Nuclear Figure 2 summarises carbon footprint estimates for various countries and operating conditions, but not for the UK. 6,13,28,29,30,31,32 The majority of estimates fall below 26 gCO2eq/kWh, though the outliers indicate that footprints can be higher. This variation arises from the general factors outlined in Box 2 and also from nuclear-specific issues, particularly the grade of the uranium ore and the method of uranium enrichment.30,33,34There are also uncertainties regarding waste disposal and decommissioning.34 For current UK conditions, recent but unpublished research from the University of Manchester15,35 estimates a footprint of 6.4 gCO2eq/kWh for a new build plant. Non-peer reviewed estimates produced by AEA Technology for existing UK plants are 5.5 gCO2eq/kWh for Sizewell B36 and 7 gCO2eq/kWh for Torness. 37
Gas Figure 1 shows footprint estimates for six European gas generation scenarios from three studies. 7,8,13 The lowest carbon footprints are achieved by the most efficient generation technology – combined cycle gas turbines (CCGT) – which predominate in the UK. One UK study 8 gives a footprint of 488 gCO2eq/kWh for a CCGT. More recent research from Imperial College London14 and separately at the University of Manchester15 is indicating that UK CCGT footprints can be as low as 365 gCO2eq/kWh for modern technology, but these estimates are excluded from the figure because they have not yet been peerreviewed and published.
Energy sources/Technology considered for the cost estimate/GHG emissions(Kg CO2eq/MWh) Natural gas/CCGT (Combined Cycle Gas Turbine)/400 Nuclear/Light water reactor/15