1. 1 NBS-M016 Contemporary Issues in Climate Change and Energy 2010 18. Energy Balance Tables N.K. Tovey ( ) 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 1

2. Professor Stephen Glaister is wrong (letter, 4 March). There will be plenty of electrical power to recharge the batteries of Boris Johnson's electric cars, without a large use of fossil fuels, at night, which is when electric car batteries are normally recharged. Relatively little electricity is used at night industrially, domestically or for transport or retail. The bulk of overnight use is met from nuclear, hydro-electric, wind and tidal generation; and generation from these sources will increase in the future. Sir Reginald E W Harland Bury St Edmunds, Suffolk 7 th March 2009 What is wrong with the following letter to the editor?

3. Sir Reginald Harland is incorrect (letter, 7 March) when he implies that there will be plenty of electricity available overnight without a large use of fossil fuels. The data of electricity generation in the UK in the night hours of midnight to 6am over the last four months show that on average 79 per cent of it came from fossil fuel. This percentage was only slightly less than the daytime use of fossil fuels, at 81.4 per cent. Indeed, during the past four months, the minimum overnight fossil fuel component (on 22 February) was 69.2 per cent, while on 6 January it reached 86.8 per cent. Thus the major part of overnight electricity is always derived from fossil fuels. Indeed, the situation will get worse in the short term with the closure of our nuclear ageing plant, as despite a significant recent increase in renewable generation from wind etc, this has not kept pace with the loss of low-carbon nuclear capacity. Dr Keith Tovey CEng Reader in Environmental Sciences, University of East Anglia NORWICH 10 th March 2009

4. 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 Energy Balance Tables

5. 5 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

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

7. 7 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 CoalManu- factured fuel(1) Primary oils Petroleum products Natural gas(2) Renewab le & waste(3) Primary electricity ElectricityHeat Total UK Production475.7-3,290.0-2,917.0182.6542.8--7,408.1 Net imports1,087.322.0544.6-331.51,009.539.7-35.9-2,407.4 Net Energy Available1,563.022.03,834.6-331.53,926.5222.3542.835.9-9,815.5 Transfers--5.3-146.1146.3-0.2--44.244.2--5.3 Net Consumption1,563.016.73,688.5-185.23,926.3222.3498.680.1-9,810.2 Energy Conversion Inputs-1488.5--3688.5--1430.1-148.1-498.6--- Outputs 69.9 3624.4 1343.853.6- Net energy balance----------2162.0 Energy Industry Use0.235.6-200.0249.1--95.63.0583.4 Transmission losses-9.9--49.1--98.70.0157.7 Delivered Energy Available74.441.1-3239.22198.074.2-1229.650.66907.1 Balance Check74.441.1-3239.22198.074.2-1229.650.66907.1 Energy Demand INDUSTRY52.231.1-266.3477.014.1-408.832.41281.8 TRANSPORT---2397.7-34.4-30.4-2462.4 OTHER22.110.0-186.51687.625.7-790.518.32740.7 Final Consumption (Energy only)74.441.1-2850.52164.674.2-1229.650.66485.0 Non-Energy use---388.733.3-0.1- 0.0422.1

8. 8 Simplified Energy Balance Tables Coal Manufactured fuel(1) Primary oils Petroleum products Natural gas UK Production 475.7-3,290.0-2,917.0 Net imports 1,087.322.0544.6-331.51,009.5 Net Energy Available 1,563.022.03,834.6-331.53,926.5 Transfers --5.3-146.1146.3-0.2 Net Consumption 1,563.016.73,688.5-185.23,926.3 Renewable & waste(3) Primary electricityElectricityHeat Total UK Production182.6542.8--7,408.1 Net imports39.7- 35.9-2,407.4 Net Energy Available222.3542.8 35.9-9,815.5 Transfers--44.2 44.2--5.3 Net Consumption 222.3 498.6 i.e. nuclear 80.1-9,810.2 A B A* 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.

9. 9 -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. Coal Manufactured fuel(1) Primary oils Petroleum products Natural gas(2) Net Consumption1,563.016.73,688.5-185.23,926.3 Energy Conversion inputs-1488.5--3688.5- -1430.1 outputs 69.9 3624.4 Renewable & waste(3) Primary electricityElectricityHeat Total Net Consumption222.3498.680.1-9,810.2 Energy Conversion inputs-148.1-498.6--- outputs 1343.853.6- net energy balance-----2162.0 Simplified Energy Balance Tables: Energy Conversion

10. 10 Coal Manufactured fuelPrimary oils Petroleum products Natural gas Transformation [Energy Conversion] -1,488.569.9-3,688.53,624.4 -1,430.1 Electricity generation -1,252.3-35.9--41.4-1,346.7 Heat generation -11.9-2.2--2.5-83.4 Petroleum refineries ---3,688.53,677.4- Coke manufacture -179.2170.1--- Blast furnaces -35.7-71.9--9.1- Patent Fuels -9.39.8--- Energy Conversion Renewable & waste Primary electricityElectricityHeat Total Transformation [Energy Conversion] -148.1-498.61343.853.6 -2,162.0 Electricity generation -148.1-498.61,343.8--1,979.3 Heat generation ---53.6-46.4 Petroleum refineries -----11.1 Coke manufacture -----9.1 Blast furnaces -----116.7 Patent Fuels ----0.5 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

11. 11 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 1343.8PJ generated. 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%

12. 12 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 FuelPrimary Energy Ratio Coal1.0227 Oil1.1292 Gas1.062 Electricity2.911 Pumped Storage

13. 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 Coal Japan in 2007 Gas derived from Coal processes Other Bituminous Coal Coke Oven Gas Blast Furnace Gas Basic Oxygen Steel Furnace Gas Unit kilotonnesTJ Total Transformation 10130529690067964322449827639 Electricity Plants 9432427644107964322449827639 CHP Plants 00000 Heat Plants 24703000 1 tonne coal has a calorific value of 29.3076 GJ Data from IEA data base for Coal for Japan

14. A more accurate estimate of emission factor in electricity generation Coal Japan in 2007 Gas derived from Coal processes Other Bituminous Coal Coke Oven Gas Blast Furnace Gas Basic Oxygen Steel Furnace Gas Unit kilotonnesTJ Total Transformation 10130529690067964322449827639 Electricity Plants 9432427644107964322449827639 CHP Plants 00000 Heat Plants 24703000 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 ~ 310 g/kWh Carbon factor for coal generation = 310/0.3451 = 898 g/kWh If efficiency ~ 30% then carbon factor would have been 1033 g/kWh Figures in Red from IEA data base for Electricity (Japan)