A rectangle of dull gray metal sits inside the core of a retired wind turbine generator in Boone, Iowa.
It looks like scrap.
It is the most rare earth rich piece of metal in the whole machine.
For years, the number everyone repeats about wind turbines is that they are overwhelmingly recyclable once they come down.
That number is true, and it is also hiding something.
Inside the part of the turbine nobody opens lies the question the rest of this story has to answer.
What the 85 percent figure actually counts, and what it leaves out
The widely cited claim is that roughly 85 percent of a turbine’s materials, mainly steel, copper wire, electronics and gearing, can be recycled or reused once a machine is retired. Federal officials describe the same picture from the other direction.
A technology manager at the Department of Energy’s wind energy technologies office has said that about 90% of the turbine, mostly the parts made of steel and concrete, has an established recycling process, while rare earth materials sit in the 10% to 15% of turbine materials that are not currently recycled.
The catch is that the figure describes recyclable by weight, and weight is exactly where the trick lives. A ton of plain steel tower counts the same as a pound of magnet, even though the magnet is far harder to replace. Tucked inside the generator of many modern turbines, especially the direct drive machines favored offshore, are magnets built from neodymium and other rare earth elements.
The scale is not trivial. Magnets inside wind turbines can weigh several tons, and while rare earths make up only about 30 percent of that weight, it still adds up to hundreds of pounds of neodymium, plus smaller amounts of dysprosium and terbium, per megawatt of capacity. The 85 percent is real. It simply was never built to flag the one component that is small by weight and nearly impossible to source any other way.
Why magnets are the hardest ounce of a turbine to recover
Steel and copper have scrap markets that have existed for a century. Rare earth magnets do not. Most spent turbine magnets end up in landfills, and it is estimated that less than 1 percent of rare earths are recycled globally, from wind turbines, dead hard drives and everything else.
That gap is less neglect than timing. The DOE wind office manager quoted above told the nonprofit outlet Grist that “Right now, to our understanding, essentially no rare-earth elements from wind are recycled,” pointing to immature recycling technology, the economics of scaling new processes, and the limited quantity of spent magnets available today.
Supply is already trickling out, though. Every year, hundreds to thousands of megawatts’ worth of US turbines are refreshed, with rotors, blades and generators swapped out, and the replaced components sometimes include magnets made with rare earth elements. As the onshore fleet is repowered and offshore projects multiply, that trickle grows.
The Iowa shop pulling magnets out by hand
That is the problem a small company outside Des Moines is trying to get ahead of. At Critical Materials Recycling in Boone, engineers break apart circuit boards, old transmissions and decommissioned wind turbines to extract rare earth materials.
The company was a prize winner among six teams honored by the Department of Energy’s Wind Turbine Materials Recycling competition. Each team received a $500,000 cash prize plus $100,000 in vouchers to work with DOE national laboratories.
The full $5.1 million prize is administered by the National Renewable Energy Laboratory and funded by the Infrastructure Investment and Jobs Act. Instead of dissolving everything in strong acid, the company uses a process developed with Ames National Laboratory.
The acid free dissolution route produces little to no waste, saves more of the metal components and does not expose technicians to dangerous acids. Bigger items, such as a car transmission or a wind turbine generator, have to be taken apart before they can go through it.
What comes out the other end of the tank
Once a magnet is freed from its housing, the Boone process uses a liquid solution rather than furnace or acid methods. Shredded feedstock goes into a machine like a rock tumbler with a copper salt that selectively dissolves the rare earth materials and pulls them into solution, a selective step not unlike the recovery work being done on retired solar panels for their silver.
The prize is the concentration. A DOE supply chain assessment notes that roughly 93% of the NdFeB magnet market is sintered magnets, which are composed of about 30% rare earth material, 69% iron and 1% boron by weight. Mined low grade rare earth minerals typically run around 1% by weight.
Some of what comes out skips the chemistry entirely. Certain magnets can be recut and used again in various components, a shortcut that removes a whole processing step.
The clock that is about to start running
None of this is solved, and the people closest to it say so. The volume of spent magnets reaching any recycler is still small, which is exactly why the real test is still ahead.
That test arrives on a schedule nobody can postpone. Repowering strips generators out of working wind farms every year, and offshore machines begin to multiply along the coasts.
Much the same shift is already playing out with fiberglass, where retired blades get ground up for concrete instead of buried whole. The recyclable share will likely climb as magnet recovery matures, not because the old number was wrong, but because that last 10 to 15 percent was always going to take the longest.
For now, in a workshop in Boone, the gray rectangles are still being pried out one generator at a time.
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