Data from the U.S. Department of Energy California's energy woes have again focused attention on our reliance on fossil fuels, which produce about 85 percent of the energy consumed in the United States. But renewable sources such as solar, wind, and geothermal have become increasingly important in the past two decades. Today they make up 7 percent of the total— about the same as nuclear power— and are growing as costs come down. Two years ago, bio-fuels such as methanol and municipal solid waste displaced hydroelectricity as the leading renewable energy source.
