Wind Turbine Blade

A wind turbine blade is the aerodynamic component, usually one of two or three mounted on the rotor hub of a wind turbine, that converts the kinetic energy of moving air into the rotational force driving the turbine generator. Modern blades are built as hollow composite structures, typically fiberglass or carbon fiber set in an epoxy resin, with internal spar caps running the length of the blade to carry bending loads and shear webs, often cored with balsa wood or rigid foam, connecting the caps to keep the structure stiff. Carbon fiber is used selectively, especially in the spar caps of larger and offshore blades, because it is lighter and stiffer than fiberglass for a given strength, letting manufacturers build longer blades that capture more energy without adding excessive weight. The finished blade is coated with a protective gelcoat to resist ultraviolet degradation and moisture over its outdoor operating life, and blade length has grown steadily as turbines have scaled up to capture more wind energy per installation.