A one-year old green marketing program offered by the Tennessee Valley Authority (TVA) in the southeastern US is so popular the federal energy supplier is building new renewable generating facilities to keep up with the demand. The TVA says that more customers want to by green energy through its Green Power Switch program than it had expected. It currently generates the energy from solar and one wind turbine and will soon bring a landfill gas generator on-line. The turbine was installed in November on Buffalo Mountain near Oliver Springs, Tennessee. The TVA will have about 5 MW of renewable energy once the gas turbine is in place. The TVA had expected to sign up customers that would use 9000 blocks of clean power a month, but got requests for nearly 11,000 blocks in the first 11 months. Each block is for 150 kWh, which customers can buy at a $4 per month premium. The TVA is now trying to catch up with the demand and hopes to add as much as 20 MW of new wind generation by 2003 or 2004, according to Jim Keiffer, of TVA.