(Bloomberg) -- Electricite de France SA said the completion of its flagship British nuclear plant project will be delayed at least six months and cost about 500 million pounds ($687 billion) more than previously planned because of the coronavirus pandemic.

The French state-controlled utility warned last year that such risks had risen as Covid-19 slowed construction of the two reactors it’s building with its Chinese partner at Hinkley Point in Southwest England.

The project completion cost at Hinkley Point C is now estimated at 22 billion to 23 billion pounds, half a billion more than estimated in 2019, EDF said in a statement Wednesday. The first reactor will begin producing power in June 2026, compared with end-2025 as initially announced in 2016, it said.

The delay and cost overruns will trim EDF’s projected rate of return on the project. The French company reiterated that units 1 and 2 still face a potential delay of 15 and 9 months, respectively, which might result in additional costs of about 700 million pounds.

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