Even renewable energy has waste byproducts that become a major recycling problem for the industry. Many wind turbine blades are reaching the end of their lifespan, and plenty more are taken out of service early to be replaced by blades that can produce more energy.
This means that by 2023, around 15,000 turbine blades will have been decommissioned across the UK and EU. Strathclyde University in Glasgow predicts that global turbine waste is going to rise from 400,000 tons per year in 2030 to a whopping two million tons by 2050.
The blades are difficult to recycle not just because of their enormity, but because the reinforced plastic and glass fiber material that they are comprised of are not biodegradable. However, other aspects of their construction, such as the strength of the material and the hollow interior of the blades have inspired scientists to explore the blades’ potential to replace steel in construction projects like pedestrian bridges.
From blade to bridge
Cork University College in Eire, Ireland has started to investigate how sections of the blades can be incorporated into a bridge across the Middleton-Younghal Greenway.
“The blades are from a decommissioned Nordex N29 turbine, 14m long,” explains Paul Leahy, lecturer in Wind Energy Engineering. “For this bridge, which has a span of 5m, we cut a short section from the blade. The blades are used as the main structural element of the bridge and are functional in the design.”
According to Leahy, the blades’ gently curved shape as an aesthetic appeal to the design which he and the team believe will become a feature of interest on the greenway route. They are also looking at other products that can incorporate repurposed blades, like outdoor furniture.
Cork University College is doing its work as a part of a wider “Re-Wind project” that involves the opinions and insights of experts from the University Belfast, City University of New York, and Georgia Institute of Technology.
High-speed rail link use
Another blade recycling initiative has been adopted y the UK’s high-speed rail link contractor, Skanska Costain Strabag. Instead of using the blades to construct bridges, the rail link contractor worked with the National Composites Center to use retired wind turbines to reinforce concrete, using a process that cuts carbon production by up to 90 percent.
Parts of the blades will be used in temporary access roads, top sections of concrete walls, and ground-bearing plinths forming the base for portacabins. If the Re-Wind and Skanska Costain Strabag projects are successful, they will open the door for retired wind turbines to become an essential part of the construction industry.
New innovative material circularity
In addition to repurposing blades, there are other initiatives that focus on recycling the materials that the blades are made of. For example, Vestas Wind Turbine Systems in Denmark worked with Aarhus University to come up with a technique that allows the thermoset composite material to be broken down into fiber and epoxy (a class of plastics).
Through a chem-cycling process, the epoxy is broken down into base components that can then be used to make new turbine blades, creating a circular pathway for epoxy resin.