For years, environmentalists have boasted about how clean sources of energy like wind and solar would be the future of how we keep ourselves powered in the U.S. Critics have scoffed at the idea saying even though it's nice to have cleaner fuels, there simply aren't enough to cover our needs.
But Mary Anne Hitt from the Sierra Club said that's starting to change.
"I think the exciting thing that's happening right now is that America's energy future is totally up for grabs, and wind and solar are being installed at record levels. They're just blowing through the predictions," Hitt said.
As the director of the organization's Beyond Coal Campaign, Hitt has an interest in seeing clean energy replace aging coal power plants that move off the grid, which she said is happening now.
"I think we have 50,000 megawatts of wind now installed in this country … that's like 50 plus coal plants worth of wind power around the country, and the more we install, the faster prices are going down. So I think we're really at a tipping point at scale and being competitive," she said.
This article appears in Nov 29 – Dec 5, 2012.