Use-case-related identification of energy storage needs for integrating electro mobility in a grid-friendly way

Philipp Puchbauer

Research output: ThesisMaster's Thesis


For complying with future climate goals as known from the Paris Agreement in 2015, the amount of emitted greenhouse gases has to be reduced significantly. Therefore, one of several approaches is the electrification of our traffic sector. However, future penetrations of electric vehicles cause increased energy demands characterised by unprecedented peak loads. These new grid costumers may trigger negative impacts on existing electricity infrastructure and may challenge distribution system operators. To support the integration of electro mobility by smoothing potential electric vehicle charging peaks, this thesis analyses the implementation of flywheel energy storage systems within electric vehicle fast charging stations. Therefore, the integration of two various electric vehicle use cases into the existing power system is investigated within this thesis: highway fast charging of passenger electric vehicles as well as electrified public buses. For this purpose, a four-stage model was developed providing real mobility patterns, future electric vehicle charging loads as well as the derivation of required flywheel storage specifications. In the first stage, distinguished scenarios are classified by varying charging power and charging strategy. Based on that, the second stage generates synthetic electric vehicle charging profiles for both defined use cases considering various electric vehicle penetration levels. Thus, required charging demands are determined based on traffic counts from highway and bus schedules from the public transport system. Finally, the simulation of stage three determines flywheel storage specifications like minimum storage capacity as well as charging and discharging power rate required for a sufficient grid support. The last stage analyses the generated storage specifications, which were summarised as followed: Generated charging demands of highway fast charging station indicate both, high partially base loads and irregularly peak load variations, especially for high charging power levels. Hence, the required flywheel storage capacities are high even for small penetration levels and moderate installed charging power. The main challenge for highway fast charging stations are high peak loads as well as required high installed transformer power. Hence, an expansion of grid infrastructure could be more (cost)-effective than a storage implementation. In contrast, the results for electrified public buses show, that energy storages are technically reasonable to reduce peak loads, especially when charging on every stop at the terminal station (charging on-arrival). Advantages of buses are constant distances travelled throughout the day, which results in a very low variation of charging demands. In addition, they enable the prediction of potential charging demand peaks caused by simultaneously charging of several busses by the means of known bus schedules. As a result, even low-capacity storage units may provide significant grid support and a grid-friendly integration of future electrified buses.
Translated title of the contributionNutzergruppenabhängige Speicherbedarfsermittlung für eine netzfreundliche Integration der Elektromobilität
Original languageEnglish
Awarding Institution
  • Montanuniversität
  • Thormann, Bernd, Co-Supervisor (internal)
  • Kienberger, Thomas, Supervisor (internal)
Award date20 Dec 2019
Publication statusPublished - 2019

Bibliographical note

no embargo


  • Electromobility
  • Fast charging stations
  • Flywheel energy storage system

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