Climate change adaptation and mitigation potential of EVs in Tokyo metropolitan area

Abstract

Penetration of low heat-emitting electric vehicles (EVs) in urban areas is expected to have a positive effect on climate change adaptation by improving the thermal environment, and indirect mitigation by reducing building CO2 emissions. To assess these effects, a case study was conducted in Tokyo using an urban canopy model. We quantified the impact and characterize its spatio-temporal structure, through a comparative evaluation with other forms of e-mobility (hybrid electric vehicles and fuel cell vehicles) and established UHI measures (ground greening and cool roofs). EVs showed the largest effect among all e-mobilities, both in absolute temperature reduction (ΔT) and cooling efficiency (ΔT per reduced heat), owing to the positive feedback on atmospheric stability. The ΔT caused by EV is more pronounced in the morning and evening hours, and in urban centers. On the other hand, the ΔT due to UHI measures peaks at midday and is more pronounced in suburban areas. In other words, they complement each other spatially and temporally. The peak ΔT caused by the EVs exceeded that of the UHI measures by approximately 40% of the total area. The contribution of indirect CO2 mitigation is negligible in the life-cycle CO2 emissions of EVs.