Energy Secretary Ed Davey has hailed a landmark deal to build Britain's first new nuclear plant in a generation.
The agreement with French-owned EDF Energy will see Hinkley Point C begin operating in 2023.
But ministers are likely to face criticism over the £92.50 per megawatt hour that will be paid for electricity produced at the Somerset site - around double the current market rate.
The so-called 'strike price' could fall by £3 if another mooted development at Sizewell goes ahead, allowing for efficiencies in development and testing.
The contract is due to run for 35 years, with the electric price increasing annually in line with CPI inflation. At full capacity the two reactors could provide up to 7% of the country's energy needs.
It is understood that China General Nuclear Power Group and China National Nuclear Corporation will be investing in the estimated £14 billion scheme.
One of the last stumbling blocks to a deal was removed last week when Chancellor George Osborne announced that Chinese firms would be allowed to invest in civil nuclear projects in the UK - even potentially taking a majority stake.
Davey insisted he had secured "good value" following more than a year of intense negotiations. The project will cut the UK's carbon emissions by nine million tonnes a year, and create thousands of jobs.
"We think it would be good value if (the strike price) was a little higher," the Liberal Democrat Cabinet minister said.
"I was determined to get them below £90 so I could prove to everybody we had got a good deal...
"What has driven a tougher deal is the fact that I made clear we could walk away from the table. We had other nuclear options."
He added: "We have got an early start on our long-term energy needs."
Davey stressed that the construction risks were being borne by the companies, and the Government would not be on the hook for any overspends.
However, if costs fell, the taxpayer would share in the savings.
There are also protections for the Government in the event that the firms are able to refinance and boost profit margins.
All decommissioning and waste management costs are also included in the deal, he said.
The initial commercial agreement is not legally binding until EU clearance has been secured for the state aid. A final contract is expected to be signed next year.
The announcement comes with energy policy high on the agenda after the Big Six power firms began unveiling hikes of more than 9% in electricity and gas prices.
Labour leader Ed Miliband has sought to gain the political initiative by pledging to freeze retail prices for 20 months if he wins the 2015 general election.
The Archbishop of Canterbury, the Most Rev Justin Welby, and Deputy Prime Minister Nick Clegg both raised concerns about the increases yesterday.
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".
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."
Prime Minister David Cameron said: "As part of our plan to help Britain succeed, after months of negotiation, today we have a deal for the first nuclear power station in a generation to be built in Britain.
"This deal means £16 billion of investment coming into the country and the creation of 25,000 jobs, which is brilliant news for the South West and for the country as a whole.
"As we compete in the tough global race, this underlines the confidence there is in Britain and makes clear that we are very much open for business.
"This also marks the next generation of nuclear power in Britain, which has an important part to play in contributing to our future energy needs and our longer term security of supply".