Rare earth elements are essential for wind turbine magnets – can we recycle them?

Overall, turbines that provide wind-generated electricity are a great asset from an environmental perspective. They have a “payback period” – that is, the time it takes for a turbine to deliver enough clean energy to offset the pollution caused by its production – of less than one year; they cause virtually no pollution once operational; and they are so powerful that a single turbine can easily fuel about 940 average American homes per month.

But they can be greener. “Right now, to our knowledge, essentially no rare earth elements are being recycled from the wind,” Tyler Christoffel, technology manager at the Department of Energy’s Wind Energy Technologies Office, told Grist.

This is not a surprising statistic: Globally, it is estimated that less than one percent of rare earth elements, including substances such as cerium, lanthanum and neodymium, are recycled. But it’s not good news either: rare earth elements are, as their name suggests, quite difficult to find in usable quantities; About 70 percent of world production is in China, and that is increasingly the case.

Moreover, rare earth metals are only becoming more important. They are vital for everything from industrial applications to personal gadgets like your laptop or smartphone – and of course they are in wind turbines.

“When the blades of a wind turbine spin, they generate kinetic energy that a permanent magnet generator then converts into electricity from the interaction between two permanent magnets of reversed polarity,” wrote Kristin Vekasi, associate professor in the Department of Political Science and School of Science. Policy and international affairs at the University of Maine, in a 2022 article for Harvard’s Weatherhead Center for International Affairs.

“While other magnets could do the job, permanent magnets have a number of advantages, including greater efficiency, smaller size, fewer moving parts that can break, and no need for an external charge,” she explains. “The wind does all the work.”

In these magnets we find the rare earth metals – usually neodymium or samarium. They are extremely powerful – the most powerful magnets in existence at all – but they are not indestructible: they can lose their magnetism through overheating, corrosion, random shocks, or even a stray magnetic field here and there.

As such, “repowering” turbines – that is, replacing tired parts, upgrading components such as generators and, yes, replacing rare earth magnets – is a near-constant process. Facing a future where rare earths become increasingly scarce, the Ministry of Energy decided to outsource the problem: in mid-2023, they launched a competition aimed at finding robust recycling solutions for the single-use components of turbines.

Last month, the twenty winners of the first phase of the competition were announced, four of which focused specifically on magnet recycling. Teams from universities and industry have submitted a wide range of possible solutions, all based on pre-existing technologies that simply have not yet been widely exploited.

The “winning teams presented innovative technology ideas that exemplify the creative, problem-solving skills we need to build a highly sustainable wind turbine recycling industry,” said Jeff Marootian, Assistant Secretary for Energy Efficiency and Renewables energy, in a statement last month. “Additionally, these domestic recycling solutions increase our energy security by reducing the country’s dependence on foreign materials.”

Those teams are now in Phase 2 of the competition: developing a prototype demonstration of their idea, plus a plan to bring the technology to scale. If all goes well, resource recovery for wind turbines could help the US avoid a rare earth supply catastrophe within the next few decades.

As the country increasingly invests in wind energy – and other technology that relies on these elements continues to proliferate – rare earth recycling “will become a much more pressing issue,” Christoffel told Grist.

“What this award really helps is to promote some of these recycling technologies that can provide lower emissions and lower resource use [path] to a magnet,” he said.

[H/T Grist]

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