Solar power plant completes the transition to carbon-neutral energy at Mirka’s Oravainen factory

Adven – News – Solar power plant completes the transition to carbon-neutral energy at Mirka’s Oravainen factory

29th April 2025

News Industries Large properties

Mirka, the world’s leading manufacturers of abrasive products, is carrying out a major energy transition at its Oravainen factory in Finland, in collaboration with Adven. The project will make the site’s heating and cooling system fully carbon neutral.

The energy solution combines geoenergy, solar power, an electric boiler and a heat recovery solution previously introduced at the factory. The final phase of the project is the construction of the solar power plant. Once completed, the Oravainen factory will begin using solar electricity in its production in the summer of 2025.

Fossil fuels were replaced with renewable energy

The first phase of the project, the renovation of the energy center at Mirka’s Oravainen factory, was completed in November 2024. During the renovation, old oil boilers were replaced with heat pumps and an electric boiler. The existing pellet boiler, which previously served as the main heat source, was retained as a backup. The combination of the new electric boiler and the old pellet boiler ensures sufficient heating capacity, even during the coldest winter temperatures.

“The dismantling of the old heating plant and the installation of the new energy center stayed well on schedule, and there were no heating outages for the customer. Based on our first winter’s experience, the renovated energy plant operates excellently as planned,” says Lasse Aitamaa, Manager, Technology and Projects at Adven.

Geoenergy is ideal for cooling industrial processes

Carbon-neutral heat for Mirka’s factory is produced using heat pumps, which draw their energy from both the factory’s waste heat and geoenergy sources. The geoenergy system is based on a geoenergy field consisting of 80 wells drilled to a depth of 350 meters. In addition to heating, the geoenergy system also provides cooling for the factory’s production processes.

A regenerative, air-cooled unit has been installed alongside the geoenergy system. It produces heat from outdoor air when the outside temperature is significantly higher than the temperature in the geoenergy wells. The unit also regenerates the geoenergy field, warming it after a cold winter, which improves the system’s efficiency and output in the following season.

Solar power plant nearing completion

The final phase of the project, the construction of a 2.5 MWp ground-mounted solar power plant, is currently underway in spring 2025. Once completed, it will supply renewable electricity to both the factory and its energy center. According to Aitamaa, the installation is progressing smoothly, with most solar panels already in place.

The field area next to the Oravainen factory has been utilized as efficiently as possible for renewable energy production, as both the geoenergy field and the solar power plant are located on the same site. The geoenergy wells have been drilled between the rows of solar panels. According to Aitamaa, combining large ground-mounted solar power plants with geoenergy systems is rare.

“To my knowledge, there haven’t been many similar energy solutions implemented in Finland, as solar panels used for property energy production are typically installed on rooftops,” Aitamaa says.

Adven has previously built a solar power plant of similar size at Mirka’s Jeppo factory, and according to Aitamaa, the experience has been very positive. Adven aims to have the energy system renewal fully completed by July, at which point the solar power plant will be connected to Mirka’s main electrical system. Through this connection, solar power can be utilized in the factory’s production processes.

The solar power plant will also be connected to Finland’s national grid, allowing any surplus solar electricity to be fed into the system and made available to other electricity users.

Lasse Aitamaa

Manager, Technology and Projects,

Strong local and customer collaboration key to success

The project has involved numerous local contractors and construction companies in different phases, including the drilling and piping of geoenergywells and the earthworks for the solar power plant. “Collaboration with local contractors has been a key factor in the project’s success,” Aitamaa says.

The collaboration with the customer has also been strong throughout the project. “Cooperation with Mirka’s personnel has gone exceptionally well. For example, we installed the power center together with Mirka’s own electrical and HVAC experts. It’s been great to see the shared commitment to getting everything just right,” Aitamaa praises.

“The project at Mirka has been a great example of how Adven’s extensive expertise in geoenergy and industrial energy can be brought together. And receiving positive feedback also from Mirka has been incredibly rewarding,” he adds.

Project highlights

Mirka’s Oravainen plant will reduce CO₂ emissions by approximately 281 tons per year
Heating and cooling system based on geoenergy, solar power, and waste heat recovery
80 geoenergy wells, each 350 meters deep
2.5 MWp solar power plant
1 MW heat pump capacity
600 kW electric boiler
700 kW pellet boiler as backup
Energy center renovation completed in November 2024
Transition to solar power in summer 2025