As policy-shapers gear up to debate whether the UK should build a new generation of nuclear reactors, the BBC News website asked two prominent experts with opposing views to debate the issue.
Vice President of the Royal Society Sir David Wallace, who believes nuclear may still have a future, exchanged e-mails with Tom Burke, a visiting Professor at Imperial College London and a nuclear sceptic.
Dear Tom Burke,
The debate about where the UK gets its energy from must be viewed in the context of climate change, which is the biggest environmental threat that we face today.
The UK is on track to meet its commitment under the Kyoto Protocol to cut its emissions of greenhouse gases by 12.5% by 2012.
However, the government's white paper on energy suggests that, if we are to avoid the worst effects of climate change, we need to reduce carbon dioxide (CO2) emissions by about 60% by the middle of this century.
Yet the UK's emissions actually rose by over 2% between 2002 and 2003.
Clearly we must wean ourselves off fossil fuels.
But the debate about where we get our energy from must not be polarised, as it so often is, as a trade-off between renewable sources of energy and nuclear power.
If we are to ensure that we are cutting our emissions of greenhouse gases drastically, while at the same time ensuring that there is security of supply, then we must develop a policy of diversity based on evidence and not ideology.
In the short to medium term it is difficult to see how we can meet our energy needs without the help of nuclear power - a relatively "climate friendly" source of energy.
Nuclear currently provides us with about a quarter of our electricity in the UK. But with almost all nuclear power stations reaching the end of their lives in the next 20 years it is not clear how we will make up this shortfall.
Unfortunately - and wishful thinking will not make it otherwise - this gap is unlikely to be filled by renewable sources of energy such as wind, wave, solar or the burning of "energy crops".
The UK's target of generating 10% of our electricity from renewable sources by 2010 is laudable but even this target looks ambitious.
In 2002, for example, renewables accounted for just 3% of electricity. Even if we achieve the full 10% we will be more reliant on fossil fuels in 2010 than we are today, if we allow nuclear power stations to close as scheduled.
As part of a comprehensive energy strategy, we should be striving energetically to meet and go beyond these targets for renewable energy.
There is clearly security in diversity of supply and in the long term we would expect renewables to be able to supply a much larger proportion of our energy needs. And the UK is in a particularly good position to exploit wave and tidal power.
The estimates of costs for various renewables and for nuclear remain persistently disputed.
However, the economics of energy production would change if the government were to introduce a cost on all emissions of carbon dioxide through, for instance, a carbon tax.
This would encourage the development of carbon free technologies - including nuclear and renewable power - and a move away from carbon based fuels in the overall energy supply, as well as promoting energy efficiency measures.
Clearly, if we were to build a new generation of nuclear power stations to replace at least some of those scheduled for decommissioning, there would be very serious issues that needed to be addressed.
Any plans to build new nuclear power stations must, of course, include a strategy for dealing with the serious issue of how we manage radioactive waste safely.
This problem needs to be resolved regardless of whether a new generation of nuclear power stations is built because of existing radioactive waste - much of which was a product of the civil and military nuclear programmes in the 1950s - as well as new waste from the operation and decommissioning of the present generation of nuclear power stations.
Additionally, the issue of how nuclear power stations would be protected from terrorist attacks would also need to be faced.
We should not underestimate the challenge involved in meeting the UK's energy demands while drastically cutting emissions of greenhouse gases.
It is for those that would say that this must be done without a contribution from nuclear power to answer why and how.
Sir David Wallace
Vice President , The Royal Society, and Vice Chancellor, Loughborough University
Dear Sir David,
We agree about a great deal.
I share your view that combating climate change is vital to the future well being of everyone on the planet.
I also agree that we must meet the growing demand for energy in a way that is compatible with a stable climate. This will indeed mean very significant reductions in greenhouse gas emissions.
You are also right to emphasise the need to base our judgements on evidence not ideology, though I am not sure who exactly you think is taking an ideological stance.
Furthermore, in relation to the UK, I agree with your conclusion that renewable energy, even with a much greater effort, will not be able to replace the electricity currently provided by those nuclear power stations that will reach the end of their life by 2020.
There are two reasons why I part company with you on the role nuclear power has to play in Britain.
The first concerns what is happening in the rest of the world. The second is particular to Britain.
The EU has indicated that it believes allowing the planet's temperature to increase by more than 2C would be dangerous.
We know from recent studies that if the concentration of carbon dioxide in the atmosphere exceeds 400 parts per million the probability of remaining within this limit is low. We also know that at the current rate of increase we will pass this point in just over a decade.
Time to act is very short.
Globally, new coal fired power stations are being commissioned at the rate of more than one a week. More than 1,400 are forecast to be built by 2030, about 600 of them in China alone.
If they are built with conventional technology there is no prospect of maintaining a stable climate whatever else we do.
Many possible routes to a stable climate are technologically and economically available but there is no politically available route that does not include Chinese, Indian and North American coal, largely for energy security reasons.
The Chinese energy future already includes the world's most ambitious nuclear programme but this does not significantly reduce the country's need for coal.
The single most urgent task, therefore, for the world community is to prevent lock-in to carbon-intensive coal-generated electricity.
This means bringing about the large scale deployment of advanced coal technologies with carbon sequestration and storage within the next decade to reduce these emissions to a safer level.
For Britain, nuclear power is irrelevant.
It is has no attractions for private investors in a competitive electricity market as it produces no revenues for at least seven years, is subject to a host of difficult to quantify socio-political risks and is only economically viable in very large tranches of perhaps 10 reactors.
Financing a programme this big means paying for it out of the public purse or rigging the electricity market sufficiently to cover the private investors' risks - which would, incidentally, also considerably reduce the scope for the diversity of supply you rightly commend.
Past experience with this course is not encouraging.
British Energy needed a £500m rescue three years ago when electricity prices fell by almost half.
To protect a 10-reactor programme from such a price fall you would have to fix the amount and price of its output long enough to at least pay for the full capital cost.
It is not difficult to work out why the rest of the electricity industry and any consumer, public service or business that uses electricity might object.
But let us suppose, bravely, that all these obstacles could be overcome. Even so, a new nuclear power programme cannot help Britain very much with its climate dilemma.
Starting from now, the very earliest an order for a new nuclear power station could be placed is 2007. Beginning there and doing better than has ever been done before, you might have your first station operating by 2015.
If you then start ordering two at a time, and do even better, you would still be lucky to have three in operation by 2020 when your nine station emission gap appears.
Fortunately, if we do what is right for the planet we will have made available to Britain the advanced coal technologies that provide a more viable option for meeting our electricity needs.
We have long experience in using coal to provide our electricity. It is far more attractive to private investors and would therefore require much less intervention by government - and cost to taxpayers.
The brutal truth is that no-one has yet managed to work out a way of getting nuclear reactors to burn uranium as effectively as they burn money.
Nor has anyone discovered how to make atoms work for peace without making them available for war.
By abandoning the nuclear chimera we offer both our ourselves and the world a far more realisable option for jointly meeting our climate and our energy needs.
Visiting Professor at Imperial and University Colleges London. Co-founder of E3G, Third Generation Environmentalism.