Energy Secretary Chris Huhne has insisted the government is fully behind the opening of a new nuclear power station in eight years' time.
He was responding to calls from the CBI business group to reassure investors that ministers were prepared to make a big push for nuclear power.
He told BBC Radio 4's Today he was in favour of a mix of more nuclear, oil and gas and renewable energy.
"I have no intention of the lights going out on my watch," he said.
Mr Huhne, seen as anti-nuclear power in the past, said his previous position had been misunderstood and he had merely pointed out there had been no private investment since the Three Mile Island accident in the US in 1979.
But he said investors had now indicated to him they were ready to press ahead as a result of rising gas, oil and carbon prices.
"We are on course to make sure that the first new nuclear power station opens on time in 2018," Mr Huhne said.
"There are a number of sites that have been identified around the country and those are generally on sites where we have previously had, for example, nuclear power stations and where the local people are very keen that there should be new nuclear build.
"What we have to do - we have eight years now before I hope that the first one will come making a contribution to the grid - and we have to get through all of the prior arrangements, like, for example, the national planning statements, like making sure that investors have got their applications formally in and approved, and then of course building can commence."
Mr Huhne said he believed MPs would vote in favour of new nuclear power stations providing there was no public subsidy.
Nuclear energy split the generally pro-nuclear power Conservative and generally anti-nuclear power Liberal Democrat partners when the government was formed in May.
Under the terms of the coalition agreement, Lib Dem MPs can abstain in Commons votes on nuclear power but cannot bring the coalition down over it in a confidence motion.
The government has also said it is to abolish the Infrastructure Planning Commission which was set up by Labour as a body designed to speed up nationally important large projects like nuclear power plants.
It is to replace it with a Major Infrastructure Unit which gives ministers the final say over such projects, although the details of how it will work are not yet known.
The Confederation of British Industry warned that the uncertainty over the planning regime and electricity market reform means investors were "wary" of committing to new projects at the moment.
Mr Huhne said: "I don't think you can determine whether a government is serious about energy policy merely in terms of whether it is prepared to write very large cheques.
"It has always been clear that our next generation of electricity power stations are going to be built by private investors with a framework put in place."
Councils to sell energy
That framework included a "very clear commitment" for a carbon price floor as part of an incentives system to encourage investment.
In a separate development, councils in England and Wales will be able to sell renewable energy directly to the National Grid under proposed reforms aimed at encouraging them to use their buildings and land to host projects that generate wind, solar and water power.
Mr Huhne said selling to the grid could allow councils to raise up to £100m a year in income.
Such sales have been restricted since legislation was introduced to privatise the electricity industry in 1989, but the lifting of the restriction takes effect from next week.
The Local Government Association said the new rules had the potential to cut energy bills and provide much-needed income to maintain services and keep council tax down.
Only 0.01% of electricity in England is currently generated by local authority-owned renewables, compared with around 1% in Germany.