Highlights Presenting an optimization model for the location of electric bus charging stations. Model application to a large-scale case study for the bus network of Stockholm, Sweden. Results show that low fuel costs for electricity can balance annual infrastructure costs. Emissions decrease up to 51% and energy consumption up to 34% with electrification. The model may assist decision-making for investments in public transport.Keywords electric bus; charging infrastructure; optimization; Mixed Integer Linear Programing; public transport; Sweden
AbstractCharging infrastructure requirements are being largely debated in the context of urban energy planning for transport electrification. As electric vehicles are gaining momentum, the issue of locating and securing the availability, efficiency and effectiveness of charging infrastructure becomes a complex question that needs to be addressed. This paper presents the structure and application of a model developed for optimizing the distribution of charging infrastructure for electric buses in the urban context, and tests the model for the bus network of Stockholm. The major public bus transport hubs connecting to the train and subway system show the highest concentration of locations chosen by the model for charging station installation. The costs estimated are within an expected range when comparing to the annual bus public transport costs in Stockholm. The model could be adapted for various urban contexts to promptly assist in the transition to fossil-free bus transport. The total costs for the operation of a partially electrified bus system in both optimization cases considered (cost and energy) differ only marginally from the costs for a 100% biodiesel system. This indicates that lower fuel costs for electric buses can balance the high investment costs incurred in building charging infrastructure, while achieving a reduction of up to 51% in emissions and up to 34% in energy use in the bus fleet.
Public transport is important for Sweden to acquire a fossil-fuel independent vehicle fleet by 2030. The aim of this paper is to assess the status of Swedish public bus fleets towards decarbonization, and explore factors affecting regional performance variations and fuel choices. Environmental performance indicators such as renewable fuel shares, CO 2 emissions, and energy efficiency are analyzed nationally and regionally. Fuel preferences and best practices are investigated through a survey and interviews with experts working with strategic planning at Public Transport Authorities. Almost 60% of the bus transport volume ran on renewables in 2014 compared to 8% in 2007, but regional variations are significant, partly due to factors such as driving conditions, bus and fuel types, typical trip lengths, and climatic conditions. However, there is no strong correlation between population densities or bus transport volume and the share of renewables achieved. This places political will, strategic planning and policies to promote public transport as key factors affecting renewable fuel deployment. Environmental factors are a priority when choosing fuels, while barriers to renewable fuels are mainly economic and political. Meanwhile, despite the overall progress, achievements in energy efficiency improvement are falling short in comparison to emissions reduction and adoption of renewable fuels, thus requiring further attention. Electricity is likely to receive increased attention according to expert survey.
Highlights
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