The Tennessee Valley Authority is requesting proposals for up to 2,000 megawatts of renewable energy to help the utility provide half of its electricity from low- or zero-carbon emission sources by 2011. Up to 1,000 megawatts of renewable energy -- an amount equal to what is produced by a large coal-fired power plant -- could be in place within six months, the utility said, with the remainder coming online in increments over the next two-and-a-half years. Go to story #1