In the current and future German power system, characterized by large penetration of intermittent renewable energy sources, the demand and the importance of flexibility options are escalating. Therefore, this contribution provides, based on a literature review and market data analysis, a comprehensive discussion of today's potential application areas for stationary battery storage systems (sBSS) in Germany. The core research focus is based on market opportunities (estimation of application monetary benefits and if possible market sizes) in combination with regulatory framework conditions for each potential sBSS application. Given the background, the analysis identifies twelve use cases for sBSS services with three market opportunity categories: low, medium and high. However, the general outcome shows that especially the policy and regulatory treatment defines the demand and dynamics for mainly all sBSS application areas and hitherto, the multi-application character does not fit into existing regulatory frameworks.