Joint charging scheduling of electric buses and active power flexibility integration

Public transport electrification stands out as a notable response to the environmental concerns in the transport sector. This study proposes a joint optimization framework for the coupled battery electric bus (BEB) transit system and active power distribution network (APDN) integrated with the flexibility of demand response (DR). The primary objective is to effectively support BEB mobility services by addressing their spatial and temporal charging demands. Special emphasis is placed on leveraging APDN capabilities to facilitate BEB operations with minimal costs. The problem is formulated as a bi-level stochastic programming by incorporating the non-profit agent at the upper level and the DR aggregators at the lower level. The upper level aims to minimize the joint costs of the APDN and BEB transit system, while the lower level seeks to maximize its profit through interaction with the upper level. The problem is then reformulated into an equivalent single-level model using Karush–Kuhn–Tucker conditions. The findings underscore the effective coupling framework in tackling the charging scheduling in the BEB sub-transit system in Skövde, Sweden, alongside the proper DR activation to meet the technical constraints of the coupled BEB transit and APDN. The proposed optimization framework can compensate for the additional burden of charging demands from BEBs by curtailing 6.4% of energy during peak hours.