Nuclear reactors are powered by a nuclear fission process which does not involve the combustion of fossil fuels that release carbon dioxide into the atmosphere.
The carbon footprint of a nuclear power station comes mainly from carbon emissions released during reactor construction and the mining, transport and processing of uranium ore needed to supply nuclear fuel for the reactor. Nuclear power stations have a carbon footprint of about 18 times less CO2 than gas-fired power stations, and 34 times less CO2 than coal-fired power stations during their entire lifecycle.
The government's 2008 White Paper on Nuclear Power concluded that nuclear power stations emit up to 22 grams of carbon per kilowatt-hour of electricity produced (22 g/kWh). This compares with 385 g/kWh for a CCGT gas-fired power station and 755 g/kWh for a coal-fired power station.
Is nuclear going to replace coal, oil and gas?
Britain's electricity mix today is 13% nuclear, 31% coal and 46% gas as measured by UK electricity consumption. Wind, oil and hydroelectric power plus French electricity imports together make up the remaining 10%. Gas-fired power stations are probably here to stay.
The economic flexibility of gas-fired power stations, their ability to be used to balance intermittency of renewables, and their much lower carbon footprint than coal means that gas-fired generation will continue to dominate UK electricity production for the foreseeable future. The major energy technology battle is now between nuclear power stations versus coal-fired power stations fitted with carbon capture and storage (CCS). Britain faces two different kinds of nuclear renaissance.
The first wave nuclear renaissance that would take place between now and 2025 simply aims to 'replace nuclear with nuclear'. All but one of Britain's 10 operating nuclear power stations are scheduled to close by 2023. Britain's existing 11 GWe nuclear fleet would be replaced with new PWR reactors as existing AGR and Magnox stations reach the end of their operating lives. Rising electricity demand during this period means that the overall percentage of nuclear in the UK electricity mix would actually fall, failing to make any significant impact on delivering the UK's low carbon objectives.
A second wave nuclear renaissance that might take place beyond 2025 is much more strategically important for the UK. The second wave would essentially mean 'replacing coal with nuclear', increasing the share of nuclear electricity generation from the present level of 13% up to around 35-40% beyond 2030 as proposed by the Wicks Review. The outcome will depend on whether coal with CCS proves to be either more or less economic than nuclear power and whether the CCS technology works at commercial scale.
Is nuclear power the answer to a low carbon economy?
Nuclear power is part of the answer but is not the whole solution to achieving a low carbon economy. Britain's electricity generation and transmission system is an integral component of the country's Critical National Infrastructure (CNI). It is sensible to build both redundancy and diversity into any technically advanced engineered system. This means that a range of proven low-carbon energy technologies will be needed to form a balanced electricity supply mix including nuclear power.
The proposed electrification of the vehicle transport sector and deployment of smartgrid network technology has game-changing implications for nuclear power. The political consensus is that deployment of electrical power will significantly expand from the home and workplace to encompass some or all of the transport sector, with substantial numbers of electric cars predicted by 2030.
A new national recharging network would be needed enabling Britain to lead the world in replacing traditional cars with electric and plug-in hybrid vehicles. Full electrification of the transport sector would perhaps double Britain's low carbon electricity generation needs. This implies a tremendous scaling-upwards of low carbon electricity generation which could probably only realistically be met by nuclear power in the medium term.