In 2007, renewable energy sources other than conventional hydropower provided the majority of new electric generating capacity in the United States for the first time, according to the Department of Energy’s Energy Information Administration (EIA).
In particular, wind power was the star in 2007, providing 5,186 megawatts of new generating capacity, compared to an overall net gain in summer capacity of 8,673 megawatts. Natural gas-fired generation came in second, accounting for 4,582 megawatts of new generating capacity.
Coal-fired capacity, however, actually decreased. Two new coal plants added 1,354 megawatts of new capacity, but retirements and capacity reductions at existing plants caused coal-fired generating capacity to drop by 217 megawatts. Meanwhile, biomass power sources added more than 700 megawatts of generating capacity, and solar electric technologies added an estimated 91 megawatts of capacity.
However, in terms of actual power generated, coal still dominates the scene, producing 48.5 percent of the electricity used in the United States. But coal-fired generation is gradually losing market share, decreasing by 4.3 percentage points over the past decade, including a half-point drop in 2007. Hydropower produced about 6 percent of the nation's electricity in 2007, while other renewable energy sources provided about 2.5 percent. Net hydropower production decreased by 14.4 percent from 2006 to 2007 because of drought conditions. Most of the remaining power was generated from natural gas and nuclear power.