Modelling the Required State of Charge of a Battery Emergency Power Supply for Temporary Islanded Grid Sections with Decentralized Generation

Inhalt:
Due to the high dependence of today’s society on an uninterrupted power supply, there is a strong demand for resilient emergency power supply concepts. Next to conventional back-up supply options, one concept could be based on integrating an emergency power supply by temporary islanded grid sections into the multi-use business model of a stand-alone battery energy storage system (SBESS). However, for this emergency power supply option, a sufficient State of Charge (SoC) must be kept available by the SBESS that is able to bridge the disruption time of the supplying grid. This could impact other revenue streams in the multi-use business model and therefore lead to opportunity costs. Therefore, in this paper a modelling approach is presented, that determines the probability that a certain starting SoC must be reserved for this use case. In a case study, the methodology is applied to a rural medium-voltage grid section and multiple sensitivity analyses are conducted in varying scenarios. The exemplary results show that the introduced methodology is suitable for estimating the probability and pattern of the required SoC resulting from the implementation of the use case while considering individual local conditions. Furthermore, it is shown, that especially for longer desired minimum supply periods Deltatmin the introduced concept could represent an attractive alternative to the conventional emergency power supply options, whereas the smallest potential was observed for the application in grid sections containing exclusively PV capacities.