Emission implications of electric vehicles in Japan considering energy structure transition and penetration uncertainty
Vehicle electrification represents a promising solution to address the challenges of energy security and sustainable mobility. The environmental performance of electric vehicles is heavily dependent on the energy structure which is undergoing a profound transition. Moreover, the deployment of electric vehicles is critically affected by policies. On the other hand, issues pertaining to reactive nitrogen have emerged as one of the most pressing environmental challenges. However, existing studies usually target the climate change mitigation effects of electric vehicles. In this context, this study investigated the mitigation effects of electric vehicles in Japan on climate change and reactive nitrogen losses considering energy structure transition and penetration uncertainty.
The vehicle stock was calculated by using a dynamic material flow analysis model. On this basis, emissions were quantified by employing life cycle inventory database and various vehicle life cycle parameters considering different energy sources. It was found that the electricity mix transition due to phasing down fossil fuel use and promoting renewable and nuclear energy is effective for climate change mitigation. The same is true for using ammonia as an energy carrier. The results also indicated that the two aforementioned routes could simultaneously lead to reactive nitrogen emission mitigation, as shown in Figure 1. On the other hand, a noteworthy distinction was identified between the two routes. For the energy source which increased renewable and nuclear energy use, a considerable reduction of reactive nitrogen emissions was achieved with relatively lower reduction on greenhouse gas emissions. On the contrary, a considerable reduction of greenhouse gas emissions was achieved with relatively less reduction of reactive nitrogen emissions for the energy source using ammonia as an energy carrier.
Figure 1. The carbon and nitrogen footprints of electric vehicles in Japan.
Firstly, this study analyzed mitigations on both climate and reactive nitrogen simultaneously, which are helpful for formulating a more optimized solution for tackling environmental challenges. Secondly, the zero-tailpipe emissions argument is only a portion of the whole picture depicting the environmental performance of electric vehicles. This study identified the increasing need of a systematic perspective for the evaluation. Finally, the energy structure is undergoing a profound transition, indicating a diversified energy portfolio in future. The results shed new lights on the next generation vehicle deployment and energy strategy planning.
※ Xue M, Lin B, Tsunemi K. Emission implications of electric vehicles in Japan considering energy structure transition and penetration uncertainty. Journal of cleaner production, 2021, 280: 124402.