Mt. Tom, one of the state's remaining coal-fired power plants, will close for good by October.
The plant's owner, GDF Suez Energy North America, notified the facility's 28 employees Monday, spokeswoman Carol Churchill said. The 146-megawatt plant in Holyoke has stopped making electricity, but workers probably will remain employed until Oct. 1.
"It's a difficult market for an old plant and a coal plant like Mt. Tom to compete in," Churchill said. "It has been operating pretty sporadically."
Coal plants are increasingly being squeezed out as cheaper fuels, particularly natural gas, are used to generate electricity.
News of Mt. Tom's closing came one day after the coal-burning Salem Harbor Power Station was shuttered, as scheduled. The Salem plant's owners plan to reopen it as a natural gas-burning facility in 2016. Brayton Point in Somerset, which also uses coal, is expected to close in 2017.
Representatives of ISO New England, the region's grid operator, said the agency has not received a formal retirement request for Mt. Tom, but does not expect an immediate impact from its loss.
Churchill said that GDF Suez is considering what to do with the property.
"We are evaluating uses, including a solar site," she said.