Power plants are being put on notice to burn cleaner... President Obama is readying new regulations.

FOX News Radio's Jon Decker has more from the White House:

In a move the President is calling the most significant step the U.S. has ever taken to fight global warming, the Obama Administration will impose even steeper cuts - than previously expected - on greenhouse gas emissions from U.S. power plants.

White House spokesman Josh Earnest told FOX News the emissions limits will cost an estimated $8.4 billion annually by 2030.

(Earnest) "This rule sets a target. So states can devise their own plan for meeting that target. We're gonna give them a year to put that plan together. And they don't actually have to start implementing this plan until 2022."

Opponents plan to sue immediately and to ask the courts to block the EPA rule temporarily.

At the White House, Jon Decker, FOX News Radio.