Effects of electric vehicles (EV) on environmental loads with consideration of regional differences of electric power generation and charging characteristic of EV users in Japan

In order to evaluate the reduction effect of electric vehicles (EVs) on various atmospheric environmental loads, we have performed a life-cycle inventory analysis (LCI), including the installation of charging stations and regional, seasonal and temporal difference of the energy mix of electricity generation. For an EV converted from a small gasoline vehicle, a regional LCI analysis was carried out in the following steps: (1) location of the charging stations, (2) modeling of charging characteristics of station users, (3) calculation of temporal life-cycle emission intensities of CO2, NOx and SOx by region, season and day. Assuming that total traveling distance is 100,000 km, the electricity consumption rate is 0.119 kWh/km and the charging/discharging efficiency is 70%, the average life-cycle emission of CO2 for that EV was 3.6 t-C throughout Japan. However, if we took regional difference into account, the emission ranged over 70–160% of the average amount. It was revealed that the regional difference of the primary energy mix significantly affected the emissions of EVs during the operation phase.