President Barack Obama's ambitious plan to reduce the gases blamed for global warming from the nation's power plants gives many coal-dependent states more lenient restrictions—and won't necessarily be the primary reason coal-fired power plants will be retired.

If Kentucky, for example, meets the new limits that the Obama administration proposed Monday, it would be allowed to release more heat-trapping carbon dioxide per unit of power in 2030 than plants in 34 states do now.

The Environmental Protection Agency's complex formula to calculate each state's reductions gives some coal-heavy states a more relaxed standard, based on what the agency deemed was realistic to achieve.

Environmentalists had hoped the proposal would shutter hundreds of coal-fired power plants. Republican critics warned of a major economic impact on .