“Wood-based carbon dioxide generated by the forest industry is a significant side stream that could be utilized better,” says Pirita Mikkanen, VP, Energy at Metsä Group.
Wood-based carbon dioxide could replace industrial fossil carbon dioxide or be used to balance the production and consumption of energy as the use of wind and solar power increases. During production peaks, excess energy and captured carbon dioxide could be utilised in the production of synthetic fuels. Carbon capture could also help combat climate change.
Pulp and bioproduct mills are ideal for carbon capture
Carbon Capture and Utilisation (CCU) is a process in which carbon dioxide is captured from industrial processes or directly from the atmosphere and used in production.
“Industrially viable carbon capture requires a sufficient point load. In practice, this means a pulp or bioproduct mill that produces a steady volume of carbon dioxide,” says Mikkanen.
Metsä Fibre generates wood-based carbon dioxide at its pulp and bioproduct mills as part of the combustion reaction of the soda recovery boiler and lime kiln, which are part of a pulp mill’s chemical recovery process.
The mills produce approximately 10 million tonnes of carbon dioxide annually, and around 80–90 per cent of it could be captured. Metsä Fibre’s sawmills produce carbon dioxide in thermal energy production, but the amounts are insignificant, making the sawmills unsuitable for a recovery plant for carbon capture.
The study conducted with ANDRITZ focuses on the capture of four million tonnes of carbon dioxide from a mill the size of the Kemi bioproduct mill. The work follows on from the carbon capture study launched in 2023. The project will proceed to the pilot phase in Metsä Fibre’s mill area in Rauma in 2025.
Fuels from wood-based carbon dioxide
Carbon dioxide has a variety of uses. At pulp and bioproduct mills it is used in the parcelling of tall oil, while the food industry uses it to carbonate soft drinks and beer, for example.
Power-to-X (P2X) processes allow carbon dioxide to be combined with hydrogen to produce methanol or other hydrocarbons for fuels or the manufacture of chemicals. This helps to reduce dependency on fossil raw materials.
P2X processes have yet to become competitive against comparable fossil products. Therefore, a political driver is needed to boost their further development. This could be, for example, a statutory obligation to mix fuels, requiring the mixing of a certain amount of biofuel with fossil fuels such as petrol or diesel oil.
Renewable energy enables greater production capacity
The use of carbon dioxide in the hydrogen economy is limited by the availability of energy. The utilisation of all the carbon dioxide produced by Metsä Fibre’s production plants in the hydrogen economy would consume approximately two thirds of Finland’s current power production.
Renewable energy could be the solution to this problem. The number of wind power projects in development in Finland greatly exceeds the current need for power. If all the envisaged projects were to be realised, the amount of power produced by wind plants annually would be significantly higher than it is now. Thus, there is potential for greater energy production capacity.
This article was originally published in Fibre Magazine issue 2025.