The US Dept. of Energy released a major report on supplies of 16 minerals critical for new technologies including "wind turbines, electric vehicles, photovoltaic cells and fluorescent lighting." The report also warned that mining and metal processing expertise "has gradually declined in countries of the Organization for Economic Co-operation and Development, although the need to develop and retain such expertise has received increasing attention in recent years." I tried to download the report and summary from multiple computers without success - error messages say the files are corrupted. But Mineweb.com published a lengthy summary of it.
Mineweb says "five rare earths metals-dysprosium, terbium, europium, neodymium and yttrium-are at risk in the short term, potentially impacting clean energy technology deployment in the years ahead." [Right, figure credit, Physorg.com]
The DOE report calls for a 3-pronged strategy to resolve the potential supply crunch: 1. "facilitate extraction, processing and manufacturing here in the United States, as well as encouraging other nations to expedite alternative supplies;" 2. develop substitutes; and 3. recycling, reuse and more efficient use could reduce global demand.
Rare earth elements (REEs) exist in Arizona, but generally not in concentrations high enough to make their mining economically viable. The DOE report notes that developing a new mine from scratch could run around $1 billion, with most of that investment upfront before any production would begin.