Estimation of CO2 Emissions of Internal Combustion Engine Vehicle and Battery Electric Vehicle Using LCA

TLDR

Vehicle GHG emissions must be evaluated across the entire life cycle—including manufacturing, fuel extraction, power generation, and end‑of‑life—rather than only during operation, and prior studies often assume fixed regions, distances, and battery production emissions. This study compares the life‑cycle CO₂ emissions of conventional gasoline and diesel internal combustion engine vehicles with battery electric vehicles, taking into account region‑specific driving distances and variations in battery production emissions. The authors performed life‑cycle CO₂ calculations for the US, EU, Japan, China, and Australia, incorporating region‑specific driving distances and battery production emission variations. The analysis showed that BEV assembly emits more CO₂ than ICV due to battery production, but in regions with abundant renewable electricity, increasing driving distance makes BEV’s total operating CO₂ lower than ICV, while battery replacement emissions become significant beyond 160,000 km, and ICV can have lower life‑cycle CO₂ when battery production emissions are high.

Abstract

In order to reduce vehicle emitted greenhouse gases (GHGs) on a global scale, the scope of consideration should be expanded to include the manufacturing, fuel extraction, refinement, power generation, and end-of-life phases of a vehicle, in addition to the actual operational phase. In this paper, the CO2 emissions of conventional gasoline and diesel internal combustion engine vehicles (ICV) were compared with mainstream alternative powertrain technologies, namely battery electric vehicles (BEV), using life-cycle assessment (LCA). In most of the current studies, CO2 emissions were calculated assuming that the region where the vehicles were used, the lifetime driving distance in that region and the CO2 emission from the battery production were fixed. However, in this paper, the life cycle CO2 emissions in each region were calculated taking into consideration the vehicle’s lifetime driving distance in each region and the deviations in CO2 emissions for battery production. For this paper, the US, European Union (EU), Japan, China, and Australia were selected as the reference regions for vehicle operation. The calculated results showed that CO2 emission from the assembly of BEV was larger than that of ICV due to the added CO2 emissions from battery production. However, in regions where renewable energy sources and low CO2 emitting forms of electric power generation are widely used, as vehicle lifetime driving distance increase, the total operating CO2 emissions of BEV become less than that of ICV. But for BEV, the CO2 emissions for replacing the battery with a new one should be added when the lifetime driving distance is over 160,000 km. Moreover, it was shown that the life cycle CO2 emission of ICV was apt to be smaller than that of BEV when the CO2 emissions for battery production were very large.