The use of wind energy has been around for well over a thousand years. Its uses are only limited by the mind. However, there are certain physics that guide us on what it can and cannot do. People have often dreamed of a small device that can be installed on the roof of a house which can provide all the needed energy. What is not understood by the non-technical are its limits. Like anything in nature, there are limits to what is possible. Below we have put together a number of interesting facts about wind.

The proper name of a wind generator is actually “Wind Energy Converter” that being a device that converts the potential energy in the wind to another form of energy. This can either be mechanical or electrical.

When the wind blows, the rotor blade stops a percentage of the wind. That percentage is what is converted into energy. According to physics, the maximum amount of wind energy that can be converted is 59.3%. This is known as the Betz Limit.

How It Works

Below is an example of a hybrid wind/PV system with a battery backup.

Various Types of Wind Generators

There are a number of types of wind generators. Research has been done on virtually every possible concept with the objective of producing the maximum amount of power for the lowest cost at the highest possible reliability. Conventional experimentation has found that the horizontal axis upwind or downwind design to be the best concept. The most common designs include:

There are two basic types of airfoils (blades) -- a lifting and a drag type.

• The drag style airfoil is typically what you see with an old Dutch wind mill or American water pumping wind mill. The blades are generally a flat plat which the wind hits and causes to rotate. This type of design is great for very low wind areas and will develop a lot of torque to perform an operation. However, in medium to higher winds, their capabilities to produce energy are limited.
  

• The lifting style airfoil is what you see in most modern wind turbines and on airplanes. A properly designed airfoil is capable of converting significantly more power in medium and higher winds. Actually, with this design, the fewer number of blades the more efficient this design can be. Two European companies actually produced one-bladed machines; however, dynamic balance issues prevented them from becoming a commercial success.

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