Wind is a clean, renewable energy source caused by the uneven heating of the Earth's surface. It can be used to generate electricity through wind turbines. Wind turbines collect kinetic energy from the wind through blades. The blades of the wind turbine are connected to a drive shaft and a generator. When the wind blows over the blades, it causes them to turn the drive shaft and generate electricity.
Wind turbines or windmills were first used in China to pump water and Persia and the Middle East to grind grain. During the 11th century, the Dutch adapted the windmill to drain lakes and marshes. In the 19th century, windmills were used to pump water and generate electricity for homes and businesses.
There are two types of wind turbines used to generate electricity: horizontal-axis wind turbines and vertical-axis wind turbines. Horizontal-axis wind turbines usually have two or three blades that face into the wind. They are the most common type of wind turbines used today. Vertical-axis wind turbines have blades that run from top to bottom and are rarely used.
Vertical-axis wind turbines are usually 50 feet wide. Horizontal-axis wind turbines are usually 200 feet wide. Wind turbines range from small to large, depending on the production capacity. Small wind turbines are used to provide energy to individual homes or businesses. Large wind turbines are grouped together over a large area to form wind farms or power plants. According to the U.S. Energy Information Administration (EIA), "The world's largest wind farm, the Horse Hollow Wind Energy Center in Texas, has 421 wind turbines that generate enough electricity to power 220,000 homes per year."
Features of the typical wind turbine include blades, brake controller, anemometer, gear box, generator, high-speed shaft, low-speed shaft, nacelle and wind vane. The blades cause the lift and rotation of the generator. The brake controller starts and stops the turbine. The anemometer measures the wind speed and transmits the data to the brake controller. The gear box is made up of gears which connect the low-speed shaft to the high-speed shaft. The high-speed shaft drives the generator. The nacelle houses the gear box, shafts, generator, controller and brake. The wind vane measures the wind direction.
Even though wind turbines do not produce air or water pollution, there are a few considerations to think about when using them. They can have a negative effect on the wild bird population and require constant wind.