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.