German wind start-up Evoblade, wind services company Deutsche Windtechnik and business management consultancy Wirtschaftsförderung Bremen have developed a retrofittable blade spoiler capable of improving turbine production.
Their EvoFlap trailing-edge spoiler consists of a glassfiber and reinforced plastic strip attached to the root of rotor blades.
This is designed to better absorb mechanical loads that act on the blade and improve the aerodynamic flow around the blade root, resulting in improved efficiency and performance of the turbine.
In a study carried out between August 2015 and March 2019, their 10-metre-long EvoFlap spoiler improved the annual energy production (AEP) of a 1.5MW NEG Micon NM 82 turbine by 6%.
More recent testing has indicated around the same increase in AEP in wind speeds averaging 7m/s, according to Evoblade, a new company spun off from the Institute of Aerospace Technology at the University of Applied Sciences Bremen.
Evoblade CEO Frank Kortenstedde added that the segmented spoiler (above) also increases the bending and torsion strength of the blade, which can prolong service life by 1.2-1.6 years.
Kortenstedde said that the spoiler can be glued on without needing to remove the blade from the hub, reducing work and costs.