Resources
A quantitative measure of the wind energy available at any location is called the Wind Power Density (WPD) It is a calculation of the mean annual power available per square meter of swept area of a turbine, and is tabulated for different heights above ground. Calculation of wind power density includes the effect of wind velocity and air density. Color-coded maps are prepared for a particular area described, for example, as "Mean Annual Power Density at 50 Metres". In the United States, the results of the above calculation are included in an index developed by the National Renewable Energy Laboratory and referred to as "NREL CLASS". The larger the WPD calculation, the higher it is rated by class. Classes range from Class 1 (200 watts per square metre or less at 50 m altitude) to Class 7 (800 to 2000 watts per square m). Commercial wind farms generally are sited in Class 3 or higher areas, although isolated points in an otherwise Class 1 area may be practical to exploit.
Read more about this topic: Wind Turbine
Famous quotes containing the word resources:
“I am willing to pledge myself that if the time should ever come that the voluntary agencies of the country together with the local and state governments are unable to find resources with which to prevent hunger and suffering ... I will ask the aid of every resource of the Federal Government.... I have the faith in the American people that such a day will not come.”
—Herbert Hoover (1874–1964)
“In Western Europe people perish from the congestion and stifling closeness, but with us it is from the spaciousness.... The expanses are so great that the little man hasn’t the resources to orient himself.... This is what I think about Russian suicides.”
—Anton Pavlovich Chekhov (1860–1904)
“The poor tread lightest on the earth. The higher our income, the more resources we control and the more havoc we wreak.”
—Paul Harrison (b. 1936)