ReWert: Resource-efficient Recycling of Rotor Blades

At a glance

• By 2037, approximately 83,000 metric tons of rotor blade waste will be generated annually in Germany alone. Current recycling options are limited to incineration or use as an additive in cement plants. 
• The ReWert research project is developing a pilot plant for the selective dismantling and recycling of rotor blades from wind turbines to enable high-quality material recovery and a circular economy.
• The project partners are examining the use of pyrolysis oil, the incorporation of glass fibers into adhesives, and their reuse in the glass processing industry. Furthermore, they develop cost estimates, sensitivity analyses, and an economic comparison of various concepts.
• Fraunhofer IWES is coordinating the project, analyzing the expected quantities of rotor blades and their components, and investigating their recycling options. Furthermore, Fraunhofer IWES is identifying the materials used, planning and automating the decommissioning process, and carrying out the preliminary dismantling.

The challenge

More than 35,000 wind turbines with a total capacity of over 60 GW are installed in Germany. By 2037, a maximum of approximately 83,000 metric tons of rotor blade waste will be generated annually in Germany alone. Rotor blades consist of complex fiber-reinforced composite structures containing glass fibers, resin systems, and core materials such as balsa wood and PVC/PET foam. High-quality recycling has so far only been possible on a laboratory scale and is cost intensive. Most rotor blades are incinerated; however, waste-to-energy plants will not be able to handle the volumes that will be generated in the future. Furthermore, from a sustainability perspective, recycling these materials is preferable.

The solution

The ReWert research project aims to decommission rotor blades in such a way that glass fibers, foams, and balsa wood can be recovered as purely sorted as possible for further use. To this end, a pilot plant for a decommissioning center is being developed. Through selective dismantling and subsequent sorting by material type, the goal is to recover glass fibers, balsa wood, PVC foam, and PET foam for reuse, as well as the pyrolysis oil produced as a byproduct of pyrolysis. Decommissioning is carried out using thermography to detect material boundaries, laser-guided visualization of cutting lines, and automated cutting technology for selective separation. For full laminates, the separated sections undergo further treatment via pyrolysis to recover the glass fibers. The sandwich sections are shredded, and the various core materials are then separated from the GFRP laminates (glass fiber reinforced plastic) using the float-sink technique. Concurrently, a life-cycle analysis is conducted, and recycling costs are determined.

The added value

The research project reduces resource waste and supports the circular economy. The recovery of pure secondary materials – glass fibers, balsa wood, foam cores, and pyrolysis oil – enables their reuse in various industrial sectors. This allows for the creation of new value chains. By returning these high-quality materials to the production process, not only is the demand for primary raw materials reduced, but the environmental footprint of the involved industries is also significantly improved.