Integrated charging scheduling and energy management for electrified-autonomous flexible transit with energy storage systems design

Electrified-autonomous flexible buses (EAB) offer promising potential for delivering efficient and demand-responsive public transit services but pose challenges in charging planning and energy management. This study proposes a flexible bus operation model as an alternative to the conventional fixed-route terminal charging approach. A series of scenarios is developed to assess system performance under the integration of fast charging stations (FCS) and energy storage systems (ESS), in conjunction with a time-of-use electricity pricing scheme and the implementation of peak voltage management (PVM) strategies. The results demonstrate that the PVM strategy effectively reduces grid peak power by 22.2 % compared to the baseline scenario, which exhibits pronounced load spikes. However, this peak reduction comes at the cost of extended charging durations and diminished utilization efficiency. In contrast, the ESS-based scenario reduces charging time by 8.9 % relative to the PVM scenario and enhances the objective function by 60.6 %, primarily due to revenue generated through ESS operation. Nonetheless, this configuration introduces a new sharp peak in grid power associated with ESS charging. The combined deployment of ESS and PVM effectively mitigates this issue, further increasing ESS-related profits by 8.4 % and offering a more sustainable and economically viable solution. In addition, this study explores the impact of ESS capacity on system performance and finds that the flexible on-demand service model of EAB provides strong support for arranging the ESS and the implementation of PVM.