The use of rare-earth materials as a key component in permanent magnet generators has raised concern around the world. China now controls approximately 97% of the rare-earth materials that are vital to clean-energy technology sources according to the U.S. Government Accountability Office. What will this do to the future supply of rare-earth materials used in PMGs? And how will China’s monopoly affect global pricing?
Although the term “rare-earth” has been selected to call a collection of 17 chemical elements in the periodic table, luckily they are relatively plentiful. In some cases, these “rare” metals are nearly as abundant as tin or lead. The reason they are determined to be “rare” results from their geochemical properties, making them rare to find in concentrated or easily exploitable forms.
“Rare-earth” magnets, then, are permanent magnets made from alloys of rare-earth elements. They were developed in the 1970s and 80s and are known to be the strongest form of permanent magnets today. They allow for relatively high temperatures and high remanence flux, both of which are essential properties for reliable wind turbine operation.
Numerous global conglomerates have been using rare-earth magnets in their applications for decades. Companies like the Japanese powerhouses TDK and Hitachi have employed them for use in their popular products such as automotive, home appliances, medical, information and communication, as well as industrial, including wind power generation.
The concern is not the fact that rare-earth materials are being used. Instead, it’s a question of how much the application requires. Traditional markets, such as disc drives, personal electronic devices and power tools require a few grams per unit. Hybrid and electric vehicles are growing rapidly in popularity. These, too, only require rare-earth materials in volumes of kilograms. PMG-based wind turbines, and in particular direct drive generators, devour a whopping metric ton per unit. In other words, every one direct-drive generator uses about as much rare-earth magnets as 3,000 clean-energy vehicles. And this is where the questions start.
