Every once in a while, an enterprising reporter turns up an intriguing story to the effect that wind energy, supposedly a domestic energy source, “depends” on permanent-magnet alternators which contain a rare-earth mineral (neodymium) that must be imported from China. Holy moley! (Or, in this case, Moly, as will be explained below.) Are we unwittingly creating a whole new problem of energy dependence?
Well, no.
Right off the bat, the first important fact is that virtually none of the utility-scale wind turbines installed in the U.S. today use “direct drive,” in which the rotor is directly linked to a permanent-magnet alternator. Instead, they use gearboxes between the rotor and generator which connect the slow-rotating rotor shaft and step up the rotational speed to the level needed to drive the generator (though some designs with gearboxes also utilize permanent magnets in their generators).
Next, the U.S. does have a domestic supply of neodymium and other rare-earth materials in California. Some years ago, rare-earth magnets were actually manufactured domestically, by a company in Indiana. Here, the plot thickens--a Chinese company bought the firm in Indiana, then pulled out of the U.S., leaving behind an empty building.
Molycorp, which owns the California mine, has been busy educating the Federal government about the importance of cultivating the domestic supply chain for wind and other clean energy technologies that rely on rare earths--and in fact, pending legislation in both the House and Senate, it says, would support rebuilding domestic magnet manufacturing capacity and leading the world in efficient mineral use and recycling technologies. Meantime, Molycorp has also signed a joint venture with Arnold Magnetic Technologies Corp. aimed at ramping up manufacturing in the U.S.
So to sum up:
• The U.S. utility-scale wind industry uses a negligible amount of permanent magnets at present.
• The U.S. does have a domestic supply of the raw materials needed to make permanent magnets, and a private business deal is in the works to resume domestic manufacturing.
• If the global wind industry were to move to direct-drive technology in the future and require more permanent magnets, the technological capability to do without them would still exist if doing so became a strategic necessity. (Additional info added 8/1/09: An article in Magnetics Business & Technology by Tony Morcos of Morcos Magnetics explores this issue further, positing that a number of permanent-magnet and control system design choices exist for wind turbines. Thanks to Gareth Hatch at Terra Magnetica for the pointer.)
For more background on materials and manufacturing requirements to dramatically expand U.S. wind power, see the “Manufacturing, Materials, and Resources” chapter of the U.S. Department of Energy’s 20% Wind Energy by 2030 Technical Report. |
