Read here and here. The problem of rare earth supply is one even shared by China's own wind turbine manufacturers. The prices have risen so sharply that production of high demand wind turbines has to be curtailed to the detriment of Chinese producers and international turbine customers.
With the massive government subsidization of renewable energy projects, the supply of rare earth production has tightened, and has become especially acute since China production represents 95% of the world's supply. Despite this known death grip on supply, the Obama administration and other western countries have done little to solve the China problem.
"The result, according to US analysts, is that the rest of the world has sleepwalked into the parlous situation it now finds itself in. 'We all know the ball has been dropped in this [rare earths] space and not only by the US but by a whole swath of Western economies,'...The GAO report estimated it could take 15 years for the West to catch up with China and develop alternative supplies...a senior metallurgist at the US Department of Energy's Ames Laboratory, has been studying rare-earth materials since the 1960s. 'There is nearly zero rare-earths mining, processing and research going on now in the US,'...Officials in the US, Japan and Europe are now debating whether to lodge a complaint with the World Trade Organisation over China's export quotas on rare earths. Their concern is that China will have an unfair price advantage as it builds up a green-tech industry that it wants to export all over the world."