Carbon Reduction Potential of Private Electric Vehicles: Synergistic Effects of Grid Carbon Intensity, Driving Intensity, and Vehicle Efficiency

This study examines the annual carbon emission differences between privately owned electric vehicles (EVs) and internal combustion engine vehicles (ICEVs) through the development of a usage-phase life cycle assessment (LCA) model, with a focus on the synergistic effects of grid carbon intensity, driving intensity (e.g., annual mileage), and vehicle efficiency. Through scenario analyses and empirical case studies in four Chinese megacities, three key findings emerge: (1) Grid carbon intensity dominates EV emission advantages—EVs retain significant carbon reduction benefits in low-CEG regions even with doubled annual mileage, while high-energy-consuming EVs risk emission reversals in coal-dependent grids under intensive usage. (2) Higher annual mileage among EV owners (1.5–2 times ICEV baselines) accelerates carbon accumulation, particularly eroding per-kilometer emission advantages in fossil-fuel-reliant regions. (3) Vehicle energy efficiency heterogeneity is critical: compact, low-energy EVs (e.g., A0-class sedans/SUVs) maintain advantages across all scenarios, whereas high-energy models (e.g., C-class sedans/SUVs) may exceed ICEV emissions in high-CEG regions. The study proposes a differentiated policy framework emphasizing synergistic optimization of grid decarbonization, vehicle-class-specific management, and user behavior guidance to maximize EVs’ carbon reduction potential. These insights provide scientific foundations for refining EV adoption strategies and achieving sustainable transportation transitions.