But despite its promise of providing a relatively clean-burning source of electricity, environmentalists are taking a dim view of the project.

The 285-megawatt plant in Orange County is being built by Southern Co., the Atlanta parent of Gulf Power Co. of Pensacola, and the Orlando Utilities Commission at a cost of $557-million.

The plant will feature a generating unit powered by coal-derived gas and as a second unit that will be powered by steam created by hot gas from the first unit. The technology, which Southern claims will sharply reduce emissions of sulfur dioxide, nitrogen oxides and other pollutants, is similar to that used at Tampa Electric Co.'s Polk Power Station near Lakeland, which received $143-million in Energy Department money.

"We believe this plant will demonstrate that coal can and should be part of a cleaner energy future," Southern chairman and chief executive David Ratcliffe said Thursday in a statement.

The plant is being subsidized as part of the Bush administration's 2002 Clean Coal Power Initiative, which plans to spend $2-billion over 10 years to encourage the development of new ways to make the coal-fired electricity generation more environmentally friendly than conventional methods. Given the political clout of the utility and coal mining industries, it is a concept that enjoys bipartisan support. Democratic presidential candidate John Kerry released a plan in August to invest $10- billion in clean-coal technologies.

But despite the emissions reductions that can be realized, environmentalists argue "clean coal" is an oxymoron and question why the federal government should invest heavily in showcase projects like the Orange County plant. They argue the money could be better spent on outfitting existing coal plants with emission control devices, furthering the development of wind and solar power and paying for programs that promote greater energy efficiency.

"Why should the taxpayer subsidize these giant corporations?" said Navin Nayak, an environmental advocate for the U.S. Public Interest Research Group in Washington. "There's no reason why these companies shouldn't be footing the bill."

David Hamilton, director of global warming and energy programs at the Sierra Club in Washington, said government investment in coal technologies hurts the development of renewable energy resources such as wind and solar power.

"If the coal industry is going to plot its future, it ought to pay for it," Hamilton said. "Otherwise, (federal subsidies) skew the cost relative to other, cleaner energy sources."

Energy Department spokesman Drew Malcomb acknowledged investing in some clean-coal technologies wouldn't be economically feasible for individual companies without federal support. But he stressed that such projects remained important because coal is the most abundant fossil fuel energy source in the United States.

"To assume we could power our country without coal at this stage is not feasible," he said.