Currently the only ways to prevent them from heading to landfill involve downcycling the blades into lower-quality materials.
But one day our wind turbine blades might become…gummy bears.
A team of US researchers has developed a resin that works as a turbine blade and at the end of its life can be reformed into another blade or other materials like plastic, lights, nappies and sugary snacks.
“At the end of its cycle we can dissolve it and that releases it from whatever matrix it’s in, so it can be used over and over again in an infinite loop,” says Dr John Dorgan, a researcher at Michigan State University, US, who is presenting the work at the 2022 Meeting of the American Chemical Society.
“That’s the goal of the circular economy.”
The resin is made from a combination of glass fibres and two types of polymers. The resin is strong enough to be used as wind turbine blades or car windows.
When the resin is dissolved in a substance called methyl methacrylate, the researchers can remove the glass fibres and re-use all the materials again in more wind turbine blades.
Or they could react the polymers further into even higher-quality products. Mixing with minerals turns the resin into cultured stone, which can be used for household objects.
“We’ve recently made a bathroom sink with the cultured stone, so we know it works,” says Dorgan.
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It can also be turned into acrylics suitable for car lights, or poly(methylacrylic acid) which is a super-absorbent substance used in disposable nappies.
Finally, the researchers turned the ex-resin into potassium lactate which is a common flavour enhancer in drinks and lollies.
“We recovered food-grade potassium lactate and used it to make gummy bear candies, which I ate,” says Dorgan.
More on wind turbine blade recycling: Renewable renewables: what happens to old wind turbines?
Could he taste the renewable energy? “A carbon atom derived from a plant, like corn or grass, is no different from a carbon atom that came from a fossil fuel,” says Dorgan.
“It’s all part of the global carbon cycle, and we’ve shown that we can go from biomass in the field to durable plastic materials and back to foodstuffs.”
The researchers are now looking to make blades they can test in the field – eventually hoping to scale up to commercial wind turbine blades, which are dozens of metres long.
“The current limitation is that there’s not enough of the bioplastic that we’re using to satisfy this market, so there needs to be considerable production volume brought online if we’re going to actually start making wind turbines out of these materials,” says Dorgan.