Decarbonization potential of Chinese PHEVs: Impact of increased battery range, power mix, and usage patterns

Climate change mitigation requires profound decarbonization of the transportation sector. As a transitional technology bridging internal combustion engine vehicles (ICEVs) and battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs) play a crucial role. This study evaluates the life-cycle CO2 emissions of PHEVs in China from 2015 to 2022, with particular focus on key factors of increased battery range, decarbonization of the power mix, and variations in electric utility factors. During the study period, PHEV battery capacity demonstrated significant growth: from 10.3–14.2 kWh to 13–20 kWh for short-range models, while long-range models with 30–40 kWh batteries emerged. Our analysis reveals that while larger battery capacities increase production-related emissions, they enhance the regulatory UF, thereby reducing well-to-wheel (WTW) CO2 emissions. For typical Chinese PHEV models (50–220 km AER in 2022), cradle-to-grave (C2G) CO2 emissions showed limited sensitivity to AER variations (<5 gCO2/km). However, the gap between regulatory and real-world UF, primarily driven by charging behavior, can significantly impact decarbonization outcomes (15–25 gCO2/km). Notably, PHEVs demonstrated a 40–50 gCO2/km reduction in C2G missions compared to ICEVs, while maintaining a 30–40 gCO2/km gap relative to BEVs currently. With further improvement in efficiency, UF increases, material and grid decarbonization, PHEVs are estimated to achieve ∼110 gCO2/km C2G missions by 2030. These findings emphasize the need for optimizing charging infrastructure and policy adjustments to align with user behavior, thereby maximizing the decarbonization potential of PHEVs.