Electric Bus Scheduling and Charging Infrastructure Planning Considering Bus Replacement Strategies at Charging Stations

Abstract

Existing studies on electric bus (EB) scheduling mainly focus on the arrangement of bus charging at the bus terminals, which can result in high scheduling costs and insufficient utilization of chargers and bus batteries. This paper proposes a bus replacement strategy during the operation of EB, i.e., during the operation, a bus with insufficient battery can be driven to a charging station, and will then be replaced at the station. Its passengers will be transferred to another fully charged 'standby bus' at the charging station. The 'standby bus' will execute the rest of the bus trip, and the replaced bus becomes a 'standby bus' after it is fully charged. In this context, we consider the electric bus scheduling and charging infrastructure planning (charger location and quantity) problem, given level of service constraints, battery power limitation, charging capacity limitation. The proposed model is a nonlinear integer programming model. We then linearize the proposed model and obtain an equivalent mixed integer linear programming (MILP) model, which can be efficiently solved by commercial solvers (e.g., CPLEX). The case study results show that bus replacement can improve the operational efficiency of the EB system when compared with battery swapping, e.g., the charger utilization rate can be increased by 14.3%, and passengers' travel time and the total cost can be reduced by 15.5% and 7.75%, respectively.