WASHINGTON -- The Obama administration is leaning toward revising its landmark proposal to regulate greenhouse gas emissions from new power plants, according to several individuals briefed on the matter, a move that would delay tougher restrictions and anger many environmentalists.

The discussions center on the first-ever greenhouse gas limits for power plants, which were proposed by the Environmental Protection Agency nearly a year ago. Rewriting the proposal would significantly postpone any action, and also might allow the agency to set more permissive standards for coal-fired power plants, which are roughly twice as polluting as those fueled by natural gas.

Any retreat on the rules would be a blow to environmental groups and their supporters, who constituted a crucial voting block for President Obama and other Democrats in last year's elections.

The move coincides with Obama's call Friday for a new federal fund to research clean energy alternatives for cars and trucks. The creation of an Energy Security Trust, which the president outlined in his State of the Union speech, would invest $2 billion in federal revenue from oil and gas leasing into breakthrough technologies.

"After years of talking about it, we're finally poised to take control of our energy future," Obama said.

The contrast between the two policies highlights the balancing act Obama is trying to strike in his second-term energy and environmental agenda -- seeking ways to combat climate change, but avoid damage to a still-struggling economy.

"It really is a tension between short- and long-term goals," said Joshua Freed, vice president for the Clean Energy Program at the liberal think tank Third Way. "Actions need to be taken now both on climate and clean energy that require sometimes painful transitions from some fuel sources to new technology and new sources that either may not be ready yet, or require some dislocations."

Ross Eisenberg, vice president of energy and resources at the National Association of Manufacturers, said the options available to the administration to combat greenhouse gas emissions "are not particularly good."

Rep. Ed Whitfield, R-Ky., who chairs the Energy and Commerce Subcommittee on Energy and Power, was scathing in his assessment of the president's approach to energy policy.

"It's being set by fiat by this administration," he said, adding that when it comes to curbing greenhouse gas emissions from new power plants, "the consequences of this are gigantic."