A power station is to close with the loss of about 170 jobs after it failed to secure new contracts.
Eggborough Power Station, near Selby, North Yorkshire, said it would meet its current contract to supply electricity which ends in September.
Owner Eggborough Power Ltd said it would not be economically viable to continue to operate.
The coal-fired plant had been expected to close in 2016 but won additional contracts enabling it to remain open.
The plant, which began producing energy in 1970, is capable of supplying electricity to two million homes.
The decision to close comes after if failed to secure funding for 2018-2019 in the "capacity market", which pays companies to be available to provide electricity if there is a shortage.
Adam Booth, managing director at the firm, said the plant had been under threat of closure for several years due to its age and government policy on phasing out coal-fired generation by 2025.
"Eggborough has a proud history of generation and a dedicated and skilled workforce," he said.
"We will work through the consultation with employee representatives and provide support to employees throughout this process."
Mr Booth did not give a timescale for the plant's closure but said there might be a number of jobs during the decommissioning process.
Prospect union negotiations officer, Mike MacDonald, said they were "deeply disappointed" with the news,
"This is the third announcement of the rapid closure of a conventional power station since the New Year," he said.
"We will continue to fight to ensure our members get the best deal."
He said the government needed an energy transition plan to ensure workers could adapt to the move to low-carbon energy.
The closure of Eggborough will leave only six dedicated coal-fired plants in England and Wales.