Maine’s Supreme Court will hear oral arguments this week in two cases that could determine the fate of Central Maine Power’s stalled Western Maine transmission line project. 

The high court is scheduled to take up CMP owner Avangrid’s challenge to the ballot initiative that halted construction on the corridor last fall, as well as Avangrid’s appeal of an earlier ruling in a separate case that said the state erred in issuing the project’s public lands lease. 

The justices of the Law Court will meet in Portland for their monthly oral arguments Monday, Tuesday and Wednesday. They are slated to hear both cases, with rulings expected in the weeks or months after that.

It means a return to the spotlight for the controversial power line project that has been on hold since late last year. CMP wants to build the 145-mile line to bring Canadian hydropower onto the New England grid under a deal to help meet Massachusetts’ climate change goals. 

Confusingly, the state Bureau of Public Lands, represented by the attorney general’s office, is the defendant in both cases. This is because the state enforces the law enacted by the voter referendum, and it also issued the public lands lease that is at issue in the separate appeal. 

In the referendum case, the state is defending an anti-corridor law against a suit from the developer. In the public lands lease case, the state is squaring off with project opponents, led by state Sen. Russell Black (R-Franklin), to defend how it initially leased land for just under one mile of the corridor’s 145-mile route. 

In another complication, the state Board of Environmental Protection will hold hearings the week after the Supreme Court arguments on another set of appeals of earlier permits for the corridor. 

Read on for details on each Supreme Court case and what the outcomes could mean for CMP: 

The referendum case: NECEC Transmission et al vs. Bureau of Public Lands


Maine voters approved a referendum last fall, on a roughly 60-40 margin, that enacted a law prohibiting high-voltage transmission lines from the so-called Upper Kennebec Region. The law applies retroactively to 2014, before the state permitted the New England Clean Energy Connect Project, the official name for the corridor and the plaintiff in the ensuing lawsuit.  

The power line developer quickly moved to challenge the law. They asked Judge Michael Duddy to temporarily stop it from going into effect and to find it unconstitutional. Avangrid argued that they’ve spent so much time and money on the project already that they have “vested rights” to continue, and that retroactively restricting the project would violate their due process rights. 

While this case was pending in late November, CMP paused construction at the request of Gov. Janet Mills. Soon after, a state regulator suspended the project’s permit that will be the subject of Board of Environmental Protection appeals the week after the Supreme Court hearings.

In December, Duddy denied Avangrid’s request for an injunction against the referendum law. He agreed with both parties in the case that the state Supreme Court should decide larger questions of law that he found are unsettled, such as whether the project has vested rights. 

The divisive nature of the corridor and transmission development in New England in general is evident in the range of stakeholders who filed briefs in support of and against the referendum.

Groups who weighed in on the corridor’s side and against the referendum include: 

  • HydroQuebec, which would supply hydropower to the project

  • The Maine State Chamber of Commerce

  • The Industrial Energy Consumer Group, an association of large Maine businesses that say the referendum will create a chilling effect on future energy development in the state

  • The construction company Cianbro and the union local that worked on the project

  • The city of Lewiston, which hoped to see economic benefits from the corridor

  • A group of Maine legislators who say the referendum violates separation of powers  

  • A group of Maine academics who argue for the project’s climate change benefits

  • Former Maine public utilities commissioners who say the referendum conflicts with their agency’s authority

  • CMP’s fellow large New England utilities National Grid, Unitil and Eversource, whose participation is especially notable given the fact that its Northern Pass transmission proposal in New Hampshire was Massachusetts’ original choice to bring hydropower into the region, and the CMP corridor took its place after denials from N.H. authorities

  • A political economist from George Washington University, an emeritus professor at the University of Maine School of Law who argued for the corridor before the referendum, and another Maine Law dean who calls the law’s retroactivity “legislative shenanigans”

Defending the referendum alongside the state Bureau of Public Lands and legislature are:

If the high court decides that the referendum can retroactively block the CMP corridor, the utility would have to find a way to reroute the project around the area of the ban in order to continue. This could require input by state agencies to pin down the borders of that area. 

But the developer has said the pause in construction and any other major changes in the future could be a death blow to the project even if it finds a viable route. Right now, the corridor is supposed to be online by the end of next year to meet the terms of its deal with Massachusetts. 

The public lands lease case: Russell Black et al vs. Bureau of Public Lands


Just under one mile out of the corridor’s route crosses public reserved land, near West Forks. In 2020, the state gave CMP a lease to use that 32-acre parcel for the corridor for 25 years.

Project opponents appealed that approval. They said the Bureau of Public Lands didn’t correctly decide whether the project represented a “substantial alteration” to the lease area, which they argued would have required more public input and two-thirds approval by the state legislature. 

Last August, Superior Court justice Michaela Murphy agreed and said the lease was issued incorrectly. In this Supreme Court appeal, the state as well as CMP are asking the justices to overturn that ruling and validate the lease. They say they didn’t need legislative approval and did correctly assess whether the project represented a substantial alteration to the public land. 

Other groups who filed briefs saying the lease should be validated include:

  • HydroQuebec, as well as Maine Law emeritus professor Orlando Delogu, who are both also supporting the corridor in the other Supreme Court case

  • A resident with a camp on another public reserve lot who says the Superior Court ruling unfairly subjects public lands lease-holders like him to “the threat of potential lawsuits challenging the validity of their leases by people claiming to have been affected in inchoate, generalized ways,” and argues state regulators should sort out the dispute

  • The Maine Forest Products Council, which says the Superior Court ruling goes against the tenets of the state’s public lands system and how it’s governed

The entities arguing against the corridor and its public lands lease in this case include state legislators and residents, partly represented by the Natural Resources Council of Maine. 

The court could decide that the lease is valid and the land can be used if the project moves forward, depending on the outcome of the referendum case. Or, it could remand the issue to the Bureau of Public Lands, telling them to revisit the decision with a different approach to their process. The court could also agree with the initial ruling and find that the lease is invalid. 

Regardless of what happens to the corridor, the referendum law – if the court upholds it – will prevent future similar projects anywhere in the state from using these public lands without two-thirds legislative approval. Critics of the law argue this could have repercussions for clean energy development needed in the coming years to avert the worst effects of climate change.