Incorporating critical material cycles into metal-energy nexus of China's 2050 renewable transition

Renewables rely heavily on critical materials. Such material (metal)-energy nexus thinking is critical to guarantee global renewable transition. As the largest energy consumer, China aims to promote the unprecedented installation of renewables to significantly decarbonize energy system till 2050. However, the material constraints to those renewable targets have been widely neglected by current stakeholders in China. In this paper, a quantitative framework is proposed to identify and quantify the corresponding material constraints on energy transition from a material cycle perspective. Accordingly, the required critical material demand for China's 2050 renewable transition and its flow, loss, and stock along the life cycle are quantified. It is found that the critical materials (i.e. Cadmium, Tellurium, Indium, Gallium, Selenium, and Germanium) required by solar power in China are all under high shortage and supply risk. Their cumulative demand from 2015 to 2050 will exceeded the present national reserve by 1.4-123-fold. Approximately 804-1056 thousand tons (kt) of Neodymium and 66-85 kt of Dysprosium are required to support the growth of wind power, which account for around 10% with the current reserve in China. Nevertheless, the limited scalability of rare earth production in China may still constrain wind power development. Hence, China should adjust its renewable pathways (e.g. more wind, less solar) based on the critical mineral endowment. Furthermore, recycling is preferred but has limited impact on material criticality mitigation before 2030, and it is then suggested more actions should be made on the international trade and material efficiency improvement along the life cycle to support future renewable needs.