How the wind is generated? The unequal heating of land and water by sun is the main cause of wind generation on the earth’s surface. The global installed capacity of wind farm is 6000MW and about 10.6 billion units of electricity were generated in 1996, thus reducing CO2 emission by 10.5 million tones. Wind energy is one of the forms of energy made available by the nature and is available at free of cost. It has been America’s greatest natural resources. As per study of NASA U.S has enough stable wind to generate 1.28 trillion KWh of electrical energy per year which is equivalent to about 200 GW or half of the annual output of all fossil fueled generating plants were powered by the wind.

Wind power plants: Wind power plants or wind farms as they are popularly called are clusters of wind machines used to produce electricity. A wind farm usually ahs hundreds of wind machines in all shapes and sizes. Unlike nuclear or coal plants most wind plants are not owned by public utility companies. Instead they are owned by and operated by business people who sell the electricity produced on the wind farm to the electric utilities. Theses private companies are known as Independent Power Producers. Operating wind power plants is not as simple as plunking down machines on a grassy field. Wind plant owners must carefully plan where to locate their machines. They must consider wind availability (amount of wind blowing), local weather conditions, nearest to electrical transmission lines and local zoning codes. Wind plants need lots of land. One wind machine needs upto two acres of land. A wind power plant takes up hundreds of acres.

The land can still be used by farmers to grow crops around the machines once they are they installed. Just plunking of wind machines doesn’t stop from your expenses there are still maintenance costs to be considered. Also depending on the rules of that particular state or area taxes may be imposed on the plant owners for the use of natural resource. History of wind machines The importance of wind power was recognized quite in early period. Over 5000 years ago, the ancient Egyptians used wind power to sail their ships over the Nile River. Later people built windmills to grind grain. The earliest known windmills looked like large paddle wheels.

Centuries later, the Holland people improved the windmill. They thought of propeller shape blades and made it so it could be turned to face the wind. Windmills helped the Holland to become the world’s most industrialized countries by the 17th century. American colonists used windmills to grind wheat and corn, to pump water and to cut wood at sawmills. In the century, people use windmills to generate electricity in rural areas in the 1930’s; the electric windmills were used less and less. Then in the early 1970’s, oil shortage created and environment eager for alternative energy sources, paving the way for there-entry of the electric windmill on the American landscape. Today wind energy is one of America’s greatest natural resource. Classification of windmill As explained earlier windmill is machine for wind energy conversion. A wind turbine the vital part of power generation converts the kinetic energy of the winds motion into mechanical energy transmitted by the shaft. It is further converted into electric energy with the help of generator, thus producing electricity.

Windmills are generally categorized into two types as: 1) Horizontal axis type and 2) Vertical axis type Further depending on their axis of rotation they are sub classified as: 1) Horizontal axis type windmills are further classified as: a) Single bladed b) Double bladed c) Multi bladed d) Bicycle multi bladed type e )Sail type f) Wing type 2) Vertical axis type windmills are further classified as: a) Savonius type machines b) Darius type machines Wind electric energy systems are classified into the following categories of utilization: 1) Wind electric energy systems connected to grid without need for energy storage facility. 2) Stand alone (isolated) wind electric energy system with need for energy storage facility. 3) Non-critical wind electric or wind mechanical energy system, without need for energy storage. 4) Wind electric hybrid or wind electric, solar electric, battery hybrid. For remote applications, farms, energy conservation non-conventional schemes. Windmill power plants have certainly risen as one of the most important resource of energy.