[Dan(9698)]

Doesn't that depend on the speed of the wind?

They have an automatic control to vary the pitch of the blades so that they always turn the same speed.

If there is not enough wind to turn them that fast, they stop.

They must match the 60 Cycles per Second of the power line they are feeding into.

The Cycles Per Second is determined by the speed they spin.

[Xcoastie]

Well again it really depends on the design. Direct drive systems are heavily dependent on blade pitch. Typically the newer gearbox designs with the larger turbines can accomodate for changes in windspeed. LWST designs can handle speeds as low as 5kts and typically feather the blades at speeds above 30kts. Contrary to some perceptions, high wind is really not ideal for most wind turbines.

The birds that dying from wind turbines are in the same vein as the whales that are being made extinct by cruise ships. Sensational extrapolations from recorded events.