Two weeks ago, officials in Woolwich voted to reconsider the town’s support of a Central Maine Power project that would connect Canadian hydropower with markets in Massachusetts.

Part of CMP’s New England Clean Energy Connect project involves upgrading a line from a substation in Woolwich to another in Windsor.

Woolwich sent a letter of support for the project in 2017, but the Select Board decided on Aug. 19 to take another look.

“I was a reluctant supporter in 2017 and I’ve come to oppose it as we’ve learned more about it,” Woolwich Selectman Allison Hepler said. “We wrote the letter based on the little information we had at the time, but I’m ready to revisit it.”

Woolwich, which is expected to vote Tuesday on whether to revoke its support, could be the latest in a string of nearly two dozen Maine towns that have either formally opposed or rescinded support for the NECEC transmission corridor, as opponents continue to try to derail the planned 145-mile line.

But their efforts may be for naught.

The towns’ opposition is largely symbolic, said Tony Buxton, a lawyer who heads the energy practice at Portland law firm Preti Flaherty and also represents an industrial electricity users group that supports the $1 billion project.

Although the utility may still need construction permits from the towns along the transmission corridor, a decision by a town planning department or board to reject CMP’s applications for permits could be appealed to the Maine Public Utilities Commission, said Harry Lanphear, the PUC’s administrative director.

Under state law, the PUC, which regulates utilities in Maine, has the power to override a denied permit at the local level if commissioners decide the project is needed for “public welfare and convenience.”

Because the PUC has already approved a certificate saying that the corridor is a “public convenience and necessity,” that decision might be a foregone conclusion.

Opponents to the project acknowledge they may not win on the municipal permitting level, but they are in it for the long game. One of the leading opposition groups, Say No to NECEC, said the hope is that town opposition will slow momentum on the project, which still has several approvals to get before construction can begin. It is contractually bound to deliver green power to Massachusetts utilities by 2022.

The plan is currently being reviewed by the state’s Department of Environmental Protection, the Maine Land Use Planning Commission and the Army Corps of Engineers, and all three are expected to announce their decisions either late this year or in early 2020.

The line would cut through Maine woods to link electricity generated by hydroelectric sources in Quebec to utilities in Massachusetts. A spokesman for Avangrid, CMP’s parent company, said the schedule calls for the company to get necessary approvals in hand early next year and complete the line by the end of 2022.

Most of the towns that have either opposed the project or withdrawn support for it are along the main line that the corridor will follow through Maine. About 100 miles of the corridor follow transmission lines already built through the woods in western Maine, but the paths would require widening to accommodate the additional transmission lines from Canada. Another 50 or so miles, primarily near Canada, would require clearing a new corridor, although CMP said the land has already been logged and the woods aren’t pristine.

The line through Woolwich isn’t part of the main corridor, which stretches from Canada to Lewiston. A shorter stretch from Windsor to Woolwich is an upgrade required by ISO New England, the organization that oversees New England’s bulk power market, largely as a backup in case the supply from Canada needs to be shifted off the main line that CMP will be building.

Despite the opposition from some towns, “there’s still a good deal of support,” said Thorn Dickinson, vice president of business development for Avangrid. The environmental benefits of importing electricity generated by Canadian rivers and dams outweigh any potential harm to the woods, Dickinson said.

Opponents said they are tapping into skepticism over the project, building on CMP’s deteriorating reputation in the wake of enduring problems with some customers receiving inexplicably high electric bills after the company launched a new billing software system in late 2017 – a process CMP mismanaged and misled the public about.

The Woolwich Select Board agreed to consider rescinding its letter of support for CMP’s proposed 145-mile transmission line that would travel from Quebec to Lewiston, sending hydropower from Canada to Massachusetts. Hannah LaClaire/The Times Record

Municipalities have objected in several ways to the corridor, from holding official votes to denounce the project to simply sending letters stating their objections.

“We haven’t lost a vote yet” and many have been by lopsided margins, said Sandra Howard, the director of Say No to NECEC.

Although the votes don’t carry any enforcement power, Howard said, they raise awareness of the plan and are helping groups like hers build opposition to the corridor. That, she said, will allow opposition groups to buy time to build momentum, perhaps in the Legislature or through a referendum vote, in an effort to derail the plan.

“It presses the pause button,” she said.

Howard said the group has worked to encourage local opponents of the corridor to lead the efforts to express opposition to the corridor or withdraw support that had previously been extended.

“We’ve mobilized our (local) members,” she said.

Early this year, CMP, Avangrid and HydroQuebec announced a package of benefits to electric customers and communities in Maine worth about $258 million. The package led Gov. Janet Mills to back the plan, which was approved by the PUC in April.