Whereas there are adequate capacities and well-defined procedures for the recycling of wind turbine components, this is not yet the case for rotor blade waste. Up to now, only a few specialised waste management companies have recycled these very large, high-strength components, but there is no data available on their re-use or recyclability. It was therefore difficult to assess or evaluate the technology or cost effectiveness of recycling.
Dirk Messner, President of the German Environment Agency, says: “Our survey shows that we must link climate action with circular economy from the very start. What goes for rotor blades also goes for lithium ion batteries, solar installations or other technologies. Waste avoidance should be the aim of every technical innovation in climate protection. And we need to develop recycling concepts for these products.”
The German Environment Agency commissioned a survey of available dismantling techniques, evaluated them according to environmental criteria and formulated requirements of occupational health and safety and of environmental protection. Grinding rotor blades on site before recycling, for example, can release dust emissions containing carbon or glass fibres. Processes must be established which prevent this dust from entering the environment or harming workers’ health. The study proposes binding quality assurance standards for subsequent rotor blade processing at a recycling plant.
The study directs particular attention to grinding technologies and fractionation methods. A multi-step flow chart was developed to illustrate the separation of components which can be applied for all types of rotor blades. All of the possible recycling processes for the different components of a rotor blade are described in detail so that recyclers now have access to the safest and most environmentally friendly processes. Pyrolysis and recovery have proven to be the most effective methods for recycling carbon fibres. In contrast, the recycling of glass fibre-reinforced plastics is still less than optimal. Recycling in cement plants is a possible option, but new research suggests that their use in higher-quality glass smelting should be investigated.
For the future, the German Environment Agency recommends technical standards that document the condition of rotor blades for the subsequent dismantling and recycling stage and which specify product-specific separation and recycling processes.