Mainers voted decisively Tuesday to kill a $1 billion transmission line project in the western part of the state in a vote that was fueled in part by distaste for the state’s largest utility and concerns about environmental impacts to the North Woods.

With 450 of 571 precincts reporting, 59 percent of voters had said “yes” to Question 1, a strong repudiation of Central Maine Power Co., its domestic parent company Avangrid and Canadian energy supplier Hydro-Quebec, as well as plans to finish the New England Clean Energy Connect project and put it into service. The “yes” vote registered a strong showing in nearly every part of the state except Aroostook County as of 12 a.m.

Former state Sen. Tom Saviello celebrates with Sandi Howard at a Yes on 1 to reject the NECEC project election night watch party at Farmhouse Beer Garden. Photo by Derek Davis

“This has been an unbelievable experience,” said Tom Saviello, a lead organizer of the campaign, celebrating at a Yes on 1 gathering in Farmington. “At the end of the day, Gov. LePage, Gov. Mills, CMP get the message: The people of Maine don’t want this corridor.”

The Natural Resources Council of Maine, which has been fighting the corridor, called on CMP to stop the project immediately.

“If CMP fails to halt construction activities right away,” said Advocacy Director Pete Didisheim, “then the Department of Environmental Protection should move quickly to suspend the permit and require that CMP begin restoring areas of Western Maine that already have been damaged.”

The group also called on Massachusetts, which has contracts for the power from NECEC, to honor the pending outcome by selecting an alternative option for meeting its climate goals “without imposing significant environmental harm on another New England state.”

Question 1 opposition group Clean Energy Matters, a political action committee funded in large part by NECEC’s developers, issued a statement late Tuesday indicating that it plans to challenge the referendum in court.

“We believe this referendum, funded by fossil fuel interests, is unconstitutional,” said Jon Breed, the group’s executive director. “With over 400 Maine jobs and our ability to meet our climate goals on the line, this fight will continue.”

The outcome also seemed likely to pave the way for the Legislature to get more involved in how to connect energy projects that experts say will be needed in a coming age of vehicles and buildings powered with electricity.

Question 1 read: “Do you want to ban the construction of high-impact electric transmission lines in the Upper Kennebec Region and to require the Legislature to approve all other such projects anywhere in Maine, both retroactively to 2020, and to require the Legislature, retroactively to 2014, to approve by a two-thirds vote such projects using public land?”

What happens next was unclear Tuesday night.

That’s because NECEC wasn’t just a proposal – it has been under construction since January. Even as votes were being cast early Tuesday, hundreds of construction workers were racing to raise steel poles and finish clearing the corridor, etching a new electric power pathway through western Maine’s working forests.

SENDING A MESSAGE

While not the final word, the vote against NECEC sent a potent message to Avangrid and Hydro-Quebec. But how it would change activity on the ground remained to be seen.

That’s because the outcome is bound to trigger more protracted legal challenges, with Avangrid expected to challenge the pending law and opponents following through with ongoing lawsuits and regulatory fights. So there’s no way to know when or if construction will be completed and whether electricity will ever flow through the line.

More immediately, the secretary of state would have 20 days to certify the election. Then Gov. Janet Mills would have 10 days to proclaim the results. The law would take effect 30 days after the governor issued that proclamation. In total, it would be around Jan. 3 before the law would take effect.

Beyond Tuesday’s win, project opponents are engaged in a handful of legal and regulatory challenges before the state Department of Environmental Protection and in state and federal courts. These are expected to go forward, and certain rulings on any one of them could delay or even kill the project.

The overwhelming vote to stop the project wasn’t a complete surprise.

The “no” side had gone into Tuesday as an underdog, as least according to a recent poll of likely voters. Nearly half the 604 respondents to a statewide poll by Digital Research of Portland said they planned to vote “yes,” against the project. Slightly more than one-third said they would vote “no,” and the rest were undecided or wouldn’t answer.

Jeff Diggins sided with the plurality opinion on Tuesday.

Speaking outside of Yarmouth’s polling station, Diggins said he struggled with his vote because he supports the idea of bringing more renewable power into the region. But in the end, he resented what he called CMP’s “fear tactics and misrepresentations,” and decided to vote “yes.” In his view, CMP is badly mismanaged, as shown by customer satisfaction surveys, and the company needs to be held accountable for its behavior.

ISSUE GARNERS RECORD SPENDING

Underlying all the fighting is what both sides have at stake and why, together, they contributed nearly $100 million to sway opinions. It adds up to record spending for a ballot question in Maine, dwarfed only by last year’s U.S. Senate race.

The torrent of money allowed both sides to flood the airwaves, social media and mailboxes with claims and counterclaims, some of them laced with half-truths and scare tactics.

For Avangrid, the domestic parent of CMP and NECEC Transmission LLC, and for Hydro-Quebec, the Canadian provincial utility, billions of dollars of income hang in the balance. That’s why Avangrid, itself a subsidiary of Spanish energy giant Iberdrola, already has taken the risk to lay out $400 million in construction expenses on NECEC. The partnership also has contributed a total of more than $67 million toward defeating the referendum.

For NECEC opponents and the political action committees they formed to fight the project – No CMP Corridor and Mainers For Local Power – it’s a more complicated calculus.

The largest financial contributor at $20 million is NextEra Energy Resources, which owns the Seabrook Station nuclear power plant in New Hampshire. Calpine and Vistra Energy, both of which own natural gas-fired power plants in Maine, together have chipped in more than $5 million. Each would lose money competing in the regional wholesale electricity market against NECEC’s cheaper power.

Clearing a 53-mile transmission corridor in forest of national significance for power of disputed origins has motivated the Natural Resources Council, the Sierra Club and the Appalachian Mountain Club to join forces with energy interests they typically might oppose.

Rounding out the opposition were residents who, among other things, don’t like or trust CMP, don’t want to see more power lines in the Upper Kennebec Valley or are against the massive reservoirs already created by Hydro-Quebec on the lands of indigenous people.

WHAT IS NECEC?

NECEC is a high-voltage, direct-current transmission line with a capacity of 1,200 megawatts, enough energy to run roughly 1 million homes. It would carry energy from Quebec to an alternate-current converter station in Lewiston, where it would enter the New England electric grid. It’s being built largely for the benefit of Massachusetts electric customers, who will pay the $1 billion cost.

The 145-mile route is on land owned or controlled by CMP, except for a one-mile patch through Maine public lands near The Forks. Two-thirds of the route follows existing CMP power line corridors, some of which are being widened up to 75 feet to accommodate another set of poles.

A 53-mile stretch between The Forks and the Quebec border bisects undeveloped commercial forest. The area has been logged for generations but has high-value qualities for wildlife, recreation and biodiversity. Permits require the power corridor in this section to be no more than 54 feet wide. Fewer than 1,000 acres are being cleared in total for the project.