Jonathon Porritt: Our nuclear future may already be decided

The acid test on economics will be opinion in the City

"The replacement of nuclear power stations, a big push on renewables and a step-change on energy efficiency are back on the agenda with a vengeance." The Prime Minister's choice of words in his recent speech to the CBI is revealing. It comes as no surprise to have it confirmed that energy efficiency and renewables have been so scandalously off the agenda since the 2003 Energy White Paper, but it's an embarrassing concession. Some argue that the principal reason why an apparently "dramatic" gap between energy supply and demand is looming is the fact that the Government has made so little progress on both these fronts over the past three years.

There's an overwhelming consensus that the most cost-effective way to reduce both emissions of CO 2 and dependence on gas imports is through serious investment in energy efficiency. Sadly, there's a generation of officials in the Department of Trade and Industry for whom this has always been of little interest.

It's not quite as bad as the picture on renewables. But the target of generating 10 per cent of our electricity from renewables by 2010 is looking increasingly at risk, with long delays on most of the big offshore wind farms and on-going confusion around a biomass programme that lags a long way behind those in many other European countries.

So much for energy efficiency and renewables. There's also no particular problem about nuclear power being "back on the agenda", so putting it there "with a vengeance" sounds like a singularly inappropriate rhetorical flourish. Any government with a nuclear programme which it knows is winding down over the next 15 years has a clear obligation to assess whether or not it needs to replace those reactors. It's ludicrous for environmentalists to argue that this is, in itself, an irresponsible decision. But where they are on much firmer ground is in accusing the Prime Minister of appearing to pre-empt the energy review process that he himself set in train after last year's general election.

As no one else has yet seen the evidence presented to him by the pro-nuclear DTI, it's hard to guess which particular arguments have persuaded him to risk an extremely controversial public debate. He might be reassured by the safety record of the nuclear industry and that a new nuclear programme will be cheaper than our existing nuclear reactors, while producing less waste.

The acid test on economics will be opinion in the City. If the review concludes that no new reactors will be built without substantive public subsidy, then this puts the Government in a quandary. Once it becomes clear that a given sum of taxpayers' money will be directed at the nuclear industry to help achieve the twin goals of reducing CO 2 emissions and improving security of supply, then a different calculus kicks in. What is the cost to the taxpayer of each tonne of carbon dioxide abated via nuclear power compared to each tonne abated via investments in efficiency or renewables? Evidence to the Sustainable Development Commission demonstrates that nuclear will never compete on those terms.

The acid test on nuclear waste will be public opinion. The Government's existing policy is crystal clear: that there will be no further investment in nuclear power until the issue of nuclear waste from existing reactors has been resolved. The interim report from the Committee on Radioactive Waste Management offers no such resolution. It merely restatesthat the only acceptable way of disposing of high-level nuclear waste is by deep burial, and that this will be massively costly.

One can only hope that these issues will be dispassionately and rigorously addressed in the review when it is published in a few weeks' time. The fear now is that evidence is being skilfully "massaged" to fit with a decision that has already been taken.

Jonathon Porritt chairs the Government's Sustainable Development Commission