The towers Central Maine Power said it is proposing for its New England Clean Energy Connect hydropower line from Canada to Lewiston. This image, looking northwest from Wilson Hill Road in West Forks Plantation toward the proposed transmission line, also contains a photosimulation of five years of vegetation growth that is 10 feet or less in height. Credit: Courtesy of Central Maine Power

This story will be updated.

After almost three years of regulatory reviews and amid efforts to derail it, the controversial western Maine hydropower corridor received its final major permit and has started construction, the parent of Central Maine Power Co. said Friday.

The project received the Presidential Perm it from the U.S. Department of Energy for the New England Clean Energy Connect project, which will bring 1,200 megawatts of hydropower through 145 miles of transmission lines from the Canadian border to Lewiston. The project has promised 1,600 jobs during its 30-month construction period and $200 million in upgrades to Maine’s energy grid.

It is the final major permit after the company previously received approvals from the Maine Public Utilities Commission, the Maine Land Use Planning Commission, the Maine Department of Environmental Protection and the U.S. Army Corps of Engineers. The company still might need permits from local communities along the hydropower corridor.

The $1 billion project is a collaboration with Hydro-Quebec. Energy from the project is targeted to meet the clean energy goals of Massachusetts.

Opposition groups claim the project doesn’t offer enough benefits to Maine.

Avangrid President Robert Kump said benefits to the state of Maine include infrastructure upgrades, rate relief for customers including a fund for low-income customers, broadband and grants for electric vehicle infrastructure.

The federal review of the project was rushed and conducted behind closed doors, said Sue Ely, staff attorney at the Natural Resources Council of Maine. She said the Department of Energy told Sen. Susan Collins, R-Maine, last November that it planned to have a 30-day public comment period for its environmental assessment of the project, which Ely said was not done.

“It has really robbed the people of Maine to have a right to be involved in reviewing this project,” she said. “This is a highly consequential project.”

Ely’s group is challenging the Army Corps of Engineers’ permit in court. Ely hinted at potential additional challenges that might include getting injunctive relief to pause construction or trying to have the new permit revoked.

“We still have plenty of avenues available to us,” she said.

Project supporters and opponents have spent millions of dollars on TV, radio, online and other advertising for the project. Ads topped $1.8 million as of last July. CMP-aligned groups spent nearly $17 million trying to persuade voters to approve the project in what turned out to be a failed initial effort to get a referendum to stop the project on last November’s ballot. That bid was deemed unconstitutional by Maine’s high court in August.

Outside groups spent another $3.7 million after the invalidation with a second referendum bid looming for 2021. During last November’s election with about 200 volunteers opposed to the corridor collected more than 23,000 signatures at 125 polling locations.

CMP partner Hydro-Quebec also was asked by current and former Maine lawmakers last July to stop trying to influence the outcome of the initial referendum after the company spent millions trying to fight the referendum. The company denied trying to influence the election of candidates.

CMP and NECEC LLC Transmission, the company formed to run the project, kept moving ahead with permits and plans during the efforts to stop it. Last April it awarded more than $300 million in contracts to build the project’s infrastructure to Pittsfield-based Cianbro in a joint venture with Irby Construction of Mississippi, Sargent Electric of Pennsylvania and Northern Clearing Inc. of Wisconsin.

The project got a big boost in February 2019 when Gov. Janet Mills said she approved of an agreement that would bring hundreds of millions of dollars in benefits to Mainers from the project. The package aimed to quell complaints that the transmission line, which extends 145 miles from Hydro-Quebec’s dam system at the Canadian border to Lewiston, doesn’t benefit Mainers adequately.

The 40-page stipulation agreement calls for a $50 million low-income customer benefits fund, a $140 million rate relief fund, a $10 million broadband fund, a $15 million heat pump fund and $10 million from Hydro-Quebec for electric vehicles.