Wind Turbine Types
Today's wind turbines are much more lightweight than the turbines used on windmills of old. The wind turbine is usually standard in design, consisting of three rotor blades. The energy output of a wind turbine is determined largely by the length of the blades, which installers and engineers call "sweep."
The most popular turbine design is the horizontal axis wind turbine (HAWT). There are also vertical axis wind turbines (VAWT), a sort of "egg-beater" design that also requires the use of guy wires. The HAWT is more practical and popular than the VAWT, and that is the assumed focus of most wind turbine discussions (as it is here).
With the horizontal axis, there are two ways of positioning the turbine, either upwind or downwind:
- a horizontal upwind turbine, the wind hits the turbine blade before it hits the tower
- a horizontal downwind turbine, the wind hits the tower first.
These have varying effects on turbine wear and tower stress.