City-Level Potential of Echelon Utilization of Electric Vehicle Batteries to Meet Wind and Solar Storage Demand in China

The rapid expansion of wind and photovoltaic power is intensifying demand for large-scale electricity storage, while the transition to electric vehicles (EVs) is accelerating consumption of critical materials. Retired EV batteries are increasingly considered for echelon utilization in stationary energy storage, yet their long-term system-level potential remains poorly quantified, particularly at fine spatial resolution. Here we develop an integrated, city-level modeling framework that couples vehicle stock projections, climate-sensitive battery degradation modeling, renewable energy storage demand estimation, and dynamic material flow analysis to assess the role of echelon utilization of retired EV batteries in China from 2010 to 2060. We show that under conservative EV penetration pathways, second-life batteries remain insufficient to meet renewable storage demand. Yet, under a high electrification scenario aligned with China's decarbonization goals, echelon-utilized batteries can fully satisfy national wind and solar storage requirements by the mid-2040s, despite persistent regional disparities. Large-scale echelon utilization substantially reduces cumulative demand for critical materials, lowering lithium and cobalt consumption by more than 50% compared with reliance on new batteries alone. These results demonstrate that reuse of EV batteries can enable renewable energy integration while enhancing resource security, underscoring the importance of coordinating transport electrification, energy storage deployment, and circular economy strategies.