Energy Efficiency Index and CO2 Emission of Public Buses in Khon Kaen City

Abstract

Currently, transportation sector in Thailand consumes highest amount of energy and emits highest amount of CO₂ emission. A replacement of existing gasoline with electric power in the city bus system is interesting. The objectives of this study are to 1) determine the factors, including service operation and vehicle characteristics, that influence energy consumption, Energy Efficiency Index (EEI), and carbon dioxide (CO₂) emissions of public buses, 2) develop models for estimating energy consumption, Energy Efficiency Index (EEI), and carbon dioxide (CO₂) emissions of public buses, and 3) propose a replacement of existing diesel buses with electric buses through a case study of the Khon Kaen City bus system. This study conducted interviews with bus drivers on twelve routes in order to gather information about service quality, vehicle characteristics, and fuel consumption. A multiple linear regression analysis was applied to develop the models. The results found that existing bus system has average energy consumption of 3.187 MJ/km, total energy consumption of 28,489,767 MJ/year, EEI of 0.376 MJ/P-km, average CO₂ emission of 0.235 t-CO₂/km, and total CO₂ emission of 2,112 t-CO₂/year. The factors influencing energy consumption and CO₂ emission of Khon Kaen City bus system are vehicle age and average overall speed. The factors influencing EEI are average ridership and vehicle age. Replacement of existing gasoline buses with electric buses could decrease 69% of total energy consumption, 70% of EEI, and 53% of total CO₂ emission.