Plant operators such as EDF and Drax had indicated their plants would close before this deadline, but they have been kept available under contracts with National Grid as part of contingency plans for winter 2022/23 against a backdrop of record gas prices and fears of supply issues. National Grid's Electricity System Operator said it had been asked by the government to explore potential contingency contracts for coal plants for the 2023/24 winter.

This winter the back-up coal plants have been used only once, when a cold snap swept the country in early March. But both EDF and Drax said they did not expect to be able keep their plants ready for operation again next winter.

EDF said it had already indicated to the government that it planned to close its two remaining coal units at the West Burton A plant on March 31, 2023. "There are a number of workforce and operational reasons that mean extending the life of West Burton A again is very challenging," it said in a statement, adding that many staff have already stayed on well beyond planned retirement dates.

Drax also said its coal units will close at the end of March 2023 as planned. With "a number of certifications expiring on the coal-fired units, the units would not be able to operate compliantly for winter 2023," a Drax spokesperson said in an emailed statement.