Signs in favor and against the Central Maine Power corridor. Credit: Fred Bever | Maine Public

Central Maine Power Co. on Monday received the third key state permit needed for its proposed transmission corridor stretching from the Quebec border to Lewiston, although a challenge awaits the project at the ballot box this November.

The state Department of Environmental Projection issued a permit after over two years of review, building on two other permits CMP has received from the state. The Maine Land Use Planning Commission voted to grant the project a land-use certification in January, and the state’s public utilities commission approved its permit for the project in April 2019.

The permit puts some restrictions on the project, which would bring hydropower from Quebec into the New England electric grid.

It requires the company to set aside more than 40,000 acres of conservation in the western part of the state and shrinks a portion of the corridor that travels through commercial timberlands from 150 to 54 feet at its widest point. CMP must also set aside $1.8 million for culvert replacement projects aimed at improving fish passage and reducing erosion.

CMP has been actively pursuing the project despite the looming referendum challenge in November, which the company was involved in fighting all the way to Maine’s highest court. In April, it awarded $300 million in contracts to clear land and upgrade existing transmission lines along the corridor, in addition to almost $20 million for construction mats. The project is expected to be completed in 2022 if it survives the referendum.

The CMP project still needs a U.S. Army Corps of Engineers wetlands permit, an ISO New England section 1.3.9 approval and a U.S. Department of Energy presidential permit. It also needs municipal approval for construction projects including substations and transmission structures along the corridor’s path.