The Obama administration forged ahead on Tuesday with the first-ever limits on heat-trapping pollution from new power plants, ignoring protests from industry and Republicans who have said the regulation will raise electricity prices and kill off coal, the dominant U.S. energy source.
But the proposal also fell short of environmentalists' hopes because it goes easier than it could have on coal-fired power, one of the largest sources of the gases blamed for global warming.
"The standard will check the previously uncontrolled amount (of carbon pollution) that power plants ... release into our atmosphere," Lisa Jackson, head of the Environmental Protection Agency, said in a conference call with reporters Tuesday. But "it also creates a path forward for future facilities to use technology that burns coal, while releasing less carbon pollution."
Older coal-fired power plants have already been shutting down across the country, thanks to low natural gas prices, demand from China driving up coal's price and weaker demand for electricity.
Regulations from the EPA to control pollution blowing downwind and toxic emissions from power plants have also helped push some into retirement, causing Republicans in Congress and on the campaign trail to claim the agency will cause blackouts. Numerous studies and an AP survey of power plant operators have shown that is not the case.
But on Tuesday, GOP leaders once again accused the administration of clamping down on cheap, home-grown sources of energy and said the regulation raised questions about the sincerity of President Barack Obama's pledge for an "all-of-the-above" energy policy.
"This rule is part of the Obama administration's aggressive plan to change America's energy portfolio and eliminate coal as a source of affordable, reliable electricity generation," said Rep. Fred Upton, R-Mich., who as chairman of the House Energy and Commerce Committee has led the charge against environmental regulations. "EPA continues to overstep its authority and ram through a series of overreaching regulations in it attacks on America's power sector."
The rule announced Tuesday could either derail or jump-start plans for 15 new coal-fired power plants in 10 states, depending on when they start construction. Those that break ground in the next year would be exempt from the new limit. Those that start construction later will have to eventually comply with the rule.
Existing power plants, even if they make changes that increase emissions, would not be covered at all. And new ones would have years to meet the standard and could average their emissions over three decades in order to meet the threshold.
But eventually, all coal-fired power plants would need to install equipment to capture half of their carbon pollution. While not commercially available now, the EPA projects that by 2030, no new coal-fired power plant will be built without carbon capture and storage.
By contrast, a new natural gas-fired power plant would meet the new standard without installing additional controls.
"There are areas where they could have made it a lot worse," said Scott Segal, director of the Electric Reliability Coordinating Council, a coalition of power companies. Still, "the numerical limit allows progress for natural gas and places compliance out of reach for coal-fired plants" not planning to capture and sequester carbon dioxide, the chief greenhouse gas.
Steve Miller, CEO and President of the American Coalition for Clean Coal Electricity, a group of coal-burning electricity producers, took a more dismal view of the proposal.
"The latest rule will make it impossible to build any new coal-fueled power plants and could cause the premature closure of many more coal-fueled power plants operating today," Miller said.
The regulation, which was due to be released last July but has been stuck at the White House since November, stemmed from a settlement with environmental groups and states. The government already controls global warming pollution at the largest industrial sources, has adopted the first-ever standards for new cars and trucks and is working on regulations to reduce greenhouse gases at refineries.
But EPA chief Jackson said Tuesday the agency has no plans to pursue regulations for existing power plants.
Some states, including Washington, Oregon and California, already limit greenhouse gas pollution. And two other states, Montana and Illinois, require carbon capture and storage for all new coal-fired power plants.
Michael Brune, executive director of the Sierra Club, an advocacy group fighting coal-fired power, said in an interview that the regulation shows that President Barack Obama is moving to a cleaner energy future.
"It's a strong move," Brune said. "It means there will never be another coal plant built without new technology, and it probably means even those won't be built because they can't compete."
Other advocacy groups, however, said the regulation was imperfect, since it "grandfathers" in existing plants.
"EPA also must focus on the main source of power plant carbon emissions existing coal-fired plants, many of them more than 50 years old, which are responsible for nearly 40 percent of U.S. carbon emissions," said Kevin Knobloch, the president of the Union of Concerned Scientists, who said the regulation was a historic step to "trim" carbon emissions.
Even if the proposal did result in no new coal-fired power plants being built in the U.S., the coal would be exported and burned for electricity elsewhere, contributing to global warming. Export would also increase emissions because of the pollution from the transportation.
But Republicans said the new rule could not come at a worse time, with concern about high gasoline prices and energy taking center stage in the presidential election.
"At a time when the Obama administration should be working to lower the price of gas at the pump, it is alarming that they have put forward more global warming regulations," said Matt Dempsey, a spokesman for Oklahoma Sen. James Inhofe, the top Republican on the Senate environment panel, who pledged on Tuesday to introduce a resolution to overturn the rule. "Republicans are committed to ensuring that the Obama EPA is finally reined in."
The 10 states with proposed new coal-fired generation that could be covered by the regulation are Texas, Illinois, Pennsylvania, Idaho, Kentucky, Michigan, Georgia, Utah, Wyoming and Kansas.
Follow Dina Cappiello's environment coverage on Twitter (at)dinacappiello