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Q&A

Wind Turbine Energy

What are the benefits of wind energy?

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 distributors of TVA power are introducing this clean technology to the Tennessee Valley. This is the first commercial-scale use of wind power to generate electricity in the southeastern United States.

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

With the inauguration of TVA’s expanded wind site in December 2004, wind energy became a major source of power supply for Green Power Switch. Fifteen new turbines were added to the TVA wind site on Buffalo Mountain near Oak Ridge, Tenn. They are located near the three smaller turbines originally built in 2000. The site is on a two-mile ridgeline facing southwest, the predominant wind direction at the location.

How much electricity is produced?

The newer turbines expanded the capacity of the Buffalo Mountain site to 29 megawatts of generation, or enough to power about 3,780 homes. The turbines are about 260 feet tall, and the blades are 135 feet long. They have a capacity of 1.8 megawatts each. The three original turbines, with a capacity of 660 kilowatts each, are 213 feet tall, and their blades are 75 feet long. Generally, the higher the tower, the better the access to the wind.

How is wind energy generated?

A turbine and switchgear are mounted at the top of each tower in a casing called a nacelle, and blades are attached to the turbine. 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 larger turbines rotate at about 15 revolutions per minute. Transformers in the nacelles step up the power to 35 kilovolts (kV), and it’s stepped up again to 161 kV at the substation located on the mountain. The substation connects to an existing TVA transmission line. The three smaller turbines are connected to the TVA system through a partnership arrangement with Clinton Utilities Board.

Do wind turbines produce electricity all the time?

Energy is generated when the wind speed reaches about 10 miles per hour, and a speed of 25 miles per hour allows the turbines to generate at their rated capacity. They shut down when the wind exceeds 55 miles per hour. Although wind speed varies according to the time of day, season, height above ground and terrain, the proper placement of a wind turbine in a breezy location away from large obstructions enhances its performance.

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 are used in the green power program cause no electromagnetic interference and don’t disrupt radio or television signals.

 

 

 

           
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