Q&A
Wind Turbine Energy

What is the role of wind energy in Green Power Switch?

How much electricity is produced, and will there be more?

How is wind energy generated?

Do wind turbines produce electricity all the time?

How are wind sites selected?

Will the turning rotor blades harm birds?

Are the wind turbines noisy?

Will the turbines interfere with radio and TV signals?

What is the role of wind energy in Green Power Switch?
The production of wind energy creates no air pollution and, if the turbines are sited properly, has minimal environmental impact. By including wind generation in Green Power Switch, TVA and the public power distributors of TVA electricity are introducing this clean technology to the Tennessee Valley. TVA has built three wind-powered generators on a two-acre site on Buffalo Mountain in Anderson County, Tennessee, about six miles northwest of Oak Ridge. This is the first commercial-scale use of wind power to generate electricity in the southeastern United States.

How much electricity is produced, and will there be more?
The turbines on Buffalo Mountain provide about two megawatts of capacity, but TVA plans to increase wind power’s share of the total Green Power Switch generation over time. Each of the wind turbines has a generating capacity of 660 kilowatts. Together the three turbines are expected to produce some six million kilowatt-hours per year—enough to serve more than 400 typical Tennessee Valley households.

How is wind energy generated?
In a modern wind machine, a turbine and switchgear are mounted at the top of a tower in a casing called a nacelle, and blades are attached to the turbine. Generally, the higher the tower, the better the access to the wind. TVA’s three wind generators sit atop towers that are 213 feet tall, and each generator drives three rotor blades. The blades are about 75 feet long, making the diameter of the rotors’ span 150 feet. Each assembly is 290 feet from the ground to the tip of an upright rotor. The turbines use moving air to produce power by transferring the wind’s momentum to the rotor blades and localizing that energy in a single rotating shaft. The resulting power can be used in many ways; modern turbines convert it into electricity.

Do wind turbines produce electricity all the time?
No, but when the wind turbines aren’t operating, other resources will continue to supply power as reliably as ever. Although wind speed varies according to the time of day, season, height above ground, and terrain, the proper placement of a a wind turbine in a breezy location away from large obstructions will enhance its performance.

How are wind sites selected?
The turbines must be situated where the wind is relatively steady and strong. Windy sites in environmentally sensitive areas, of course, will be excluded. For cost-control reasons, it’s helpful to have access to transmission or distribution lines nearby, and access by road is needed for construction and maintenance. TVA’s Buffalo Mountain Wind Park is located on a reclaimed strip mine owned by Coal Creek Mining and Manufacturing of Knoxville, Tennessee. TVA is using the land through a long-term lease for the life of the project, which is expected to be two to three decades.

Will the turning rotor blades harm birds?
TVA has studied potential wind sites to make sure that they aren’t located on bird migration routes and that endangered species don’t inhabit or frequently visit them. Careful site selection will ensure that there is no significant hazard to birds.

Are the wind turbines noisy?
Large modern turbines are very quiet. At distances of more than 650 feet, the swishing sound of the rotor blades is usually masked completely by wind noise in the leaves of trees or shrubs. The turbine sites will be distant enough from neighbors so that people won’t hear any sound at all unless they’re standing close to the towers.

Will the turbines interfere with radio and TV signals?
No. In fact, some turbines even double as communications towers—for cellular phone transmitters, among other things. The turbine blades are made not of metal but of glass-reinforced epoxy (a material similar to fiberglass), and the turbines are equipped with asynchronous (brushless) generators that don’t create any electrical disturbance. For these reasons the turbines that will be used in the green power program will cause no electromagnetic interference and won’t disrupt radio or television signals.