The Environmental Protection Agency now has the authority to regulate greenhouse gas emissions from power plants, the U.S. Supreme Court said on Monday. The ruling blocked a federal lawsuit by states and conservation groups that were trying to force cuts in power plant emissions.

The lawsuit brought by eight states—California, Connecticut, Iowa, New Jersey, New York, Rhode Island, Vermont and Wisconsin—targeted the five largest utility companies, Xcel Energy, American Electric Power Co. of Ohio, Cinergy Co., Southern Co. Inc. of Georgia and the federal Tennessee Valley Authority.

The Supreme Court voted 8-0 to block the suit. 

Xcel welcomed the high court's ruling and said it looks forward to working with the EPA on regulations regarding carbon dioxide and other gasses without the threat of lawsuits.

Greenhouse gases, particularly carbon dioxide, have been linked to climate change.

The court had declared in 2007 that carbon dioxide and other greenhouse gases are air pollutants under the Clean Air Act, and that the EPA had authority to regulate those emissions for new cars and trucks. The same reasoning now applies to power plants.

The EPA said it will impose new regulations regarding the greenhouse gasses by May 2012.

Xcel Energy applauded the Supreme Court decision because it will allow the utility to work with the EPA on greenhouse gas regulations “without the threat of continued litigation,” Xcel spokesman Steve Roalstad said.