Wind turbine blades are getting ever larger and producing more power, but fluctuations in wind speed mean they are not always efficient. Blades can now be 85m long (and will be longer in the future) and they swing through an area the size of four football pitches. The wind speed will vary at the top and bottom of each rotation. The blades also have to be robust to withstand the pressure of high winds. Even so, in the worst weather operators sometimes need to angle the blades away from the wind and turn the turbines off to avoid damage. Then they lose production altogether.

Engineers have realised that by developing blades that can automatically twist slightly to reduce wind pressure they will get the best out of the airflow, and prevent gusts damaging them. It would also mean that the blades could be lighter and therefore cheaper. The prize is to get more energy from each turbine, whatever the wind speed.



The German Federal Ministry for Energy is putting €15m into building four trial turbines in turbulent air at the bottom of the Rocky Mountains to test this new type of blade. With 28,000 turbines in Germany alone there is an enormous potential boost to Europe’s renewable energy production.