27-06-2012, 05:03 PM
Seminar on Wind power
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Introduction
Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships.
The total amount of available power from the wind is considerably more than present human power use from all sources.[3] At the end of 2011, worldwide nameplate capacity of wind-powered generators was 238 gigawatts (GW), growing by 41 GW over the preceding year.[4] Wind power now (2010 data) has the capacity to generate 430 TWh annually, which is about 2.5% of worldwide electricity usage.[5][6] Over the past five years (2010 data) the average annual growth in new installations has been 27.6 percent. Wind power market penetration is expected to reach 3.35 percent by 2013 and 8 percent by 2018.[7][8] Several countries have already achieved relatively high levels of wind power penetration, such as 21% of stationary electricity production in Denmark,[5] 18% in Portugal,[5] 16% in Spain,[5] 14% in Ireland[9] and 9% in Germany in 2010.[5][10] As of 2011, 83 countries around the world are using wind power on a commercial basis.[10].
Wind energy
The Earth is unevenly heated by the sun, such that the poles receive less energy from the sun than the equator; along with this, dry land heats up (and cools down) more quickly than the seas do. The differential heating drives a global atmospheric convection system reaching from the Earth's surface to the stratosphere which acts as a virtual ceiling. Most of the energy stored in these wind movements can be found at high altitudes where continuous wind speeds of over 160 km/h (99 mph) occur. Eventually, the wind energy is converted through friction into diffuse heat throughout the Earth's surface and the atmosphere.
Wind farms
A wind farm is a group of wind turbines in the same location used for production of electric power. A large wind farm may consist of several hundred individual wind turbines, and cover an extended area of hundreds of square miles, but the land between the turbines may be used for agricultural or other purposes. A wind farm may also be located offshore.
Many of the largest operational onshore wind farms are located in the US. As of November 2010, the Roscoe Wind Farm is the largest onshore wind farm in the world at 781.5 MW, followed by the Horse Hollow Wind Energy Center (735.5 MW). As of November 2010, the Thanet Wind Farm in the UK is the largest offshore wind farm in the world at 300 MW, followed by Horns Rev II (209 MW) in Denmark.
Wind power capacity and production
Worldwide there are now many thousands of wind turbines operating, with a total nameplate capacity of 194,400 MW.[22] World wind generation capacity more than quadrupled between 2000 and 2006, doubling about every three years. The United States pioneered wind farms and led the world in installed capacity in the 1980s and into the 1990s. In 1997 German installed capacity surpassed the U.S. and led until once again overtaken by the U.S. in 2008. China has been rapidly expanding its wind installations the late 2000s and passed the U.S. in 2010 to become the world leader.