Food waste-to-biochar conversion could cut 93,000 tonnes of CO₂ each year, study finds

A new study, led by the University of Nottingham’s Faculty of Engineering, has shown that converting food waste into biochar could lead to a reduction of 93,000 tonnes of CO₂ each year by 2030.
The study explored how converting food waste into biochar can help reduce greenhouse gas emissions and also improve soil quality.
It was published in Biochar, and conducted as part of the Department for Energy Security and Net Zero (DESNZ) Phase 2 project in collaboration with Invica Industries.
The report demonstrates that converting food-waste digestate, a residue from biogas production, into biochar offers a low-cost, high-impact climate solution.
Results from the study show that each tonne of biochar can sequester up to 1.2 tonnes of CO₂ equivalent, and co-locating production with anaerobic digestion plants, where food waste digestate is generated, could keep carbon removal costs below £100 per tonne.
The biochar produced retains about 88% of its carbon content, effectively locking away approximately 1.15 to 1.20 tonnes of CO₂ per tonne of biochar.
Applying this biochar to agricultural soils can also enhance soil fertility and structure.
If implemented nationally, using 50% of the UK’s projected available food-waste digestate, this approach could sequester around 93,000 tonnes of CO₂ annually by 2030.
Despite challenges such as plastic contamination and fossil fuel inputs, this study highlights a promising GGR pathway that aligns with national climate targets by transforming organic waste into a stable carbon sink.
To process 50% of the UK's projected food waste digestate by 2030, 28 biochar production facilities would be required, each with a capacity of 20,000 tonnes per year.
"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," stated Disni Gamaralalage, 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."