Intelligent wind turbine rotor blade copes with gusts

Wind is rarely constant. It varies in strength and direction from moment to moment, and although wind turbines have some movement built into them, they cannot adapt quickly. The Fraunhofer Institute for Wind Energy Systems (IWES) in Bremerhaven has developed a turbine whose blades have a “bend-twist coupling” (BTC) that helps them react to changes in wind intensity in a moment.

In a turbine whose blades are 85m long, the rotor sweeps out a circular area of 22,670m². Even within this area, wind strength can vary considerably. For example, the pressure acting on the blade that is pointing upwards can be very different from the pressures on the other two blades. If there is a gust when the wind is already strong, the only option the operators have to protect the blades from the sudden very strong force is to turn the rotor away from wind. This results in long downtime, even during windy conditions when no electricity is being produced.