As a key stage in the government's energy review is reached, ministers have been urged to focus on renewable sources of power.

Energy minister Malcolm Wicks is conducting a review for the prime minister, with the deadline for submissions now passing and the results due to be announced by the summer.

Tony Blair, however, has already expressed doubts about whether targets to cut carbon dioxide emissions can be met without the construction of a new generation of civil nuclear reactors.

And Liberal Democrat energy spokesman David Howarth warned: "The government has already made up its mind to go with the nuclear option and is only using this review to justify its decision.

"Going through a long review process, only to come up with whatever answer Tony Blair wants to hear, is no use to anyone.

"Nuclear power is not renewable. The expense of any new program would risk crowding out all development of genuinely renewable technologies. 

"We need to get going on tackling climate change and reducing our dependence on fossil fuels."

His comments come a day after the British Wind Energy Association said that by 2020 wind, wave and tidal power could generate 21 per cent of the UK's projected electricity needs.

BWEA chief executive Marcus Rand said ministers should have "confidence to commit this nation to generating at least a fifth of our power needs from renewables by 2020".

"The arguments for doing so are compelling; huge public support, significant carbon reduction, increased energy security, and affordable power delivered quickly by a dynamic and innovative industry ready and willing to deliver," he said.