Neither do many researchers. A 2003 Massachusetts Institute of Technology study recommended vast expansion of nuclear power to make a dent in the climate-change problem. Princeton researchers also cited it as an option, although they acknowledged concerns about terror threats and potential accidents.
One University of Wisconsin life-cycle emissions study in 2003 found even lower carbon emissions for nuclear than for most renewables. "We found wind and nuclear fission to have the lowest greenhouse-gas emissions over their life-cycle," says Paul Meier, director of the energy institute at the university. "We didn't include biomass and some of the others now available."
Yet it's not so much nuclear's carbon emissions, which are still relatively modest, but its cost-effectiveness in reducing carbon-dioxide emissions globally that's the key question, researchers say. Few studies have addressed that question.
According to one study that has studied the question, nuclear power may not fare as well when its life-cycle cost of reducing CO2 emissions is compared with other energy alternatives. An Öko Institut study last year found that countries would get more bang for their buck by moving to other forms of energy – such as biomass and even some natural-gas power plants – rather than nuclear power.
Wind surprisingly has about the same carbon footprint as nuclear when manufacturing and load factors are included. But wind power also doesn't produce long-lived nuclear waste – storage of which includes an energy cost that's unknown and is not factored into the Öko or most other analyses – yet.
Just improving a nation's energy efficiency would produce far less CO2 than a new nuclear plant (5 grams vs. 32 grams per kilowatt-hour), the study found. And it would do so at lower cost (4.8 cents vs. 5.2 cents per kilowatt-hour).
A handful of other studies show far higher life-cycle CO2 emissions for nuclear than the Öko study. One Dutch researcher, for instance, finds that a vast expansion of nuclear powerr could deplete ore reserves and lead to a far higher level of energy use – and carbon emissions – from extracting uranium and refining it.