The expansion of renewable energy with its volatile feed-in character places higher demands on the electricity grid of the future. Large-scale stationary storage systems are a promising option for supporting the electricity grid and have been gaining importance in recent years, both in the primary reserve market and in research. Most of the publications investigating the interaction between storage and the primary reserve market are based on simulations, however field measurements are rare. This paper presents the analyses of the multi-year, high-resolution field measurements of the hybrid 5 MW / 5 MWh battery storage “M5Bat” to address this issue.
This work investigates four years of operational data of the large-scale storage “M5Bat” and analyses, quantifies and compares the influence of the primary reserve market on the aging, efficiency and operating costs of the large-scale storage and the individual battery technologies (two types of lead-acid and three types of lithium-ion batteries). The results of the analysis of the operational data indicate a high overall efficiency of 72.8% as well as a low cyclic load of an average of 8.1 equivalent full cycles per month. In this context, the lithium batteries have a higher efficiency and a lower age-related capacity reduction than the lead-acid batteries.
The presented results can be used to investigate and model the influence of primary reserve market operation on the efficiency, aging and performance variables of the different battery technologies. Furthermore, the processed operating data will be published in the future and contribute to the research of stationary and hybrid large-scale storage.