Pyrolysis systems for renewable energy and permanent carbon removal
SkyClean pyrolysis plants convert the renewable energy from organic residues to useful green fuels and stabilize part of the carbon as biochar for permanent storage.
From residue to value, via pyrolysis
Biomass residues are often underutilised, even though they contain biogenic carbon that can deliver both carbon-neutral energy and durable carbon capture and storage.
In the SkyClean pyrolysis process, part of the biomass carbon into carbon-neutral renewable fuels, while the remaining carbon is retained as biochar for long-term storage.
How SkyClean works
Built on the natural carbon cycle, the SkyClean pyrolysis process stabilises carbon in biochar while recovering useful energy from biomass residues.
Residue to revenue
The SkyClean plant is a modular solution for industrial-scale carbon removal and renewable energy production.
Develop your project
Planning a pyrolysis project? Tell us about your feedstock and local energy opportunities. A member of the Stiesdal SkyClean team will assess your project’s potential.
Operating at commercial scale
The 20 MW SkyClean plant in Vrå demonstrates commercial deployment of the SkyClean platform.
Integrated with a biogas facility, the plant converts biogas digestate into biochar while supplying carbon-neutral fuel to the co-located biogas-upgrading facility.
- 40,000 tonnes digestate processed annually
- 57,000 MWh carbon-neutral fuel supplied annually, avoiding 11,000 tonnes of fossil-fuel CO₂-emissions
- 25,000 tons CO₂ removed annually
Operational since 2024.
Designed, built, and delivered by one team
SkyClean provides the process engineering, thermal integration, commissioning and operational expertise required to deliver a SkyClean plant.
By integrating the technologies into a complete industrial plant, we reduce project interfaces, manage technical risk and help optimise the customer’s business case.
Find out what you can get out of your biomass
Plant configuration
Plant energy output: 0 MW
Output
Green energy
Green energy: 0 MWh per year
Carbon removal
Carbon removal: 0 t CO2 per year
Frequently asked questions
Is pyrolysis a mature technology?
Pyrolysis is a well-established process that has been used for millennia to produce biochar, mainly in the form of charcoal.
The production of biochar through pyrolysis for durable carbon removal is now well established commercially. Technology providers in Europe and North America offer complete industrial systems, and a growing number of projects issue independently verified carbon-removal certificates.
By the end of 2024, nearly 8 million tonnes of durable CO₂ removal had been contracted globally, and more than 318,000 tonnes had been delivered and permanently stored.Of these delivered removals, approximately 274,000 tons came from biochar projects, and biochar represented 86% of durable carbon removal delivered in 2024, making it the largest commercially operating durable-removal pathway at that time.
Established biomass supply chains and proven industrial processes give pyrolysis substantial potential for further scale-up.
Taken together, this makes pyrolysis a mature process, and at the present time biochar is by far the most commercially advanced pathways for durable carbon removal.
How much CO₂ can be removed from the atmosphere through pyrolysis?
Pyrolysis of one million tonnes of dry straw can capture and store approximately 0.7 million tonnes of CO₂ as biochar. This is accompanied by emissions reductions of about 0.45 million tonnes of CO₂ through the substitution of fossil fuels with carbon-neutral green fuels, totalling about 1.15 million tons of CO₂ stored and substituted.
Pyrolysis of one million tonnes of dry residues from biogas production can capture and store approximately 0.75 million tonnes of CO₂ as biochar. This is accompanied by emissions reductions of about 0.3 million tonnes of CO₂ through the substitution of fossil fuels with carbon-neutral green fuels, and by methane emission reductions corresponding to about 0.1 million tonnes of CO₂, again totalling about 1.15 million tons of CO₂ stored and substituted.
A useful rule of thumb: One million tons of CO₂ is captured or displaced per million tons of dry matter feedstock.
On a global level, IPCC estimates that up to 6.5 billion tonnes of CO₂ can be captured and stored annually by the commercial production of biochar through pyrolysis.
Could the same climate benefits be achieved simply by incorporating agricultural residues into the soil?
When straw is incorporated into soil, it is estimated that about 25% of its original carbon remains after two years. After 20 years, approximately 7.5% remains, and after 100 years, around 3%.
By comparison, after 100 years more than 90% of the carbon is preserved in biochar produced by the Stiesdal SkyClean process when the biochar is applied to agricultural soil in Denmark.
Incorporating straw directly into soil therefore cannot provide the same long-term carbon storage as converting part of it into stable biochar.
Will the deployment of pyrolysis lead to increased deforestation?
Commercial pyrolysis projects depend on sustainably sourced feedstock and credible documentation of carbon storage.
Carbon-removal certification systems require evidence of biomass sustainability, traceability and additionality. Projects that cannot document these conditions are not eligible to issue high-quality carbon-removal certificates.
Feedstock associated with deforestation would therefore be inconsistent with the sustainability requirements applied to credible biochar carbon-removal projects.
Is there a risk that the introduction of commercial methods for capturing and storing CO₂ from the atmosphere may be seen as a kind of free pass to continue emitting fossil CO₂?
That risk exists if carbon removal is presented as a substitute for cutting emissions.
However, this is not an argument against starting to capture and store CO₂ from the atmosphere.
The first priority remains rapid reduction of fossil CO₂ emissions. Durable carbon removal is a complementary measure that can address residual emissions and help reduce the excess CO₂ already accumulated in the atmosphere.
Clear communication and robust carbon accounting are therefore essential.
Planning a pyrolysis project?
SkyClean supports projects from early concept and business case development to system delivery, integration, and operation.