It is said that nature has all the best inventions. Wind power turbines have been with us for a long time, but only recently has someone thought of applying the biodynamics of bird wings to them to improve performance. That person is mechanical and environmental engineer Klaus Röhm, founder of the start-up Wind-Tuning-Systems (WTS).

After receiving early stage funding from Innoenergy, an EU-backed sustainable energy accelerator, Röhm developed and patented WTS 3D-Serrations and WTS back-flow-flaps. The WTS serrations are aerodynamically-optimised blades for new turbines based on a 3D design. They build on trailing-edge-serration technology (2D triangular serrations) which were developed for noise reduction. WTS claims its 3D-Serrations are capable of reducing noise up to 5 dB(A), while increasing (indirect) yields up to 20 percent.

The back-flow-flaps – which are based on the way birds’ wings flip upward during landing – can be retrofitted to existing turbines, resulting in a yield hike of 6 percent through improved night mode operation. When fitted to stall-controlled turbines, for example, energy production can be boosted by up to 1.5 percent in daytime mode, while at the same time reducing static and dynamic load by optimising air circulation around the blade.

Furthermore, the back-flow-flaps could enable the construction of larger turbines in offshore wind parks. At the moment, the physical load limits of these wind giants have been reached, but with the with cross-flow (YAW-effect) of back-flow technology, the rotor blade diameters could be increased and hence the yield.

Noise emissions from wind turbines remain one of the greatest restrictions on the expansion of inland wind energy in Germany. Even stricter new LAI guidelines threaten a number of planned wind power projects. Speaking to Energie Zukunft, Klaus Röhm describes his wind-tuning-systems as an “extraordinary problem solution” for the wind industry. “Noise reduction and yield improvement could help the expansion of onshore wind power and thus not only maintain but also expand jobs,” he says.