Analysis and evaluation of operations strategies based on a large scale 5 MW and 5 MWh battery storage system

Abstract The increasing trend of replacing traditional fossil fuels by renewable energy sources in the last 5 years leads to a more sustainable energy supply. In particular, the volatile energy generation and the fluctuating consumption cause imbalances in the power grid. Furthermore, the trading interactions in the electricity exchange market result in frequency deviations. To ensure a stable energy supply, robust balancing systems are necessary. This challenging issue can be solved by the integration of battery storage systems in the power grid. Based on this motivation the M5BAT project was established. Within this project, a 5 MW and 5 MWh battery storage system was built. The system is composed of five different battery technologies. One of the aims of the project is to investigate what kind of battery type or which combinations of batteries can be used in an economical way, with respect to different marketing strategies. Within this context frequency control reserve market has a great profiability potential in Germany. In order to ensure a holistic understanding and to derive a resilient evaluation of the BSS, it was operated with 2 MW in the frequency control market. The operation is controlled by an intelligent energy management system, which has a high influence on an economical operation. For analyzing these effects, the energy throughput for each trading week will be determined with regards to the degrees of freedom. Furthermore, the saving potentials by using degree of freedom compared to non-using degree of freedom are evaluated. A further aim of this contribution is the investigation of lifetime. Therefore, the aging rates based on the average state of energy and cycling are determined. Moreover, the profitability of the M5BAT system during frequency control reserve operation is analyzed.