Small scale horizontal axis wind turbines (HAWT) and vertical access wind turbines (VAWT) are unable to handle high winds or turbulent conditions. At very high wind speeds wind turbines shut down. Existing designs focus on external mechanical and electrical systems to reduce the output rather than exploit the attributes of low and high wind conditions. Turbines with static blades cannot effectively capture the direct wind energy for all the blades. Existing designs rely on a small proportion of the total blade area and typically feature a symmetrical profile (equal profile each side). Existing vertical axis machines have an inherent inefficiency because while one blade is working well with the wind, other blades are effectively pulling in the wrong direction – causing them to behave as a brake. Vertogen Ltd have identified a gap
in the market for a variable pitch VAWT.