HYBKomp bundles system services

Hybrid compensation system for the provision of system services in medium-voltage networks

© Fraunhofer UMSICHT

Fully welded redox stack

The construction without seals significantly increases reliability compared to previous technologies.

Project aims

The German government's energy policy stipulates that the share of renewable energies in the electricity supply must be at least 35 percent by 2020 and a good 80 percent by 2050. To achieve this, the individual elements of the energy transition must interlock seamlessly. Electric energy storage is an important system element in order to stabilize the unsteady flow of electricity from wind power and solar plants in line with demand. Another element is a power converter that feeds the required type of voltage into the grid. However, power converters have a negative influence on the course of the voltage signal. In order to guarantee a constant voltage quality, the grid operators use system services. At present, storage and system services are still technically implemented in separate elements/assemblies – a large number of different systems are required for the different services. As part of the HYBKomp joint project, a technically new solution is being demonstrated that unites the individual components in one system.


The hybrid compensation system, consisting of two storage elements – a redox flow battery and flywheel mass storage – is equipped with a freely parameterizable power converter as well as corresponding measuring, control, and communication equipment.

The new hybrid compensator can be optimally adapted to suit the required feed equalization and system services with low investment costs. The largely modular redox battery output, independently scalable redox battery capacity, modular flywheel mass storage, and scalable power converters are all used for this purpose. Due to the different characteristics of the components – redox flow batteries for long-term storage and provision of larger amounts of energy, flywheel mass storage for short-term storage and provision of larger capacities – the system can react flexibly to changing requirements regarding active power storage and provision as well as reactive power storage and provision.



During the first step, the requirements for the hybrid compensator are specified. This is done by means of analysis, electrotechnical modeling and simulation of an example distribution network in the network areas of the distribution network operators involved in the project. Based on the knowledge gained, a low-power setup of the converter will initially be implemented in the laboratory environment. The setup serves as a platform for research, implementation, and validation of the required functionalities and algorithms. The researchers analyze available multifunctional converter concepts and select a suitable configuration. The storage systems and the network behavior are simulated using corresponding sources or loads and network simulations in the laboratory environment. At the same time, the storage system is designed in terms of performance and capacity. In order to confirm the functionality in real network operation and to optimize measures, a field structure is set up after successful laboratory testing of the individual components.

Project partners

  • Stadtwerk Haßfurt GmbH
  • SWW Wunsiedel GmbH
  • Kautz Starkstromanlagen GmbH
  • Energieversorgung Wenzenbach GmbH
  • Technische Universität Dortmund ie³ – Institut für Energiesysteme, Energieeffizienz und Energiewirtschaft
  • Friedrich-Alexander Universität Erlangen-Nürnberg FAPS – Lehrstuhl für Fertigungsautomatisierung und Produktionssystematik

Duration: September 2017 to June 2022
Website: www.bmwk.de