With Entergy pulling the plug on the Pilgrim Nuclear Power Station in Plymouth, Mass., the New England region loses a significant electricity supplier.

But several more are to come online in coming years to offset Pilgrim’s closure and the decommissioning of other older plants.

Prior to the recent shutdown that was years in the planning, Pilgrim supplied nearly 700 megawatts of power to the New England grid, contributing to supplies that generated 13,500 megawatts on Friday, according to ISO New England. Based in Holyoke, Mass., ISO is the nonprofit that oversees the region’s electricity markets.

Even with Pilgrim coming offline heading into the weekend, the loss was well within the bounds of an electric grid capable of generating more than 18,500 megawatts.

Last week, ISO stated the region has sufficient resources in place to handle summer demand that could hit 22,000 megawatts or more, whether through incentives for building owners to cut electricity use during heat waves, generators that can be put into service on a temporary basis, or electricity imports from adjacent regions.

Dominion’s Millstone Power Plant provides close to half of Connecticut’s electricity, with the company having raised the threat of an early shutdown of the Waterford nuclear plant to wrangle new terms of a contract reached with the state last year to supply power through a zero-emissions incentive program, pending approval by the state Public Utilities Regulatory Authority.

Millstone is one of two remaining nuclear plants in New England along with NextEra Energy’s Seabrook Station in New Hampshire, which produces more than 1,200 megawatts of power.

Pilgrim joins several other conventional power plants in New England to be mothballed the past few years, including NRG’s 350-megawatt Norwalk Harbor Station plant on Manresa Island that closed in 2013. The shutdowns include the Brayton Point Power Plant in Somerset, Mass., which Dominion shut down two years ago, and which provided a spectacle in April with the demolition of its massive twin cooling towers.

At Bridgeport Harbor Station, PSEG is replacing historic coal- and oil-fired generators with a natural-gas plant designed to produce 485 megawatts of power. Last year, Competitive Power Ventures fired up the 800-megawatt Towantic Energy Center in Oxford that burns natural gas.

And NTE Energy anticipates the start on construction this summer of a 650-megawatt plant in Killingly near the Rhode Island border.

Eversource Energy also is awaiting a New Hampshire Supreme Court decision after oral arguments in mid-May on its Northern Pass proposal to run transmission lines south from hydroelectric plants in Canada, a potential source for more than 1,000 megawatts of additional electricity.

On Thursday, Eversource announced a sale of stock with gross proceeds of more than $1.1 billion, with the company indicating plans to use some of the resources on renewable energy resources, which heading into this summer accounted for less than 10 percent of New England’s power.

Eversource is developing the Revolution Wind turbine plant 65 miles off the New England coast in partnership with wind farm developer Orsted — which if initial phases are completed as planned would furnish Connecticut with 300 megawatts.

That would equate to just under 5 percent of the state’s total consumption as calculated by the U.S. Energy Information Administration, with Eversource and Orsted hopeful of expanding those installations to as much as 2,000 megawatts under optimal winds, approaching Millstone’s output.

“Beyond 2023 is where you would see the more appreciable contributions from the offshore wind,” said Phil Lembo, chief financial officer of Eversource, during a conference call in early May. “The permitting process is probably a few years (and) the construction process is a few years.”

Connecticut Media Group