Does battery electric vehicle always help to reduce CO₂ emission?

A study conducted by Ryosuke Kataoka et al. in collaboration with Energy System Integration, Social Cooperation Program, Institute of Industrial Science, The University of Tokyo was published in the Transportation Research Part-D: Transport and Environment.

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 (CO₂) 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 CO₂ prices and flexibility requirements in Japan in 2030 using a production cost model. The results showed that uncontrolled charging increases CO₂ emissions, whereas V1G or V2G reduces them. Further, the impact of BEVs was non-monotonic with respect to CO₂ prices, implying that policymakers should carefully evaluate CO₂ prices to achieve decarbonization as BEVs do not always reduce CO₂ emissions. This study provides useful insights for policymakers in countries with low-cost, inflexible, and high-emission power plants.

Title: Does BEV Always Help to Reduce CO₂ Emission? Impact of Charging Strategy
Authors: Kataoka, R., Ogimoto, K., Iwafune, Y., Nishi, T.
Journal Name: Transportation Research Part D: Transport and Environment
Published: April 1, 2024
https://doi.org/10.1016/j.trd.2024.104124