Researchers are optimistic about creating wind blades made from bio-based materials that can be chemically recycled, thus preventing old blades from ending up in landfills once they have served their purpose.
Experts at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) are optimistic about a promising approach to create wind blades that utilize bio-derived resources and can be chemically recycled, keeping obsolete blades out of landfills after they reach the end of their lifespan.
The results of their study are detailed in the latest edition of the journal Science. The newly developed resin, made from bio-sourced materials, performs similarly to conventional blades crafted from thermoset resin and surpasses the performance of certain thermoplastic resins, which are aimed at recyclability.
To showcase the potential for manufacturing, the researchers created a 9-meter prototype blade using a biomass-based resin they call PECAN, short for PolyEster Covalently Adaptable Network. This method aligns well with current manufacturing practices. Currently, wind blades typically last around 20 years, entering mechanical recycling processes afterward, like being shredded for concrete filler. PECAN represents significant progress, as it allows for the recycling of blades through mild chemical methods.
This chemical recycling method enables the components of the blades to be recovered and reused multiple times, facilitating the remanufacturing of identical products, as explained by Ryan Clarke, a postdoctoral researcher at NREL and the lead author of the paper. “If done properly, this method offers virtually limitless possibilities.”
Clarke noted that the chemical process could completely decompose the prototype blade in just six hours.
The study, titled “Manufacture and testing of biomass-derivable thermosets for wind blade recycling,” involved collaboration among researchers from five NREL facilities, including the National Wind Technology Center and the BOTTLE Consortium. They showcased a strategy for the end-of-life phase for PECAN blades and suggested recovery and reuse methods for each component.
“The PECAN approach to crafting recyclable wind turbine blades plays a vital role in advancing a circular economy for energy materials,” stated Johney Green, NREL’s associate director for Mechanical and Thermal Engineering Sciences.
The research into PECAN resin began with the end goal of creating a recyclable wind blade, prompting scientists to explore various feedstocks to reach that aim. The resin made from bio-derived sugars counters the common belief that recyclable blades cannot perform effectively.
“Just because something is made from bio-derived materials or is recyclable doesn’t mean it has to underperform,” remarked Nic Rorrer, one of the corresponding authors of the Science article. He also recalled concerns that such materials might lead to greater “creep,” where the blade could lose its shape over time. “This really disputes the prevailing notion that recyclable components cannot yield high performance or could suffer too much deformation.”
Composites created from the PECAN resin maintained their structural integrity, passed accelerated weathering tests, and could be manufactured within a timeframe comparable to existing methods used for wind turbine blades.
Although wind blades can extend as long as a football field, the size of the prototype effectively demonstrated the process.
“Nine meters is a scale that allowed us to demonstrate all the manufacturing processes that would apply to blades measuring 60, 80, or even 100 meters,” said Robynne Murray, the co-author of the study.
Other co-authors from NREL include Erik Rognerud, Allen Puente-Urbina, David Barnes, Paul Murdy, Michael McGraw, Jimmy Newkirk, Ryan Beach, Jacob Wrubel, Levi Hamernik, Katherine Chism, Andrea Baer, and Gregg Beckham.
The U.S. Department of Energy provided funding for this research through its Advanced Materials and Manufacturing Technologies Office and Bioenergy Technologies Office, as part of its support for the BOTTLE Consortium. Further research and funding will help the team create larger blades and investigate additional bio-derived formulations.
NREL serves as the main national laboratory for the U.S. Department of Energy, focusing on renewable energy and energy efficiency research and development, operated by the Alliance for Sustainable Energy LLC.
