Piles of coal are shown at NRG Energy's W.A. Parish Electric Generating Station Wednesday, March 16, 2011, in Thompsons, Texas. The plant, which operates natural gas and coal-fired units, is one of the largest power plants in the United States. The U.S. Environmental Protection Agency will begin regulating mercury emissions from coal-fired power plants for the first time, the latest in a string of new regulations that has Republicans bent on reining in the federal body. The new rules will have the greatest impact on Texas, home to more coal-fired power plants than any other state. (AP Photo)
