The Kentucky Utilities Electric Power Plant in Ghent, shown here in a 2002 file photo, is one of some 600 coal-fired power plants in the US. At least 86 older plants will be forced into early retirement as a result of a new EPA rule, unveiled Thursday. The EPA’s tough new air pollution regulations will force scores of older, dirty, inefficient plants to shut down. Those that remain open must dramatically clean up their emissions. The Environmental Protection Agency hopes these and other measures will improve air quality across 27 states. Effects should appear relatively quickly. Under the new Cross-State...