Changing role of battery electric vehicle charging strategies in decarbonizing Japanese power systems

Integrating variable renewable energy (VRE) and battery electric vehicles (BEVs) is expected to be a climate change mitigation measure. The role of BEV charging strategies in climate change mitigation should be evaluated considering the variety of power generation mixes since decarbonization pathways consistent with climate goals are diverse. This study assessed the robustness of BEV charging strategies using a detailed time-resolved power system model under diverse Japanese decarbonization pathways derived from a long-term energy system planning model. The results underscore the critical role of integrating BEVs and VRE, consistent across various decarbonization pathways, toward 2050. The main contribution of charging strategies will change from reducing CO2 emissions by supporting the efficient operation of thermal power generations in 2030 to reducing production costs by avoiding using expensive synthetic fuels in 2050. Bi-directional controlled charging (V2G) integrated with solar power will reduce production costs by approximately 5.1–23.7-fold from 2030 to 2050. The contribution of individual BEVs due to V2G will not necessarily decrease by 2050 despite concerns that their value will become saturated due to their mass adoption. The results have useful implications for policymakers and stakeholders in Japan and other countries with decarbonization pathways, high solar shares, and synthetic fuel costs.