Viborg Varme transforms its heating system with Gradyent’s Digital Twin
Viborg Varme is a Danish energy company that delivers heat to 12,500 customers with a total of 260 GWh of heat consumption. The transformation of Viborg Varme focuses on the switch from a gas-powered operation to a fully electrified heating grid. To this end, the company aims to provide a resilient heating supply at the lowest possible price for its residents, generating minimal CO2 emissions.
Challenge
Transforming towards a smart and energy efficient energy system, Viborg Varme has been working on reducing temperatures and has successfully managed to operate the heating grid with average temperatures of 65-75 °C.
To transform the heat production, the company has introduced three large heat pumps, each of approximately 7 MW, in different locations across the network. Moreover, Viborg Varme has implemented a 50 MW E-boiler next to the 19,000 m3 heat accumulator.
Beyond this, an energy hub with waste heat from a data centre and an electricity substation will be integrated in 2027. This combination of production assets will be able to replace 99 % of the current gas-fired CHP and boilers.
The district heating system has many interdependencies, any changes may have a broader impact - something at one end has an impact somewhere else. At the same time, in the new decentralised setup, the company needs to understand in detail what's happening throughout the system and be ready to take corrective action within a much shorter time interval (i.e. virtually in real-time).
To fully harness the potential of this transformation and the enhanced system flexibility provided by the new assets, optimal control of the heating grid through real-time optimisation was essential. This is why Viborg Varme required innovative digital tools to achieve this goal.
The starting point was the implementation of several IT solutions that collect data individually in separate data silos, optimising different parts of the heating system such as heat production, distribution, and consumer data. However, to operate the network with the highest possible efficiency and security of supply, Viborg Varme needs to be able to optimise its operation across the entire system end-to-end.
Solution
Following a search for a long-term digitalisation partner, Viborg Varme decided to team up with Gradyent and implement Gradyent's Digital Twin. A Digital Twin is a digital copy of the end-to-end physical heating system, which combines geographical, weather, and sensor data with physics-based models and AI. The first phase of the project involved the creation of the Digital Twin of Viborg Varme’s distribution network end-to-end, also considering each individual user connection.
As our district heating network is growing in complexity, having an end-to-end view of the system is critical. In our search for a digital partner, Gradyent emerged as the only player that can achieve this end-to-end view in real-time.
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Results
Towards heating network control
The first phase in the implementation of the Digital Twin focused on the distribution network control. The goal is to optimise the forward temperatures in real-time, which is crucial to enabling higher heat pumps’ COPs.
The Digital Twin also provides deeper insight into areas of the network where sensors are not present, giving operators an improved understanding of the network. The solution is therefore not limited to areas where all data points are in place and accessible.
Operators can see the supply area of each heat production unit and improve their understanding of the system dynamics. The online Digital Twin Platform serves as the single source of truth; it’s updated every few minutes and shows the current state of the network, and historical states can be replayed as needed.
Live temperature optimisation
The Digital Twin temperature optimisation is now running live, and operators will be using the delivered setpoints live in the control room. Optimal temperature setpoints are sent for 6 control locations in the network for the next 24 hours ahead.
Thanks to temperature optimisation, it is estimated, based on the network operation in 2023, that Viborg Varme could save EUR 50,000-110,000 and 100-390 tCO2 per year by reducing thermal losses in its distribution network.
Analyses of historical data and conditions have shown that Viborg's network can be operated with 2-5 °C lower flow temperatures, depending on the season. This is significant considering Viborg Varme's current very low flow temperatures.
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The Digital Twin has proven valuable in several specific cases. For example, the solution enabled a rapid scenario analysis for the replacement of a main pipe that resulted in uncertainty around changed dimensioning and pressure conditions in the network. Thanks to this, the company achieved 2-5 % reduction in heat loss and 1-3% energy savings for heat pumps due to increased COP values for these at lower temperatures.
Supporting network growth
To provide optimal recommendations, Gradyent ensures that the Digital Twin is continuously updated and in sync with real-life circumstances. This is particularly relevant for Viborg Varme as the company keeps onboarding new customers with an estimated network growth of 40% over the next seven to ten years.
As Viborg Varme’s district heating grid is rapidly changing, the Digital Twin will play a crucial role in effectively managing the growing system complexity and providing a resilient heating supply at the lowest possible price with minimal CO2 emissions.
“The Digital Twin has already given us a valuable overview of the network and the supply areas of the production units, which has made it possible to quickly control the new production sources into the network. At the same time, the first tests show that we can lower the flow from 65 to 62 degrees without problems. This means less heat loss in the pipeline network and higher efficiency of the heat pumps, which means cheaper and greener district heating.”
Tom Diget, Viborg Varme