Turning pulp mill emissions into renewable value

Mitigating climate change and replacing fossil raw materials have brought biogenic carbon dioxide into a new light. Experts believe that biogenic carbon dioxide recovered from pulp mill flue gases could be the key to a new industrial revolution.  

In early September, Finnish forestry company Metsä Group announced that it had launched a pilot project in Rauma – a coastal town in western Finland – to test the capture of carbon dioxide from pulp mill flue gases in collaboration with its technology partner Andritz. Although similar technology is already in use globally in coal-fired power plants and waste incineration plants, among others, its application in the forest industry is new.   

“So far, it looks like the technology also works well with pulp mill flue gases,” says Kaija Pehu-Lehtonen, head of Metsä Group’s carbon dioxide capture project.  

The goal of Metsä Group’s pilot project is not yet commercial exploitation. Still, there is a bigger vision beyond it: in the future, biogenic carbon dioxide could be used as a raw material in the production of synthetic fuels and chemicals, among other things, as the hydrogen economy develops and solutions that replace fossil fuels become more common.   

According to Pehu-Lehtonen, various process conditions will be tested at Metsä Group’s pilot plant in Rauma during the autumn, affecting factors such as energy consumption, the need for flue gas cleaning, and the quality of the captured carbon dioxide.   

The pilot plant, which started up at the end of June 2025, is capable of capturing around one metric ton of carbon dioxide per day.  

“Based on the results of the five-month pilot, we will also investigate the possibility of building a larger-scale pilot plant with a capacity of 30,000–100,000 tons of captured carbon dioxide per year. This would be more than a hundred times the capacity of the current pilot plant.”   

However, no decision has yet been made on the construction of a larger pilot plant. The reason for this is that the investments are significant and the market for biogenic carbon dioxide is still developing, according to the company. For carbon dioxide capture to be economically viable, partners are needed who can utilise the captured carbon dioxide in their own production processes. The entire value chain must be economically viable.  

“We are proceeding with the project in stages. The value chains from raw materials to finished products are often new and complex, so close cooperation and understanding of industrial operations are required between the parties involved,” Pehu-Lehtonen explains.  

Biogenic carbon dioxide can accelerate the green transition    

Professor Kristian Melin at the LUT University in Finland sees value in Metsä Group’s pilot in that it provides new information on carbon dioxide capture from forest industry processes:  

“It’s good to test how the technology works in forest industry processes. If we can obtain valuable information on a smaller scale, we can ensure that when larger plants are built in the future, everything will work as expected.”  

Bio-based carbon dioxide from pulp mills is currently an almost completely untapped by-product. It could have great potential, and its importance will grow as the hydrogen economy advances and the production and demand for synthetic fuels increase.  

“In practice, current fuels – methanol, methane, kerosene – contain carbon. And a convenient and environmentally friendly source of carbon is precisely captured biogenic carbon dioxide,” Melin explains.  

According to the professor, capturing biogenic carbon dioxide not only promotes climate goals but can also create new business and export opportunities for forest companies.  

“Biogenic carbon dioxide is not just an emission, but a renewable raw material that can link the forest industry and the hydrogen economy. As the hydrogen economy develops, this by-product could become a key part of the green transition.”  

A versatile substitute for fossil raw materials  

Biogenic carbon dioxide (CO₂) originates from renewable sources such as wood, biomass, and agricultural by-products. Unlike fossil CO₂, which adds new carbon to the atmosphere, biogenic CO₂ is part of the short-term carbon cycle and can be used in a more climate-neutral way.  

Captured biogenic CO₂ can replace fossil raw materials in fuels and chemicals. Combined with green hydrogen, it enables the production of synthetic fuels such as jet fuel, methanol, and methane. It also has applications in fertilisers, plastics, and construction. For example, the Finnish company Carbonaide uses CO₂ to strengthen concrete and make it carbon negative, while U.S.-based Carbix develops technology that turns emissions into durable building materials.  

According to Pehu-Lehtonen, Metsä Group’s goal is now to accelerate the emergence of the market, but success also requires political decisions:  

“Market development depends on EU and national regulations as well as green transition investment subsidies. Government subsidies for the green transition play a key role in accelerating industrial investment.”  

Emissions are reduced, and competitiveness increases  

The use of biogenic CO₂ as a raw material for synthetic fuels and materials can significantly reduce emissions, especially if hydrogen is produced with renewable electricity, says Professor Melin. Replacing fossil fuels also brings opportunities for the Finnish forest industry.  

“The international competitiveness of the forest industry can be strengthened, especially in markets where the state or the EU uses steering measures such as blending obligations,” Melin adds.  

A blending obligation means that fuel distributors must blend a certain proportion of renewable or low-emission fuels, such as synthetic fuels, into fossil fuels. This also creates demand for the most environmentally friendly fuel options, which might otherwise not be competitive in terms of price.  

Professor Melin considers air transport to be a particularly promising sector from the perspective of the forest industry and the bioeconomy more broadly. EU regulation, in particular the ReFuelEU Aviation Regulation, is creating strong demand for more sustainable aviation fuels, including both bio-based and synthetic alternatives.  

“In 2030, the EU is set to use at least 3 million tons of more sustainable bio-based aviation fuel, which will open up significant markets for renewable fuel producers,” Melin emphasises.  

The targets will increase further in the 2050s, which, according to the professor, could make Finland and Sweden leading players.   

“The countries have the advantage of abundant sources of biogenic carbon dioxide. Finland also has relatively inexpensive electricity, which is essential for the production of renewable hydrogen.”  

For production or storage?   

In early September, Finland and Norway signed a memorandum of understanding that will enable carbon dioxide to be transported from Finland to Norway for storage in geological formations in the seabed.  

“This memorandum of understanding with Norway is a significant step for Finland towards the large-scale implementation of carbon dioxide capture and cross-border storage solutions,” said Sari Multala, Finland’s Minister of the Environment and Climate, in a press release.  

Norway already has nearly 30 years of experience in the safe storage of carbon dioxide in the seabed and is developing storage into a commercial service for other European countries. According to Melin, this kind of cooperation complements Finland’s own solutions and enables a more diverse climate policy.  

“Technical carbon sinks and cross-border storage can certainly complement the utilisation of biogenic carbon dioxide, but in Finland’s conditions, manufacturing products from it is a more practical solution,” Melin says.  

The market for biogenic CO₂ is expected to grow, but political steering will have a key role. If the price of fossil fuels is raised through taxation or emissions trading, green alternatives will become even more attractive.  

“Of course, there is always a risk that politicians will decide to abandon some of their goals. In any case, it is worthwhile to find ways to make the technology as cost-effective as possible,” Melin says.