Wien Energie: Reducing forward temperature by 4 degrees

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For two years, Wien Energie has been optimising various heating grids by working with Gradyent’s Digital Twin Platform, and by doing this, has decreased heat loss and CO2 emissions and saved operating costs. In April 2023, Wien Energie and Gradyent are starting the heat pump optimisation project to lower the temperature of the thermal network in Oberlaa.


Wien Energie plans to be net zero by 2040 regarding district heat. The target state includes a substantial share of heat pumps and geothermal. In order to make this possible, the entire Wien Energie grid requires a major transformation. Digitisation is recognised as a key enabler and therefore Wien Energie follows an open innovation approach including transformation and innovation of its heating systems.


In 2021, Gradyent participated in the Wien Energie Innovation Challenge. For this competition, within 6 weeks Gradyent developed a Digital Twin for one of the nearly 600 secondary networks of Wien Energie to showcase the value of temperature optimisation for the grid and won the competition.

With the real-time Digital Twin Platform, Gradyent created a digital copy of the complete grid that runs in real-time, combining geographical, weather, and sensor data with physics-based models and AI. Digital Twin provided insights for the entire system – even for places where no data or smart meters were available. After this successful pilot, Wien Energie and Gradyent expanded their collaboration and developed Digital Twins of other secondary networks to scale up the savings and impact.

Seeing the results of digital twin integration, Wien Energie saw a lot of potential in this approach: if rolled out to the 20 largest secondary networks, the company could save up to 4,000 MWh of heat.


With the Digital Twin, we ensure our district heating network is fit for the future! By optimising the temperature, we can reduce the forward temperature in the selected district heating secondary networks by an average of 4 degrees. This enables us to deliver valuable heating energy to our customers even more efficiently.”
Michael Strebl
CEO Wien Energie


Lowering the temperature and heat loss and saving operational costs

Ines Lindmeier, Project Lead Smart Thermal Networks at Wien Energie: "We connected the first network in just a few weeks and have been successfully using the Gradyent Digital Twin for temperature optimisation in various networks for two years."  

In those two years of temperature optimisation, Wien Energie has decreased heat losses and CO2 emissions and saved operating costs. For instance, as the result of Digital Twin integration, the temperatures were dynamically reduced on average by 4°C.

Besides the direct savings, the security of supply could be increased, and valuable insights could be delivered on the network showing a detailed potential on return temperature, hydraulics, and pump efficiencies. By building the Digital Twin, Wien Energie gathered valuable insights about the behavior of their network. Anomalies, alerts, and maintenance as well as potential savings in networks including heat pumps have been outlined leading to a deeper understanding of the Digital Twin value at Wien Energie.

Expanding to heat pump optimisation to increase efficiency and added value

From February 2023, Wien Energie and Gradyent expanded the cooperation to further optimize the Wien Energie heating system by optimising the heat pump operation at the bathing spa “Therme Wien”. By lowering the forward temperature in the district heating network, the efficiency of the heat pumps in that network will be increased. By lowering the forward temperature, the company expects to save up to 10% electricity consumption from the heat pump. That means that around 10% more heat can be produced with the same amount of electricity.

This project is partially funded with an Austrian research grant. The first results are expected in mid-2023.

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