Closed-loop recycling of wind turbine blades: Designing materials that are made to be recycled

As the number one contributor to global climate change, it’s no secret that fossil fuels are bad for the environment. They account for a staggering 75% of greenhouse gas emissions and nearly 90% of all carbon dioxide emissions. This has led to an increase in global temperatures, severity, and frequency of natural disasters, as well as rising ocean levels. Finding alternative and sustainable energy sources is now more important than ever, and luckily, scientists have found ways to harness energy from renewable sources such as wind. 

Did you know that wind is the most prevalent renewable energy source and that it currently generates 10% of U.S. electricity? This percentage will grow as we continue to engineer bigger, better, and more efficient wind turbines. This has been an incredible and essential scientific feat that has helped us move away from fossil fuels, but I would be lying if I told you it was 100% sustainable.

Although wind is a source of renewable energy, it has a fatal flaw: there is currently no viable way to recycle wind turbine blades. Most people don’t realize that wind blades are replaced every 10-20 years, creating a large influx of waste material that is sent straight to a landfill. Estimates say between 200,000 to 800,000 tons of wind blade waste are produced every year. This is–quite literally–a massive problem as current wind blades can be as long as a football field, meaning that this waste takes up acres of land, creating so-called wind blade “graveyards.” In addition, wind blades are only getting bigger and bigger, creating an even more massive problem. 

Although scientists have been working on methods for recycling wind blades, a clear solution hasn’t been found due to the nature of the material. Wind blades are composite materials made of two main components: glass fibers and thermoset polymer resins. The glass fibers help reinforce the composite material by providing strength and rigidity. The polymer resin binds the glass fibers together, giving the composite its shape and properties. Thermoset polymer resins are a special class of resins that are engineered to be unyielding and robust, which is needed for their application, but it makes them extremely difficult to recycle.

Extreme conditions are usually needed to break down the material, but due to glass fibers being sensitive to degradation, these conditions will recycle the resin at the cost of the fibers. If we want to have a truly circular system, it is essential that we find conditions to break down the wind blades that will allow us to recover value from both the glass fibers and the polymer resin. 

I am a PhD student in the Travis J. Williams Research Group at USC, and this problem is right up our alley. Our group focuses on using chemistry to solve the different sustainability crises we face in the world. Whether the problem is trying to find value from decommissioned airplanes, used motor oil, plastic, or wind blade waste, our group strongly believes that chemistry is the way we can turn trash into treasure.

Specifically, my project aims to tackle the wind blade waste crisis we face. As I previously mentioned, this material is incredibly difficult to break down for many reasons, which has brought our group to raise the question: What if we designed thermosetting polymer resins that were made to be recycled?

This has become the central goal of my research. I work on designing and synthesizing resins that are strong enough to work for wind blade use but can be broken down under specific stimuli when they need to be discarded.

You may be wondering, “Well, how do you make a resilient resin that can also be recycled?”

Good question! The answer: it’s not easy.

Our first approach has been to mimic the currently used resin formulation, but incorporate a small amount of bonds that are easier to break. In chemistry, not all bonds are made equally. Some are extremely strong, while some will break down under the slightest conditions. If we can selectively incorporate a weaker bond into the current resin formulation, then we can make a resin that still has all the necessary properties wind blades require but that can be broken down with a specific stimuli. This would enable us to break down the wind blades with milder conditions, meaning we could recover value from both the glass fibers and the polymer resin.

Our goal is to make the first fully recyclable wind blade, and with some preliminary results under our belt, our progress looks promising! Stay on the lookout for updates from our group as we work towards publishing our first paper about this new methodology. 

I would like to thank the Wrigley Institute for Environment and Sustainability for supporting this research and for selecting me to be a 2025 Wrigley Institute Graduate Fellow. This fellowship has not only supported my research financially, but it has also provided me with a network full of wonderful and diverse people. Throughout my fellowship, I have been given the opportunity to learn from people all across the board, be it scientists, policy makers, museum curators, journalists, and many more. It truly has been a unique and invaluable experience for me, and I’ve really enjoyed learning from so many different perspectives. Thank you!

Madison Fette is supported by the Diane Sonosky Montgomery and Jerol Sonosky Graduate Fellowship for Environmental Sustainability Research.