This report examines the role that rare earth metals and other key materials play in clean energy technologies such as wind turbines, electric vehicles, solar cells and energy-efficient lighting. The report found that several clean energy technologies use materials at risk of supply disruptions in the short term, with risks generally decreasing in the medium and long terms. Supply challenges for five rare earth metals (dysprosium, neodymium, terbium, europium and yttrium) may affect clean energy technology deployment in the years ahead.