N.K. Tovey ( 杜伟贤 ) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук

1. NBSLM01E Climate Change and Energy: Past, Present and Future N.K. Tovey (杜伟贤) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук Energy Science DirectorCRedProject HSBC Director of Low Carbon Innovation • 10. Energy Balance Tables Recipient of James Watt Gold Medal 1

2. Energy Balance Tables • Energy balance tables provide information on: • Overall energy consumption in a country for a given year. • Details of production and consumption of specific fuels • Allow overall efficiency of energy use within a country to be ascertained • Give information on energy losses • Give information on sector split of energy consumption • Information from Balance tables is needed as a first stage in an accurate estimate of carbon emission factors in a country

3. Energy Balance Tables • Best Constructed on a Heat Supplied basis – i.e. potential that fuel has – usually based on calorific value. • Units vary widely for one source to another • Many use MTOE – but what is calorific value of oil - many sources (but not all) assume 41.868 GJ/tonne – this is International Standard • Check what value is actually used. • Scientifically it is better to use Joules throughout • For a country use either PJ or EJ, depending on size of country. • Primary Electricity convention is not always consistent - • may include hydro and nuclear, but may be specified in thermal equivalent. • sometimes hydro is included in renewable electricity – sometime as primary electricity

4. UK Aggregate Energy Balance 2008 - Dukes (2009) Energy Supply including imports/exports Energy Conversion Energy Industry Use Industrial Demand Transport Demand Other Energy Demand PetaJoules ( PJ)

5. Simplified Aggregate Energy Balance 2008 - from Table 1.1 Dukes (2009) • Aggregate Energy Balance Tables • Summarises overall situation for a country • Specific Fuel Energy Balance Tables • Covers more detailed split of energy and uses for that fuel PetaJoules (PJ) A B A* =A+B C D E F = A*+ C-D-E G H I J=G+H+I K = F-J 5

6. Simplified Energy Balance Tables Transfers represent transfers between columns – e.g. Primary electricity is generally large scale renewables and nuclear, but the non-nuclear component is transferred as it is not involved in the energy conversion process in next section. i.e 498.6 PJ is attributed to gross nuclear generation (i.e. before conversion), and 44.2 is transferred as renewables. A B A* 6

7. Simplified Energy Balance Tables: Energy Conversion -ve quantities indicate inputs to conversion, +ve indicates outputs. 1488.5 PJ of coal was used as input to conversion processes of which 1252.3 PJ (see box in full table) went to electricity production. 3688.5 PJ of crude oil produced 3624.4 PJ of Petroleum products. 7

8. Energy Conversion 1252.3 PJ of coal went into electricity generation as did 35.9 PJ of coke, 41.4 PJ of oil, 1346.7 PJ of natural gas. 148.1 PJ of waste/biomass and 498.6PJ of nuclear equivalent. In total 1343.8PJ were generated from thermal plants with an input of 8

9. Energy Conversion In 2008, 1252.3 PJ of coal went into electricity generation as did 35.9 PJ of coke, 41.4 PJ of oil, 1346.7 PJ of natural gas. 148.1 PJ of waste/biomass and 498.6PJ of nuclear equivalent. Total Input = 3323.1 PJ with 1343.8PJgenerated. Thus the overall thermodynamic efficiency of generation = 1343.8 / 3323.1 = 40.4% In the balance table 498.6PJ was nuclear input, actual amount of nuclear electricity generated = 498.6 * 0.404 = 201.6PJ Electricity use on stations = 58.7PJ (from full table) Overall station efficiency of fossil fuel plant allowing for station use = (1343.8 – 58.7 ) / 3323.1 = 38.67% Transmission Losses = 98.7PJ or 98.7/(1343.8-58.7) = 7.68% 9

10. The supply of electricity is 1388.4 from thermal plants The total losses associated with the electricity industry = 58.7 + 98.7 + 4.6 = 162.1 So first order Primary Energy Ratio for electricity = 3323.1/(1343.8 – 162.1) = 2.81 assumes that the PER for coal, oil and gas is 1.0 Similar first order analysis gives a PER of 1.11 for oil. Using an iterative approach second order estimates are obtained as follows. However, what about fuel extracted overseas. This second order analysis assumes that the PERs in those countries are same as UK. Energy Conversion Pumped Storage 10

11. Exercise on Energy Balance Tables • Download the Electricity Balance Table Spreadsheet • Using the following approximate carbon factors work out the overall carbon emission factor for the countries allocated to you: • coal ~ 900 gms / kWh • oil ~ 800 gms / kWh • gas ~ 430 gms / kWh • nuclear ~ 15 gms /kWh • These factors vary according to efficiency of the plant and to some extent the actualgrade of the fuel.

12. What is the magnitude of the CO2 problem? How does UK compare with other countries? Why do some countries emit more CO2 than others? China UK Per capita Carbon Emissions 12

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14. r Electricity Generation i n selected Countries

15. A more accurate estimate of emission factor in electricity generation • Emission factor in electricity generation depends on: • Carbon emission factor of burning fuel • Efficiency of power station • Transmission losses • Example Japan Data from IEA data base for Coal for Japan

16. A more accurate estimate of emission factor in electricity generation Total coal based products consumed in power stations = 3096190 TJ Total Electricity generated 310796 GWH = 118866 TJ Efficiency of coal fired generation = 118866/3096190 = 36.14% Transmission Losses 4.50% so overall efficiency = 36.14 * 0.955 = 34.51% If carbon factor for direct combustion is ~ 320 g/kWh Carbon factor for coal generation = 320/0.3451 = 927 g/kWh If efficiency ~ 30% then carbon factor would have been 1067 g/kWh Figures in Red from IEA data base for Electricity (Japan)