The part of a wind turbine that captures wind energy, made of laminate or carbon fibre. The blade has an aerodynamic profile similar to an aircraft wing. Air flowing around it causes lift towards the upper side of the blade. Because the blade is attached to the rotor hub at one end, the entire turbine rotates. A typical horizontal axis turbine has three blades. The largest turbines have them more than 100 metres long. The blades are made of fibreglass, carbon fibre or a combination of these, and is coated to withstand harsh weather conditions. The lifespan of the blade is 20 to 25 years.