A Maine jury has ruled that construction can proceed on the controversial 145-mile, high-voltage transmission line that will carry hydropower from Quebec to Massachusetts. The decision overturns the result of a 2021 ballot initiative in Maine that passed with the support of nearly 60 percent of voters.

Environmental groups have long opposed the project on the grounds that it would damage the forests and harm the wildlife of western Maine. Further, they point out that energy companies offering renewable solar and wind options would face increased competition from the hydropower line, thereby reducing their viability. Then there’s the debate over the actual amount of greenhouse gas emissions offset by hydropower (some hydropower reservoirs emit large amounts of methane).

Avangrid, the company behind the transmission line project—also known as NECEC—had already invested $450 million once state regulators gave their initial approval to the project in 2021, but were forced to halt construction within a year when the ballot initiative passed. However, the recent court decision reverses the initiative on the grounds that Avangrid had already proceeded with construction of the power line “in good faith” based on the approval it had received from Maine regulators. If completed, the power line would transmit enough electricity to power approximately one million homes, mostly in Massachusetts.

An appeal to the ruling will be forthcoming.