Wind Turbines: Converting Wind Energy Into Electricity

Where Wind Comes From

Wind is caused by the uneven heating of the earth by the sun. The differences in air temperature and pressure caused by this uneven heating results in the movement of air masses over the surface of the earth, which we refer to as wind. Summer sea breezes, for example, are caused by the increase of air temperature over land which causes that air to rise and be replaced by cooler air from over the ocean.

From Wind to Electricity

Wind turbines consists of four parts:

  1. The foundation is the base on which the entire structure is built.
  2. The tower holds the turbine high in the air where the wind is best.
  3. The nacelle is situated at the top of the tower and houses the electrical generation equipment.
  4. The rotor, consisting of three blades, act as wings which convert the motion of the wind into a rotating force that turns the electric generator.

Wind exerts pressure against the rotor blades causing them to turn in much the same way that a moving wing lifts an airplane. This mechanical energy is then converted into electrical energy by the gearbox and generator, which are located in the nacelle. The electricity from the generator is linked to an electrical output system that channels the electricity from the turbine to the transmission grid, where it is distributed to consumers.

The turbine maximizes the amount of captured wind, and therefore the energy created, by constantly changing the angle and direction of the blades. This is very similar to how a sailor trims her sails. Instruments affixed to the top of the turbine gauge wind speed and direction, and computer controllers then use this information to position the blades in order to capture the most wind.

In very high winds the turbine may shut down to prevent damage to itself. The turbine does this by turning its blades into the wind to allow the wind to simply pass by. Mechanical brakes, similar to automobile brakes, are also used. These same brakes are automatically released should the power to the control system fail.

A long history of harnessing the wind

People have been harnessing the power of wind for thousands of years. The American landscape has been dotted by windmills for much of its history, first by early settlers who erected Dutch-style windmills around the Northeast for grinding grain and other purposes, and later by ranchers in the West who used wind to pump water and generate electricity. Indeed, American inventor Charles Brush pioneered the modern wind turbine in 1887 when he developed the first prototype for a windmill intended to create electricity. Nearly 100 years later, the world’s first wind farms were built in California. Modern wind energy technology is built on a long history of continuing technological improvement and proven experience.

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