In this Aug. 20, 2020, file photo, the Kennebec River is seen alongside Route 201 in Caratunk. The proposed Central Maine Power corridor would run through the town and cross the Kennebec River. Credit: Natalie Williams / BDN

A federal judge denied the motion filed by conservation groups last month that would’ve halted construction of the much-debated Central Maine Power Co. transmission line.

The 145-mile hydropower transmission line from Quebec to New England has been a controversial project since its announcement.

On Wednesday, U.S. District Judge Lance Walker rejected the lawsuit filed by Sierra Club Maine, the Natural Resources Council of Maine, and the Appalachian Mountain Club, according to the Portland Press Herald.

The groups filed the request for a preliminary injunction in November to delay the start of construction until the U.S. Army Corps of Engineers agreed to conduct a more rigorous environmental impact statement instead of the less-stringent environmental assessment.

Supporters of the $1 billion transmission line have said the corridor would provide a conduit for up to 1,200 megawatts of Canadian hydropower to reach the regional power grid, reducing greenhouse emissions and stabilizing energy costs.

But the plaintiffs alleged that the corridor — which will cut through 53 miles of forest owned or controlled by Central Maine Power in western Maine — will have a lasting negative impact on Maine’s natural environment.

The Army Corps concluded the project would not significantly affect the environment, which meant the agency was not required to file an environment impact statement, according to the Press Herald.

The plaintiffs’ attorney, Sue Ely, said the judge’s ruling does not resolve the central legal dispute, saying Mainers deserve an explanation as to why the corps conducted a closed-door assessment, the Press Herald reported.

Walker said the plaintiffs’ had not presented a strong enough argument against the Army Corps’ review or presented a contrary assessment by a regulatory agency such as the Maine Department of Environmental Protection.

Since there was no other regulatory agency that had issued a contradictory assessment, Walker said he did not find the corps’ assessment arbitrary or unreasonable, according to the Press Herald.

Construction won’t start until January at the earliest, according to project developers. The corridor still needs to get a presidential permit from the U.S. Department of Energy to cross international boundaries.