Pyrolysis processes promise sustainable recycling of fiber composites from rotor blades

15 September 2023

Wind turbines typically operate for 20 to 30 years before they are undergoing dismantling and recycling. However, the recycling of fiber composites, especially from the thick-walled rotor blade parts, has been inadequate until now. The prevailing methods involve thermal or mechanical recycling. For a sustainable and holistic recycling process, a research consortium led by Fraunhofer IFAM is pooling their expertise to recover the fibers through pyrolysis. Subsequent surface treatment and quality testing of the recyclates allow for them to be used again in industry.

Today, the vast majority of wind turbines can already be recycled cleanly. In the case of rotor blades, however, recycling is only just beginning. Due to the 20-year operation period and the installation rates, the blade volume for recycling will be increasing in the coming years and decades. In 2000, for example, around 6,000 wind turbines were erected in Germany, which now need to be fed into a sustainable recycling process. In 2022, about 30,000 onshore and offshore wind turbines with a capacity of 65 gigawatts were in operation in Germany alone.

As wind energy is the most important cornerstone for a climate-neutral power supply, the German government has set itself the goal of further increasing its wind energy capacity by 2030 by installing larger and more modern turbines. Rotor blades will become longer, the proportion of carbon fibers used will continue to increase - and so will the amount of waste. In addition, the existing material mix in rotor blades is expected to increase in the future and precise knowledge of the structure of the components will become even more important for recycling. This underscores the urgency of developing sustainable processing methods, especially for recycling the thick-walled fiber composites in the rotor blades.