Sustainability impacts of the dynamic interaction between vehicle electrification and lightweighting

Electrification of automobiles is a crucial step towards achieving net-zero emission targets. This transition, combined with the ongoing trend of lightweighting in the automotive industry, is altering the material composition not only of batteries but also of entire vehicle structures. While the emission reduction benefits of electric vehicles during their use phase are well-documented, the impact of these material and design changes on the overall life cycle environmental performance remains unclear in the fleet level. This paper investigates the interaction between powertrain electrification and vehicle body lightweighting through a System Dynamics model, and their implications on material availability and the energy footprint of the material supply in the U.S.. We find that battery electric vehicles will see an increase in aluminium use in body manufacturing in the short term in support of increased driving range, while potentially reverting to steel-intensive body designs in the longer term as battery technology improves. These changes in material use result in fluctuations in the recycled content and therefore the primary energy demand of the aluminium supply, impacting the life cycle energy and carbon footprint of the automotive industry and beyond. This study stresses the need for dynamic life cycle assessment to analyse the sustainability impacts of these trends and offer insights into managing material selections in the electrification era to improve overall life cycle sustainability performance.