Trial begins Monday against New England’s last coal-fired power plant

Posted: 10/13/2022 6:26:44 PM

A lawsuit begins Monday over whether the Merrimack Station in Bow is discharging too much hot water into the Merrimack River in violation of its EPA permit, a case that could decide the fate of New England’s last coal-fired power plant.

The lawsuit, brought by the Sierra Club and the Conservation Law Foundation against the mill’s owner, Granite Shore Power, begins Monday in U.S. District Court in Concord. This is a trial without a jury before Judge Joseph Laplante and could last all week or more. Both sides have a number of experts on their witness list.

If they win, the plaintiffs ask Granite Shore Power to install cooling ponds or other equipment to lower the temperature of the water returned to the river and also pay a penalty. It’s unclear what effect those costs would have on the decision to keep it open. All the other coal-fired plants in New England closed because they were uneconomical to operate.

The Merrimack station only generates electricity during peak demand periods such as hot spells or cold snaps, because its electricity is too expensive to use on a regular basis. The plant receives millions of dollars a year from taxpayers in return for guaranteed availability during peak periods through a process known as forward capacity auctions.

The issue in the lawsuit is straightforward, though the technical details can be obtuse.

Like most thermal power plants, those that burn fuel to produce steam that spins turbines and creates electricity, Merrimack Station uses water to remove “waste heat” that has not been used in the production of electricity. This is why most of these power plants are built along rivers, lakes or the ocean.

During operation, the Merrimack Station absorbs water from the Merrimack River and then releases it at a higher temperature, known as thermal discharge. The temperature differential and amount of release is regulated by the Environmental Protection Agency in a 1992 permit. A renewal permit was issued in 2020 under the Trump administration which changed thermal release requirements, but it was challenged in court by environmental groups and is only partially in force.

Water temperature is an issue because it is extremely important to some aquatic wildlife, including fish that migrate up or down. A release of hot water can act as a barrier.

“If the shad have a migration and there’s a plume in how they can die or expend excess energy … be prone to predation,” said Reed Super, senior counsel for the Sierra Club. “The river favors thermally tolerant fish as opposed to the cold water fish it’s supposed to have.”

Granite Shore Power argued that they do not violate permits and operate within legal limits.

Granite Shore Power is an investment group that bought Merrimack Station from Eversource in 2017. It also owns Schiller Station in Portsmouth, a much smaller coal-fired power station that closed two years ago.