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Green energy today relies on multiple advanced technologies like solar cells, hybrid gas-electric motors, compact fluorescent light bulbs, and giant wind turbines. Once deployed, these devices allow people to minimize their environmental impact by reducing their dependence on conventional natural resources such as coal and oil. I strongly support green energy development, as I'm sure many people do, and I look forward to when all the world's power sources are ecologically responsible. My belief in the potential of green energy has always been based on the premise that these alternatives were sustainable, as clean resources such as wind and sunlight seem to be unlimited.
In fact, I've never really thought about the supply chain of materials involved in the manufacture of these products until I read a recent report by the American Physical Society (APS) and the Materials Research Society (MRS) about that topic. Apparently all of the innovations I mentioned earlier, as well as countless other green technologies, are made with components constructed from a set of minerals known as the rare earth elements. In their report, APS and MRS scientists assert that green energy growth depends on the availability of these materials, but as one country currently produces almost all of the world's supply, the rare earth elements unfortunately live up to their name.
The first rare earth metal was discovered in a quarry near Ytterby, Sweden, in 1787. This element was named yttrium once its purified form was isolated in 1828, and now sixteen others have been added to the set with names like promethium, thulium, and neodymium. The oil refining and glass manufacturing industries were the first to use rare earth minerals commercially, but other applications were explored in the early 1900s. During the 1960s, after television screen researchers discovered that one named europium could depict the color red, large-scale mining of the metals began.1
Rare earth mines emerged in South Africa, India, and Brazil, but from the 1960s to the 1980s, the greatest producer was a mine in Mountain Pass, California. Its position changed in the 1980s, however, when China accelerated its rare earth production and undercut global prices. Because of this financial pressure, mines around the world began closing in the 1990s, with the Mountain Pass mine shutting down in 2002. Consequently, China is currently the world's largest producer of rare earth elements by an extreme margin, providing between 95% to 97% of the world's total supply from its mines in Inner Mongolia.2
In addition to green technologies, rare earth metals are found in devices as diverse as smart phones, loudspeakers, magnets, medical imaging equipment, and guided missiles. In this way, it seems that environmentalists, commercial industrialists, and military leaders would all have a stake in gaining increased access to rare earth elements. The Chinese government nonetheless has continually reduced its export quotas: in December 2010, its commerce ministry announced that for 2011, it would award 14,446 tons of rare earth metals to domestic and foreign-owned companies, which is a 35% drop from its quota of 22,282 tons the prior year.3
Considering that economists estimate world consumption of rare earth minerals outside of China to be about 55,000 tons a year, the current quota hardly seems sufficient. Many specialists expect that China will release a supplemental allocation this summer, as it has done in the past, but it seems to me that more countries should begin exploring domestic production of rare earth metals. China has already used the minerals for leverage during diplomatic negotiations with Japan over a territorial dispute,4 and I think green energy is too important to depend on politics. Current assessments of Chinese mines show that they contain only 37% of the world's proven supply.5 Exploring untapped sources could alleviate commodity shortages; the US Geological Survey (USGS), for example, released a study in 2010 maintaining that the US contains 13 million tons of unmined rare earth metals.6
What I think is critical is not only that these resources be developed, but also that this expansion is conducted sustainably. Rare earth mining can be harmful to the environment,7 as the acids that are used to retrieve the metals can create toxic by-products, but better ways do exist and China seems interested in pursuing these methods.8 The Mountain Pass mine in California is actually on track to re-open in 2012, and the company that owns it, Molycorp Minerals, has committed itself to running "a cleaner operation."9 As rare earth mining progresses and the world enters a new power paradigm, I hope that everyone involved similarly seizes the opportunity to make green energy sustainable at every point of its process.
Image credit: US Department of Agriculture
This image shows seven samples of rare earth minerals, clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium and gadolinium.
1. Jones, A.P., Wall, F., & Williams, C.T., eds. Rare Earth Minerals: Chemistry, Origin, and Ore Deposits. London: Chapman & Hall, 1996.
2. Kay, K. & Pederson, C. "Rare Earth Minerals' Scarcity Worrisome for Growing Tech Sector." PBS NewsHour. June 14 2010.
3. Bradsher, K. "China to Tighten Limits on Rare Earth Exports." The New York Times. December 28, 2010.
4. Gelineau, K., Yuasa, S., Zhang, C. "Traders: China Halts Rare Earth Exports to Japan." The Boston Globe. September 23, 2010.
5. Bradsher, K. "After China's Rare Earth Embargo, a New Calculus." The New York Times. October 29, 2010.
6. Long, K., Van Gosen, B., Johnson, K. "Rare Earth Elements in U.S. Not So Rare: Significant Deposits Found in 14 States." US Geological Survey, Department of the Interior. November 17, 2010.
7. Parry, S. and Douglas, E. "In China, the True Cost of Britain's Clean, Green Wind Power Experiment: Pollution on a Disastrous Scale." The Daily Mail. January 29, 2011.
8. Areddy, J.T. "China Cites Pollution in Tightening Rare-Earth Exports." The Wall Street Journal. November 15, 2010.
9. Jaffe, I. "California Challenges China In Rare Earths Mining." US National Public Radio. January 31, 2011.
http://www.nytimes.com/2010/06/27/opinion/27kristof.html?_r=1