Impacts of expected state-of-charge satisfaction for electric vehicles participating in frequency containment reserve

The impacts of expected state-of-charge (SoC) satisfaction for electric vehicles (EVs) participating in frequency containment reserve (FCR) are evaluated for the first time. To achieve this, the study develops a comprehensive methodology considering technical and economic aspects. Firstly, historical frequency data of Nordic power systems obtained from the Finnish transmission system operator (called “Fingrid”) are preprocessed and used to determine the FCR activation. Next, the FCR activation and market models are established based on the European context, especially the Finnish balancing market. A comparative study is conducted using four existing expected SoC satisfaction strategies: half-power, constant-power, adjustable-power, and forced charging. Moreover, sensitivity analyses are conducted to explore the influence of different arrival SoC levels. The average departure SoC is then used to evaluate the strategies’ effectiveness, while the equivalent number of battery cycles is used to estimate the impact on the battery cycle life. Further, the EV aggregator income is determined to evaluate the impacts of expected SoC satisfaction on economic benefits. The simulation results demonstrated that the adjustable-power and forced charging strategies could effectively satisfy the expected SoC at departure time. Moreover, the forced charging demonstrated superiority in terms of cost saving (compared with normal charging), but the EV aggregator’s cost saving was reduced substantially when the arrival SoC decreased. •Impacts of expected SoC satisfaction for EVs participating in FCR are evaluated.•A comprehensive methodology considering technical and economic aspects.•The FCR activation and market models are established based on the European context.•Four existing expected SoC satisfaction strategies are compared.