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Wind Energy

Wind energy has been harnessed in many different ways by various human civilizations over thousands of years. For more than 5,000 years, ships and boats have been making use of wind for propulsion over water. It was also used as a way of providing natural ventilation for buildings.

Another ancient form of wind technology is the windmill. These first showed up in Persia (modern-day Iran), with a vertical axis system. The horizontal axle styles began showing up in Europe during the 12th century.

Windmills were used to accomplish such tasks as grinding wheat, corn and other grains. Other early uses included drawing water and chopping up wood. The ability to pump water was a major step for people in the United States to be able to farm and ranch the large expanses of land.

Today, wind energy is generally harnessed for the creation of electricity. This is done through the use of wind turbines. These big generators take the kinetic energy of wind and convert it into a mechanical energy. Other terms for wind turbines include wind power units (WPUs), wind energy converters (WECs), or aerogenerators.

The power which a wind turbine captures can still be used for specific tasks as with windmills. On the other hand, electricity can be created for general purposes such as supplementing the electrical grid of a building or city. A group of turbines is generally assembled to accomplish this latter task. Such a collection is known as a “wind farm”.

A wind turbine operates like a backwards fan. Instead of using electricity to create wind, these machines use wind energy to generate electricity. Each will generally have either two or three blades. As the wind spins these blades, they lift and rotate, spinning a low-speed shaft. Gears within a gear box connect this low-speed shaft to a high-speed shaft, increasing the rotations to a higher speed necessary for the creation of electricity.

The gear box is a heavy part of the wind turbine, as well as a costly one. For this reason, engineers today are experimenting with ways to do away with gear boxes. Of course, a necessary step for this is to find a way to operate the generator at a lower speed of rotation.

A controller within the machine ensures that it starts up when wind levels are appropriate for the generation of electricity. It will also shut down the device if wind speeds are too high. This is because powerful winds are capable of damaging the machine.
The generator, controller, and the shafts of the machine are located within and encasement known as the nacelle. This is the part of the turbine mounted atop the tower to which the blades are attached. It is generally bulb- or box-shaped and can easily be the size of a school bus.

Wind turbines may be upward or downward. Upward types must be facing the wind, as a result their design incorporates a yaw drive which ensures that they are facing the correct direction. A downward turbine will just be blown into the appropriate position.