X is a coefficient for power, related to alternative electricity supply options. Similarly, Y is a coefficient for heat generation, related to alternative heat generation options. These coefficients vary to reflect conditions affecting particular classes of CHP plant. For a scheme that supplies electricity only, Efficiencyheat is zero. Efficiencies are expressed in terms of gross calorific values (GCV), since the proposed regime will use metered values for fuel use, electricity generation and heat supplied. Annual heat supply is the useful heat supplied by the scheme, displacing heat that would otherwise have to be supplied by boilers or by direct heating. The methodology reflects the technical factors affecting the selection of CHP plant in different applications and circumstances. These factors include: - Alternative power supply options for CHP, taking account of the generation methodology that would be employed - The improvement in generating efficiency that can be - - achieved with increasing scale Reduced transmission and distribution (T&D) losses for smaller embedded generating plant, as compared to larger, grid-connected generating plant Different alternative heat supply options. in industrial applications, CHP will typically displace boilers across a range of sizes, fuels and thermal efficiencies. in district heating, communal boilers, electric heating and small individual boilers are displaced by heat from CHP. in order to be designated 'Good Quality' CHP, schemes should achieve a QI of 110 in design, and at least 100 in operation using the proposed definitions in Table 1. Schemes with a QI less than 100 may be eligible for a proportion of benefits. These criteria will be operated using series of definitions outlined below so that it is clear what is, and is not, defined as part of the scheme and eligible for benefits. C02 SAVINGS FROM COGENERATION Carbon content of fuel • Coal 328 kg/MWh (GCV) • Gas 180 kg/MWh (GCV) • Mix oil 255 kg/MWh (GCV) • Typical mix of power 185 kg/MWh (GCV) (based on 40% coal, 30% gas and 30% non-fossil) • Fossil mix 264 kg/MWh (GCV) (based on 57% coal and 43% gas) Network losses • EU average T&D losses • EU average own use • Total losses Emlssions from central generatlon Coal • Steam cycle efficiency • Emissions of co2 at power station • Emissions of co2 at average customer Gas • Combined cycle efficiency • Emissions of co2 at power station • Emissions of co2 at average customer Mix of al! electricity • Efficiency • Emissions of co2 at power station • Emissions of CO 2 at average customer Mix of fossil • Efficiency • Emissions of co2 at power station • Emissions of co2 at average customer Boilers • Efficiency • Coal • Gas • Oil Cogeneratlon (Most new cogeneration wi/1 be gas-fired) Gas turbine with waste heat boiler • Heat-to-power ratio • Efficiency • Emission of co 2 per unit of fuel • Emission of co 2 per kWh of electricity 52 rı ECOGENERATION WORLO 7% 5% 12% 38% 862 g/kWh 980 g/kWh 55% 430 g/kWh 372 g/kWh 43% 430 g/kWh 489 g/kWh 45% 587 g/kWh 489 g/kWh 80% 410 g/kWh 225 g//kWh 333 g/kWh 1 .6:1 80% 587 g/kWh 489 g/kWh CCGTCHP • Heat-to-power ratio • Efficiency • Emission of co 2 per unit of fuel • Emission of co 2 per kWh of electricity Gas engine CHP • Heat-to-power ratio • Efficiency • Emission of co 2 per unit of fuel • Emission of co 2 per kWh of electricity Total generation • 1995 • 2010 1 :1 80% 225 g/kWh 450 g/kWh 1 .6:1 80% 225 g/kWh 581 g/kWh 2310 TWh 2882 TWh (Source: European Union Energy Outlook to 2020-'Conventional Wisdom' scenario) Cogeneratlon share • 1995 • 2010 • New CHP generation • Heat supplied on CHP Addltlonal cogeneration emisslons • Gas turbine 9%-208 TWh 18%-519 TWh 311 TWh 435 TWh 54,149,806 tonnes CO 2 • CCGT CHP • Gas engine • Total (assumption 30% GT; 40% CCGT; 30% GE CHP) 55,954,800 tonnes CO 2 54,149,806 tonnes CO 2 164,254,413 tonnes CO 2 Displaced electricity • Ali coal • AII gas • Mix • Mix fossil Dlsplaced bollers • AII gas • AII coal • Mix coal 30%; gas 40%; oil 30% Carbon dioxlde savings • CHP displaces coal electricity and coal boilers • CHP displaces gas electricity and gas boilers • CHP displaces fossil mix electricity and boilers 304,538,684 tonnes CO 2 54,149,806 tonnes CO 2 54,149,806 tonnes CO2 54,149,806 tonnes CO 2 97,920,900 tonnes CO 2 178,216,038 tonnes CO 2 136,110,051 tonnes CO 2 319 million tonnes 49 million tonnes 179 million tonnes
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