Stadtwerke Flensburg supplies a six-figure number of customers nationwide with electricity and natural gas, as well as electricity, district heating, and drinking water in its own supply network. The utility has installed around 19,400 heat meters in its own district heating network on the Flensburg Fjord, which the company digitalised at a very early stage.

Stadtwerke Flensburg has been using electronic meters for its heat supply since the 1990s and has been using special readout modules since the 2000s. Until now, they have been read once a year, in exceptional cases monthly.

“The more data that is available, the more accurate the assessments can be. However, the more difficult it also becomes to filter out the "right" or decisive data. In order to make quick and reliable statements, it requires technical support with help from an appropriate software solution.”
- Dennis Faulhaber, Team lead of network services at Stadtwerke Flensburg GmbH

Everything revolves around data – finding the balance

Digitalisation in the area of meter data collection and processing offers a wide range of opportunities and challenges for suppliers. This means that most customer enquiries about consumption can be answered reliably from the desktop, as all the data is available promptly. In addition, malfunctions can be recognised and tracked at short notice.
"The more data that is available, the more accurate the assessments can be. However, the more difficult it also becomes to filter out the "right" or decisive data," Dennis Faulhaber says of his experience. "In order to make quick and reliable statements, it requires technical support with help from an appropriate software solution," he continues. The municipal utilities initially tested this on a small scale.

Fixed network brings transparency

Around 17 kilometres south of Flensburg in the municipality of Tarp, Stadtwerke built a new district heating network in 2010, which currently supplies around 470 households with district heating. One step towards optimising the supply was the establishment of a fixed network in 2020. Due to its young distribution system of a standardised design and a manageable number of house connections, Tarp was ideal for setting up a fixed network. Dennis Faulhaber, Team Leader Network Services, Stadtwerke Flensburg GmbH, says that this will allow for quickly gained experience and important learnings of the effects generated before such a system is realised on a larger scale, as in Flensburg with more than 19,400 meters. Another complicating factor here is that the pipe network in Flensburg has been built up since the end of the 1960s and consists of a wide variety of materials.

But first, back to Tarp. Here, the municipal utilities first analysed the local framework conditions such as terrain, development, building types, and planting in detail. Based on this analysis, meters with data that could not be received were retrofitted with external antennas or supplemented with NB-IoT.

Major highlights at Stadtwerke Flensburg 

Approx. 19,400 heat meters installed

Enhanced data availability enables more accurate assessments

Fixed network with Heat Intelligence software improves operation

Network efficiency through continuous monitoring and analysis

Approx. 19,400 heat meters installed

Heat Intelligence software

The right, powerful software is important for everything. In Tarp, the "Heat Intelligence" system is used to provide the heat supplier with all the data on the status of the network, temperature fluctuations, flow rates, etc. at the click of a button. This was not easily possible before. In fact, without a system solution, checking the house connections would only be feasible with a considerable amount of manpower. Neither was it ever possible to create a complete picture of the network status, as the operating status of one system might have already changed again while the next one was being analysed.

When selecting the readout frequency, the resulting data volume must not be disregarded in addition to data protection regulations. Faulhaber calculates that after the introduction of such a system in Flensburg, there would be generated more than 1.5 billion registered values annually from the Flensburg district heating meters alone with meter readings performed on an hourly basis. It must therefore be clear in advance for what purpose and under what conditions the data is collected, according to the expert. It is important to weigh how much and which data is required for network monitoring.

More efficiency in the network 

For Faulhaber, the added value of a fixed network clearly lies in network monitoring – from the distribution of temperature and the identification of bottlenecks to the possibility of checking the operating situation. Is sufficient temperature still available at the network’s end points? What about the return temperatures? Can capacities be reduced if the system becomes even more efficient in one place or another?

Stadtwerke Flensburg is constantly analysing its network to locate where to make improvements, to find potential bottlenecks, and to pinpoint locations that require reinforcement or resizing. With regular digital readings of important meter data, system and control errors can be detected remotely so that countermeasures can be taken at an early stage.

Practical example – improving the return temperature

In a public building in Tarp, digital data logging was used to determine an extremely poor return temperature. With a forward temperature of 78 degrees and a return temperature of 76 degrees, the water was actually just circulating without giving off enough heat. When we contacted the customer, it turned out that he had problems with the heat exchanger in his system. Together with the heating engineer, the heat exchanger was adapted, and the return temperature was reduced to well below 60 degrees. Thanks to modern technology, the defect could be recognised and rectified quickly, which prevented longer efficiency losses in the grid operation.

About the project:

  • Continuous network monitoring and analysis
  • More efficiency in generation and grid operation with the help of data
  • Real meter readings available for billing at the touch of a button
  • Avoidance of reading errors and transposed figures
  • Short-term detection of measurement faults
  • Possibility of reading the meters on site in the presence of the consumer – clarification of any discrepancies in the billing
  • Possibility to check the operating situation at any time – conspicuous systems or old buildings can be specifically filtered out

A look into the future

In Flensburg as well, water, heat, and electricity meters will also become remotely readable in future. To guarantee security of supply and remain independent and invulnerable, secure interoperability is important to the supplier.

The ideal situation for Faulhaber would be perfect grid operation. This means that there would be no unnecessary heat losses in the grid, but only grid losses that are physically unavoidable. This requires correctly dimensioned cables and good insulation at every point, which sounds easier than it is in practice. Because of the seasons alone, the pipes must be designed for higher power requirements in winter. If the flow rates are low, as during the summer, it must be ensured that the water reaches the consumer at a warm temperature so that there for example is no legionella infestation in the drinking water. These are all challenges that the municipal utilities will take on. An important step towards the necessary transparency is to make their meters remotely readable in the coming years.

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Heat Intelligence 

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