In green biorefineries, forage crops such as grass and clover are processed to extract protein and energy. An important by-product of this process is the press cake, a fibre-rich residue that is produced when the liquid is pressed out of the biomass. The press cake can be used as animal feed or for biogas production, but it can also be converted into biochar through a process called pyrolysis.
Using biochar as a long-term carbon sink not only has environmental benefits but can also be an economic opportunity.
Research shows that biochar can store carbon in the soil for thousands of years, making it one of the most stable forms of carbon dioxide storage. By documenting how much biochar is produced and used in the soil, farmers and companies can register and certify this as a carbon sink and have the opportunity to sell carbon credits.
The carbon credit market works in such a way that companies and organisations that find it difficult to reduce their emissions can buy credits from projects that bind carbon, for example through biochar.
This allows farmers to earn extra income by producing and using biochar on their land.
A climate-smart choice for the future
Converting grass press cake into biochar is an innovative way to create more sustainable and profitable agriculture. It offers several benefits:
• Reduced greenhouse gas emissions – Biochar stores carbon that would otherwise return to the atmosphere
• Improved soil health and higher yields – Biochar improves soil water retention, nutrient balance and micro-organisms.
• Less nutrient leaching – Fewer nutrient losses to lakes and waterways, which reduces eutrophication.
• More efficient use of resources – Press cake that would otherwise be used as feed or biogas becomes a long-term carbon sink.
• Economic opportunities – Through carbon credits and improved harvest potential, biochar can become a profitable investment.
• By using biochar, agriculture can become part of the solution to climate challenges, while creating more sustainable food production and healthier soils for future generations.
Semiconductor electron microscope image of the pores in two different biocolours. Photo Oskar Modin.
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