The Obama administration unveiled on Friday new regulations that set strict limits on the amount of carbon pollution generated by any new U.S. power plants and that will likely face legal challenges and a backlash from congressional supporters of the coal industry.
The Environmental Protection Agency's long-awaited guidelines are expected reshape where Americans get electricity, steering them from a coal-dependent past toward a future powered by cleaner sources of energy.
It's also a key step in President Barack Obama's global-warming plans, because it would help end what he has called "the limitless dumping of carbon pollution" from power plants.
Although the proposed rules wouldn't affect power plants already operating, their adoption could eventually force the government to limit emissions from existing plants, which account for a third of all U.S. greenhouse-gas emissions. Obama has given the EPA until next summer to propose those regulations.
The EPA released its proposal for new coal-fired plants Friday morning, and the public will have a chance to comment on it before it becomes final.
Despite some tweaks, the rule packs the same punch as one announced last year, which was widely criticized by the power industry and Republicans as effectively banning any new coal projects in the U.S.
In order to meet the standard -- the plans for which the AP received in advance of Friday's announcement -- new coal-fired power plants would need to install expensive technology to capture carbon dioxide and bury it underground, otherwise known as carbon sequestration.
No coal-fired power plant has done that yet, in large part because of the cost. And those plants that the EPA points to as models, like a coal plant being built in Kemper County, Miss., by Southern Co., have received hundreds of millions of dollars in federal grants and tax credits.
Coal, which is struggling to compete with cheap natural gas, accounts for 40 percent of U.S. electricity -- a share that has been shrinking. And natural gas plants would need no additional pollution controls to comply.
A powerful Republican opponent of the EPA plan, Senate Minority Leader Mitch McConnell of Kentucky, said in an emailed statement that "the president is leading a war on coal."
The regulations have been in the works since 2011 and stem from a 1970 law passed by Congress to control air pollution. In 2007 the Supreme Court ruled that that law, the Clean Air Act, could be applied to heat-trapping pollution.
The EPA has already issued rules aimed at curbing global-warming pollution from automobiles and the largest industrial sources.
An EPA official told the AP that the rule doesn't specify any particular technology. But the official acknowledged that carbon capture was the only current means available for a company to meet the threshold of 1,100 pounds of carbon dioxide emissions per megawatt hour of electricity. To put that in perspective, a modern coal plant without carbon controls releases about 1,800 pounds per megawatt hour.
The official spoke on condition of anonymity because the announcement of the rule had not yet been made.
The administration went back to the drawing board after receiving more than 2 million comments on its first proposal, which was legally vulnerable because it required coal and natural gas to meet the same limit. (Coal and natural gas now have separate standards.) Regardless, the latest proposal will almost certainly be litigated once it is made final, as the EPA is required to do within a year.
The legal argument likely will be based on whether carbon capture and storage is a demonstrated technology.
"EPA has set a dangerous and far-reaching precedent for the broader economy by failing to base environmental standards on reliable technology," said Hall Quinn, president and CEO of the National Mining Association. The EPA regulation "effectively bans coal from America's power portfolio," he said.
Al Jazeera and wire services