Wind turbines could be given a truly sweet second life thanks to a new discovery from engineers in the US.
They have invented a new type of resin, the material that coats turbine blades, that could be reused to make countertops, car tail lights, power tools, nappies and even gummy bears.
The breakthrough, from chemical engineers at the University of Michigan, could hold the key to one of the biggest challenges that comes with wind power: how to recycle turbine blades.
A new way to save wind turbine blades from landfill
Made of resin-coated fibreglass that is difficult to separate and recycle, wind turbine blades average 50 metres each in length - half the length of a professional football field. Although some can be recycled into lower-value materials, most discarded blades end up in landfills.
As bigger, more efficient turbines replace old ones in a process known as ‘repowering’, defunct blades are a growing problem. Wind power association WindEurope expects around 52,000 tonnes of blades to be decommissioned annually by 2030.
With the wind industry calling for a Europe-wide ban on landfilling turbine blades by 2025, green-minded scientists are coming up with creative solutions.
The recyclable resin could be used to make turbine blades
Chemical engineers at the University of Michigan, USA, have developed a new, recyclable composite resin that could be used to make turbine blades.
Once the blade is decommissioned, the resin can be recycled into household items and sweet treats. Or it can be dissolved and made into new turbine blades, according to research published by the American Chemical Society (ACS).
“It can be used over and over again in an infinite loop,” says professor and researcher John Dorgan, PhD. "That's the goal of the circular economy."
How is the recyclable resin made?
To create the new turbine material, Dorgan and his colleagues combined glass fibres with a plant-derived polymer and a synthetic one.
Panels made from the resulting thermoplastic resin were strong and durable enough to be used in turbines and cars.
After dissolving the panels and removing the glass fibres, they were able to recast the material into new products with the same physical properties.
By mixing the resin with various minerals and solutions at different temperatures, they were also able to create completely different products. These range from a super-absorbent polymer used in nappies to potassium lactate, which can be purified and made into sweets and sports drinks.
"We recovered food-grade potassium lactate and used it to make gummy bear candies, which I ate," says Dorgan.
Is there a ‘yuck factor’ involved in eating candy that was once part of a wind turbine?
Dorgan doesn't think so. "A carbon atom derived from a plant, like corn or grass, is no different from a carbon atom that came from a fossil fuel," he says. "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."
Having demonstrated that the resin has suitable physical properties for wind turbines, researchers now hope to make some moderately sized blades for field testing.
"The current limitation is that there's not enough of the bioplastic that we're using to satisfy this market,” notes Dorgan. “There needs to be considerable production volume… if we're going to actually start making wind turbines out of these materials."