Further modernisation at Gratkorn brings increased sustainability dividends

Over the past few years, Sappi’s Gratkorn mill in Austria has been undergoing a multi-million-euro modernisation as part of Sappi Europe’s ongoing commitment to significant decarbonisation. The latest stage of the project focuses on increasing capacity for the delivery, handling and processing of biomass to feed the plant’s state-of-the-art boiler. Co-created through an alliance of technology, nature and people, it’s a key strand of Sappi Europe’s push towards a low-carbon future.

The updated boiler, which previously ran on coal, requires up to 300,000 tons of biomass a year to power it – a considerable amount. Consequently, the existing biomass infrastructure at the mill needed upgrading, alongside improved transport logistics and the construction of intermediate storage terminals in the surrounding region. 

The project, which also received funding from the European Union, has been split into two parts. BioFit Step 1 focused on the handling of biomass at the mill and required the building of two storage silos – each of 10,000m3 – alongside an open storage area of 5,000m2. Conveyor belts to move the biomass around were also constructed. 

The second phase, BioFit Step 2, is nearing completion. This has involved the building of railway infrastructure to deliver the biomass to the mill – something that improves efficiency at the same time as reducing scope 3 transport emissions. Unloading tracks, a terminal and a photovoltaic system are also being constructed, as well as another silo for biomass storage. 

Why Gratkorn modernisation is a key step in Sappi Europe’s sustainability journey
Modernising Sappi’s largest production site in Europe was always going to be a vital element within Sappi Europe’s decarbonisation roadmap. This is a mill that produces 950,000 tons of premium, multi-coated paper for magazines, brochures, books, art catalogues and labels, alongside containerboard and 250,000 tons of pulp. 

Significant levels of energy are inevitably required to run a mill of this size. Until 2021, much of Gratkorn’s production was powered by a coal-fired boiler. After that, however, a EUR 35m-plus investment in state-of-the-art technology converted the power plant boiler to running wholly on biomass and natural gas – resulting in a near -30% reduction in the mill’s carbon footprint. 

Modernising the boiler was a massive venture three years in the making that, at the busiest times, involved more than 200 people working together in dedicated teams. The complexity of the boiler re-build project, meanwhile, required a huge effort across engineering disciplines. 

“The BioFit project is an important step for Gratkorn on our path to decarbonisation,” says mill director Peter Putz. “We have the largest biomass plant in Austria and, with this project, have created the necessary infrastructure to continue to consistently replace fossil fuels. After the successful implementation, we will be able to save a further 100,000 tonnes of CO₂ per year – with the aim being to progress towards an ever-greater share of renewables.”

Working in alliance with nature and technology
The biomass that now fuels the boiler comes predominantly from residual woody biomass and valuable black liquor recovered during the pulping process. As part of Sappi’s continuous commitment to harnessing the power of nature and to making the most efficient use of resources, biomass is being sourced from residual materials from across the forest industry value chain – from harvesting operations through to product manufacturing. 

That final switch to all-renewable energy will come when the use of natural gas is also phased out in favour of biomass. “Our ultimate goal is to use only sustainable and renewable fuels,” continues Peter Putz. “This will also make us more independent in the future, especially in times of gas shortages and uncertainty on the energy market.”

The Gratkorn project is scheduled for completion by mid-2025. Thanks to the incremental increase in the use of biomass and reduced use of natural gas, the plant has already lowered its fossil-based CO₂ emissions by 35% compared to 2019 – equivalent to more than 200,000 tons of CO₂ a year. That reduction is estimated to rise to 55% reduction by project completion.  

This project is just one of 80 projects that Sappi Europe has implemented across its mills as part of its ambitious decarbonisation roadmap. The company’s objective has been to reduce emissions of CO₂ by 25% and increase the share of renewable energy by 50% by 2025 (compared to 2019). By the end of 2024, company-wide emissions had already reduced by 48%, with the share of renewable energy at a level of almost 65%. 

These developments at Gratkorn vividly illustrate the effort and industry going into reaching and surpassing our targets right across the company.