Fraunhofer Institute for Experimental Software Engineering IESEHow cities are using digital models to make their energy supply climate-friendly
Digital twins make municipal heat planning tangible
Local authorities that want to make their heat supply climate-neutral face major challenges: they have to evaluate gas and district heating networks, assess future energy requirements, and develop suitable solutions for a CO2-free energy supply. In practice, there is often a lack of overview: data is scattered, scenarios are difficult to compare, and connections remain invisible. A practical report by the Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR) shows how digital twins can strategically support municipal heat planning.
From data set to decision space
Urban digital twins bundle spatial, technical, and organizational information. In this way, they digitally map the municipality. They show where and how much heat is needed, make existing networks visible, and identify sensible heating solutions on site.
The study is based on 189 municipalities that had already created heating plans or were still working on them in spring 2025. The result: Digital twins are mainly used at the beginning of the planning process – for inventory and potential analyses or to develop target scenarios. Municipalities often rely on external service providers for this.
The greatest benefit is achieved when digital twins match the municipality's existing data, resources, and structures. From simple visualization to complex simulation – the added value depends on the possibilities available locally.
Four municipalities, four different approaches
The study shows that each municipality takes a different approach:
- Munich manages its heating planning internally and based on data. Analysis and simulation form the basis for strategic decisions.
- Halle (Saale) uses an externally developed digital twin that visualizes building stocks and evaluates energy consumption. The district of Lörrach relies on an inter-municipal approach that creates transparency and relieves smaller municipalities.
- Zurich complements the German perspective with a European example. Here, the focus is on data sovereignty and clearly defined responsibilities in administration.
Develop step by step instead of all at once
The practical report recommends introducing digital twins gradually. A clear use case makes it easier to get started. Reliable data and simple representations are sufficient at first; further analysis or simulation functions can be added later. This keeps heat planning manageable and expandable—even when time and personnel are in short supply.
With the legal obligation for municipal heat planning [in German], this task is becoming even more important. "Urban digital twins help municipalities bring heat planning from the abstract data level into the concrete urban space," says Dr. Ralf Schüle, project manager in the "Digital City, Risk Prevention, and Transportation" department at the BBSR. "They provide orientation, make scenarios comparable, and support decisions—provided they fit in with municipal structures."
Click here for Study [in German]!
Smart City Research
The practical report "Urban Digital Twins in Municipal Heat Planning" was published by the Federal Institute for Research on Building, Urban Planning, and Spatial Development (BBSR). The publication is part of the accompanying research in the Smart Cities Model Projects program. The German Institute for Urban Studies (Difu) and the Fraunhofer Institute for Experimental Software Engineering IESE developed the practical guide.
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