Sizewell C has been given an extra £1.3bn from government so work can 'steam ahead' as it seeks private investors to support its construction.
The new nuclear plant - capable of producing about 7% of the UK's electricity needs - received a big boost earlier this month when construction work was officially given the green light with the triggering of its Development Consent Order (DCO).
The taxpayer funds will support ongoing preparatory works including road and rail improvements around the Suffolk site so the necessary local infrastructure is in place before full construction begins.
Financing the project is now the biggest hurdle to clear this year - with objectors sceptical of the government's ability to raise the huge funds needed.
But with two previous government funding pledges of £700m and £511m, the Suffolk site is now in line for £2.5bn of taxpayer cash. The latest pledge will come from "existing budgets", the government - the project's major shareholder - said.
The amount the construction will cost remains unclear but could be around £20bn-plus.
The government says it expects to make a "final investment decision" later this year. When he visited Suffolk on January 22, Mr Bowie said the Final Investment Decision would be made "by the end of this parliament".
"Committing further government support at this stage will help the project stay on schedule and keep down overall costs," the government said.
Earlier this month it announced the biggest expansion of nuclear power for 70 years, with a Civil Nuclear Roadmap with the aim of quadrupling nuclear power generation to up to 24GW by 2050.
Among the plans are another power plant of the magnitude of Sizewell C and a fleet of Small Modular Reactors.
Nuclear Minister Andrew Bowie said: “We are making fantastic progress on the next GW-scale power plant in the UK’s nuclear pipeline.
“This investment injection means we can steam ahead with work on Sizewell C ahead of the final investment decision targeted later this year.
“It’s a win for our energy security and sends a strong message to investors that Britain is serious about its low-carbon, homegrown nuclear-powered future, providing reliable, cheaper power for British families.”
Sizewell C joint managing directors Julia Pyke and Nigel Cann said the "significant" investment was a "further sign of confidence" in their team to deliver the project.
“The funding means we can step up activity in Suffolk and deliver on our commitments to local communities.
“Sizewell C will build on the huge contribution of Hinkley Point C in restarting nuclear construction in Britain.”
But Alison Downes of campaign group Stop Sizewell C claimed there was "grave uncertainty" about the government's ability to make a Final Investment Decision - or even how much the project will cost.
"There's little indication external investors have serious interest in Sizewell C at this point, and every sign that Hinkley Point C's costs and schedule in building the same type of reactors are heading south," she said.
"It is inexplicable why the government is intent on shackling taxpayers and consumers to such a disastrous project, especially with an election approaching."
Once operational, the plant is expected to generate 3.2GW of electricity - enough to power up to 6 million homes for more than 60 years.
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