Minimizing the costs of constructing an all plug-in electric bus transportation system: A case study in Penghu

To facilitate the development of environmentally friendly public transportation, this study proposes a model for simulating the operation and battery charging schedule of plug-in e-buses on the basis of an existing schedule and line network. The model was used to estimate the overall construction cost of converting the existent bus transportation system into an all plug-in e-bus one. Focusing on the bus transportation system in Penghu, an archipelago of Taiwan, this case study examined the effects of day- and nighttime charging requirements on the construction cost of an e-bus transportation system to improve the practicability of e-buses. It also applied a genetic algorithm to determine the minimum construction cost, which varied depending on the number of e-buses, level of battery capacity, number of chargers, and electricity costs. The optimized parameters involved the hourly residual battery capacity and battery charging times during the daytime operating hours. The results showed that although daytime charging involved electricity uses during peak hours and thus incurred additional costs, it contributed to the use of e-buses and an overall reduction in the construction cost. In summary, the proposed optimization method would successfully reduce the construction cost of the Penghu e-bus transportation system.