Life Cycle Analysis on Energy Efficiency and CO2 Emissions of China's New Energy City Bus

Life cycle analysis provides global research methods for the assessment of life cycle performance. In this research, a WTW (well to wheel) model was introduced to study and compare the energy efficiency and CO2 emissions from diesel bus, CNG bus and electric bus. The results show that the WTW total energy efficiency of diesel bus is 1790MJ/100km. The energy efficiency of CNG bus is 6% lower than that of diesel bus, while the energy efficiency of electric bus is 36% higher than that of diesel bus. Both CNG bus and electric bus show good potential of oil replacement with oil consumption decrease of 98% and 90%. As more than 80% of China's electricity is produced by coal, electric bus has equal effect as CNG bus on CO2 reduction. Compared to diesel bus, CO2 emissions from new energy bus are reduced by 14%.