Two environmental groups plan to sue the owners of a coal-fired power plant outside Concord – Merrimack Station, the largest of its kind left in New England.
The Sierra Club and the Conservation Law Foundation say they'll file suit under the Clean Water Act in January if things don't change at the power plant.
It was owned by Eversource until earlier this year, when it sold to Connecticut-based Granite Shore Power as part of a years-long effort to deregulate New Hampshire’s energy sector.
Merrimack Station, in Bow, doesn’t generate power often – New England relies primarily on natural gas and nuclear for its electricity, and coal now makes up just 3 percent of the fuel mix.
That’s down from 12 percent in 2000, and the region’s grid manager projects it will zero out by 2025.
But when Merrimack Station does switch on – with its smokestack visible over I-93 in the Concord area – it can draw in and discharge millions of gallons of water a day from the adjacent Merrimack River.
The nonprofits’ notice of intent to sue alleges that the water is often discharged into the river at temperatures above 90 degrees Fahrenheit. Heat is considered a pollutant under federal law.
Its owners have said upgrades to cool the discharged water would cost millions.
But the nonprofits have long held that this “thermal discharge” harms the ecosystem – killing native fish species and encouraging invasive species to move in.
“Not only is this coal-burning plant damaging our climate, but it has also dramatically undermined the health of one of our most iconic natural resources, the Merrimack River,” says CLF attorney Tom Irwin in a statement. “It’s time for this damage to finally be addressed.”
The plant's federal discharge permit, issued in 1992, is also long overdue for an update.
Eversource spokesman William Hinkle says though they no longer own or operate the plant, they deny the allegations.
“Prior to the sale of the plant almost a year ago, we worked closely with the EPA to meet all environmental permitting requirements, including those cited in CLF's and Sierra Club's legal notice,” Hinkle says in a statement.
Granite Shore Power did not immediately respond to a request for comment.
Merrimack Station is the largest coal-fired plant left in New England by capacity, at 440 megawatts. Another former Eversource coal plant, the 94-megawatt Schiller Station in Portsmouth, was part of the same sale to Granite Shore Power earlier this year.
They’re the last two coal plants in the region that aren’t currently set for retirement. A third coal plant, Connecticut’s 384-megawatt Bridgeport Harbor Station, is due to shut down by 2021.
Those three plants combined still generate less coal-fired power than the last big New England coal plant to go offline. Brayton Point in Massachusetts, which had a capacity of more than 1,500 megawatts, shut down in 2017.
