Thousand Palms, Calif. -

The Environmental Protection Agency's proposed standards for power plants will call for a 30 percent cut in emissions by 2030, according to a report in The Wall Street Journal on Sunday afternoon.

The piece cites two unnamed sources who were briefed on the rule's contents. The sources said the plan will lead to a 25 percent cut in emissions by 2020. The standard would use a 2005 baseline for the cuts, according to the piece.

In a statement to The Huffington Post on Sunday afternoon, the EPA declined to comment on the information in the Wall Street Journal piece. "EPA will release its proposed carbon pollution reduction rule on Monday," EPA spokeswoman Liz Purchia said. "Until then the agency will not comment on any information that may or may not be in the proposal."

The draft rules coming Monday will be the first-ever carbon standards for the fleet of existing power plants in the U.S., which generate 39 percent of total emissions in this country, according to the Energy Information Administration.

Economy wide, U.S. emissions already declined 10 percent between 2005 and 2012, due in large part to increased use of natural gas and lower overall energy consumption. The United States has committed to a 17 percent overall cut by 2020.

The agency is expected to finalize the draft rule by June 2015. How to meet the standards is left largely up to individual states, which will need to develop their own plans for meeting the standard within a year after the rule is finalized.

The EPA plans to officially release the rules at a press conference scheduled for 10:30 a.m. Monday.