I actually have 3 windmills in my back yard (the local industrial estate across the busy through-road)
You never hear them and hardly ever notice them once they are placed.
https://www.google.nl/maps/@52.037446,4.506723,3a,75y,90t/da... < is one of them.
Zoetermeer used to have 3 other windmills about 20 years ago, those were replaced with these.
Only thing i would like is to get cheaper power, that has not happened :|