Merrimack Station power plant in Bow gets EPA water permit after decade of dispute

  • The Merrimack Station power plant in Bow is seen at dusk on Thursday, Oct. 12, 2017. (ELIZABETH FRANTZ / Monitor staff) Elizabeth Frantz

Monitor staff
Published: 5/27/2020 4:13:58 PM

Merrimack Station, the power plant in Bow, has come out on top of a multiyear fight over the use of Merrimack River water for cooling.

The EPA has released a water-pollution permit for the coal-fired plant that does not require the construction of any kind of pool or tower to cool hundreds of thousands of gallons of water taken from the Merrimack River for the plant’s boilers and then returned to the river.

Such closed-cycle cooling was included in a draft permit issued in 2011 by the EPA and has been sought for decades by environmental groups, who say removing that much water and returning it at a much higher temperature kills river life and alters the ecosystem of the Merrimack River.

Granite Shore Power, which bought the plant from Eversource three years ago, said in a statement that the permit “continues to be protective of the environment while also reflecting the reality of Merrimack Station’s reduced level of operation.”

The permit requires the plan to restrict the times that it discharges water to protect nearby wildlife, and install “wedgewire” screens to limit which organisms get sucked into the plant when it takes water out of the river.

Merrimack Station seldom runs these days because much cheaper electricity is usually available from gas-fired plants or solar and wind farms. It ran roughly the equivalent of one month during 2019, turning on only to meet high electricity demand during summer heat waves or, more often, during winter cold snaps when natural gas was not available because it was used for heating.

The six-decade-old power plant is financially viable because it receives tens of millions of dollars in what are known as capacity payments that are made regardless of how much electricity it produces. Capacity payments are designed to keep “peaker plants” open to provide power during times of peak need. Similar payments are made to the state’s only other coal-fired plant, Schiller in Portsmouth, also owned by Granite Shore.

Schiller will stop receiving the money in two years because it did not win any capacity payments in the most recent auction run by ISO-New England.

The question about water permits for Merrimack Station dates back decades – discussion began in the early 1990s. The EPA under the Trump administration has been much less likely to pursue pollution controls than the agency did in past years.

The EPA permit for Merrimack Station does not affect a lawsuit in federal court that seeks to force Granite Shore to build some sort of cooling system, said Reed Super, an attorney for the Conservation Law Foundation. That group and the Sierra Club sued the plant two years ago; the case is proceeding through U.S. District Court in Concord, although the COVID-19 shutdown has stalled all litigation.

“We believe the evidence will clearly support that the plant is continuing to violate its permit when it operates as a peaker plant,” said Super. “The number of violations are probably fewer than they were because of the reduced operation, but they haven’t gone away. …When it runs, it runs. And when it runs it heats the river, and when it heats the river, it causes environmental impact – that hasn’t changed.”

The 448-megawatt Merrimack Station is the largest coal-fired plant in New England. The only other large plant, 383 MW Bridgeport Harbor in Connecticut, is slated to close next year. The two coal-fired plants at Schiller are 50 MW each; Schiller also has a 50 MW plant that runs on wood chips.

Regional environmental groups have targeted Merrimack Station in protests, sometimes blocking shipments of coal to the plant along the rail line that runs up from Massachusetts. Coal is by fa r the most polluting of fuels used to produce electricity.

(David Brooks can be reached at 369-3313 or or on Twitter @GraniteGeek.)

David Brooks bio photo

David Brooks is a reporter and the writer of the sci/tech column Granite Geek and blog, as well as moderator of Science Cafe Concord events. After obtaining a bachelor’s degree in mathematics he became a newspaperman, working in Virginia and Tennessee before spending 28 years at the Nashua Telegraph . He joined the Monitor in 2015.

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