Nearly all studies of the amount of carbon dioxide (CO2) released by different power sources show that atomic power stations rival hydroelectric dams and wind turbines in lifetime emissions per unit of electricity.
Comparisons of emissions over a full life cycle count the energy cost of construction, extracting and delivering fuel, and the gas given off while generating power. Excess CO2 is accused of being the greenhouse gas most to blame for global warming.
Tony Blair, for long a sceptic over nuclear power, has been convinced by business groups that it is the only energy source low in CO2 that is reliable and comparable in cost to power from fossil fuels such as gas and coal.
A study delivered last month by EEF, the manufacturers’ association, claimed that atomic power could compete on cost with efficient gas-fired plants, if the costs of carbon permits that must be bought from the European Union emissions market are high.
If carbon charges are low — as they are today — power from gas is cheaper, but atomic power is comparable in cost to coal-fired power stations, is two thirds the cost of wind turbines on cliffs and hillsides and is half the price of offshore wind power.
Like the turning of wind turbines and the hydroelectricity created by damming river valleys, generating nuclear power gives off virtually no CO2 directly. Like these renewable forms of energy, however, the process of building, equipping, fuelling and dismantling atomic power stations uses substantial amounts of energy, often fossil fuels, such as oil and petrol.
French methods of enriching uranium for the country’s atomic power stations are judged by rivals to be relatively inefficient in energy use. But this energy itself comes from nuclear plants, which generate three quarters of the country’s power.
Using average energy sources, however, a series of studies have concluded that, over its life cycle, nuclear power emits between 6 grams and 26 grams of CO2 per kilowatt hour of electricity, the amount needed to power a one-bar electric fire for an hour. The biggest sources are construction, decommissioning and converting uranium ore into fuel.
Emissions from nuclear plants are higher than from hydroelectricity generators in Japan and Scandinavia. But they are tiny compared with a thermal gas or coal-burning plant.
One respected study comes from Vattenfall, a big Swedish power utility operating in Scandinavia, northern Germany and Poland. It uses gas, coal, nuclear, hydro and wind power and has published estimates for regulatory purposes. These suggest that coal stations emit almost a kilogram of carbon per kilowatt hour of power over their lives and efficient gas stations about half that. Wind, nuclear and hydro, which are the safest in terms of global warming, emit less than 10 grams.
The carbon costs of wind power come mainly from manufacturing the huge metal turbines and from the high costs of connecting many far-flung wind farms to the national electricity grid.
The nuclear power cycle is more complex. Wildly different assumptions can be made about the costs of fuel, radioactive waste and cleaning up nuclear sites. The British Nuclear Group and the Government’s Nuclear Decommissioning Authority have clashed over whether sites simply can be secured and left for 100 years to cool, or should be restored as soon as possible, at greater expense.
Little effort was made to find new uranium deposits for 20 years because cheap oil, gas and coal, allied with worries about nuclear waste and the Chernobyl accident, stalled the world nuclear industry. By the turn of the century, uranium sold at a third the price of two decades earlier. The price has recovered to half its peak since China and India became interested in atomic power. Explorers are active again.
Roland Clift, Professor of Environmental Technology at the University of Surrey, argues that although new discoveries are likely, they are most likely to be low-grade ore, such as that now drawn from Rio Tinto’s Rössing mine in Namibia. Low-grade ore takes twice as much energy to convert and raises carbon emissions nearer the top of the accepted range of estimates. Energy used could rise to an average 3 per cent of energy generated. But that would still be better than coal or gas and there is a limit.
Round the world, 30 fast-breeder neutron reactors were built before the richest uranium deposits were discovered. This technology is more costly to build and more complex to operate than conventional pressurised water reactors such as Britain’s Sizewell B.
Most of the experimental fast-breeder reactors either were abandoned, like Dounreay in Scotland, or mothballed because they had become uneconomical when uranium became cheaper. Uranium prices would have to double, regaining their peak, before neutron reactors would become economical again. But if they did, even critics of nuclear power agree that the world’s effective nuclear fuel reserves would multiply by a factor of 60.