Carbon dioxide emissions estimation of conventional diesel buses electrification: A well-to-well analysis in Shenzhen, China

Abstract

Electrification of public transit bus has been rapidly promoted to reduce carbon dioxide (CO2) emissions in China. It is essential to evaluate the impacts of battery electric buses (BEBs) adoption on real-world CO2 emissions. This paper conducted a well-to-well (WTW) analysis to estimate the CO2 emissions of BEBs in Shenzhen. First, we identified the regional inventory from an extensive review of research papers and data. Based on the mobile BEBs data, we explored the impacts of different driving conditions on WTW CO2 emissions. Moreover, a sensitivity analysis was performed to assess the reliability of the WTW results. The experiments results show that BEBs can reduce WTW CO2 emission by 21.8% relative to conventional diesel buses (CDBs) in 2018. And the WTW CO2 emissions factor of BEBs has a negative correlation with stop headway and average speed. Notably, the impacts of CO2 emissions reduction are more sensitive when the stop headway is over 2 km or the average speed is under 25 km/h. Besides, for the current power structure and charging technology in Guangdong, if the growths of the thermal power share and the charging loss are over 5%, BEB has more CO2 emissions reduction benefits by improving the charging efficiency. Moreover, if the thermal power share and the charging loss are decreased, BEB can obtain more CO2 emissions reduction potential by reducing the thermal share. The improvement of these two technologies can achieve close CO2 emission reduction effects in other situations.