Gradyent chosen to power digital transformation of Tallinn’s heating system

Utilitas has entered into a multi-year partnership with Gradyent to implement a real-time Digital Twin of the capital city’s district heating system – one of the largest and most complex systems in the Baltic region. The collaboration marks a major step in Utilitas’ digitalization strategy as it supports the ongoing development of the system to accommodate continuous growth, new production assets, and ambitious decarbonization targets.

Tallinn’s district heating system is a critical part of the city’s energy infrastructure, supplying heat to 4,950 buildings and 194,000 households across a network of 536 km of pipes. With an annual heat demand of roughly 2 TWh, it is one of the larger systems in Europe.

Today, 70% of Tallinn’s heat production is renewable, and Utilitas has committed to raising that share to over 90% by 2027. To reach that goal, the company has been transforming its production landscape. New heat pumps, electric boilers, and thermal storages are being added to an already diverse portfolio that includes large-scale CHP plants and high-efficiency boiler plants.

At the same time, Utilitas is modernizing and reconstructing its district heating system, gradually lowering operating temperatures to improve performance and enable greater integration of climate-neutral heat, while continuing to expand the system as new buildings connect.

“Tallinn’s district heating system is growing, both in scale and in complexity. To operate it efficiently, we need full visibility and the ability to test decisions before implementing them in the real world. With Gradyent’s real-time Digital Twin, we gain a live, systemwide model that lets us simulate and validate operational decisions before applying them in the field. This technology gives us the visibility, predictive capability, and confidence we need to accelerate the transition toward a smarter, more sustainable energy system.”

Janek Trumsi, Chief Technology Officer at Utilitas

Complexity rises faster than visibility

As Utilitas’ heating system continues to evolve, its operational complexity has increased significantly. With more assets, variability, and interdependencies, the system now requires more advanced tools than traditional methods that don’t consider the full system end-to-end.

After evaluating the market, Utilitas selected Gradyent for its proven ability to model large, dynamic district heating systems and deliver actionable insights directly into daily operations.

The implementation process includes:

• Building a high-fidelity, real-time Digital Twin of Tallinn’s full 536 km network
• Integrating real-time SCADA and weather data
• Calibrating the model to reflect the behavior of both existing and upcoming production assets
• Deploying optimization modules focused on temperature, losses, and operational efficiency

This phased approach ensures that Utilitas can start benefiting from the Digital Twin immediately while keeping the door open for future extensions into production optimization and flexibility management.

Proven value for end users

Estonia uses a fully regulated, ex-ante cost-plus pricing model for district heating. This means companies must get tariff changes approved in advance, and prices are based strictly on actual costs with a regulated return added. Because of this, any efficiency gains – like reduced heat losses, higher COP, or lower maintenance costs – can directly lower prices for end users.

By optimizing forward temperatures, improving heat pump performance, and supporting more efficient production planning, Gradyent’s Digital Twin will help Utilitas reduce system losses and operate more efficiently, contributing to stable and affordable heat delivery.

Building the digital backbone of Tallinn’s energy future

With the Digital Twin now live across part of the network, operators already benefit from improved system visibility and faster reaction times. The ability to simulate operational scenarios enables more confident planning as new assets, including heat pumps, e-boilers, and storage, are integrated into the system.

By implementing a real-time, end-to-end Digital Twin at the core of operations, Utilitas is building the digital backbone of Tallinn’s heating infrastructure – positioning the city as one of the most forward-looking district heating systems in the Baltic region and a model for how capital cities can scale renewable heat while maintaining operational excellence and affordability.

“Tallinn’s system is entering a new era of scale and complexity as new and renewable assets scale rapidly. By embedding a real-time Digital Twin at the core of operations, Utilitas is redefining how a capital-city heating system is managed in Northern Europe. We’re proud to support them with technology that delivers clarity, control, and measurable efficiency gains from day one.”

Martino Dossi, Chief Operating Officer at Gradyent