MH> These are turbines, not mills. Nothing milled there.
From Wikipedia:
A windmill is a structure that converts wind power into rotational energy by means of vanes called sails or blades, specifically to mill grain (gristmills), but the term is also extended to windpumps, wind turbines and other applications
The Dutch verb "malen" (which I suspect is the mother of the English verb to mill) is used for pumping water as well. The later installations for pumping water, driven by steam, diesel or electricity are called "gemaal". And "windmolen" is used for anything extracting rotational energy from the wind.