The three-member panel rejected a staff recommendation in voting unanimously for the proposal on Tuesday. But Maine would participate only if four other New England states follow suit with similar plans. Vermont wasn't included.
The PUC said expanded capacity is necessary to prevent winter price spikes, even though the staff concluded low oil and gas prices and new pipelines already under construction or being permitted could temper price spikes without ratepayers getting involved.
Supporters say it'll lower energy costs but critics contend the benefits are overstated. A staff attorney with the Conservation Law Foundation said the environmental group will fight to ensure the proposal "dies on the vine."