New England’s last coal-fired power plant loses key revenue source
Non-carbon resources account for 25% of 2026-2027 capacity commitments
AN AUCTION for commitments to deliver electricity to the New England power grid three years from now provides two interesting clues about the region’s energy future.
First, New England’s last active coal-fired generator, Merrimack Station in Bow, New Hampshire, failed to qualify in the auction, suggesting its days may be numbered.
The other big takeaway was that non-carbon-emitting resources – nuclear, hydro, solar, and wind — will account for nearly a quarter of the region’s electricity capacity during the year covered by the 2026-2027 auction.
That’s an increase over previous auctions, but it’s also another indicator that the regional power grid has a long way to go in reducing its reliance on fossil fuels. In Massachusetts, Gov. Maura Healey has set a goal of 100 percent clean electricity supply in 2030.
The New England grid operator, ISO-New England, holds an auction every year to secure enough generating capacity to cover the region’s estimated electricity needs three years out. The so-called capacity auction pays generators to be available whether their power is actually needed or not; they also get paid through a separate auction for actually delivering electricity in real time.
The 2026-2027 capacity auction secured commitments to provide a total of 31,370 megawatts from more than 1,200 contractors, including companies generating electricity as well as firms able to significantly reduce power consumption at peak demand periods.
The region’s two nuclear power plants – Seabrook in New Hampshire and Millstone in Connecticut — provide the bulk of New England’s non-carbon-emitting power.
Solar and wind accounted for 3.5 percent of the total capacity obligations. Offshore wind, which is expected to be a major source of clean energy in the future, played only a minor role in the auction. Vineyard Wind, which is scheduled to open partially later this year, won a capacity agreement for 186 megawatts. Revolution Wind, a joint venture of Orsted and Eversource, won a capacity agreement for 69 megawatts. Massachusetts ratepayers are paying for Vineyard Wind, while Connecticut ratepayers are paying for Revolution Wind.
Battery storage, which did not register in auctions five years ago, also accounted for 3.5 percent of capacity obligations. Battery storage doesn’t generate electricity, but it stores previously generated power and releases it when needed at peak demand periods.
Another 9 percent of the capacity obligations came from demand-response resources, which don’t increase the supply of electricity but reduce demand for it at peak periods.
Combining the non-carbon-emitting resources and those that reduce demand, the total comes to 34 percent. The rest of the region’s electricity capacity comes from power generated using fossil fuels.
Coal-fired power plants have slowly been closing in New England and the last active one may be on its last legs. Merrimack Station in New Hampshire, a so-called peaker plant that comes online occasionally to meet peak demand, participated in the auction but didn’t secure an obligation. That means it will be without a significant source of income three years from now.
In last year’s auction, for the 2025-2026 period, Merrimack secured a capacity agreement that paid it $785,000 a month to be available if needed.
Merrimack is owned by Granite Shore Power, an investment group that bought it from Eversource in 2017.