The optimization of electric buses in Iskandar Malaysia

Abstract

The public transport sector has a significant share of global CO2 emission due to combustion of fossil fuel that could be catastrophic to the environment. Hence, evidence suggests that the implementation of battery electric buses (BEB) is necessary in order to reduce climate change and other environmental impacts. However, it raises a concern to bus operators regarding the conversion to BEB. This is because BEB have a fixed battery capacity, which have limited mileage, and the number of buses required to replace conventional buses due to limited charging stations available. In order to alleviate this situation, a proper fleet planning is required in order to know the amount of buses that are dispatched and the distance that the specific bus can travel. Hence, this study is conducted to optimize the cost of implementing electric buses in Iskandar Malaysia. Moreover, this study is also done to determine the optimal charging cycle that is required to cover Iskandar Malaysia and the number of buses needed to replace the existing conventional buses in order to fulfil the number of trips set by Perbadanan Pengangkutan Awam Johor (PAJ) Furthermore, a scenario analysis will be done by selecting two routes around Johor Bahru (i.e., the longest route and shortest route) with consideration of worst case scenario (i.e. high traffic) using the existing Bas Muafakat Johor’s routes, which will assist in optimizing the ideal charging cycle and number of electric buses required for each location using an optimization software called General Algebraic Modelling System (GAMS) through various scenario selection such as (a) the buses will be charged for every trip or (b) the buses will be charged after complete depletion of its battery level (i.e. 3 trips) or (c) another bus will be added for the subsequent trip. Based on the GAMS, scenario (a) and scenario (b) is both selected. This is because continuous flow of buses is required during peak hours hence suitable for scenario (b) whereas scenario (a) is much more suitable for nonpeak hours. Electric buses can save up to 132.52 kg of CO2 per trip and also saves about 536.45 kWh of energy which equivalent to 53.65 L of diesel when compared to diesel buses.