The U.S. Department of Energy Tuesday awarded $15 million in federal stimulus funds to the company that is expanding its plant at the state’s Central Landfill that generates electricity by burning the methane gas given off by decomposing garbage.

The grant goes to Rhode Island LFG Genco, an affiliate of Ridgewood Renewable Power, the company that operates a smaller generating plant at the landfill now.

The proposed 42-megawatt power plant was supposed to cost $80 million. But Stephen Galowitz, a managing director in charge of development and marketing at Ridgewood, said the costs have risen to about $100 million.

Galowitz said the federal stimulus grant, part of about $150 million distributed around the country by the Energy Department Tuesday for industrial-energy projects, comes at just the right time for Ridgewood because this is a difficult time to raise funds for industrial projects.

“The timing of this couldn’t be better,” Galowitz said in a telephone interview. “This is a challenging financing environment.”

He added that he was stunned by how quickly the Energy Department went through the process of soliciting proposals, reviewing them and awarding the grants. “It was lightning fast.”

Galowitz and Michael O’Connell, executive director of the Rhode Island Resource Recovery Authority, the state agency that operates the landfill, said construction of the new plant should begin in the spring.

Previously, the company has said it hoped to complete construction next year.

But O’Connell said it has taken time for Ridgewood to get all the necessary permits and easements to build the plant, which would be the second largest in the country.

O’Connell said he has a good working relationship with Ridgewood and he’s confident it will get the plant built.

“I haven’t had a lot of good news around here lately, so this is good,” he said.

Revenues have dropped dramatically at the landfill because of declining trash collection and competition from out-of-state incinerators. A recent audit found previous managers of the agency squandered $75 million on bad land deals, cronyism and suspected fraud. And, recently, The Providence Journal reported that an employee was fired for not doing the school presentations he reported to his superiors.

Also, this week it was learned that the state has been soliciting proposals from businesses to buy or lease the landfill.

But Galowitz said yesterday he doesn’t foresee any obstacles that would prevent Ridgewood from completing the generating plant.

The grant was announced by the state’s congressional delegation Tuesday. Galowitz said he deeply appreciated the letters of support submitted by the delegation for the project.

“By turning Rhode Island’s waste depository into a source of renewable energy, this project will help reduce our dependence on foreign oil and create new clean energy jobs for our Ocean State,” U.S. Sen. Sheldon Whitehouse said in a statement.

plord@projo.com