Merrimack Station1

The coal-fired Merrimack Station power plant in Bow will not have to install cooling towers.

CONCORD — A federal judge has allowed a lawsuit to proceed against the owners of the Merrimack Station coal burning power plant in Bow.

U.S. District Court Judge Joseph Laplante ruled that enough evidence exists about the harmful temperatures of the water that the plant operator, Granite Shore Power LLC, uses to cool turbines and then discharges into the Merrimack River.

Granite Shore had sought summary judgment, a key point in a case where a defendant tries to get a lawsuit thrown out based on the law.

“This is about significant impacts to the Merrimack River over the years. The decision paves the way for us to now make our case at trial in court,” said Tom Irwin, director of Conservation Law Foundation-New Hampshire, which filed suit along with the Sierra Club.

The 482-megawatt power plant operates when demand surges. It is the target of occasional protests.

This past weekend, four protestors were arrested at the Bow plant, two who chained themselves to the base of the stack and two who scaled a tower to hang a banner that read “shut it down.”

Most protests focus on the air emissions and their effect on climate change. But the lawsuit dwells on the effect on river water. Merrimack Station uses water from the river to cool turbines and then returns heated water to the river.

The March 2019 suit claims that the heated water violates the terms of the plant’s EPA license because it blocks the zone of fish passage, changes indigenous populations and has substantial contact with surrounding shorelines.

In his ruling, Laplante said testimony from experts convinced him that enough material facts are in dispute that the case can move forward.

Scientists found that the thermal limit for cold-water species such as brook trout, alewives and yellow perch was exceeded during four periods studied, he pointed out. The Hooksett Pool, where the water is discharged, has conditions that favor warm-water fish, Laplante wrote, quoting the scientists.

The judge agreed with Granite Shore lawyers that the discharge did not amount to waste and sewage disposal and issued summary judgment on claims that it violated New Hampshire water quality standards.