Thursday, May 10, 2012

Wind Energy Is Proven Technology:


Some European countries have had Wind Turbines in operation for over 20 years. Wind Energy production costs in Europe are now competing with coal fired power stations. Since 1990 the Wind Energy Industry has been the fastest growing sector of the power generation industry and continues to be so.  Large scale Wind Turbines can be installed for about $2.00 per watt or about  two million dollars per megawatt. A typical Wind Farm will use about 1% of the area where it is constructed leaving the rest for normal farming or grazing practices. Wind Turbines have a designed working life of 20 to 25 years and require very little maintenance during this time.  


Wind Turbines
Wind Turbines will typically be installed in small groups of 2 to 5 units connected to the existing utility grid, or in larger  groups of 10 to 30 units with a dedicated transmission line to a suitable connection point  at a nearby high voltage cable or switchyard.  The Turbine consists of a large set of 3 blades which drive a generator via a large gearbox, this is installed in a nacelle which is mounted on a powered turntable at the top of a tall tower.  When the wind speed increases above a certain speed , known as the cut in speed typically about 3 to 4m/s (meters per second)  The Turbine will begin to generate electricity, and will continue to do so until the wind speed reaches the cut out speed, (about 25m/s) at this point the turbine will shut down, rotate out of the wind and wait for the wind speed to drop to a suitable speed to allow the Turbine to start again. The Turbine will have an optimum operating wind speed at which maximum output will be achieved, this is typically about 13 to 16m/s During operation the generator ensures that the blades maintain a constant speed of about 20 revolutions per minute, which the gearbox transforms into 1500 revolutions per minute. Higher wind loads acting on the blades result in increased power production but not a higher number of revolutions per minute.

Environmental Benefits and Drawbacks:


A wind turbine that produces electricity from inexhaustible winds creates no pollution. By comparison, coal, oil, and natural gas produce one to two pounds of carbon dioxide (an emission that contributes to the greenhouse effect and global warming) per kilowatt-hour produced. When windenergy is used for electrical needs, dependence on fossil fuels for this purpose is reduced. The current annual production of electricity by wind turbines (3.7 billion kilowatt-hours) is equivalent to four million barrels of oil or one million tons of coal.
Wind turbines are not completely free of environmental drawbacks. Many people consider them to be unaesthetic, especially when huge wind farms are built near pristine wilderness areas. Bird kills have been documented, and the whirring blades do produce quite a bit of noise. Efforts to reduce these effects include selecting sites that do not coincide with wilderness areas or bird migration routes and researching ways to reduce noise.