Integrating Battery Degradation in the Network Design for Electrical Buses with Fast Charging Technology

The reduction of greenhouse gas emissions is a major issue in worldwide governmental policy making. The transportation industry is responsible for a considerable part of greenhouse gas emissions. Electrification of the sector is a viable approach to reduce these emissions, as even electric cars powered by coal-generated electricity could cut emissions of the sector in half. In public transport electric transportation is currently mainly implemented with visually polluting catenary-powered trams or buses. Recent innovations in battery technology allow for public transport buses to be battery-driven and recharged at distinguished stops, rather than powered by catenary wires. Various trial projects have shown this technology is feasible for public transport operations and the contribution to gas emission control in urban areas is significant. Creating a network for an electrical catenary-free public transport system is very costly due to their battery usage and installing high-tech charging stations. Cost optimization is therefore key for the promotion of battery-driven buses. In recent years, several papers have addressed designing such networks from technological as well as operational aspects. The operational decisions have a major impact on battery degradation in such systems. In order to achieve accurate cost optimization the maximization of battery life is crucial. In this paper, we introduce a linearized battery degradation model incorporated in an MILP for the design of such electrical public transport networks. Two commonly used approaches are applied for designing a Multicriteria Optimization Problem, weighted sum and ε-constraint. A case study with semi-real data is conducted to compare the impact of incorporating battery aging on the costs and battery life with the results of a model without battery lifetime optimization.