Renewable energy, such as wind power, promises to help reduce the country’s carbon footprint. But the wind industry has a growing source of waste material—windmill blades—which could undercut its green reputation.
One researcher at the University of Tennessee in Knoxville is working to fix that by finding a way to recycle the blades.
Most of a wind turbine’s vast structure is made out of metals like steel or copper, which can be repurposed. But the propeller blades, some well over 100 feet long, are a bit more complicated.
“You want something that is very stiff but also very light, so to do that, wind blade manufacturers turn to fiber-reinforced polymer composites,”says Ryan Ginder, an assistant professor at UT.
Ginder says this material is hard to reshape and has historically been difficult to recycle. The blades have a lifespan of about 20 years. After that, most of them are being heaped into landfills with the rest of America’s discarded items. The Electric Power Research Institute estimates that in the next 30 years cumulative blade waste could amount to 4 million tons.
“They still take up a lot of space in the landfill,” Ginder says. “Plus being designed to take extreme weather and so forth, you can’t really crush them or compress them to take up less space.”
But Ginder is working with a private recycling company called Carbon Rivers to scale-up technology he developed to recycle the blades. His process breaks them down into components that have alternative uses. Some components, such as resins, can be converted into energy. Others, like the glass fiber, are altered into materials with higher value that can be repurposed by industries such as auto manufacturing.
“As we move forward, one of the things that we’re going to have to work very carefully on is the logistics supply chain and how do you route these materials around the country as they move from one application and get recycled into another,” he says.
The pilot project has already received its first shipment of blades from out of state. Its goal is to recycle 100 tons by early 2022.
This article has been updated to correct the spelling and pronunciation of Ryan Ginder's last name and correct his position. We regret the error.