@A J Stiles @JonB Windmill Speed
Think of a factory where there is sheet material rolled onto a big roller - steel mills, paper mills etc (anyone in the UK can use a history book as reference). There's a lot of energy to be dumped when the roller is stopped. This uses the motor as a generator, some fancy electronics to convert the energy to DC, then to AC in phase with the mains input and dumps it back into the mains supply.
Now think of the electronics as just the mechanism for stopping the blades on the rare occasions the wind wants to turn them.
Advantages:
The blades can run at optimum pitch for the wind irrespective of the output requirements.
The system can be run in reverse to start the blades spinning or keep them running when it is politically wise to do so.
Wind generated by spinning the blades can be picked up and used by the next wind farm so giving a way of storing energy much like a stored water system (OK, I made this one up but when you see it in a politician's or expert's proposal you saw it here first)
Please note that I am an Aging Version 1 Hippy - "make love not war", "make tea not war" (English version), overthrow goverments etc. <RANT>The Reg - please do not mix verion 1 hippies with the new age hippies who only seem to want to jump onto the latest bandwagon of scientific mumbo-jumbo to allow goverments to exploit the masses. The sooner these windmills start falling down the better.</RANT>