PORTLAND, Maine (AP) — Three Massachusetts utilities and the parent company of Central Maine Power have agreed that Massachusetts ratepayers will bear $512 million in additional costs caused by delays in the construction of a transmission project. electricity in Maine which will allow Canadian hydroelectricity to reach the New England power grid.

Supporters said Wednesday that the project aimed at providing enough clean energy to power around a million homes still represents a good deal for taxpayers and the environment, despite delays and new costs.

“Even with these unforeseen costs, this is clean energy at a very good price. I’m not sure we’ll be at such low prices in the future. So we should bite the bullet, absorb the additional spending and move on,” said Massachusetts State Sen. Michael Barrett of Lexington, co-chair of the Assembly Telecommunications, Utilities and Energy Committee. legislative.

The cost of the project rose from $1 billion to at least $1.5 billion due to inflation and delays caused by opponents, forcing the Massachusetts legislature to give approval late in last year so that most of the additional costs would be passed on to taxpayers.

The Massachusetts Department of Energy Resources and the Attorney General’s Office signed the agreement, which the parties submitted Monday to the state Department of Public Utilities for approval. Central Maine Power’s parent company, Avangrid, has not sought to recoup the $100 million it spent in a legal and referendum battle, according to an official.

Supporters of the project say the 1,200 megawatts of electricity it provides would lower electricity rates in the region, reduce carbon pollution and help Massachusetts meet its clean energy goals. Construction is expected to be completed by the end of next year or summer 2026,

“This transmission line is expected to lower overall electricity prices and provide new, reliable energy to Massachusetts and New England as we transition to clean energy.” We are hopeful that clean hydropower will begin to arrive in our state soon,” said Energy Resources Commissioner Elizabeth Mahoney and Liz Anderson of the Attorney General’s Office.

Despite the change, Massachusetts taxpayers would save about $3.4 billion over the 20-year contract, and the use of hydropower represents the carbon reduction equivalent of removing 660,000 cars from the road, a said Kim Harriman, senior vice president of public and regulatory affairs at Avangrid.

Avangrid and Canada’s Hydro Quebec partnered on the project, which included a 145-mile (233-kilometer) power transmission line, primarily following existing corridors. But a new 85-kilometer section had to be cut through the woods to reach the Canadian border, which environmental and conservation groups have decried.

The project had to overcome many obstacles.

It obtained all regulatory approvals, but work was halted after Maine voters rejected the project in a November 2021 referendum. A jury concluded the referendum was unconstitutional because it violated the acquired rights of the developers.