A wind powered generator converts wind energy into electrical energy. Assume that the generator converts a fixed fraction of wind energy intercepted by its blades into electrical energy. For wind speed v electric power will be proportional to

a) v⁴

b) v²

c) v

d) v³

I'd go for b) v squared.

Wind is air in motion. So, it has kinetic energy. For a given mass of air at a certain speed, the kinetic energy would be (1/2) mv^2.

Since everything else in the chain seems to be proportional, then it's the v^2 bit that seems to be important. Hence the answer I post here.