Central Maine Power utility lines are seen, Wednesday, Oct. 6, 2021, in Pownal. Credit: Robert F. Bukaty / AP

The upcoming referendum over a transmission line through western Maine will have broad implications for New England and Quebec’s energy future, as the demand for massive quantities of clean energy will persist regardless of the outcome.

Mainers will vote Nov. 2 on a question that aims to block the $1 billion corridor being built by Central Maine Power affiliates and Hydro-Quebec through western Maine while requiring legislative approval for infrastructure projects on public lands. A yes vote in the referendum would block the project, while a no vote would allow work to continue.

It has been an all-consuming political fight in Maine, where more than $60 million in political spending has come from the energy companies on both sides of the project. The tension over the project has overshadowed New England’s persistent demand for new power. It was a response to a massive clean-power request from Massachusetts in 2017 that only took center stage after a similar proposal in New Hampshire was nixed by regulators.

The region has much riding on the outcome, but hydropower and long, controversial transmission lines are likely to play some role in a broad effort to slash carbon emissions whether the corridor is built or not. While alternatives including offshore wind are on the way, they are not likely to bridge the gap as quickly.

“Fighting climate change is a wicked problem, and there’s no easy fix because otherwise we would have found it,” said Francois Bouffard, an engineering professor at McGill University in Montreal. “So there’s always going to be winners and losers.”

The tradeoffs for Maine are straightforward: The project requires a 145-miles corridor, including 53 miles that requires clearing land. In exchange, the state will get $190 million in electricity subsidies, along with funding for broadband, electric vehicles and heat pumps. Opponents of the project call the benefits paltry when spread across the 40-year term of the deal.

But the project has broader consequences for the rest of New England, as well as in neighboring Quebec. In the short-run, the success or failure of the corridor is “very significant” for Massachusetts, which needs the power to meet its aggressive low-carbon energy goals, said Paul Hibbard, an energy consultant and former chair of the public utilities department there.

The Massachusetts attorney general’s office left a comment left before the Federal Energy Regulatory Commission earlier this month urging quick resolution to disputes surrounding the project, saying the 1,200-megawatt transmission line was of “vital importance.”

Massachusetts’ shift toward hydropower would have secondary effects for the rest of the New England market, with more power available for others to buy. Although some corridor opponents have been skeptical, experts said there is little doubt that gas-fired power plants would be the first source displaced. Some of their owners have funded the political fight against the corridor.

“We cannot develop enough low-carbon sources fast enough,” Hibbard said. “So any incremental piece of energy coming from any zero carbon source right now is not going to be displacing renewables, it’ll be displacing fossil fuels.”

Other alternative sources under development, including wind and solar power, are still essential to New England’s transition toward low-carbon power, Hibbard said. But he and others framed hydropower as a useful backstop even as the region begins relying on those sources more.

Wind and solar are what energy analysts refer to as intermittent sources, said Pierre-Oliver Pineau, a professor at the University of Montreal’s business school, because they stop producing under conditions such as inclement weather. That is a problem in New England, because conditions like a winter storm can reduce wind and solar production at a time when demand is especially high.

Imported hydropower could replace fossil fuels as the backup for solar or wind in the long run, Pineau said. Any energy source transmitted over a long distance also helps, as weather conditions might not be the same between places hundreds of miles apart.

“There will be a huge amount of wind and solar needed,” he said. “But the system needs to be able to balance that, and that’s what transmission lines are about.”

The completion of the line will have major consequences in Quebec, where Hydro-Quebec is looking to take a much bigger role as an exporter. The province-owned company also inked a deal last month for a nearly 340-mile transmission line under Lake Champlain to bring hydropower to New York City. Anti-corridor groups have raised concerns that exporting power means Quebec will consume more fossil fuels locally.

HydroQuebec, which has faced backlash among Indigenous groups in Canada for past dam construction, has maintained that it has excess capacity right now and is not building new dams to supply power for the corridor. The company says it could increase capacity to meet future demand by integrating other renewable sources or upgrading existing dams.

While Quebec sometimes imports electricity from other provinces at peak consumption times during the winter months, the province also participates in a cap-and-trade system, said Pineau, the business school professor. That makes fossil fuel purchases more expensive and incentivizes Hydro-Quebec to seek out other renewables, such as wind power.

A rejection of the corridor in Maine would be “a bad sign for decarbonization,” Pineau said. At the same time, he recognized why there is hesitancy in a place that is not the primary benefactor of the project.

“There’s a lack of regional communication and planning to make sure that everyone benefits,” he said.