As Germany accelerates its energy transition, the rapid growth of renewable generation is placing increasing pressure on the transmission network. While this transformation is creating significant opportunities for Battery Energy Storage Systems (BESS), it is also introducing new challenges around network congestion and market access.
To maintain system security and keep power flows within network limits, German Transmission System Operators (TSOs) regularly implement redispatch measures, instructing generators and other network users to increase or reduce their power output. As the German energy mix continues to shift towards greater renewable generation, these interventions are becoming increasingly important for managing transmission constraints. Unlike conventional generation assets, BESS operators are not always compensated for redispatch-related restrictions on charging (import) or discharging (export). As a result, understanding potential network constraints before committing to a project has become a critical part of BESS site selection and investment decisions.
Why Curtailment Matters for BESS
A BESS generates value by optimising when it imports and exports electricity. If congestion on the transmission network restricts these activities, the asset's access to energy markets can be reduced, impacting revenues and overall project economics.
To maintain system security and keep power flows within network limits, German TSOs, including 50Hertz Transmission and TenneT, regularly implement redispatch measures, instructing generators and other network users to increase or reduce their power output.
For developers, investors and asset owners, key questions include:
Answering these questions early can provide a significant commercial advantage.
Smarter Grid Solutions has extensive experience delivering transmission and distribution curtailment assessments across the UK, utilising approaches ranging from data-driven analysis to sophisticated non-linear load flow and probabilistic modelling techniques.
Building on this expertise, we are now applying our power systems, data analytics and network modelling capabilities to assess potential curtailment impacts for BESS projects connecting to the German transmission network.
For a deeper insight into how advanced network modelling can be used to evaluate BESS dispatch decisions and curtailment risk, read our blog: BESS, Curtailment and the Grid: Modelling Smarter Dispatch Decisions.
Our established UK methodology incorporates time-series transmission modelling with Security Constrained Economic Dispatch (SCED) optimisation. While this detailed approach can be adapted for the German system, many clients require rapid insights during the early stages of project development. In response, SGS has developed a fast, data-driven German Transmission Constraint Indication Study designed to identify potential network risks efficiently and cost-effectively.
Our German Transmission Constraint Indication studies use a European Static Grid Model and redispatch instructions issued by German TSOs to identify the key constraints that a study site may be sensitive to, providing valuable insight into potential drivers of site import and export restriction.
Rather than focusing solely on the asset, we start with the network.
Our Network-first approach provides a qualitative assessment of the network associated with a proposed connecting asset. We then consider electrically sensitive constraints to the proposed site, and utilising publicly available generation, load, meteorological and redispatch instruction data, highlight conditions in the transmission network that indicate times where there could be a need to increase or decrease active grid power feed-in to the proposed site. This is illustrated in the diagram below:
As Germany's electricity system continues to evolve, transmission constraints are becoming an increasingly important factor in BESS project performance. Understanding these risks early can help developers avoid unexpected operational limitations, improve revenue forecasts and make more informed siting decisions.
SGS's German Transmission Constraint Indication Studies provide a fast, data-driven assessment of potential curtailment risks, helping project stakeholders better understand how the transmission network could influence future BESS operations and market access.
If you are interested in finding out more about this service, or our wider consultancy services, get in touch.