Tervakoski builds new €100 million production line amid paper mill closures

While paper mills across Finland shut down, Tervakoski Oy in Janakkala is expanding with a new €100 million production line for pressboard used in electrical transformers, Yle reports.

The line, set to launch next year, will produce specialty pressboard—a material in high demand due to global electrification. It will create 20–30 new jobs.

This marks the first entirely new paper or board production line built in Finland since the 1990s. Tervakoski Oy’s CEO Christopher Diesen cited soaring global demand for pressboard, used as insulation and structural support in large transformers, as the driving force behind the investment.

The mill has also spent €50 million in recent years electrifying its steam production, now powered by what it calls the world’s largest steam heat pump—a 13 MW unit paired with a 50 MW electric boiler. The system, with an efficiency exceeding 100%, recovers excess energy and has allowed the plant to phase out fossil fuels.

Test runs on the new line are planned for August 2027, with full production expected by September. Management acknowledges it may take up to a year to reach optimal efficiency, though quality standards will be prioritized from the start.

Energy manager Petri Malkamäki noted that the shift to electrification was made possible by Finland’s growing wind power capacity, making electricity a competitive energy source. The electric boiler, when operating at full capacity, consumes 50 MWh per hour—enough to power 2,000 average homes annually.

For workers like operator Pekka Tamminen, a fifth-generation employee, the investment is a rare positive development in an industry dominated by closures. Forest economist Marjo Maidell of Pellervo Economic Research confirmed that while paper production has declined, the forest industry has increasingly diversified into other products.