Renewable energy today supplies only 6 percent of the country's energy needs, and much of that comes from decades-old dams supplying hydropower. Under current policies, the Energy Information Administration estimates, renewables will increase only slightly in importance in the decades ahead. They would supply 7 percent of United States energy supplies by 2030, while coal would increase over the same period from 23 percent to 26 percent.
"Denmark gets 22 percent of its electrical energy from wind today and we get 0.5 percent," noted Robert Thresher, director of the lab's National Wind Technology Center. "That shows you what you can do when you really want to."