Rare earth elements (REE) include the 17 elements on the periodic table of chemical elements. Industrial demand for these elements is small in terms of volume but they are essential for a wide and growing array of green technology and security uses. REEs are important parts of defense technologies such as radar and sonar systems precision-guided weapons cruise missiles and lasers for example. They are also especially critical for the expanding energy efficiency and renewable energy industries. Lanthanum for example is used in batteries for hybrid cars. Other REEs are used in magnets for electric generators in wind turbines and in coloured phosphors for energy-efficient lighting (Long and others 2010). Today clean energy technologies account for about 20 per cent of global REE consumption but as the demand for them increases their share of critical rare earth minerals is likely to grow (US DoE 2010).