MONTGOMERY — Citing federal environmental regulations, Alabama Power announced Friday that it will convert some of its coal-fired generators to natural gas by 2016, a move that could dramatically reduce the use of coal by the utility.

The move drew praise from environmentalists, and criticism from Republican elected officials, who have long accused the Obama administration of waging a "war on coal."

"I don't believe it's right for Washington to tell us what our fuel mix should be," said Twinkle Cavanaugh, president of the state's Public Service Commission.

In a press release Friday, Alabama Power wrote that it will shut down two coal-fired generators at its Gorgas power plant in Walker County. Three other units at the Barry power plant in Mobile will be converted to use natural gas, as will one generator at the company's Greene County power plant. All of those plants use multiple generators, and none of the plants will close.

The changes will affect roughly 60 workers, all of them at the Greene County plant, Alabama Power spokesman Michael Sznajderman said. The company doesn't plan to lay off any of the workers, Sznajderman said, and will try to transfer some while not replacing others who are near retirement.

"It's not all etched in stone, but we're hoping we can avoid layoffs," he said. "We have other plants across the state, and we have a need for new positions at those plants."

Sznajderman said the move is part of the company's efforts to comply with federal regulations on mercury emissions, which go into effect next year.

Federal regulators have mulled the idea of limits on mercury emissions from power plants since the late 1990s, as scientists began to accumulate evidence that power plants were a major source of emissions of the toxic metal.

"The EPA is regulating mercury because it's a potent neurotoxin," said Amelia Shenstone, a spokeswoman for the Southern Alliance for Clean Energy, an environmental group. "It goes into the water and is eaten by tiny critters, who then are eaten by bigger and bigger fish, which accumulate large amounts of mercury in their bodies."

Shenstone said mercury causes lower IQ and other health problems, and is the reason pregnant women are often advised not to eat fish.

"It's most of concern for developing young children, children who are still in the mother's womb," Shenstone said.

Alabama Power has spent billions, Sznajderman said, on efforts to fit out its largest power plants with scrubbers and baghouses, equipment that cleans pollutants like mercury out of their emissions.

The coal-fired plants at Gorgas, Barry and Greene County were smaller plants that had never been equipped with those measures. Sznajderman said the company's board of directors decided weeks ago to close or convert the plants rather than bring them into compliance with the law.

The generators at Barry and Gorgas were used only at times of peak production, Sznajderman said. The Greene County plant ran more frequently.

Cavanaugh said the change would have a major effect on the state's coal use.

"Right now we're using coal for 55 percent of our production," she said. "After this, we'll be at 45 percent."

Sznajderman confirmed those numbers.

The utility's use of coal has been a contentious point in Alabama politics recently, and particularly this week. Cavanaugh and other Alabama Republicans testified in Atlanta earlier this week against proposed regulations on greenhouse gas emissions from coal-fired plants.

Opponents of coal-fired plant regulation say it will harm jobs in Alabama, a coal-producing state. Still, it's not clear that Alabama Power's generator change will affect Alabama coal miners. Sznajderman said the company buys much of its coal from Wyoming.

Preparation for the new mercury standards may have already affected mercury emissions in Alabama. In 2009, the group Environmental Defense Fund named the company's James H. Miller Plant near Birmingham as the country's fourth-largest emitter of mercury. Earlier this week, the company sent out a press release touting the plant's selection by the magazine Power Engineering as one of the cleanest in the country.

Cavanaugh said she doesn't believe the changes announced Friday will have a major effect on the health of Alabama residents.

"The health benefits are actually very debatable," she said. "You get to a point of diminishing returns."

The move was likely no surprise to Cavanaugh or other members of the Public Service Commission. Every three years, the utility must submit a detailed set of projections, known as the Integrated Resource Plan, to the PSC for review.

Many states make that document public. The Anniston Star has asked for access to Alabama Power's IRP, though the commission has released only a 15-page summary of the complete plan.

In that summary, Alabama Power said it had plans to "derate" some of its coal-fired generators due to the cost of environmental compliance.

Shenstone said a release of the full plan would let the public know more about the economics of the decision to close the coal-fired generators.

"If we had those numbers, we'd understand the business side of it much better," she said.

Capitol & statewide reporter Tim Lockette: 256-294-4193. On Twitter @TLockette_Star.