Material efficiency strategies across the industrial chain to secure indium availability for global carbon neutrality

A global energy transition toward carbon neutrality system requires increased critical metals, and the availability of critical byproduct metals raises concerns due to their dependence on host metals. To ensure the supply security of critical byproduct metals, material efficiency (ME) strategies are needed. Taking indium as an example, this paper explores the indium availability for global energy transition goals, and then illustrates the effects of ME strategies on securing indium availability throughout the whole industry chain. The system dynamics model serves to understand the joint production mechanism of zinc-indium and the nexus between energy transition and indium demand. Results show that the indium supply shortage for global energy transition could be intensified due to a less zinc-intensive economy. To address this challenge, focusing on indium demand reduction is more effective than emphasizing expanding indium supply for global sustainable development goals and material content reduction is the most promising strategy among the five ME strategies. Whereas, eliminating the concerns of indium availability thoroughly for facilitating a carbon neutrality transition requires coordinated ME strategies both from supply-side and demand-side. Moreover, the proposed analysis framework of ME strategies for securing indium availability for energy transition could also be applied for other byproduct metals.