In this aerial view, wind turbines grace the landscape in the southern Lake District on November 25, 2022 in Lambrigg, England.Christopher Furlong/Getty Images

(CNN) — Windmills are built to last. Their tall bodies are adorned with long fiberglass shovels, some more than half a football field long, made to withstand the harshest and windiest conditions.

But this robustness comes with a big problem: what to do with those blades when they reach the end of their useful life.

90% of the turbines are easily recyclable, but their blades are not. They are made of fiberglass bonded with epoxy resin, a material so strong that it is incredibly difficult and expensive to break. Most shovels end up in landfills or are incinerated.

It is a problem that has been tormenting the wind energy industry and that gave arguments to those who seek to discredit it.

However, last February, the Danish wind company Vestas said it had solved the problem. He announced an "innovative solution" that would allow windmill blades to be recycled without changing their design or materials.

According to the company, a "newly discovered chemical technology" breaks down old blades into a liquid to produce high-quality materials, which can eventually be used to make new blades as well as components from other industries.

Claire Barlow, a sustainability and materials engineer at the University of Cambridge, told CNN that if this kind of technology can be scaled up, "it could be a game changer."

A new method for a big problem

Windmill blades waiting to be buried at the Casper, Wyoming, regional landfill.
Benjamin Rasmussen/Getty Images

In 2019, an image from the Casper regional landfill in Wyoming went viral, showing piles of long, white blades waiting to be buried, prompting criticism of wind energy's environmental credentials.

Wind energy has grown at a breakneck pace. It is the world's first renewable energy technology, after hydropower, and plays a vital role in helping countries move away from fossil fuel energy, which generates planet-warming pollution.

But as the first generation of wind turbines reach the end of their useful life and are prematurely replaced by others to make way for new technologies – such as longer blades that can sweep more wind and generate more power – the question of what to do with the huge blades becomes more urgent.

Blade waste is projected to reach 2.2 million tons in the United States by 2050. Globally, the figure could be around 43 million tonnes by 2050.

And there are few easy ways to fix it.

Current options not only involve waste, but also have environmental drawbacks. Incineration leads to pollution, and while wind companies claim the blade dump poses no toxicity concerns, Barlow says that's still not entirely clear.

"It's not as benign as you might think," he says.

The materials of the turbine blades make it difficult and expensive to recycle. The epoxy resins used to make turbine blades are called "thermosets".

"If you heat them, they don't change their properties until they end up burning," Barlow explained. "You can't just squeeze them and recycle the material into something easily reusable."

For that reason, Vestas is confident in the promise of its new technology.

"This has been the main sustainability challenge of the sector. We are very happy that we have found a solution," Lisa Ekstrand, head of sustainability at Vestas, told CNN.

The process, which the company worked on in collaboration with Aarhus University, the Danish Institute of Technology and US epoxy company Olin, uses a liquid chemical solution to break down the leaf into epoxy fragments and fibers. The epoxy resin is then sent to Olin, which transforms it into "virgin" epoxy, explains Ekstrand.

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The process uses cheap, nontoxic chemicals that are available in large quantities, he added. "We expect it to be a technology that consumes little energy and generates low CO2 emissions."

The company has not given further details, including those on which chemicals are used and how many times the process can be repeated.

Ekstrand says they are processing the patents and the plan is to license other companies.

So far, Vestas has tested the technology in a lab, but is now building a pilot plant to test it on a larger scale over the next two years, after which it hopes to commercialize it.

Gummy bears of turbine blades

Vestas is not the first company to try to solve this complicated problem. Companies and scientists have been working on different approaches for years, although many potential solutions are nascent or still small-scale.

One of them is to crush the blades and use the material in other industries. The drawback is that the huge blades are difficult to transport and crush. "Because the material isn't worth much, it's not worth doing," Barlow says.

An old blade is preparing to be transported to a landfill in Nebraska.
Olivia Sun/The Des Moines Register/USA Today Network.

But some companies say they're succeeding.

Veolia, a resource management company based in France, turns old blades into an ingredient for cement production.

It crushes, sorts and mixes the blade materials before sending them to cement kilns. The use of this mixture reduces – according to Veolia – by 27% the pollution produced by global warming in the manufacture of cement. The program has so far processed 2,600 blades.

Tennessee-based Carbon Rivers collaborated with the U.S. Department of Energy to help scale up its technology for "pyrolysis," a form of chemical recycling that uses very high heat in an oxygen-free environment.

The company's process produces fiberglass that can be used in new windmill blades, as well as in the automotive and marine industries. David Morgan, chief strategy officer at Carbon Rivers, told CNN it also produces oil that can be used in energy production.

The technology allows them to "fully and completely recycle windmill blades" in a process that is "energy positive," Morgan added.

To date, Carbon Rivers has recycled 41 blades weighing 268 tonnes and is building recycling facilities with the aim of reaching more than 5,800 tonnes a day.

Other efforts are focused on changing the materials from which turbines are made, to create a new generation of blades that are easier to recycle.

In 2022, researchers at the University of Michigan announced that they had made a new blade resin by combining glass fibers with a plant-derived polymer and a synthetic polymer, which could be recycled into ingredients for products such as new turbine blades, laptop covers, power tools, and even gummy candies.

"We recovered food-grade potassium lactate and used it to make gummy candies, which I ate," John Dorgan, a professor of chemical engineering at Michigan State University, said in a statement.

For those worried about eating an old turbine, Dorgan said, "A carbon atom from a plant, like corn or grass, is no different from a carbon atom from a fossil fuel. It's all part of the global carbon cycle, and we've shown that we can move from biomass in the field to durable plastic materials and back to food."

Of course, this will not help with the shovels that are being dismantled now.

The reason Vestas' discovery could be so compelling, according to Barlow, is that it promises a process for recovering reusable materials from current turbine blades, without using harmful chemicals or huge amounts of energy. "Now that's winning," he says.

Now the company has to scale up.

"There will be all kinds of problems that they haven't conceived. So it may go slowly, but it's a good start," Barlow said.

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