Associated Press: In the face of looming legislative pressures for cleaner energy, the nation’s largest public utility agreed Thursday to buy more than a nuclear reactor’s worth of electricity from renewable energy sources. The Tennessee Valley Authority board gave President and CEO Tom Kilgore authority to sign contracts totaling up to 2,000 megawatts of renewable and clean energy by 2011, with some of the power entering TVA’s seven-state system as early as 2010. TVA began the search in …