Topology Optimizer - ToOP

Addressing congestion management with ToOp, cross-system operator cooperation and open-source.

For system operators, congestions management is a key to ensure grid stability when excess electricity generation outpaces physical transmission capacity. With the increasing volumes of renewable and distributed generation, power flows become more dynamic and complex. Therefore, identifying efficient remedial actions has become increasingly challenging. This importance is further reflected in the redispatch costs that amount to multiple billion euros every year. In Germany alone, the redispatch cost to address congestion management has reached around 3.129 bn Euro in 2026 (Bundesnetzagentur).

Congestion management may be addressed through coordinated mechanisms such as expanding transmission infrastructure or market policies such as “redispatch 2.0” (Bundesnetzagentur). In addition, topology optimization (identifying potential changes to the network topology that could alleviate network constraints) is playing an increasingly prominent role identify potential changes to the network topology that could alleviate network constraints.

In this context, Elia Group has developed the software product Topology Optimizer (ToOp) as part of the MCCS program. The goal of the ToOp is to support grid operators manage complex network situations through cost-efficient topological actions that reduce the need for redispatch and lessen reliance on operator experience when identifying remedial actions. The challenge is significant. In a single control are, there can be more than 10¹²⁰ theoretical switch combinations, making manual evaluation impossible. ToOp addresses this complexity by rapidly assessing vast numbers of potential grid topologies and identifying switching actions. The solution provides measurable benefits, including:

Decreased stress for operators
Reduced redispatch costs
Better utilization of existing grid infrastructure
Lower CO₂ emissions
High cost efficiency for grid operators

ToOp is specifically designed to run on graphics processing units (GPUs), which can execute large numbers of calculations simultaneously. By leveraging GPU technology, ToOp can process up to one billion load-flow calculations per second, enabling the rapid simulation of a vast range of grid scenarios.

Based on these simulations, ToOp identifies optimal switching actions that effectively reroute power flows across the network and help alleviate congestion. Control centre operators can filter and prioritize recommendations according to predefined criteria, supporting faster and more informed operational decisions.

Today, ToOp has progressed beyond the research and development phase and is being tested in daily operations by a dedicated group of control centre user. The tool already supports operators by evaluating large numbers of network topologies and providing actionable recommendations that enhance decision-making in real operational environments.