A Wind Turbine on the Roof of Your House: What’s Wrong with this Picture?

Something about the picture here looks amiss, though it may be hard to put your finger on.

Here’s the problem: the microscopically small amount of power that comes from small wind.

Let’s say that the turbines shown here are 10′ X 6′ apiece (a reasonable guess I think).  In terms of “swept area,” that’s the equivalent of a rotating blade with a radius of 4.4 feet.

The average solar installation is 4KW.  If you want 4KW from that turbine, you need the wind to be blowing, on average, 32 mph.  That’s what’s called a “near gale.”

I don’t know about you, but I don’t have that blowing across my roof.  Part of the problem, of course, is that wind velocities in this range tear off your shingles and distributes them around your neighborhood.