A deal to build Britain's first new nuclear plant in a generation is due to be announced tomorrow.
The government has been in negotiations with French-owned EDF Energy over the Hinkley Point C project for more than a year.
However, ministers are now believed to have agreed on a "strike price" - the guaranteed rate to be paid for electricity produced at the Somerset site.
Chancellor George Osborne removed another obstacle last week when he announced that Chinese firms will be allowed to invest in civil nuclear projects in the UK - even potentially taking a majority stake.
The two reactors proposed for Hinkley are a key part of the coalition's drive to shift the UK away from fossil fuels towards low-carbon power.
Energy policy has shot up the agenda since the party conference season, when Labour leader Ed Miliband pledged to freeze retail prices for 20 months.
The issue has become even more controversial with the Big Six power firms unveiling hikes of more than 9% in electricity and gas prices.
The Archbishop of Canterbury Justin Welby and Deputy Prime Minister Nick Clegg both raised concerns about the increases today.
Mr Welby told the Mail on Sunday the companies had to be "conscious of their social obligations" and "behave with generosity and not merely to maximise opportunity".
Mr Clegg demanded more evidence that the hikes were needed at all.
"Clearly the companies need to justify the bill increases that they are now announcing," the Liberal Democrat leader told Sky News' Murnaghan programme.
"It cannot be right that people who are really struggling - many, many people still struggling to pay their weekly, their monthly bills, where electricity and gas bills for this winter are a looming worry - it can't be right that those bills are increased for those households in our country and yet it is all rather opaque about what drives these increases.
"Because some of the companies are not really open enough yet and transparent enough yet about their own balance sheet."
