Electrification of urban mobility: the case of catenary-free buses

Electric mobility is now a reality, and services based on electric vehicles, such as electric car-sharing and electric buses, are becoming part of urban mobility. These new modes bring new challenges for the design and operations of the systems that require specific decision support tools for the evaluation of the service performance. In order to pave the way toward integrated electrified urban mobility, we need operational tools that enable the technology to be successfully implemented in practice. In this paper, we propose a simulation framework for the evaluation of electric vehicle operations. The framework is composed of a simplified traffic simulator, an energy consumption model, and a speed profile model. We estimate a macroscopic representation of the energy consumption derived from a nanosomic energy model. This allows a trade-off between accuracy and computation time. Then, we define a stochastic representation of the stopping profile, which is essential to derive the speed profile in case of missing data. The framework generates a distribution of the key performance indicators, like the battery state of charge, for a large number of scenarios. The utility of the framework is illustrated on the case study of a public transport service using catenary-free electric buses in combination with fast-charging stations. The results quantify the probability that the on-board batteries reach a low state of charge, and they evaluate the effects of different strategies to reduce this probability. This information is useful for transport planners to dimension the system correctly.