How much more potential energy does a 12 MPH wind have VS a 6 MPH wind?

Question

How much more potential energy does a 12 MPH wind have VS a 6 MPH wind?

Answer 1

Well, first let´s convert to standard units (m/s)

6mph=2.68m/s

12mph=5.36m/s

The power of a wind turbine can be expressed as:

P=(Betz factor) x (air density) x (area) x (windspeed)³

With

Betz factor=0.47 for modern 3-blades turbines

Air density=0.0012 tonne/m³

Area= (Pi x r²)

Windspeed in m/s

-------------------------

All factors being constant:

P1/P2 = (5.36)³/(2.68)³ =154/19.3 = 8 times higher

Answer 2

i've always heard the energy goes as the square of the wind speed, so i would think four times the power. But if that equation is right, and those other factors do not change with wind speed, then 8 times would be right.

Answer 3

I cannot provide a better answer than N, however from the viewpoint of a commercial grade wind turbine, a 6 mph wind would not produce energy, while a 12 mph wind would.  

Answer 4

That depends on several things including air density.

Basically, given the same density, wind force progresses by the 'square' (twice the speed gives 4 times the power), rather than simply doubling for double the speed.