A bill allowing all capped municipal landfills to serve as sites for solar projects, even if previous state capping grants had restricted their future use to recreational purposes, passed the state's House of Representatives unanimously last week.

For Amherst, the vote, which mirrored one taken by the state Senate in November, could mean an end to a lawsuit filed in Hampshire County Superior Court last year by landfill abutters seeking to stop the installation of a solar array at the Belchertown Road site. Town Manager John Musante says the project could generate up to 4.75 megawatts of power annually for the town.

"We think the amendment is sensible and consistent with the original intent of the legislation, which was for the life of the landfill after capping," said Musante.

State Rep. Ellen Story, D-Amherst, said Amherst was one of about 20 communities that received landfill capping grants from the state Department of Environmental Protection with language designating the dumps' future use "solely for the purpose of active and passive recreation."

The legislation amends this language by adding renewable energy projects as legitimate uses for capped landfills.

"This might make the lawsuit moot," Story said.

A hearing on the lawsuit was held in Hampshire Superior Court the day after the legislation was adopted, but Judge Mary Lou Rup made no decision on the case.

Musante said the town has always felt it was on solid legal ground and has pledged to meet with the landfill's neighbors.

"We are confident that we can build a solar array on a portion of the old landfill that is safe and sensitive to mitigation concerns from abutters," Musante said.

Story said the House and Senate bills are not identical, but should be ready for Gov. Deval Patrick's signature soon.

"It will have to be reconciled, but that should not be a problem," Story said. "The spirit is the same in both."

Michael Pill, the Northampton attorney representing the plaintiffs in the lawsuit, said the lawsuit raises other issues not affected by the legislation, including possible contamination of properties in the nearby Amherst Woods neighborhoods.

Beyond that he declined comment on the legislation, saying: "I want to see what finally gets enacted."

Story said Musante and other town officials have supported the revised legislation, an idea that came from the Patrick administration. Story said the governor recognized that the tax credits for such renewable energy projects were nearing expiration and that solar projects would be more challenging to complete without them.

"This came from the governor's office, the Executive Office of Environmental Affairs," Story said. "This was not done on behalf of Amherst."

About 20 landfills across the state are affected by the current restriction. Besides Amherst, they include ones in Williamstown, Leominster, Auburn and Worcester.

Story said the legislation is a victory for Amherst residents. She said the projects are beneficial on both a philosophical level and for the financial benefit of stabilizing electricity costs. They could save up to $25 million in energy costs and, with the possibility that municipalities can tax these projects, bring in up to $350,000 in new revenue to the town, she said.

Town Meeting last May overwhelmingly supported the project, giving Musante authority to lease all or a portion of the landfill to BlueWave Capital for up to 30 years. The town is continuing to negotiate a power purchasing agreement with BlueWave.

If the lawsuit is resolved, BlueWave can move from a conceptual proposal to one that is refined and presented to the state's Department of Environmental Protection and the town's Zoning Board of Appeals for permits.

An interconnection agreement with Western Massachusetts Electric Co. also must be finalized.

Musante has said there will be opportunity to hear from the public throughout the process and that he is committed to productive dialogue with residents.

Story said she expects Musante to meet with neighbors and try to make the issue less contentious.

"The town has every interest in meeting with them, figuring out the footprint and make this as palatable as possible to people who live near the landfill," she said.