How do you spell that? doxycycline mono drug interactions Under the proposal, new coal-powered power plants would have to install expensive technology to capture carbon dioxide and bury it underground. No coal-fired power plant has done that yet, in large part because of the cost. The coal industry, which is struggling to compete with cheaper and cleaner natural gas, accounts for 40 percent of US electricity. But coal’s share is declining. The regulations have been in the works since 2011 and stem from a 1970 law passed by Congress to control air pollution. In 2007, the Supreme Court ruled that that law, the Clean Air Act, could be applied to heat-trapping pollution.