The allegation is frequently made in newspaper articles that permanent magnets, and by extension, rare earths, are critical to the manufacture of wind turbines. Since China is the leading world producer of rare earth ores, and since it is beginning to restrict production for its own internal manufacturing use, the question arises as to whether more wind energy means setting up a dependence on China for rare earths similar to U.S. dependence on oil imports.
My previous post ended with this summary:
"[1] The U.S. utility-scale wind power industry uses a negligible amount of permanent magnets at present.
"[2] 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.
"[3] If the global wind power 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."
In the year and a half since that post, things have changed. I’ll stick with #1 and #3, but there is some good news to report on #2: Molycorp, the U.S. company that was planning to resume domestic rare-earth production at its mine at Mountain Pass, California, has resumed active mining and is building out the downstream manufacturing capabilities to produce rare earth metals and magnets in the U.S. According to information presented recently to AWEA staff, the company is now executing plans to dramatically increase output from the mine, from a current level of 3,000-5,000 metric tons per year to 20,000 metric tons per year by the end of 2012 and as much as 40,000 metric tons/year by 2013. That would be a major addition in a global market where demand for rare-earth oxides is currently 125,000 metric tons/year.
On the environmental front (rare-earth mines in China are notorious for releasing toxic materials into the nearby countryside), there is good news as well. Molycorp, which had environmental challenges of its own in the late 90s, said it has re-engineered its process in a variety of ways that emphasize energy and resource efficiency and environmental stewardship. Its new processes will feature full recycling of its waste water, the ability to produce the same amount of usable rare earth material from half the amount of ore (effectively doubling the life of the ore body and cutting the physical footprint in half), and a dramatic reduction in the use of fresh feed water, among other advances.
As Molycorp outlined to AWEA, these efficiency improvements have enabled the company to produce rare-earth oxides at half the cost of its Chinese competitors.
While AWEA has never felt that wind energy’s use of rare-earth magnets would give rise to a critical national dependence or pose a serious obstacle to the wind industry’s expansion, it’s great to know that a low-cost domestic option for the supply of rare-earth materials – from oxides to metals and magnets – exists and is under active development. Molycorp’s advances will add to the array of choices available to wind turbine designers and manufacturers, ultimately helping to keep this clean energy source affordable and homegrown.
Those Pesky Magnets
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.
By Tom Gray, www.awea.org/
