Signs protesting the CMP corridor are seen in a Jackman lawn on May 29. Credit: Natalie Williams / BDN

Just after Central Maine Power’s parent company said it had received the final key permit for its hydropower corridor and started construction, a federal appeals court ruled Friday that the company could not start work on the last 53 miles of the project from The Forks to the Canadian border.

Three environmental groups, the Sierra Club, the Natural Resources Council of Maine and the Appalachian Club, filed for a preliminary injunction last November, just after the Army Corps of Engineers approved a key permit for the 145-mile project, which aims to bring hydropower from the Canadian border to Lewiston.

That request was denied by a federal judge in December. The group won in a Boston-based U.S. Court of Appeals. Judges granted a request to stop CMP from cutting trees in the 53-mile segment that comprises the final portion of the hydropower line.

While much of the power line is along existing infrastructure, the final section needs to be cleared for poles, lines and other infrastructure equipment. That is the most environmentally sensitive area of the project, said Sue Ely, an attorney for the Natural Resources Council of Maine.

The decision prevents CMP from proceeding on that segment for at least 25 days as the various parties file briefs in the case.

The company stopped construction in that segment today and will abide by the injunction, said Thorn Dickinson, CEO and president of NECEC Transmission LLC, which was established to run the hydropower corridor.

He said the company was on the verge of starting construction in the disputed area but now will look to other parts of the hydropower line and work there. One could be the $200 million converter station in Lewiston, which was approved by the city planning board this week.

Dickinson said the project still is on track for power to flow from Quebec to the regional grid in the second quarter of 2023.