Developing an hourly-resolution well-to-wheel carbon dioxide emission inventory of electric vehicles

Vehicle electrification is reshaping global road transport, whereas the understanding of the well-to-wheel (WTW) CO₂ emissions of electric vehicles (EVs) is mostly limited to the annual average, ignoring short-term variation. This study developed a framework to quantify the heterogeneity in the WTW CO₂ emissions of EVs with different charging hours for multiple regions. The framework incorporates the consumption-based grid's CO₂ emission factor, dynamic EV fuel consumption rate, and different charging levels and EV types. A three-year hourly-resolution WTW CO₂ emission inventory of EVs was established for 71 regions across the contiguous United States. Results show that the EV's WTW CO₂ emissions vary by season, charging hour, region, and EV type; up to 26% of WTW CO₂ emissions could be reduced by shifting the current most common charging time. The study built a foundation inventory for policymakers to formulate daily smart charging schemes to minimize EV's WTW CO₂ emissions.