Digital Twin helps Porvoon Energia manage the transformation of heat production

Porvoon Energia is integrating waste heat, heat pumps and thermal storage into its district heating system, transforming the way heat is produced and managed. Heat and Production Manager Ari Raunio explains why production assets and the network can no longer be planned separately, and how a real-time Digital Twin helps optimize them as one system.

Originally published in Finnish by Kaukolämpö ry on 31 August 2026 as "Digitaalinen kaksonen auttaa Porvoon Energiaa hallitsemaan lämmöntuotannon murrosta". Translated and republished in English by Gradyent with the publisher's permission. Read the original at kaukolampo.fi.  

Porvoon Energia's business portfolio is broad. Alongside district heating, the company also sells electricity and operates the local electricity grid, and it has carried out energy renovations for individual customer sites.

Ari Raunio, Heat and Production Manager, says that although the whole sector has been in transition in recent years, in Porvoo the change began considerably earlier.

"In 2014 our heat production was practically entirely based on biofuels, so in principle we had already completed our move away from fossil fuels," Raunio says. "At the same time we started thinking about the next steps forward, since our older power plant is nearing the end of its life. Heat production across the district heating industry is electrifying fast, and this affects us too."

In 2018 the company carried out a study on what district heat production in Porvoo could look like in 2035. At the start of the study, the top priority was ensuring heat production in all situations.

"We started building a thermal storage facility, which was completed during the COVID period in 2020. In 2022 that storage really proved its worth amid the war in Ukraine and the energy crisis," Raunio says.

By this stage the company already had many different production options on the table, such as utilizing waste heat and heat pumps. One distinctive feature is using the district heating return line to heat a school.

"There were, and still are, many variables in district heat production. As this grew more complex, we needed outside expertise, and that's how Gradyent was chosen as our partner," Raunio says.

Image: Ari Raunio during the Kaukolämpö ry interview

Multiple heat sources in the Digital Twin

The need to simulate different production scenarios was one reason that led to choosing Gradyent and, soon after, to creating a real-time Digital Twin. Gradyent helped Porvoon Energia map available waste heat sources as well as sites where return heat could be used as efficiently as possible.

"This development fits well with the company's vision, but the need also comes from changes in the operating environment that we've had to adapt to," Raunio reflects.

The company is currently looking for a fairly large, 30 MW waste heat source to replace a retiring heating plant by 2030.

"Whether that ends up being a hydrogen plant or a data center, I can't say yet," Raunio adds. "We don't currently have industry near the network with waste heat we could make efficient use of."

The overall picture is complex compared to the traditional model, where a single point-source power plant feeds heat into the whole network.

"In the traditional model, pressures and temperature levels are relatively easy to manage. In the new type of district heat production, different parts of the network have different temperature and pressure levels, and heat sources of varying quality," Raunio says. "Of course, backup plants have been run during hard frosts before too, but they follow the same profile as the main plant. Now every heat source in the network is unique."

Image: Porvoon Energia

Gradyent as the operator's right hand

There are so many different ways to run the system that a tool like Gradyent's Digital Twin has become essential. From the operator's perspective, the traditional challenge has been keeping pressure and heat sufficient at every point in the network. The amount of near-real-time data and options is now so large that hitting the best decision every day is hard without a physics-based model of the whole system.

"On the other hand, the optimal way of running the system can differ from the forecast. The operator needs an up-to-date picture of the network and how it's behaving," Raunio says. "Porvoon Energia's production plants are also being synchronized with Gradyent's tool. A view of production alone, or of the network's state alone, isn't enough: the two need to communicate with each other."

Contrary to what was originally planned, the new forms of production aren't arriving in stages but almost all at once. The company faces a winter with new equipment and new production types.

"If you think back to our 2018 study — what hasn't happened since then?" Raunio asks, laughing. "Since 2019 we've been living through a kind of continuous state of exception. Nothing has gone the way we planned it in that study."

Porvoon Energia and Gradyent began working together in 2023, initially on the planning side, where Raunio says valuable insights emerged.

"Simulation in particular has been useful as we've studied the network's characteristics and behavior under different operating conditions," Raunio says. "Gradyent's tools have given us confidence that our development work is heading in the right direction."

The Digital Twin has also been used to simulate scenarios for utilizing return heat and where in the network it works best. Raunio believes that in the future, mastering various tools will also be a normal part of an operator's everyday work.

"Our goal is an autonomous network, where the operator only steps in when truly necessary to interrupt operations, if there's a real reason to do so. In autonomous operation, costly safety margins are eliminated, and charging and discharging the thermal buffers is automated," Raunio says.

Image: Gradyent's Digital Twin platform inside Porvoon Energia's control room

Production plants and the network are one

Large fluctuations in outdoor temperatures, now and in the future, make forecasting and operational planning increasingly challenging. The network's temperatures and production schedules also need to be synchronized inside one tool. Raunio says that at the scale of Porvoon Energia's network, this is achievable.

"Production plants and the network are one whole," he sums up. "It's impossible to talk about real optimization if the view only covers production. We keep developing this visibility further together with Gradyent. We see the need in the network, and figure out how that heat can be produced in the most economically sensible way."

A district heating company has to operate so that district heating is the best option for the customer — including on price. That takes unbiased, open-minded development work.

"I'd call for courage to try new solutions. Old ways of thinking need to be shaken up," Raunio says. "We've now been working with Gradyent for a few years. Gradyent hasn't just been a system supplier, but a partner we hold meetings with practically every week."

Image: Ari Raunio and Petter Nissinen

Grounded in the laws of thermodynamics

Gradyent treats regular contact and hands-on collaboration as central to its client relationships. At times, Gradyent's people have sat alongside Porvoon Energia's staff in the control room. New operational situations deepen Gradyent's own understanding, because the Digital Twin is above all part of operators' daily work.

Petter Nissinen, Account Executive for the Nordics at Gradyent, sees Finland as a frontrunner.

"District heating has been the main form of heating in Finnish cities for decades, so the systems and their development possibilities are well understood. Another good thing about this sector is that companies barely compete with one another," Nissinen says. "Experiences are shared openly in Finland and across borders, and good practices spread."

Nissinen notes that in district heating, everything is ultimately governed by the same laws of thermodynamics, which don't change between Porvoo and, say, Warsaw.

"Right now there's strong electrification underway, as electric boilers paired with thermal storage, and heat pumps upgrading waste heat, are becoming more common," Nissinen says. "For many district heating companies this means production becomes decentralized across the network, and the new electricity markets force faster decisions. That's why it's no longer possible to view electricity trading and the optimization of production and the network as separate matters. In the future, precise end-to-end control and the ability to unlock full-system flexibility will become increasingly important."

Text: Justus Luokkanen 

Photos: Gradyent & Porvoon Energia