Forecasting life cycle CO₂ emissions of electrified vehicles by 2030 considering Japan’s energy mix

This paper presents a comprehensive life-cycle analysis of CO₂ (LCCO₂) emissions from automobiles using a hybrid life-cycle inventory approach to predict the growth of electrified vehicles in Japan. Herein, the hybrid electric vehicle (HEV), plug-in HEV (PHEV), and battery electric vehicle (BEV) versions of the mass-produced Toyota Prius hatchback are analyzed, considering the automobile-usage environment in Japan. In particular, a breakeven analysis of HEV vs. PHEV vs. BEV is conducted in terms of LCCO₂ emissions that are affected by (i) outside air temperature and (ii) CO₂ emissions during power generation from the present day up to 2030. Our results show that HEV has the lowest LCCO₂ emissions when the current thermal-power-dependent electricity generation mix (average for 2012–2014) is considered, followed in order by PHEV and BEV. However, it is predicted that in 2030, PHEV will have the lowest LCCO₂ emissions, followed in order by HEV and BEV, as it is anticipated that nuclear and renewable energy sources will be widely available by 2030. PHEV is expected to gain popularity by 2030. Regarding BEV, large quantities of CO₂ emissions are emitted during battery production. Furthermore, due to the domestic electricity generation mix from the present day up to 2030, the LCCO₂ emissions of BEV will exceed those of HEV and PHEV.