Status: 07/27/2021 12:08 p.m.
For more than a third of German wind turbines, support for electricity payments will end by 2025. A large part will probably be dismantled. But recycling old rotor blades still creates problems.
“That is a challenge,” says Sebastian Haase when asked how the rotor blades of decommissioned wind turbines can be recycled. Haase is the spokesman for the German Wind Energy Association (BWE) in Brandenburg and Berlin. As early as 2019, his association formulated the challenge in a background paper as follows: “So far, relatively few systems have been dismantled. Some of these systems have been transferred to the secondary market, mostly outside the EU.
Concrete, steel and copper are not the problem
For around 90 percent of a wind turbine, recovery is not a problem in terms of process technology. There is sufficient use in the construction and metal industries for the parts made of concrete, steel and copper. But the rotor blades are made of various plastics that are reinforced with glass or carbon fibers. These composite materials, which are difficult to recycle, are used even more than in wind turbines in the automotive, aviation or boat building industries.
This type of plastic has been banned from being disposed of in landfills since 2005. The options for disposal and, above all, recycling are limited. Using the glass or carbon fiber reinforced materials as fuel in cement production is an option, but it has nothing to do with recycling. Burning also produces CO2, which reduces the environmental balance. Most recently in June, the German WindEnergie Association once again supported the European commitment to “reuse, recycle or recycle 100 percent of discarded rotor blades,” according to a press release.
Researchers develop methods
At the Fraunhofer Institute for Applied Polymer Research IAP, researchers are working, among other things, on technologies to chemically break down these composites into their components: in carbon or glass fibers and the respective plastics in which the fibers were embedded. The fibers can then be processed into door handles, for example in automobile production.
Christian Dreyer, responsible for the fiber composite material technology department, also considers this to be “currently still a challenge”: “Many of these rotor blades are not designed in such a way that they can be easily recycled, it is a multi-material system.” Here the chemist sees approaches for the future to manufacture the composite materials in such a way that they can be reused more easily after they have been used as rotor blades. Dreyer calls this “design for recycling”.
After twenty years of funding it’s over
In Brandenburg, for example, there are currently 3,904 wind turbines, of which around 1,760 will be withdrawn from funding under the Renewable Energy Act (EEG) by 2025. They were then in operation for 20 years. In principle, the operators then have three options: They can continue to operate the system, replace it completely or in part with new, usually more powerful technology (“repowering”), or dismantle and recycle the wind turbines.
“That is a problem that can be solved,” says Christian Wenger-Rosenau on the subject of recycling. “When demand grows, there are companies that do it. So far, there have been no incentives.” The engineer planned and built wind turbines in the north of Brandenburg for many years. Now he has five left. He has already dismantled one and sold it to Eastern Europe, while others will be phased out in the next few years. So the question arises for the windmill about the demolition.
Elaborate approval
But how should the failures be compensated? Repower? For this, an almost as complex approval process is necessary – just as for a new plant, and that takes time. According to BWE spokesman Haase, politics is called upon here: The conflicts over distance rules, species and nature conservation must finally be resolved so that more new wind turbines can be built.
Brandenburg will currently not achieve its self-imposed expansion target of 10,500 megawatts (MW) of wind power by 2030. This would require an annual increase of 300 MW, according to the BWE in 2020 it was 205 MW, also because 43 plants were dismantled without replacement.
Windmüller Wenger-Rosenau is at one of his wind turbines near Zehdenick. He is considering producing hydrogen with its electricity in the future instead of tearing it down.