Researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) have pioneered a significant advancement in wind energy technology: the creation of wind turbine blades that are bio-derivable and chemically recyclable. This innovation could dramatically reduce the environmental impact of wind energy by eliminating the need to discard old blades in landfills, a growing concern as wind power becomes a central pillar of the global renewable energy landscape.
The research, published in Science, unveils a bio-based resin developed by NREL, known as PECAN (PolyEster Covalently Adaptable Network). Made from biomass-derived sugars, the PECAN resin represents a leap forward in performance and sustainability. Wind turbine blades from this resin can be broken down and chemically recycled, allowing the components to be reused repeatedly.
Currently, wind turbine blades typically have a lifespan of about 20 years. At the end of their lifecycle, most are either landfilled or mechanically recycled into low-value products like concrete filler. This disposal practice contributes to the mounting issue of waste associated with renewable energy infrastructure, which ironically was intended to help mitigate environmental damage.
The PECAN resin offers a promising alternative. The chemical recycling process developed by NREL researchers allows the materials in the blades to be broken down in just six hours, an impressive reduction in time compared to other recycling methods. “It is truly a limitless approach if it’s done right,” said Ryan Clarke, NREL postdoctoral researcher and study’s lead author.
The research was carried out by a multi-disciplinary team from five NREL research hubs, including the National Wind Technology Center and the Bio-Optimized Technologies to Keep Thermoplastics out of Landfills and the Environment (BOTTLE) Consortium. The team demonstrated that the PECAN resin is recyclable and performs on par with, or better than, conventional thermoset resins currently used in wind blades.
One of the longstanding concerns in the field of polymer science has been the belief that bio-derivable or recyclable materials inherently underperform compared to traditional, petroleum-based materials. The NREL team’s research has dispelled these worries.
“Just because something is bio-derivable or recyclable does not mean it’s going to be worse,” said Nic Rorrer, one of the paper’s lead authors. Rorrer pointed out that PECAN composites have successfully passed rigorous weatherization tests without exhibiting the “creep” deformation, which has plagued other recyclable materials. This breakthrough challenges the common perception that recyclable materials cannot meet the high-performance demands of wind turbine blades.
To prove the manufacturability of the PECAN resin at scale, the researchers built a prototype 9-meter wind blade, which is about 10% the length of a full-scale commercial turbine blade. According to Robynne Murray, co-author of the study, the team demonstrated that the manufacturing process for PECAN blades is consistent with existing industry techniques, paving the way for scaling up the technology.
“Nine meters is a scale that we were able to demonstrate all of the same manufacturing processes that would be used at the 60-, 80-, 100-meter blade scale,” Murray said.
With further research and funding from the U.S. Department of Energy’s Advanced Materials and Manufacturing Technologies Office and Bioenergy Technologies Office, the NREL team plans to develop larger blades and refine the bio-derived formulations used in PECAN.
This research holds significant implications for the wind energy industry. According to the Global Wind Energy Council, global wind power capacity is expected to reach 2,100 gigawatts by 2050, a sharp increase from the current capacity of 837 gigawatts. As more wind farms are built and older turbines are decommissioned, the waste management issue becomes increasingly urgent. The ability to recycle wind blades at the end of their lifecycle is a critical step toward ensuring that wind energy remains a sustainable and environmentally friendly option for the future.
The PECAN resin could also help to foster a circular economy in energy materials, reducing reliance on raw materials and minimizing waste. As NREL’s associate laboratory director for Mechanical and Thermal Engineering Sciences, Johney Green, noted, “The PECAN method for developing recyclable wind turbine blades is a critically important step in our efforts to foster a circular economy for energy materials.”
The development of recyclable wind blades is part of a broader push toward sustainability in renewable energy technologies. Similar efforts are underway in the solar industry, where scientists are researching ways to recycle photovoltaic panels. According to the International Renewable Energy Agency (IRENA), the world could see up to 78 million metric tons of solar panel waste by 2050 if solutions for recycling and reuse are not scaled up.
As the renewable energy sector continues to grow, innovations like PECAN resin are essential for addressing the lifecycle challenges of energy infrastructure. These advancements ensure that renewable energy systems produce clean energy and manage the materials and waste associated with their manufacture and end-of-life disposal.
NREL's research into bio-derivable, recyclable wind blades marks a turning point for sustainable wind energy. By challenging assumptions about performance and demonstrating the viability of chemical recycling processes, the development of the PECAN resin shows that it is possible to create high-performing wind blades that contribute to a circular economy.
