Members of the Minnesota House sparred Thursday over whether proposed federal environmental mandates would cost hundreds of jobs or spur a clean-energy revolution, with the fate of Minnesota's biggest power plant hanging in the balance.

The Sherco (Sherburne County) Generating Station, which includes three coal-burning towers in Becker, Minn., is also the state's largest emitter of carbon dioxide. Xcel Energy, which operates the plant, has come under pressure from environmentalists to close the two oldest units, which were built in the mid-1970s.

A new draft plan released by the U.S. Environmental Protection Agency (EPA), dubbed the Clean Power Plan, requires a 40 percent reduction in Minnesota's emissions by 2030.

State Rep. Pat Garofalo, who leads the House Job Growth and Energy Affordability Policy and Finance Committee, planned a public hearing for Monday night in Becker to hear from those who might be most affected by changes at Sherco.

"We want renewable energy," Garofalo, R-Farmington, said at a news conference earlier in the day. "But let's recognize the fact that it ain't always windy, it ain't always sunny, and when [the] wind is not blowing and the sun isn't shining, I still want my heart monitor at the hospital to work for me."

DFLers say any coal-plant closings would be offset by new jobs in wind and solar energy.

But Garofalo and Rep. Jim Newberger, R-Becker, said the initiative would raise energy prices and kill jobs, particularly after the state has already spent billions to clean up the environment and reduce carbon-dioxide emissions by 20 percent over the past decade.

"Minnesota is being punished because we took this action without the federal government telling us," Garofalo said. "So whatever that percentage is — reasonable people can disagree about that — but why would we support a policy that punishes the state of Minnesota for acting on our own?"

Sherco, whose third unit was built in the '80s, is ground zero for the emissions debate. The plant burns up to three trainloads of coal a day; the U.S. Department of the Interior as far back as 2009 contended that emissions from Sherco smokestacks were affecting visibility in Voyageurs and Isle Royale national parks.

The Minnesota Department of Commerce recently recommended that the utility convert one of the two older Sherco units to burning natural gas in 10 years. Clean-energy groups want the older Sherco units closed even sooner. Xcel is currently evaluating its options.

In a letter to Garofalo, Gov. Mark Dayton said that the Minnesota Pollution Control Agency is still working to grasp the impact of the EPA Clean Power Plan and that he has ordered the agency to be transparent in doing so. He said that he, too, was frustrated that Minnesota was not given credit for its earlier work but that he was pleased with adjusted targets to reflect that work. "Like you, I am also concerned about federal laws and rules that seem to provide no environmental or human health benefit to Minnesotans or the rest of the country," Dayton wrote. "However, the EPA has outlined several important benefits from the Clean Power Plan."

Melissa Hortman, DFL-Brooklyn Park, backed the Clean Power Plan in the midst of the hottest year on record and an increase in severe weather — which she attributes to climate change. On Monday, she proposed a tax credit of up to $1,000 for Minnesotans who invest in clean energy, such as installing solar power at their homes or investing in electric cars.

If Xcel proposes to close Sherco to comply with the EPA, she said the state must make sure displaced workers receive benefits and can transition into clean-energy jobs. She cited a proposed clean-energy training facility in north Minneapolis on the Interstate 94 corridor "that would be very convenient for workers from Becker to get to."

Hortman presented a letter signed by 78 DFLers encouraging a strong implementation of the Clean Power Plan.

Acknowledging that at least one of the Sherco units could close, Hortman said it is part of an explosion of alternative energy development statewide. The nation now has more solar jobs than coal-industry jobs, she said.

"Just as we no longer have horse and buggy jobs because we now make automobiles," she said, "we are on the verge of a transition."