It wasn’t his first choice, but Sean Mahoney isn’t fighting a 150-mile proposed power line sending Canadian hydropower to New England as part of the region’s climate-change goals.

Why he matters: Mahoney, a senior expert at the nonprofit Conservation Law Foundation who lives in Maine, is seeking to compromise in a bitter battle over the proposal. Expect more fights like this as President Biden and other political leaders pursue zero-carbon economies over the next 30 years.

Catch up fast: Last week, opponents of the $1 billion project got state approval to move forward with a referendum that would effectively kill the power line, if approved by either the Maine legislature or voters. This development poses “significant risk” to the project, according to ClearView Energy Partners, a nonpartisan research firm.

What they’re saying: Mahoney said his organization is not opposing the project because the developer made concessions, including financial support for low-income customers, electric-car funding and land conservation.

• He’s also not fighting it because the line would force some closure of power plants fueled by natural gas, which are the region’s primary electricity source but also contribute to climate change.
• “Could it have been better? Do we wish it had been a different project with solar, wind and batteries? Absolutely. But this was the reality,” said Mahoney, executive vice president of the foundation.
• “We’re going to leave our kids and our grandkids with a mess if we don’t make the hard choices.”

Where it stands: Responding to a request from Massachusetts as part of its climate goals, Avangrid proposed the project and has begun construction on parts of it, which will send existing hydropower from Quebec through Maine to flow into New England’s grid.

• Controversy is swirling around 53 miles in Maine’s Western forest, which is used for logging but also recreational purposes. The line requires 54 feet of newly cleared land along that route.
• Through the public referendum, legislation and lawsuits, some environmental groups and natural-gas companies are — for different reasons — fighting the project.

How it works: Electricity is core to climate change action in two ways. 

1. Getting as many parts of our economy as possible — like cars, manufacturing and heating — running on electricity makes it easier to clean up those sectors because of increasingly affordable clean electricity.
2. That goal depends on another one: ensuring that electricity is both clean and available. This requires additional planning and constructing way more transmission lines connecting clean energy to heavily populated areas.

The big picture: This New England project is the latest strange bedfellows fight over energy infrastructure in America.

• NIMBYism — not in my backyard — opposition crops up for almost everything because of the general aversion to disruption to one’s home.
• Although oil and gas facilities have traditionally faced the brunt of energy NIMBYism, rapidly growing renewables aren't immune to it despite helping to combat climate change.
• This Maine project only exists because another one — called Northern Pass, which would have gone through New Hampshire — failed under similar opposition.
• These fights look easy compared to a 700-mile power line that would have sent wind power from America’s central plains to its east coast. It failed too, as WSJ reporter Russell Gold writes in his book, Superpower.

The intrigue: The strange bedfellows lined up on either side of the Maine project have the makings of a blockbuster drama — if Hollywood found electricity exciting.

• Environmental groups are divided. The Sierra Club and some local groups oppose it because of the inclusion of existing Canadian hydropower over wind and solar, as well as concerns about forest impact.
• NextEra Energy, the world’s largest producer of wind and solar, is fighting the project. It operates two natural-gas plants in the region.
• One opposition group is trying to shield its anonymous donors.
• Developers include Hydro-Quebec, a provincial government-owned utility whose track record with Canada’s indigenous people is mixed at best, and Central Power Maine, which received the lowest score in a residential consumer satisfaction survey of U.S. utilities.
• Corporations on both sides are pouring millions into the fight, with the developers so far vastly outspending opponents, according to state disclosures.

The bottom line: Despite opponents’ arguments otherwise, the Maine Public Utilities Commission concluded in 2019 that the transmission line would reduce greenhouse gas emissions and electricity costs in the region.

What’s next: Environmental groups may try to pressure Biden to further review the project. “This is something that deserves a close look by the new administration,” said Sue Ely, an attorney for one of the local groups opposing the project, Natural Resources Council of Maine.

What we’re watching: In another strange bedfellow’s twist, the new administration has so far indicated, via a legal filing, that it agrees with the last one when it comes to this project: It supports it.

Editor's note: Amy Harder is vice president of publishing atBreakthrough Energy, a network of investment vehicles, philanthropic programs, policy advocacy, and other activities committed to scaling the technologies needed to reach net-zero emissions by 2050. She is launching a new journalism initiative there. Previously full time at Axios, Amy is now writing her Harder Line column monthly as an outside contributor.