Consortium Develops World’s Largest Recyclable Wind Turbine Blade
LM Wind Power, a Danish subsidiary of General Electric (GE), developed the blade in collaboration with researchers and a number of industry players.
The deployment of renewable wind energy is on the rise. As of January this year, there are nearly 71,000 wind turbines in operation across the U.S. alone. That in mind, concerns regarding turbine recyclability have increasingly been brought to light across the industry.
In September 2020, a slew of industry players, including GE Renewable Energy, the research institute IRT Jules Verne, and the French chemicals giant Arkema, partnered to launch the ZEBRA (Zero wastE Blade ReseArch) consortium, with the unified aim of developing a fully recyclable wind turbine blade.
Now LM Wind Power, GE’s Danish wind turbine blade manufacturer, has produced its first prototype at its Ponferrada plant in Spain.
Composed of Arkema’s Elium thermoplastic resin, the prototype blade is 100% recyclable. Image used courtesy of GE
At 62 meters long, the thermoplastic blade is the largest of its kind in the world, and is entirely recyclable.
Are Wind Turbine Blades Destined For Landfills?
Before diving further into the details of LM’s prototype, it’s useful to first examine the claim that turbine blades are not, in fact, recyclable.
Since their introduction, the design of wind turbine blades has traditionally targeted a lifespan of roughly 20 to 25 years. But beyond those two decades of operation, manufacturers have opted not to prioritize recyclability; They instead have engineered their blades to best withstand the environmental rigors inherent to wind production.
Decomissioned blades at a staging yard in Sweetwater, Texas. Image used courtesy of the Pacific Northwest National Laboratory
That sparked the claim, now widespread and oft-accepted, that all blades decommissioned will inevitably make their way to graves in landfills. Researchers around the globe, though, are working to develop solutions.
KTU Researchers Develop Novel Recycling Method
Today’s wind turbine blades, constructed of steel and fiberglass, are not easy to recycle. But that isn't stopping researchers from the Lithuanian Energy Institute and the Kansas University of Technology (KTU).
Publishing in the journal Fuel, the researchers discovered that they could apply pyrolysis to different batches of fiberglass thermoset and thermoplastic to break down blades’ components. They then analyzed the remaining materials to see if each batch could be repurposed. Though the yield of reusable materials varied depending on temperature, the researchers were able to successfully extract both phenol and fiber residue, which can be reused to manufacture a variety of products.
Still, for the research team to confidently assert that they have developed a reliable method for recycling existing fiberglass-based blades, they will need to experiment and test their process on a full-length version.
Recycling ZEBRA’s Thermoplastic Blade
The launch of ZEBRA’s thermoplastic prototype leaves one question begging to be answered: How are these things actually recycled?
Thermoplastic blades can be broken down using two methods. The first, mechanical recycling, takes thermoplastic parts, crushes them, and then heats them to yield materials that can later be turned into panels with high mechanical resistance. The second, chemical recycling, involves crushing the composite and then heating it to around 400 degrees, turning the solid resin of the blade into a gaseous monomer that can then be purified and reused. And that holds true even for end-of-life and badly damaged blades.
The remains of a crushed thermoplastic blade. Image used courtesy of Arkema
The consortium hopes to validate these methods with the prototype blade, which will now head to LM’s Test and Validation Center in Denmark to undergo full-scale structural lifetime testing. From there, it will be broken down for a full recycling analysis by the consortium.
The project is slated for completion by 2023, and though GE claims the consortium “will have met the challenge of bringing the wind energy sector into the circular economy loop,” the company provided no timeline for commercialization.