Promoting future sustainable utilization of rare earth elements for efficient lighting technologies

Abstract

Energy efficient lights, such as fluorescent lamps (FLs) and light-emitting diode (LED) lamps, can greatly help energy saving, which is critical for achieving carbon neutrality in the building sector. Yttrium, europium, and terbium are three essential rare earth elements (REEs) for energy efficient lighting. However, due to the ongoing lighting technology transition from FLs to LED lamps, the demands for yttrium, europium, and terbium have decreased significantly. It resulted in oversupplies of these three REEs in the lighting sector, indicating an economically and environmentally unsustainable supply chain. This study aims to estimate the supply and demand dynamics of yttrium, europium, and terbium in China from 2021 to 2060 under China’s carbon neutrality target by applying a dynamic-material-flow-analysis framework. Key flows and stocks along their life cycles are examined. Results show that the annual demands for yttrium, europium, and terbium in China’s lighting sector will decrease by 87%–100% from 2021 to 2060 under two demand scenarios. Driven by the demands for other co-produced critical REEs, the overall growing REEs supply will result in high surplus risks of yttrium and europium. Meanwhile, terbium deficit risk deserves more attentions due to its demand growth in other fields. Such surpluses of these three REEs in 2060 under six combined demand and supply scenarios are estimated to reach between 71 727 tonnes and 274 869 tonnes for yttrium, 530 tonnes and 1712 tonnes for europium, and −1360 tonnes (i.e. deficit) and 540 tonnes for terbium. Recycling activities of major co-produced REEs, such as neodymium, and the export expansion of surplus products can effectively mitigate such surplus risks. Finally, policy recommendations are proposed to improve the overall REEs efficiency by addressing the supply–demand imbalance and mitigating corresponding environmental impacts.