Vertical Axis Wind Turbine (VAWT), 50 metres high, 34 metres across and capable of generating 500 kilowatts of electricity from a 45km/h wind. Two catenary-shaped aluminium blades are fixed along a rotating column giving the structure a distinctive 'eggbeater' appearance. The design, also called a Darreius Turbine, has an axial symmetry which obviates the need for adjustments in response to shifting wind direction. Efficiency is improved by a variable speed capability, a first for VAWT systems, however the optimum rotor speed is from 25 to 40 RPM. In addition to providing research data, the turbine meets half the power needs for the community at nearby Bushland, Texas.