AUGUSTA, Maine — Maine regulators are proposing changes to an energy policy that lets solar owners receive credits on their utility bill for energy they sell back to the grid.

Critics including GOP Gov. Paul LePage have criticized the policy for selling back electricity at “above-market” rates. On Tuesday, Maine public utility commissioners, all appointed by LePage, appeared to agree that current solar rules are not equitable and don’t take into account the market.

Public Utilities Commission Chairman Mark Vannoy said though legislators set statewide energy policy, the commission must continue overseeing such policies to protect electricity customers. He called net energy billing a “promotional program” that uses ratepayer funding to encourage solar buildout.

Vannoy said proposed rules, which haven’t yet been released and would begin in January, would reduce the value of credits over the next decade as installation costs continue to decline. Current customers would be grandfathered in for 15 years.

Currently, solar customers get credits for energy as well as transmission and distribution costs. The new rules would keep energy supply credits the same while gradually reducing transmission and distribution credits.

Solar energy advocates had asked regulators to wait on any reform until legislators return in January. A Natural Resources Council of Maine spokesman called the proposed rules “unnecessary” and pointed to several studies showing solar energy lowers costs for all ratepayers.

“It’ll be complex, controversial and take a lot of people’s attention when I think we should be focused on what’s a solar policy we can adopt that will move Maine forward on solar,” NRCM Clean Energy Director Dylan Voorhees said.

But Voorhees said he was glad the grandfather period wasn’t “more draconian.”

The rules, which the public can now weigh in on, would also expand the solar billing policy in part. Commissioners want to increase the size cap for an eligible solar facility to 1,000 kilowatts, up from 660 kilowatts.

The rules would also authorize community net billing and add new consumer protections for solar billing and leasing arrangements.