HINKLEY Point C could cost around £500m more than expected, according to EDF.
The energy giant said “significant progress” has been made on the Bridgwater site, but the cost is now expected to be in the range of £22billion to £23billion.
This could be up to £500million more than originally thought, as previous cost estimates were between £21.5billion to £22.5billion.
The completion of the project will also be delayed. The start of electricity generation from Unit 1 is now expected in June 2026, when it was expected to open at the end of 2025.
The Hinkley site reached a major milestone last summer, with EDF completing the 49,000-tonne base for the second reactor on schedule.
It came less than a year after completion of the first reactor’s base in June 2019.
Once completed, Hinkley C will generate electricity for around 7% of the country’s homes.
EDF said the delay and increased costs mean the expected rate of return from its investment will fall from between 7.6 per cent and 7.8 per cent to between 7.1 per cent and 7.2 per cent.
It added that a delay of nine to 15 months for Units 1 and 2 would cost around £700 million and knock the rate of return by a further 0.3 per cent.
Roy Pumfrey, spokesperson for the Stop Hinkley campaign, said: “This delay and cost increase is totally unsurprising. In fact delays and cost overruns for HPC are as predictable as night following day.
“We note that EDF makes no mention of the previously announced risk of a (non-Covid-related) 15 month delay and £700m cost overrun.”