From Research to Full Scale: Danish Collaboration Paves the Way for Pyrolysis as a Green Energy Technology

The agricultural and transport sectors account for a significant share of Denmark’s greenhouse gas emissions. To achieve climate neutrality, it is therefore necessary to continue developing innovative technologies such as pyrolysis, which the Danish government states can deliver reductions averaging 1.2 million tons of carbon per year by 2035.

In the SkyClean Scale-up project, companies and researchers have joined forces to mature and scale up the SkyClean pyrolysis technology and to investigate the stability of biochar in soil as well as its CO₂ storage, environmental and fertilizer effects. The partners are now presenting new experience and research indicating that pyrolysis offers major benefits for industry, climate and the environment alike.

World’s largest industrial pyrolysis plant is ready
In October 2024, Stiesdal inaugurated the world’s largest pyrolysis plant, with a capacity of 20 MW, in Vrå and has just received a new expansion permit. The plant uses biogas digestate fibres from the Agri Energy Vrå biogas facility and delivers biochar for carbon storage and green energy to replace fossil fuels. Annually, the plant can store up to 28,000 tons of CO₂ through the production of biochar and displace natural gas corresponding to 9,500 tons of CO₂.

“We believe that Denmark can be a beacon for how pyrolysis can be implemented internationally. We have built a 20 MW plant in Vrå that can deliver high-quality biochar for carbon storage of more than 20,000 tons per year. Furthermore, we have verified that the plant is economically viable and has a commercial future. This is a big step in the right direction,” says Peder Nickelsen, CEO, Stiesdal.

“But things still need to move fast. If we are to achieve the targets in Denmark’s agricultural agreement, we will need 70–100 plants similar to the one in Vrå. We believe this is realistic. The technology is ready – the biggest bottleneck right now is getting the regulatory framework in place,” he continues.

Pyrolysis delivers major climate and environmental benefits
Researchers from several Danish universities have studied everything from the stability and quality of biochar to the effects of biochar in agriculture, on soil life and on the climate. New research confirms that biochar produced through pyrolysis provides stable long-term carbon storage in agricultural soils, and that pyrolysis holds great potential for realizing the government’s CO₂ reduction targets in Denmark.

“The climate impact of pyrolysis is significant – in a short time, Danish energy technologies can remove CO₂ from the air and store it permanently for hundreds or thousands of years, and we can easily exceed 1 million tons of carbon storage effect per year in Denmark. In addition, there is the benefit of being able to produce energy in the form of, for example, heat or green fuels that can substitute natural gas,” says Tobias Pape Thomsen, Associate Professor, Roskilde University.

At the same time, new studies show that biochar improves soil properties and can be an effective alternative fertilizer. Biochar contains nutrients from the biomass, such as phosphorus, which can benefit agricultural fields.

“When it comes to using biochar as a base fertilizer to maintain the soil’s phosphorus status and even increase it in soils with low phosphorus levels, biochar is a suitable product. It may also provide a better microflora, better conditions for microorganisms and fungi, which overall improve soil fertility and nutrient uptake in general,” says Henrik Nørskov Pedersen, Senior Specialist, SEGES Innovation.

High-level collaboration and sector coupling
The results of the SkyClean Scale-up project build on several years of cross-sector collaboration, starting with the SkyClean 2 MW project from 2021, supported by EUDP. Since then, the pyrolysis plant has been scaled up by a factor of ten, and the collaboration continues through new pyrolysis projects facilitated by Energy Cluster Denmark. These include the FRO-supported projects PytoN, PytoX and PytoCCUS.

“We have succeeded in creating a major collaboration in the name of pyrolysis across the energy and agricultural sectors and across companies and knowledge institutions. I am proud of the work that has been done, from when we began the journey with the 2 MW project to now concluding the project with the scaling up of the plant to 20 MW. Together with some of the project partners, I look forward to rolling out the experience and knowledge that have been built up through new pyrolysis projects for the benefit of the climate and the green transition,” says Glenda Napier, CEO, Energy Cluster Denmark.

Facts about pyrolysis
Pyrolysis converts biomass such as straw, residues from biogas plants, and wastewater into biochar and gas by heating it in an oxygen-free environment. Biochar can be ploughed into agricultural fields or used in concrete and asphalt to store CO₂, and pyrolysis gas can, for example, be used to produce heat or upgraded to products such as bio-oil to replace fossil fuels in the transport sector.

Learn more about pyrolysis here: https://www.youtube.com/watch?v=Rb37wvDX5-k

Facts about the project
The SkyClean Scale-up pyrolysis project runs from 2022 to 2025 with a total budget of DKK 200,582,061. The innovation project has received funding from the Danish Energy Agency’s Pyrolysis Fund, financed by the European Union under the NextGenerationEU initiative.

The partners include Stiesdal, Agri Energy Vrå, KK Wind Solutions, Topsoe, Technical University of Denmark, University of Copenhagen, Aarhus University, Roskilde University, SEGES Innovation, Food & Bio Cluster Denmark and Energy Cluster Denmark.

Read more about the project here: https://energycluster.dk/en/projects/skyclean-scale-up