Maine’s first wind farm, proposed for Mars Hill, will move forward now that the federal energy bill has been approved.

The bill, however, is at best a mixed bag for Maine, environmentalists said Friday.

The bill includes a production tax credit for renewable forms of energy such as wind, biomass and landfill gas. The policy offers developers a 1.9 cent per kilowatt-hour tax break for new projects constructed by the end of 2008. Hydropower operations that increase their efficiency to boost power production also qualify.

The tax credit could be worth $2.7 billion nationally, according to Maine Sens. Olympia Snowe and Susan Collins.

The bill will be key to several proposals in Maine, from keeping biomass plants that use mill waste in business, to the Mars Hill wind farm, to a potential methane-burning operation proposed by Casella for the West Old Town Landfill, Dave Wilby of the Independent Energy Producers of Maine said Friday.

A provision that would require that 10 percent of American energy come from renewable sources by 2020 failed, however. And renewable energy alone can’t solve the larger problems of climate change, critics said.

“This bill demonstrates no leadership and no courage,” Susan Sargent, Maine spokeswoman for the National Environmental Trust, said in a statement released Friday.

A controversial provision that would have offered liability protection to the makers of MTBE, a highly polluting gasoline additive, was removed from the bill, as was a proposal to drill for oil in the Arctic National Wildlife Refuge, in part because of opposition from Maine’s congressional delegation.

And the bill gives states a slightly stronger voice in approving sites for liquefied natural gas projects.

A proposal to explore the outer continental shelf for oil resources, however, was included in the final bill, to the dismay of Maine’s senators, who fear damage to the marine ecology near valuable fisheries resources.