Power Out of Thin Air

TVA harvests clean wind energy on Buffalo Mountain in East Tennessee.

  • After introducing three small wind turbines in 2001, TVA received a positive response and invested in 15 more units.
  • The new wind turbines are 260 feet tall with 135-foot long blades, and each has the capacity to generate 1.8 megawatts of power.
  • Today, Buffalo Mountain generates 29 megawatts, or enough to power about 3,800 homes.

That headline is no joke—TVA is making more and more power from air with its investment in wind turbine energy at Buffalo Mountain near Oak Ridge, Tenn.

Originally, TVA invested in three small wind turbines on the site as part of its Green Power Switch program, each of which stood 213 feet tall, with blades 75 feet long and a capacity to generate 660 kilowatts each. These were installed in 2001. It was the first commercial use of this clean, green wind energy in the Southeastern United States.

But as interest in Green Power Switch grew, so did demand for wind power.

TVA answered that call in 2004 by installing 15 new, larger turbines at the Buffalo Mountain site. These turbines are bigger—260 feet tall—with blades that are longer—135 feet. And each has the capacity to generate about 1.8 megawatts. Today, the site has the capacity to generate about 29 megawatts, or enough energy to power 3,780 homes.

Here’s a quick science lesson on how wind power works: A turbine and switchgear are mounted at the top of each tower in a casing called a nacelle. The blades are mounted to the turbine itself. The moving air produces power by transferring wind momentum to the rotor blades and localizing that energy in a single rotating shaft. Transformers in the nacelles step the power up to 30 kilovolts, and its stepped up again to 161 kilovolts at the substation located on the mountain, where it is connected with an existing TVA transmission line. Energy is produced whenever the wind speed reaches 10 miles per hour; when it reaches 25 miles per hour, turbines are able to produce at their optimal rated capacity.

 As the Green Power Switch program thrives, so too will TVA’s investment in clean and green energy such as wind power.