Alternative Energy, Wind

WIND IS A source of solar energy that does not rely on the condition of the sky. Unlike fossil fuels, wind energy can be collected during storms, snow, or the night. Wind power is the alteration of wind energy into more purposeful forms, usually electricity using wind turbines, and is a form of renewable [Page 41]energy. Wind power is greenhouse gas extenuating, clean, abundant, infinitely renewable, domestically produced, widely distributed, and supportive of rural economies.

The International Energy Agency (IEA) projects that, 2000–30, global energy consumption will increase and electricity use could double, placing pressure on nonrenewable resources, public health, international stability, and the natural environment. One solution lies in finding and utilizing alternative energy sources. Renewable energy sources pose lower costs, whether environmental or health-related. The use of alternative energies to generate electricity is especially advantageous to developing countries, because of the new employment opportunities it will create, as well as the stimulation of local economies by attracting investment. One of the resources leading the way to a more sustainable future through the use of alternative energy is wind power.

People have been harvesting the wind for hundreds to thousands of years, with functions varying from sailing, to grinding grain, to pumping water. Windmills have been found dating back to 10th century Persia, while their appearance in Europe is believed to have begun around the Middle Ages. It was not until the 20th century that people became interested in using the wind to generate electricity. In 1941, the 1,250 kilowatt (kW) Smith-Putnam wind turbine was constructed in the United States. There are records of 100 kW turbines in the former Soviet Union in 1931, and other innovative designs originating in Germany during the 1950s to the 1960s. However, after the 1950s, lower-cost fossil fuels made wind energy technology economically unprofitable, and only in the 1970s did rising fuel prices bring it back into popularity.

Mechanics

Wind energy moves over the Earth's surface as kinetic energy. This energy is received by the blades of a turbine, which is attached to an electrical generator that sits atop a collection tower. Collection sites consist of a single turbine, or many, constituting a wind farm. [Page 42]Each turbine consists of a tower structure, rotor with blades attached to the hub, shaft with mechanical gear, electrical generator, yaw mechanism, and sensors and control. Modern structures must come equipped with a control system for operational and safety functions.

Projects like this wind farm in California may help the U.S. Department of Energy's Wind Powering America Initiative reach its goal of generating 5 percent of the nation's electricity through wind power by the year 2020.

Certain terms are necessary to understanding of the wind industry. The gearbox increases the turbine speed from around 45 rotations per min. (rpm) to about 14,500 rpm. The rotor connects to the nacelle, which sits atop the tower and contains the gearbox. Upwind refers to a turbine operating facing the wind in front of the tower. Downwind turbines run facing away from the wind behind the tower. Finally, the yaw drive maintains the direction of the upwind turbine facing the wind.

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