Gov. Janet Mills speaks at an event in the Hall of Flag at the State House in Augusta in this file photo.

Democratic Gov. Janet Mills said she does not plan to get involved in a potential referendum that could determine whether Central Maine Power can build a controversial transmission line through western Maine, even though she supports the project.

Opponents of the transmission line are still gathering signatures for a referendum that would allow voters to decide its fate next November.

But CMP, through a political action committee called Clean Energy Matters, is not waiting to kick off its influence campaign. The group announced Tuesday that it has begun airing a television ad called “Good Questions,” a spot acknowledging that the 145-mile project has sparked concerns in the minds of Maine residents.

The ad was released alongside two endorsements from the Maine State Chamber of Commerce and a union of electrical workers.

[Jared Golden concerned about ‘lack of transparency’ in federal permitting of CMP corridor]

But Mills, who earlier this year announced support for the project, did not join the campaign rollout, and she isn’t listed on the campaign website as a backer.

In a statement, Mills’ office said that she supports the project, in part, because of its purported carbon reduction impacts and a benefits package that includes funding for broadband expansion, subsidies for heat pumps and scholarships.

But her office also said the governor doesn’t see a role for herself in the campaign, and highlights her commitment to a separate matter — an investigation into CMP’s customer billing issues.

“Governor Mills believes CMP owes Maine people complete and direct answers about their billing errors, why they happened, and how they are fixing them,” the governor’s office said. “The Governor’s Energy Office will be an active participant in this investigation to ensure that these issues are resolved and that CMP is held accountable.”

The billing issue will not be on the ballot next year, but it could color perceptions of a project that has already proven unpopular in the communities it could pass through.

The same goes for CMP’s reputation, which has taken a hit in recent years. The company is not mentioned in its new ad, and there is a single, oblique reference to it on the website promoting the transmission project.

This article appears through a media partnership with Maine Public.