Impact assessment of electric vehicles as curtailment mitigating mobile storage in high PV penetration grid

Abstract

Electric vehicles are seen as a potential solution in reducing the fossil fuel dependence of the transport sector and could also serve as secondary storage for renewable energy. This study aims to clarify the role of EV in managing curtailment in electricity grid with high PV penetration. An energy balance analysis was conducted to assess the impact of various EV adoption rates and PV capacity growth rates on curtailment throughout a 10-year planning period. Results show that EV as mobile storage has a significant impact in reducing curtailment. In the case of Kyushu, Japan, the analysis showed that 20 GWh was sufficient by 2031. It will require 300,000 to 570,000 electric vehicles as mobile storage to reach this capacity, depending on the combinations of EV classes used. Additional capacity will only benefit spring and autumn, which does not merit an increased target due to the low capacity factor. Following the logistics growth model, the current adaption rate is insufficient to reach target volume, and external support will be necessary. EV as mobile storage can keep the curtailment to around 10%–15% but has less impact initially; thus, stalling the additional capacity until sufficient EV capacity is available might be necessary to keep the curtailment below 10%. Overall, EV as secondary storage is ideal for regions experiencing PV curtailment, and cars are only used for specific activities.