Greenpeace has published a report arguing that Japan could get 43% of its electricity from renewables by 2020 (see The Japan Times: Nation could get 43% of power from renewable energy by ’20, report says). So it could, though that would be a quadrupling of renewables’ contribution from the 2008 contribution in just 12 years, and that’s just electricity – not heating or transport fuel. Most of the transport fuel in Japan, as everywhere else at present, is oil, and most of the heating fuel is gas (see Japan – climate and energy statistics).
Greenpeace argues that Japan should phase out its nuclear stations by the end of next year, and replace them with gas power stations, which pollute less than coal or oil stations do. This is correct. However, gas power stations produce over three times as much carbon dioxide per unit of electricity as nuclear stations do (see How low-carbon are different generating technologies?).
So the crucial question is this: Is gas a sufficiently low-carbon technology to act as a bridge until we can be 100% reliant on renewables? Or, more bluntly, is nuclear worse than gas? Nuclear power obviously has serious disadvantages: cost, proliferation risk and risk of accidents. Thorium molten salt reactors would reduce the risk of proliferation and accident, but wouldn’t be cheap (see Centre for European Reform policy brief: Thorium: How to save Europe’s nuclear revival).
However, gas also has serious disadvantages. Its carbon emissions are much too high to make it a low-carbon bridge technology, unless it is combined with carbon capture and storage – which has yet to be demonstrated at scale and also won’t be cheap. And much of the gas has to be imported from countries run by undemocratic or dubiously democratic governments – think Iran or Russia. The USA now has plenty of its own gas due to shale gas which it extracts by cracking open rocks and getting the gas out. This is good in energy security and economic terms, but the lifecycle climate impact of shale gas remains essentially unknown. One study by Cornell University argues that the emissions from shale gas are as high as from coal (see The New York Times: Shale Gas Isn’t Cleaner Than Coal, Cornell Researchers Say), though this report is highly contested.
Even if one assumes that the emissions from shale gas are similar to those from conventional gas, the fact remains that the global climate cannot afford the emissions from four or five more decades of burning gas. Climate change is the greatest threat that humanity has ever faced – greater than any danger posed by nuclear power. Therefore, gas is worse than nuclear.
Having worked for Greenpeace for several years, I try to avoid criticising the organisation. Greenpeace is forty years old today, and was founded as part of an anti-nuclear weapons campaign (hence the name). And being anti-nuclear is not just part of a historical hangover – there are many good people working for Greenpeace who are genuinely and deeply convinced that nuclear power is not part of the solution. However, they are wrong to suggest that gas is an adequate low-carbon bridge technology.