Under the plan, the EPA will adopt a rule that regulates carbon pollution from existing power plants for the first time, and in the video, Obama called it "the biggest, most important step we've ever taken to combat climate change."

Compared to the proposed rule, the new final version cuts more carbon pollution from the power sector, does it with more renewable energy and less natural gas, while providing more flexibility along the way to states trying to meet their targets.

The final version of the regulation, according to a senior administration official, will actually reduce power sector carbon pollution 32 percent from 2005 levels by 2030. This is more ambitious than the 30 percent reduction over the same period in the proposed rule.

In the proposed rule, renewable energy generation capacity was expected to be 22 percent in 2030. In the final rule, that share is projected to be 28 percent. Instead of the plan leading to a significant, early shift to natural gas, the projection for gas-fired power plant generation will instead flatten to a business-as-usual trendline.