Fig. 3. System boundary of life cycle assessment for both battery electric vehicles (BEVs) and internal combustion engine vehicles (ICEVs) in this study.

The life cycle system boundary evaluated in this study includes the vehicle cycle and fuel cycle of passenger vehicles. The vehicle cycle starts with raw material acquisition, then moves to material processing and manufacturing, complete vehicle production, and maintenance (tire, lead battery, and fluid replacement). The fuel cycle refers to “Well to Wheels (WTW)”, including the production of fuel (Well to Pump/WTP) and the use of energy (Pump to Wheels/PTW). For BEVs, the fuel terminology is used in a conventional sense, referring to electricity production, transmission, and use.