Climate and air quality co-benefits of electric vehicle fleet lightweighting. A modelling assessment

Electrification of the vehicle fleet is a key strategy for decarbonizing transportation. However, electric vehicles (EVs) typically have higher weight than traditional vehicles, resulting in increased energy consumption, diminished driving range, and raised non-exhaust emissions. This study presents a modelling framework to assess the benefits of EV fleet lightweighting on driving range, greenhouse gas emissions, and air quality. The framework integrates a longitudinal vehicle dynamics simulation tool (TEST) and an integrated assessment model (MAQ). TEST determines the energy consumption, the traditional hydraulic braking system energy, and the maximum driving range as a function of the vehicle's weight. MAQ estimates the reduction of greenhouse gases (including carbon dioxide) and particulate matter emissions, and the impact on PM2.5 and NO2 concentrations of different scenarios defined by assuming a fleet with 10 % and 25 % of electric vehicles. The study focuses on the Po Valley, a vast area in northern Italy characterized by some of the highest levels of air pollution in Europe. Results show that increasing the fleet electrification from 10 % to 25 % without altering the average vehicle's mass reduces the NO2 levels in urban areas by up to 9.3 %, but increases non-exhaust emissions, with possible local negative impact on PM2.5 levels if the energy production is supplied by natural gas. When combined with vehicle lightweighting, electrification yields consistent benefits, including improved driving range, PM2.5 concentration reduction up to 3 % in major and most populated cities, and CO2 emissions decrease by up to 3 %. The framework provides a methodology for evaluating the environmental trade-offs of EV diffusion at the regional scale and the role of EV weight for maximizing the co-benefits on the environment.