The UK has become gripped by a debate on the future of nuclear power. I am glad this has happened, but I want the debate to be rigorous and impartial. We need to get on with the discussion because our decision-making processes are slow, especially when public engagement is paramount.

What are the key issues? We have obligations to protect the planet’s environment, but energy policy must also deliver sustainable, secure, and affordable supplies. UK gas reserves, previously abundant and cheap, are declining. But government figures show that 70 per cent of Britain’s electricity will come from gas by 2020, and 90 per cent of that will be imported.

We need to increase the amount of power generated from renewable sources: wind turbines, wave and tidal generators, nuclear, solar and, in the long term, perhaps, nuclear fusion. However in the short term it seems inevitable that the major contribution will have to come from nuclear and wind power.

Nuclear power generation has made great strides. After a period when it was believed to be hopelessly uneconomic, it is now close to competing in real economic terms with gas-powered generation. And even after making allowance for decommissioning costs, nuclear is significantly cheaper than wind or wave power. In any case, cost cannot be the only factor determining energy policy. If it were, our strategy would almost certainly be to rely on carbon-generating sources. A price will have to be paid if we are to beat climate change.

The disposal of nuclear waste is the issue that has created most public concern, but it will have to be dealt with whether or not we build new nuclear plants. It is important to realise that if we were to build 10 new nuclear stations and operate them for 60 years, there would be an increase in the UK’s existing waste stockpile of only about 10 per cent. It is crucial that the government’s Committee on Radioactive Waste Management accelerates its deliberations and delivers recommendations on the way ahead. Other countries – notably France, Sweden, and Finland- are ahead of us in arriving at practical and acceptable long-term solutions.

We must also concentrate as much on more efficient use of energy as we do on its generation. It is arguable that one solution to our looming energy crisis is to cut back consumption drastically, and there is indeed scope for this. Our housing stock is the least efficient in northern Europe and our transport policy far from optimal. There is also scope for wider use of truly renewable and less polluting sources, which in practical terms today means wind power. This twin-track approach is broadly current government policy. But how realistic is it without building new nuclear capability?

The UK needs about 50 gigawatts of generating capacity. There are those who argue that reserve capacity, for example to deal with exceptional weather conditions, is already too small. The British Wind Energy Association has calculated that to use wind power alone to meet the government’s target of supplying 10 per cent of our electricity needs from renewable sources by 2010 would require more than 6,000 large turbines. These would occupy an area of between 300 and 460 sq miles - that is more than half the area of Greater London. Finding such an area for turbines 100 metres high and 100 metres in diameter would be extremely difficult.

The grid network would also have to be strengthened, itself a controversial project, as the wind capacity has to be backed up with non-intermittent generators requiring more feed points to the grid. The country cannot plunge into darkness whenever we have a calm, cold night. The National Audit Office has calculated that this could cost up to £1.3bn by 2010.

My conclusion is that we have to reopen the nuclear option, and without delay. We need to reintroduce nuclear energy generation as a subject in our universities, and to start the licensing processes for new plant. Ironically, British Nuclear Fuels, through its Westinghouse subsidiary, already builds nuclear plants for other countries, but it would take three years to license these in Britain under the present rules.

The UK needs to pursue a balanced energy policy that makes the most of all the opportunities at its disposal: gas, clean coal, renewable and, yes, nuclear. Whatever we choose, in whichever combination, there will be associated costs, but the costs will be far greater if we delay action.

Lord Broers, chairman of the House of Lords science and technology committee, is president of the Royal Academy of Engineering

This article first appeared in the Financial Times on Wednesday 18th May 2005