"My legislation says no new plants without emissions controls," said Rep. Henry Waxman of California, chairman of the House oversight committee that has held hearings on the government's response to global warming.

The bill by Waxman and Rep. Edward Markey of Massachusetts would forbid the Environmental Protection Agency or states from issuing air permits for plants that lack "state-of-the-art controls" to capture carbon dioxide emissions, with such technology said to be years away.

The moratorium would be in place at least until the government develops an emissions-control program. Congress is debating bills that would cap greenhouse gas emissions while allowing companies to buy and sell emissions "credits" depending on how their plants perform on pollution limits.

Sen. John Kerry, D-Mass., introduced a similar bill in the Senate last April.

Three Nevada coal projects have been issued draft air permits by the state Division of Environmental Protection, and could have their final air permits in hand by year's end, said Charles Benjamin, director of the Nevada office of Western Resource Advocates, an environmental group that opposes the ventures.

Project developers also are awaiting the completion of environmental impact studies from the Bureau of Land Management before they can start construction, he said.

With the possibility that newly constructed plants would be grandfathered into a cap-and-trade program, the Waxman bill limits their participation for as long as they operate without carbon dioxide controls.

"(The bill) sends a political signal to the industry as well as to the investment industry that going forward with these plants will be highly risky or at least increase the risk and costs," Benjamin said.

But the bill is not realistic, said Frank Maisano, a spokesman for Sithe Global Power, which is planning a 750-megawatt coal-fired power plant near Mesquite.

"To say we are not going to have any coal plants is pie-in-the-sky legislation," Maisano said.

Similarly, spokesman Adam Grant for Sierra Pacific Resources, which is planning a 1,500 megawatt coal-driven power plant 20 miles north of Ely, said, "stopping production of the most abundant energy source is not the answer."

A third company, LS Power, is developing a 1,600-megawatt coal power plant in White Pine County, 25 miles north of Ely.

Contact Stephens Washington Bureau Chief Steve Tetreault at stetreault@stephensmedia.com or (202) 783-1760.