Rare earths are a group of 17 elements with chemical properties that make them useful for a range of high-tech applications. Because of geological good fortune and early manufacturing investments, today China dominates the rare earth supply chain, producing more than half of the world’s raw rare earths and over 90 percent of the powerful rare earth magnets used in consumer electronics, electric vehicle motors, and offshore wind turbine generators. While the magnets inside smartphones might weigh a couple of grams, those inside wind turbines can tip the scales at several tons. Given the industry’s large and fast-growing rare earth needs, European and U.S. wind companies are anxious to secure future supplies — as well as suppliers in countries that have better relationships with the West.

Wind turbines are essentially steel towers topped with long, propellor-like blades. As the wind blows, those blades twirl around a rotor hub, which spins a generator to produce electricity. Most land-based turbines use an electromagnetic generator, in which copper coils rotate through a magnetic field to produce electricity. But another option, popular in offshore wind, is a permanent magnet generator, which contains an enormous ring of brick-shaped rare earth magnets that spin with the rotor to produce electricity.

Permanent magnet generators have one big drawback, though: They need a lot of rare earths. A large direct drive offshore wind turbine equipped with one of these generators can contain upwards of 5 tons of magnets, according to Alla Kolesnikova, the data and analytics lead for the critical minerals research firm Adamas Intelligence. While rare earths only represent about 30 percent of the weight of these magnets, that can still add up to hundreds of pounds of the rare earth metal neodymium — and often, smaller amounts of the heavy rare earths dysprosium and terbium — per megawatt of electricity produced.

Limited supplies of rare earths are one concern for the wind industry. Another is the reality that nearly all rare earth processing and magnet-making takes place in China today. Daan de Jonge, a rare earth analyst at the research firm Benchmark Mineral Intelligence, said that rare earth-reliant industries are increasingly concerned about how “tensions between the U.S. and China” could impact future supplies.

Read the full article about climate and energy by Maddie Stone at Grist.