Potential for reducing CO2 emissions from passenger cars in Japan by 2030 to achieve carbon neutrality

For Japan to achieve its targets for carbon neutrality and reduction of carbon dioxide (CO₂) emissions, decarbonization of road transport is essential. Japan regards next-generation vehicles, including hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and fuel cell vehicles, as a key means of reducing carbon emissions from road transport. Four scenarios were proposed to predict the potential carbon emissions reduction of passenger car use in 2030: baseline, business-as-usual, government's target-based, and aggressive scenarios. Economic input–output life cycle assessment was used to evaluate potential CO₂ emissions, acidification, eutrophication, human toxicity, and photochemical oxidation associated with passenger cars. In this study, all environmental impacts were calculated using the multi-regional environmentally extended supply and use/input–output database by applying the CML 2001 impact assessment method. The findings indicate that PHEVs have the lowest CO₂ emissions per km traveled, followed by HEVs and BEVs. The prediction for carbon emissions from passenger cars shows that adopting electrified vehicles, such as HEVs, PHEVs, and BEVs could help decarbonize the passenger car sector. The population of vehicles, vehicle manufacturing, well-to-wheel cycle of fuel, and fuel economy will significantly contribute to CO₂ emissions. Finally, this study recommends policies to steer Japan into achieving its goal of carbon neutrality.