Knight & Carver, a Californian company, has developed an innovative wind blade that produces energy in low wind speed regions. The longer-than-conventional blade automatically twists during high wind to reduce loads on the machine thus producing a maximized amount of wind energy. Therefore, longer blades than normal can be safely used in regions regarded as lower-wind production areas. In wind-energy production, the term "low wind speed" means winds of up to 15 knots.
Today, a standard HAWT (Horizontal Axis Wind Turbine) captures the wind's energy with three propeller-like blades mounted on a rotor. The turbine sits more than 200 feet atop a tower to take advantage of stronger and less-turbulent wind. Elevated so high above the surface makes maintenance and repair costly; bearings and shafts that transfer wind power from the turbine blades must be to withstand exceptional rigors in various weather conditions. Development was was conducted as part of a $2.8 million shared cost Department of Energy contract to design, fabricate and field test a sweep-twist adaptive blade for utility scale wind turbines as part of the Low Wind Speed Turbine Initiative.
Sized at 27.2 (85 ft) meters x 2.4 meters (7 ft), the Adaptive Sweep Twist Blade is designed both for maximum efficiency at lower-speed wind conditions and to automatically adjust to higher wind gusts when necessary. Production is expected to begin next year.