PORTLAND, Maine (AP) Maine election officials say opponents of a $1 billion electricity transmission corridor have collected enough signatures to move forward with a referendum.

Secretary of State Shenna Bellows says more than 80,000 signatures were certified, exceeding the threshold of 63,067 for the ballot.

The Maine Legislature will now consider the initiative. If they reject it, then there would be a vote in November.

The referendum would require legislative approval for any electrical power line project that exceeds 50 miles and would be retroactive to September 2014.

Orlando Delogu, professor emeritus at the University of Maine School of Law, has questioned whether the referendum is constitutional.