Smart energy systems for sustainable smart cities: Current developments, trends and future directions

Electric bus fleet size and mix problem with optimization of charging infrastructure

Charging 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.

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Locating charging infrastructure for electric buses in Stockholm

https://www.econstor.eu/bitstream/10419/142023/1/860342468.pdf

Electrification of a city bus network—An optimization model for cost-effective placing of charging infrastructure and battery sizing of fast-charging electric bus systems

Lifecycle costs and charging requirements of electric buses with different charging methods

The electrification of public transport bus networks can be carried out utilizing different technological solutions, like trolley, battery or fuel cell buses. The purpose of this paper is to analyze how and to what extent existing bus networks can be electrified with fast charging battery buses. The so called opportunity chargers use mainly the regular dwell time at the stops to charge their batteries. This results in a strong linkage between the vehicle scheduling and the infrastructure planning. The analysis is based on real-world data of the bus network in Muenster, a mid-sized city in Germany. The outcomes underline the necessity to focus on entire vehicle schedules instead on individual trips. The tradeoff between required battery capacity and charging power is explained in detail. Furthermore, the impact on the electricity grid is discussed based on the load profiles of a selected charging station and a combined load profile of the entire network.

/pdf/fast-charging-battery-buses-for-the-electrification-of-urban-20qjl113wa.pdf

Fast Charging Battery Buses for the Electrification of Urban Public Transport : A Feasibility Study Focusing on Charging Infrastructure and Energy Storage Requirements

Public transport is an especially promising sector for full electric vehicles due to the high amount of cycles and predictable workload. This leads to a high amount of different vehicle concepts ranging from large batteries, designed for a full day of operation without charging, to fast-charging systems with charging power up to a few hundred kilowatts. Hence, many different issues have to be addressed in the whole design and production process regarding high-voltage (HV) batteries for buses. In this work, the design process for electric public buses is analyzed in detail, based on two systems developed by the research projects Smart Wheels/econnect and SEB eOPNV. The complete development process starting, with the demand analysis and the operating scenario, including the charging routine, is discussed. This paper also features details on cell selection and cost estimations as well as technical details on the system layout, such as the management system and passive components as well as thermal management.

/pdf/battery-design-for-successful-electrification-in-public-17o3jtfyxz.pdf

Battery Design for Successful Electrification in Public Transport

Range extenders are claimed to be the enabler for electric mobility. They offer the possibility of reducing the battery capacity and therefore the system costs. Furthermore, they can ease the range anxiety. The overall system performance is determined by the operating strategy. In this paper, a simulation model of an electric vehicle with a range extender is described. The model is used to analyze three different operating strategies regarding fuel consumption and battery aging.

http://ieeexplore.ieee.org/iel7/6664715/6671645/06671695.pdf

Matthias Rogge

Papers

Electric bus fleet size and mix problem with optimization of charging infrastructure

Fast Charging Battery Buses for the Electrification of Urban Public Transport : A Feasibility Study Focusing on Charging Infrastructure and Energy Storage Requirements

Battery Design for Successful Electrification in Public Transport

Operating Strategies for a Range Extender Used in Battery Electric Vehicles

Lithium-Titanate Cells for Fast Charging Battery Buses - Results of a Performance and Aging Analysis