Getting bigger all the time.

Here we see the mechanical parts to a large windmill being installed into the top of a windmill tower. See the size of the man next to the mechanical parts? These parts include the flange where the three windmill blades are attached. The brake to stop the blades if they need to service the machine or if the winds get too high and the gearbox and the generator which makes the electricity. Groups of windmills or wind turbines are called wind farms and they can produce enough power for millions of people.