Global hidden material flows triggered by China’s vehicle supply chain far exceed eventual material use
Binze Wang, Qiance Liu, Xin Ouyang, Wu Chen, Zhengyang Zhang, Gang Liu, Kazuyo Matsubae
Abstract
Electric mobility (e-mobility) transition is vital for reducing greenhouse gas emissions but increases demand for minerals and results in substantial ‘hidden flows’—mined materials but unused, such as overburden, waste rock, and tailings—which remain underexamined compared to battery materials. Here, we develop a global mine-site-specific database and a supply-chain-based framework to quantify the total material requirement (TMR) of passenger car supply chain, using China, the world’s largest producer and consumer for new energy vehicle (NEV), as an example. We find that an NEV generates over three times the hidden flows of a conventional vehicle. These hidden flows exceed the eventual used resources by 35 times, with only 3% of the extracted materials entering the car sector. Notably, 48% of these hidden flows occur outside manufacturing countries, highlighting the global environmental burden of China’s e-mobility transition. Our findings provide insights for balancing greenhouse gas emissions reduction with other environmental sustainability issues in the shift to e-mobility. Binze Wang and colleagues reveal that hidden flows (overburden, waste rock, and tailings) in China’s car supply chain are 35 times greater than the final material use, with about half originating from overseas sources.