Supporters of “No CMP Corridor” attend a rally after submitting more than 75,000 signatures to election officials at the State Office Building, Monday, Feb. 3, 2020, in Augusta, Maine. Opponents of a proposed $1 billion transmission line aimed at bringing Canadian hydropower to the New England grid collected more than enough signatures to put the proposal to a statewide vote. Credit: Robert F. Bukaty | AP

AUGUSTA, Maine — A referendum aiming to stop Central Maine Power’s transmission line project through western Maine has qualified for the November ballot, setting up a high-stakes showdown as the project appears to be progressing through regulatory channels.

The Maine secretary of state’s office said Wednesday that the anti-corridor campaign submitted nearly 70,000 signatures, easily clearing a threshold needed to put a question on the ballot aiming to kill the $1 billion project. The proposal will now go to the Maine Legislature, which is allowed to pass the measure as written, send it to voters or place it on the ballot alongside a competing measure.

It means voters are likely to decide whether the 145-mile corridor that would take Hydro-Quebec power to the regional grid — formally called the New England Clean Energy Connect — is in the public’s interest. If a majority votes “no,” it would force the Maine Public Utilities Commission to find the project is not in the public’s interest.

The announcement was a formality after months of campaigning on both sides. Referendum supporters were confident last month that they would have the signatures to take the issue to a statewide vote. Opponents and supporters have traded ethics complaints, with Hydro-Quebec, the providence-owned power company partnering with CMP, paying a $35,000 ethics fine and two complaints pending against anti-corridor groups.

The utility is taking the referendum seriously. Through a political committee, it has poured millions of dollars into messaging designed to restore confidence in its flagging reputation and promoting the project, which proponents say will result in cheaper and cleaner energy.

At the same time, CMP’s parent company is expressing confidence that the project will succeed. Avangrid executives said they expect construction on the corridor is expected to begin later this year during a phone conference last week, although they said they would monitor the referendum situation before deciding how much to invest.

CMP has gotten approval from the PUC and the state’s Land Use Planning Commission, but it still needs approval from the Department of Environmental Protection, the Army Corps of Engineers, ISO-New England and a presidential permit for the project.

There are efforts to undercut the corridor making their way through the State House, too. A bill that would void a lease agreement between the state and the utility got unanimous support from the Legislature’s conservation committee. If the bill succeeds, it will require the state to reconsider the lease and give the Legislature approval power over any leases in the future.