Almost all methods of generating electricity depend on using
some other form of energy to spin an electrical generator.
If the other form of energy is kinetic energy robbed from wind,
then the wind turns the blades of a big 'fan', and the blades
spin the electrical generator.
In a commercial windmill, the electrical generator is in that 'box'
on top of the pole, right behind the hub of the blades.
They actually DO have velocity limits. There are legal restrictions on both speed and direction.
-- Speeds are limited according to the black numbers on white signs that you see on sign-posts everywhere.
-- Directions are limited by the layout of the pavement and curbs on all the highways, avenues, roads, boulevards and streets, as well as the countless signs that say "One Way", "No Left Turn", "Keep Right", "Keep Left", etc. Violate one of these, and you get nailed as sure as if you had exceeded a posted speed limit.
Infrared radiations can be detected by a thermopile