美国能源部认定五种稀土元素和金属元素铟为清洁能源技术和供应风险最关键材料。在美国新近公布的长达171页的《危急材料战略》中,稀土元素镝、钕、铽、铕和钇被列入其中,说明稀土元素和其它材料在清洁能源经济中的作用。定义“关键”材料是根据在清洁经济中的重要性和材料供应链中断的风险因素综合考虑的。能源部官员称该 The United States Department of Energy identified five rare earth elements and indium metal elements as the most critical clean energy technology and supply risk materials. Among the recently announced 171-page Critical Material Strategy in the United States, rare earth elements such as dysprosium, neodymium, terbium, europium and yttrium are included to illustrate the role of rare earths and other materials in a clean energy economy. The definition of “key” materials is based on a combination of the importance of cleaning up the economy and the risk factors of material supply chain disruptions. Department of Energy officials said it