Recently, SWTE received several requests for grid connection of large-scale battery storage systems. SWTE had to respond to these requests, but the impact on grid operations was unclear. Large battery storage systems are a new technology and – at least on a large scale – have not yet been connected to SWTE’s grid. Potential grid effects needed to be investigated in detail.
The connection of a battery storage system was planned directly to the “ECI” substation on the 10 kV side. However, the connection also affected the equipment of the upstream grid operator WestNetz (110 kV). Both granting and denying the grid connection could therefore be well justified.

All relevant large-scale battery storage business models that influenced storage operation and thus had an impact on the network were qualitatively classified. A model-based analysis of network effect was carried out. The battery storage operation resulting from these business models was simulated and analyzed in connection with the grid utilization. Exemplary storage profiles were created to evaluate grid utilization. In addition, critical grid situations and their causes were systematically recorded in conjunction with large battery storage systems. The connection of a storage system had an impact on grid operations. Instead of rejecting a grid connection request, there were also alternative options to enable the operation of a battery storage system, and these options were comprehensively presented.

SWTE gained an understanding of battery storage business systems and the factors that determine the operation of a battery storage system. By providing profiles typical of storage systems, the effects on grid operations could also be quantified. Based on these findings, optimal strategies for integrating BESS into the grid area were derived.