Chattanooga Times Free Press: TVA will shutter part of its aging fleet of coal power plants and turn to nuclear power and energy conservation to power the Tennessee Valley under a 10-year plan adopted Friday. Tennessee Valley Authority President Tom Kilgore outlined a vision that calls for the nation’s biggest government utility to idle at least 1,000 megawatts of coal generation — or more than 7 percent of its biggest source of power — by 2015. TVA directors approved plans here Friday to move ahead with …