WIND STILL INNOVATING

Powerful Ideas: Wind Turbine Blades Change Shape; A wind turbine that adapts to windy conditions may harness more energy.
Charles Q. Choi, August 24, 2009 (LiveScience via U.S. News & World Report)

"Morphing blades made of advanced composite materials that can rapidly change their shape depending on the wind could help lead to advanced wind turbines that perform better and last longer.

"Wind energy is growing more and more popular worldwide. The United States is currently the world's largest generator of wind energy by total megawatts, and by 2030, the Department of Energy predicts that as much as one-fifth of the nation's power might come from wind. On a per capita basis, other nations are even further ahead…Denmark, for instance, already gets one-fifth of its power from the wind."

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"…[M]orphing blades…rapidly change their aerodynamic profile to best suit the prevailing wind conditions…[Flying and swimming animals are more efficient because they have geometric adaptability to varying flow conditions]…[Teams at San Diego State University and the University of Bristol in England are working on morphing blades that use the wind to their advantage rather than fighting it, increasing their efficiency and durability]…

"Modern wind turbine blades are typically made from a combination of glass and carbon-fiber-reinforced plastics. During manufacture, the plastic resin is heated and cooled in a controlled manner so that it bonds with the fibers and sets to form a rigid structure."

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"By carefully controlling the direction and tension of the fibers, the researchers at the University of Bristol note it is also possible to create a composite that can snap between two distinct rigid shapes. For instance, when given an electric signal, the blade might flex one way instead of another, showing more or less of its surface to the wind…[They made] a working demonstration of a morphing helicopter rotor blade...[and] entered into an agreement with Denmark-based Vestas Wind Systems to develop composite materials for future products.

"…[The San Diego State team leader] envisions morphing wind turbine blades made out of plastic materials similar to urethane rubber that flexibly bend and twist shape to reach the optimal angles that get as much energy from the wind as possible, depending on the wind's strength…[T]hey have completed [promising] lab tests with a number of roughly 3-foot-wide (meter-wide) rotors made from a number of different materials…"