Converting food waste into biochar could slash our carbon emissions by up to 93,000 tonnes annually by 2030, according to a new study by the University of Nottingham’s Faculty of Engineering.
The research, published in Biochar, was conducted as part of the Department for Energy Security and Net Zero (DESNZ) Phase 2 project in collaboration with Invica Industries.
It explores how transforming food-waste digestate – a by-product of biogas production – into biochar can act as a stable carbon sink while improving soil quality.
The study highlights biochar’s potential as a scalable and low-cost greenhouse gas removal (GGR) technology.
Each tonne of biochar can sequester up to 1.2 tonnes of CO₂ equivalent, while retaining 88% of its carbon content.
When applied to agricultural soils, biochar enhances soil fertility and structure, supporting sustainable farming practices.
Co-locating biochar production facilities with existing anaerobic digestion plants could keep carbon removal costs under £100 per tonne, a competitive figure in the race to Net Zero.
To achieve these emissions reductions, we would need to build 28 facilities capable of processing 20,000 tonnes of food-waste digestate per year, utilising half the nation’s projected supply by 2030.
“Our research shows that food waste digestate, typically seen as a low-value, hard-to-use material, can be converted into a stable carbon sink through biochar production,” said Dr Disni Gamaralalage, from the university’s Sustainable Technologies research group. “This offers a cost-effective carbon removal pathway while turning a problematic waste stream into a valuable climate solution aligned with the UK’s emissions targets.”
While challenges remain, such as plastic contamination and fossil fuel inputs, the study positions biochar as a promising tool in the climate mitigation toolkit.
