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Fuel Matters
     Wind is the fuel for the wind turbine. The more fuel the wind tur­bine has available to it, the more electricity it will generate. Wind fuel has two components, both equally important. One is the quantity of wind available. The other is the quality of the wind passing through the rotor. Let’s look at these separately.

fuel matters

Wind Quantity Matters
     The equation that defines how much power is available to any wind turbine rotor is P = 1/2dA V3, where P is the power in the wind, d is the density of the air (affected by both elevation above sea level and air temperature), A is the swept area of the rotor, and V is the wind velocity (speed). For a given wind turbine and site, swept area and density are constants. As such, the power available in the wind is approximately the cube of the wind speed.




wind quality matters     So, the power that is in the wind (P) is proportional to the cube of the wind speed, or V3. The interesting thing about this relationship is the effect of increasing wind speed. For example, a 2.5 mph difference in wind speed—say, from 10 to 12.5 mph, is an increase of only 25% in wind speed. However, since P ~ V3 (not just V), the numerical increase in the power equation attributable to wind speed is nearly 100%: 10 × 10 × 10 = 1,000, while 12.5 × 12.5 × 12.5 = 1,953. So even small increases in wind speed result in very large increases in power available in the wind that can be converted to electricity.

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