subota, 10. srpnja 2010.


In most locations, GENTLE winds (5-15 mph) are the most common, and strong winds are much more rare. As you'll see by examining our latest machines, our philosophy about designing wind turbines is to make large, sturdy machines that produce good power in low wind speeds, and are able to survive high wind events while still producing maximum power. The power available in the wind goes up by a factor of 8 as the windspeed doubles.
Other critical factors are rotor size and tower height. The power a wind turbine can harvest goes up by at least a factor of 4 as you double the rotor size. And making a tower higher gets you above turbulence for better performance and substially increased power output. Putting a wind turbine on a short tower is like mounting solar panels in the shade! More info at
Wind turbines are used to generate electricity from the kinetic power of the wind. Historical they were more frequently used as a mechanical device to turn machinery. There are two main kinds of wind generators, those with a vertical axis, and those with a horizontal axis. Wind turbines can be used to generate large amounts of electricity in wind farms both onshore and offshore.
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. They 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.More info at

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 will be used in the green power program will cause no electromagnetic interference and won’t disrupt radio or television signals.

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