short term variations can be explored. With Daily readings, variations with day of week can be explored e.g. Weekend –shut down, do Mondays see extra consumption Two parts to graph Heating part represented by sloping line Base load for cooking/hot water by horizontal line. Do not merely do a regression line Analysis of Energy Consumption Data in a Building – Mean Temperature Method (not heated electrically)

43. Norwich Business School 43 Gradient of line is related to heat loss rate (coefficient) Adjust for boiler efficiency Multiply by  to get heat loss rate (coefficient) – e.g. – 70% for non condensing boiler, – 90% for condensing boiler – 300% for heat pump Efficiencies of all boilers are available on SEDBUK Database www.sedbuk.com/index.htm Two parts to graph Heating part represented by sloping line Base load for cooking/hot water by horizontal line. Analysis of Energy Consumption Data in a Building – Mean Temperature Method (not heated electrically)

44. Norwich Business School 44 Data before conservation Intercept = appliance and refrigeration load (A). Gradient is Lighting load (L) Low energy lighting installed – should reduce L by 80% Actual data after installation Suggests that improvement of 80% is not achieved. If actual data are shown as blue line – improvements in energy management have taken place – or replacement of appliances with more energy efficient ones. Analysis of Lighting in a Building not heated by electricity – An Example

45. Norwich Business School 45 A – appliance Load W – water heating Load H – heat loss parameter L – lighting Load parameter More complex for analysis as both H & L are unknown Combine A & W to give overall appliance + hot water load (A*) E = (degree days * H + lighting hours * L) * 86400 + A* – Where E = energy consumption 3 unknowns – H, L & A – If we have data for 3 quarters – Estimate values for H, L & A by solving 3 simultaneous equations If appliance load is known calculation is easier Actual analysis is beyond the scope of this scope, but the potential does exist. If more than three month data are available then opportunities for statistical analysis exist. Analysis of Heating and lighting in an electricilly heated Building – Method 1

46. Norwich Business School 46 6 5 4 1 2 3 + + + + + + + + + + + + + + + + + Time Saving Excess + + + + + + + + + + + + + + + 1.No energy conservation – horizontal line 2.Winter following improved insulation 3.Summer – no savings – heat conservation only 4.Winter – parallel to 2 5.Summer - improved management of hot water 6.Should be (4) + (5) but gradient is in fact less - energy conservation performance has got worse Cumulative Saving Cumulative Deviation Method Not as detailed as other methods, but good for displaying monetary savings in Lay Man’s terms

47. Norwich Business School Actual data from large residential building in Shanghai in 2006 Fudan University – Twin Tower Gradients of lines 43.05 MWh per deg C per month heating 52.12 MWh per deg C per month cooling Assume 720 hours in a month 59.8 kW o C -1 heating and 72.4 kW o C -1 cooling =43.05/720 = 52.12/720 ANALYSIS OF BUILDING WITH HEATING AND COOLING All energy consumption is from electricity 47

48. Norwich Business School Annual Heating Demand - 1675 MWh Annual Cooling Demand - 2515 MWh Annual Baseline (Functional) Demand - 2304 MWh Functional Energy Use is 35.5% of total energy use. Baseline consumption Analysis of Energy Data - Fudan University – Twin Towers ANALYSIS OF BUILDING WITH HEATING AND COOLING Neutral Temperature - 17.5 o C Baseline consumption - 192.0 MWh/month 48

49. Norwich Business School 49 10. Energy Conservation in Buildings: The Basics 11. Heat Loss Calculations 12. Energy Management 13. Carbon Emission Factors 49 NBSLM03E (2010) Low Carbon Technologies and Solutions N.K. Tovey ( 杜伟贤 ) M.A, PhD, CEng, MICE, CEnv

50. Norwich Business School Emission Factors for Fossil Fuels in UK Emission factors for Fossil fuels as used in the UK are available at: http://www.decc.gov.uk/en/content/cms/statistics/climate_change/gg_emissions/intro/intro.aspxhttp://www.decc.gov.uk/en/content/cms/statistics/climate_change/gg_emissions/intro/intro.aspx. Single values if emission factors are quoted per unit volume or mass Two different values are quoted if specified in terms of energy content – e.g. GJ, kWh depending on whether Lower or Higher Calorific Value is used. Which calorific value should be used., If lower CV is used then emission factor is higher when specified in energy terms If higher CV is used the emission factor is lower when specified in energy terms CO2 Fuel TypeUnitskg CO2 per unit Natural GaskWh net0.20374 kWh gross0.18358 cum2.0091 therms net5.9712 therms gross5.3801 Emission Factors 50

51. Norwich Business School 51 Charging ZoneCalorific Value MJ/cum Eastern 38.9 East Midlands 39.4 Northern 40.2 North East 39.5 North Thames 39.0 North West 39.0 Scotland 39.7 South East 39.1 Southern 39.1 South West 39.1 West Midlands 39.1 Wales North 39.0 Wales South 39.3 Scottish Independents 38.3 Stranraer 39.6 Calorific Values across the UK on 29/05/2010 Emission Factors: Calorific Values of Natural Gas Calorific values vary slightly among fuels For natural gas it also depends on pressure and composition Is becoming more variable as increased amounts are imported from overseas

52. Norwich Business School Emission Factors for electricity depend on – Fuel mix – Efficiency of Generation by each fuel – Fuel mix varies from day to day – less coal at weekends – Fuel mix varies from day to night 52 Emission Factors: Electricity Generation Fuel Mix December - January 2008/92009/10 Coal44%34% CCGT36%46% Nuclear15%17%

53. Norwich Business School Efficiency of Electricity Generation (DUKES 2009) [r – revised] 20042005200620072008 CCGT47.049.048.9r48.951.9 Coal fired36.235.635.7r 36.0 53 Emission Factors: Electricity Generation Emission Factors for electricity depend on – Efficiency of Generation by each fuel – Upstream Carbon Emissions – Transmission Losses to point of end use. Emission Factor for generation (kg/kWh) excluding upstream and transmission losses 20042005200620072008 CCGT0.3910.375 0.354 Coal fired0.8560.8710.868 0.861 For gas in 2004, emission factor = 0.18358 / 0.47 = 0.391 kg/kWh

54. Norwich Business School Emission Factor for generation (kg/kWh) including upstream but excluding transmission losses. 20042005200620072008 CCGT0.4150.3980.399 0.376 Coal fired0.8760.8910.888 0.881 54 Emission Factors: Electricity Generation & Supply Emission Factor for electricity supply (kg/kWh) including upstream and transmission losses. 20042005200620072008 Transmission Losses8.30%7.40% 7.20% CCGT0.4520.4300.4310.4300.405 Coal fired0.9550.9620.9590.9570.949 Emission Factors for electricity generation including extraction of fuels: depends on primary energy ratio. For consumption of electricity – transmission losses must be included in calculations.

55. Norwich Business School 55 UK Emission Factors: Electricity Generation & Supply