Wind Energy is defined as, energy contained in the force of the winds blowing across the earth’s surface. When attached, wind energy can be converted into mechanical energy for performing work such as pumping water, grinding grain, and milling lumber. By connecting a spinning rotor to an electric generator, modern wind turbines convert wind energy into electrical energy (Windpower,2003).
Wind is created when air that has been warmed over sun-heated land rises, leaving a vacuum in the space it once occupied. Cooler surrounding air then rushes in to fill the vacuum. This movement of rushing air is what we know as wind.
 

History

Egyptians may have been the first to capture wind energy when they sailed boats up the Nile River beginning around the 4th century BC. For centuries afterward, wind-powered sailing boats sailed the world's seas and oceans, serving as the major form of profitable transport. Wind energy has been controlled on land since the first windmill was developed by the ancient Persians in the 7th century AD. Windmills have since been used to mill grain, pump water, saw timber, and provide other forms of mechanical energy (Britannica,2003).
Modern wind energy systems consist of three basic components: a tower on which the wind turbine is mounted, a rotor that is turned by the wind, and the nacelle, which houses the equipment, including the generator, that converts the mechanical energy in the spinning rotor into electricity. The tower supporting the rotor and generator must be strong. Rotor blades need to be light and strong in order to be efficient and to withstand prolonged use in high winds(Windpower,2003).
 

Development of Wind Turbines

During the 1930s, interest in powering electric lighting and appliances on homesteads across the Great Plains led to the development of small, battery-charging wind turbines. These wind chargers were early indicators of the small two- and three-bladed wind turbines used today to provide electricity for secluded residences, and to provide electricity to villages in developing countries. 
The modern wind turbine is the result of design and material advances made during the 1980s and 1990s, which have enabled wind turbines to become increasingly efficient (Britanica,2003). Today, wind turbines the same size as the traditional European windmill can generate 250 to 300 kilowatts of power!

                                                                      Wind Turbines

Today and The Future

Many countries began exploring alternative sources of energy during the oil shortages of the 1970s. As improvements in wind energy technology have evolved, the modern wind energy industry has emerged. Increasingly, modern wind turbines produce electric power as efficiently as other power generation technologies. One of the major obstacles for developing wind energy is finding suitable ground and wind conditions. 
With the growing worldwide demand for electric power and the rising concern about global warming, many experts believe that the use of wind energy will continue to increase. As wind power becomes an increasingly cost-effective source of electricity, the market for wind power should continue to expand(Bown,1998).