The challenge
In January 2024, Germany signed it into law that all communities with more than 100,000 inhabitants must have a municipal heat plan in place by 30 June 2026. The city of Erfurt is working closely with several expert committees to draft this plan.
Currently, Erfurt's district heating network is approximately 200 km long and operated with different temperatures and pressures. It supplies around 1,700 domestic substations, which means 50,000 residential units that are home to roughly 90,000 people. The market share of district heating is at almost 40 % at the moment. Around 600 GWh of final heat are supplied to end customers every year.
Mastering the transition in the heating sector is an essential element of the energy transition. The company's goals based on recent estimations are as follows: increase the final energy output to one terawatt hour by 2045, almost double the length of the heating network and grow the number of domestic substations supplied from 1,700 to around 7,400.
The project
A project was set up to digitalize Erfurt's district heating network. The goal was to reach digitalization level 4 for the smart domestic substations (iHAST). Features at this level include remote polling of physical measured values as well as active interventions and plant optimizations.
Our cloud-based solution SAM DISTRICT ENERGY was selected to perform these tasks. Implementing the communication infrastructure took merely 30 months to complete. This involved integrating approximately 2,400 heat meters and around 350 controllers.
Shortly after the go-live, the immense benefits of the smart substations started to become evident.
Valuable experience was gathered throughout the project and, after one year in service, the following positive effects have been achieved:
- Almost 100 % digitalization of the meter-to-cash process (from event-triggered meter reading to invoicing)
- Compliance with legal transparency requirements to provide district heating consumption data on a monthly basis through connection to the customer web portal
- Possibility of remote adjustment of the controller set points for room heating and hot water including changes of the operating mode (Auto/Day/Night/Standby)
- Optional changes of the heating schedules
- Use of domestic substations (iHAST) fitted with buffer storage capacities to serve as temporary decentralized heat storage
- Possibility of remote intervention for thermal disinfection (changes of the disinfection temperature, disinfection day, switching times) to prevent legionella, for example
- Option to change outdoor temperature reference (relative, external value in the event of a fault)
- Possibility of remote operation, for example to operate valves or circulation pumps including feedback
- Possibility to start fault detection before service staff even arrive on site. This helps decide whether and which tools to bring for fault removal.
- Considerable optimization of the primary energy procurement process as the customer load behavior is known and transparent
- Fault monitoring based on adjusted alarms and threshold values (temperatures and binary signals)
- Systematic detection of inefficient customer systems. Removing these issues creates the following positive effects:
- Lower return temperatures
- Less heating water circulated through the system
- Less electric work required for circulation pumps
- Lower thermal loss in the return systems
- Optimized COGAS plant process by higher electric work on steam turbines based on lower condensation parameters
Having implemented digitalization level 4, there is now further potential for optimization up to digitalization level 6. This level involves the active integration of additional renewable generation plants and the automation of the entire system also using AI technology.
Lessons learned
Work on large-scale projects always calls for a certain readiness to deal with unforeseen obstacles. Such unexpected challenges can only be handled by working closely with a strong partner. This applies to all contracting parties.
Fewer work steps are needed for invoicing. The interfaces of the meter polling subprocess have also been harmonized and digitalized. These improvements have led to considerable work, time and monetary savings throughout the billing process. Measured values are not only available for the specified polling dates: they can be read on demand in 15 minute intervals.
All in all, the positive effects described above would not have been possible without digitalization, particularly when it comes to reaching the ambitious goals of the heating transition. Dynamics and flexibility have been added all throughout the heat generation and transmission process, which is ready for heat intake from volatile renewable generation sources as well as heat output to storage systems. Last but not least, customers benefit from greater transparency, which, according to SWE Energie, is a key to whether the energy transition will be widely accepted and succeed in the end.
About SWE Energie GmbH
SWE Energie GmbH is a key player in the energy supply of the German city of Erfurt. Founded in 1993, SWE Energie provides reliable and sustainable energy solutions for today and tomorrow. Its portfolio includes electricity, gas and district heating, which are supplied to more than 100,000 customers in the region. The company tackles the energy transition with its state-of-the-art power plant technology and innovative mobility solutions. As a company within the Erfurt public utilities group, SWE Energie combines efficiency with social responsibility to shape the energy future of the region.