Stora Enso commissions Valmet for the energy modernization of its Ostrołęka containerboard mill

A strategic upgrade for higher RDF utilization

The push for energy efficiency and circularity in the packaging sector continues to drive significant industrial investments. Stora Enso has officially awarded Valmet the contract to modernize the circulating fluidized bed (CFB) boiler at its Ostrołęka pulp and paper mill in Poland. This facility, a cornerstone of Stora Enso's Packaging Materials division, is dedicated to the high-volume production of recycled containerboard and kraft paper.

The decision to upgrade the boiler, originally delivered by Valmet in 2010, responds directly to the mill's evolving energy matrix. Over recent years, the Ostrołęka plant has steadily increased its reliance on refuse-derived fuel (RDF). While this shift supports circular economy goals by diverting waste from landfills and reducing fossil fuel dependence, it also introduces complex operational challenges, particularly concerning bottom ash management and coarse material accumulation.

Technical scope and operational impact

To address these bottlenecks, Valmet's engineering intervention will focus on the lower section of the CFB boiler. The modernization package includes the complete replacement of the boiler bottom, the integration of an upgraded coarse material removal system, and the installation of a new bottom ash sieving system. Additionally, the agreement covers a two-year supply of spare parts to guarantee long-term operational stability.

Przemysław Niedźwiecki, Engineering and Investments Manager at Stora Enso Narew, confirmed that as the share of RDF increased, the operating conditions of the boiler changed significantly. This targeted upgrade is designed to resolve specific material handling challenges, thereby reducing sand consumption and minimizing unplanned maintenance stops.

From the supplier's perspective, Jouni Koskinen, Senior Manager of Rebuild and Conversion Technologies at Valmet, emphasized that this project builds upon a long-standing lifecycle service partnership between the two companies, ensuring that the 2010 infrastructure adapts to 2026 operational demands.

Execution timeline and market context

The financial value of the order, which was booked in Valmet's third-quarter 2026 results, remains undisclosed. However, the execution timeline is firmly set. The physical installation of the upgraded equipment is scheduled to take place during the Ostrołęka mill's annual maintenance shutdown in June and July 2027.

For the European containerboard market, this investment highlights a broader industry trend: the necessity to continuously retrofit existing energy infrastructure to handle alternative fuels efficiently. By optimizing its CFB boiler, Stora Enso not only secures the operational reliability of a critical packaging materials plant but also reinforces its capacity to maintain competitive production costs in a demanding macroeconomic environment.