Sandia National Laboratories in the United States, in partnership with US glassfibre company Knight and Carver, has developed a new wind turbine blade design which, the partners claim, is more efficient than current designs and should significantly reduce the cost of energy from wind turbines operating at low wind speed sites. The principal features of the Sweep Twist Adaptive Rotor, known as STAR, are a gently curved tip (the sweep) and curvature towards the trailing edge, which allows the blade to respond to turbulent gusts, so lowering fatigue loads. The 27.1 metre blade, intended for a wind turbine of 750 kW capacity, is manufactured from glassfibre and epoxy resin. The blade is designed to make sites with mean wind speeds of 5.8 m/s at ten metres more commercially attractive propositions for harnessing wind energy. Sites of this nature are abundant in the US. The aim with the new blade is to increase energy capture by up to 10% compared with a conventional blade, without affecting the blade's fatigue life.