1 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 1 NBSLM01E Climate Change and Energy: Past, Present and Future 10. Energy Balance Tables Recipient of James Watt Gold Medal

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

3 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 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

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

5 Simplified Aggregate Energy Balance 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 Production , , ,408.1 Net imports1, , ,407.4 Net Energy Available1, , , ,815.5 Transfers Net Consumption1, , , ,810.2 Energy Conversion Inputs Outputs Net energy balance Energy Industry Use Transmission losses Delivered Energy Available Balance Check Energy Demand INDUSTRY TRANSPORT OTHER Final Consumption (Energy only) Non-Energy use

6 Simplified Energy Balance Tables Coal Manufactured fuel(1) Primary oils Petroleum products Natural gas UK Production , ,917.0 Net imports 1, ,009.5 Net Energy Available 1, , ,926.5 Transfers Net Consumption 1, , ,926.3 Renewable & waste(3) Primary electricityElectricityHeat Total UK Production ,408.1 Net imports ,407.4 Net Energy Available ,815.5 Transfers Net Consumption i.e. nuclear ,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 PJ is attributed to gross nuclear generation (i.e. before conversion), and 44.2 is transferred as renewables.

7 -ve quantities indicate inputs to conversion, +ve indicates outputs PJ of coal was used as input to conversion processes of which PJ (see box in full table) went to electricity production PJ of crude oil produced PJ of Petroleum products. Coal Manufactured fuel(1) Primary oils Petroleum products Natural gas(2) Net Consumption1, , ,926.3 Energy Conversion inputs outputs Renewable & waste(3) Primary electricityElectricityHeat Total Net Consumption ,810.2 Energy Conversion inputs outputs net energy balance Simplified Energy Balance Tables: Energy Conversion

8 Coal Manufactured fuelPrimary oils Petroleum products Natural gas Transformation [Energy Conversion] -1, ,688.53, ,430.1 Electricity generation -1, ,346.7 Heat generation Petroleum refineries ---3,688.53, Coke manufacture Blast furnaces Patent Fuels Energy Conversion Renewable & waste Primary electricityElectricityHeat Total Transformation [Energy Conversion] ,162.0 Electricity generation , ,979.3 Heat generation Petroleum refineries Coke manufacture Blast furnaces Patent Fuels PJ of coal went into electricity generation as did 35.9 PJ of coke, 41.4 PJ of oil, PJ of natural gas PJ of waste/biomass and 498.6PJ of nuclear equivalent. In total PJ were generated from thermal plants with an input of

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

10 The supply of electricity is from thermal plants The total losses associated with the electricity industry = = So first order Primary Energy Ratio for electricity = /( – 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 Coal Oil Gas1.062 Electricity2.911 Pumped Storage

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 Per capita Carbon Emissions UK How does UK compare with other countries? Why do some countries emit more CO 2 than others? What is the magnitude of the CO 2 problem? China

13

r Electricity Generation i n selected Countries

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 Electricity Plants CHP Plants Heat Plants tonne coal has a calorific value of GJ Data from IEA data base for Coal for Japan

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 Electricity Plants CHP Plants Heat Plants Total coal based products consumed in power stations = TJ Total Electricity generated GWH = TJ Efficiency of coal fired generation = / = 36.14% Transmission Losses 4.50% so overall efficiency = * = 34.51% If carbon factor for direct combustion is ~ 320 g/kWh Carbon factor for coal generation = 320/ = 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)