The environmental impact of battery electric vehicles (BEVs), which are an integral part of climate change mitigation measures, depends on charging strategies, such as uncontrolled charging, controlled charging (V1G), and discharging (V2G). However, the impact is unclear because power system operation involves the cost of carbon dioxide (CO) emissions and flexibility requirements for imbalances caused by renewable energies. To clarify the robustness of the environmental impact of BEVs, we assessed the interactions between CO prices and flexibility requirements in Japan in 2030 using a production cost model. The results showed that uncontrolled charging increases CO emissions, whereas V1G or V2G reduces them. Further, the impact of BEVs was non-monotonic with respect to CO prices, implying that policymakers should carefully evaluate CO prices to achieve decarbonization as BEVs do not always reduce CO emissions. This study provides useful insights for policymakers in countries with low-cost, inflexible, and high-emission power plants.

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BEV 总是有助于减少二氧化碳排放吗？收费策略的影响

纯电动汽车 (BEV) 是减缓气候变化措施的重要组成部分，其对环境的影响取决于充电策略，例如非受控充电、受控充电 (V1G) 和放电 (V2G)。然而，影响尚不清楚，因为电力系统运行涉及二氧化碳（CO）排放的成本以及可再生能源造成的不平衡的灵活性要求。为了阐明纯电动汽车对环境影响的稳健性，我们使用生产成本模型评估了 2030 年日本二氧化碳价格与灵活性要求之间的相互作用。结果表明，不受控制的充电会增加二氧化碳排放，而 V1G 或 V2G 则会减少二氧化碳排放。此外，纯电动汽车对二氧化碳价格的影响是非单调的，这意味着政策制定者应仔细评估二氧化碳价格以实现脱碳，因为纯电动汽车并不总是能减少二氧化碳排放。这项研究为拥有低成本、不灵活和高排放发电厂的国家的政策制定者提供了有用的见解。