Limits to growth not only apply to Fossil Fuels but also includes rare earth metals, according to researches at MIT. Rare Earth metals such as Neodymium and Dysprosium are in very strong demand due to their use in electricity generation (wind turbines) and electric cars. The main source of these minerals is China; which produces around 98% of all the worlds rare Earth metals. Researchers suggest that in the coming decades these resources will be become scarce and expensive, making alternatives energy less and less competitive. A double edged sword for renewewables.
Excerpt from article:
As the world moves toward greater use of zero- carbon energy sources, the supply of certain key metals needed for such clean-energy technologies may dry up, inflating per unit costs and driving the renewable energy market out of business. We’ve talked about peak phosphorus for food; now consider that rare earth metals like neodymium which are used in magnets to help drive wind energy turbines, and dysprosium needed for electric car performance are becoming less available on the planet.