
Control systems are a central element for controlling critical infrastructures, in particular energy supply systems. They have grown historically, are monolithic, proprietary and generally antiquated in their appearance and handling, and they demand great expertise from operating personnel, with lengthy qualification paths.
All of this is problematic in light of the numerous challenges posed by the energy transition. Decentralised generation by small and very small installations, including at lower voltage levels, leads to an enormous increase in complexity. Added to this is the growing need to couple both different energy sectors and, in connection with this, the IT systems in the background. These factors in turn make a high degree of automation and the introduction of new operational management approaches necessary, in particular innovative and possibly AI-based solutions. Accordingly, among grid operators there is an ambition to harmonise and couple control systems in order to increase efficiency and to open up the possibility of taking over grid operation for other, mostly small grid operators at defined times (e.g. night-time operation). However, this also increases the complexity for the operating personnel, who are already confronted with increasing critical grid states as well as rising threats from cyberattacks.
The historically grown control systems are reaching their limits both internally and externally. Owing to outdated software technologies and concepts, natural performance limits arise, among other things with regard to real-time capability as well as extensibility and maintainability. Control systems also reach their limits on the topic of IT security, since IT security was not yet a focus during their development and consequently has to be implemented in a cumbersome way. The harmonisation and coupling of control systems sought by grid operators is made largely to entirely impossible by vendor lock-in; the same applies to extending control systems with functionalities provided by third parties.
Furthermore, the expertise required to operate the control systems is confronted with a shortage of skilled personnel, which is further aggravated by the use of outdated software concepts. Skilled personnel trained today are taught modern software and interaction concepts. Accordingly, working with software that is outdated and that appears archaic in terms of human-machine interaction is not intuitive and is unattractive on the labour market.
In summary, the challenges posed by the energy transition in particular are all the harder to master with the current, antiquated control systems. For this reason, the TWO group researches the use of digital twins for monitoring and controlling energy systems, in short Energy Systems Twins (EST).
OFFIS defines digital twins in a domain-independent way as follows:
The following characteristics can be highlighted in particular:
A major advantage of the definition is the mapping of passive physical objects (objects with insufficient sensor technology) by a digital twin. A schematic representation of a digital twin derived from the definition is shown in the figure.
The concept of digital twins is suitable insofar as it goes beyond – potentially hierarchical or nested – digital representations and provides for an automated adaptation of the physical infrastructure on the basis of changes in the digital twin. The representation and modification of the physical infrastructure should, as far as possible, happen in real time. This real-time capability is realised through the use of data stream processing, which makes it possible to process, analyse and display data in an event-driven manner.
A further essential feature of EST is the possibility of holistic modelling of (coupled) energy and ICT systems. In particular, their interactions will be essential for resilient grid operation. Moreover, the increasing interaction between the control system and external actors and installations requires interoperability as a central goal, in order to be able to connect third-party processes and applications to the control system. Specifically, this requires defined interfaces that create the basis for modular exchange and extensibility.
The TWO group focuses, among other things, on the following research questions:

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Duration: 2020 - 2024Wibbeke, Jelke and Ribeiro, Rita P. and Rohjans, Sebastian and Rauh, Andreas; Discovery Science; 2027
Brand, Michael and Blümel, Kersten and Bruhn, Jan-Henrik and Geiger, Alexander and Kulkarni, Pranav J. and Ulbig, Andreas and Monti, Antonello and Lehnhoff, Sebastian; IET Conference Proceedings; October / 2026
Jelke Wibbeke and Nico Schönfisch and Sebastian Rohjans and Andreas Rauh; International Journal of Approximate Reasoning; 2026
Danila Valko and Sharaf Alsharif and Kaja Petersen and Jorge Marx Gómez; Proc. of the 3nd ICTA-EMOS conference (ICTA-EMOS 2026); August / 2026
Kulkarni, Pranav J. and Geiger, Alexander and Gaikwad, Sanket and Brand, Michael and Ulbig, Andreas and Monti, Antonello and Lehnhoff, Sebastian; IET Conference Proceedings; October / 2026
Brand, Michael and Stark, Sanja and Holly, Stefanie and Kamsamrong, Jirapa and Mayer, Christoph and Lehnhoff, Sebastian; Towards Energy System Resilience; 2026
van Doren, Davy and Droste-Franke, Bert and Brand, Michael and Derendorf, Karen and Fohr, Gabriele and Gils, Hans Christian and Kaiser, Matthias and Knieling, Jörg and Lehnhoff, Sebastian and von Maydell, Karsten and others; Towards Energy System Resilience; 2026
Blümel, Kersten and Brand, Michael and Lehnhoff, Sebastian; 2025 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT Europe); Oct / 2025
Wibbeke, Jelke and Rohjans, Sebastian and Rauh, Andreas; 2025
Brand, Michael and Blümel, Kersten and Bruhn, Jan-Henrik and Fatemi, Armin and Huxoll, Nils and Lehnhoff, Sebastian; 2025 IEEE Kiel PowerTech; 2025