Researchers develop biochar production design to tackle agriculture emissions

Researchers from the University of Leeds in the United Kingdom have developed a regulation-compliant design for biochar production on farms that could reduce greenhouse gas emissions from agriculture while permanently removing carbon dioxide from the atmosphere.

According to university researchers, agriculture contributes approximately 12 per cent of the United Kingdom’s total greenhouse gas emissions, with manure management alone responsible for nearly 10 per cent of sector-wide emissions.

At the same time, large volumes of crop residue such as straw are often underutilised, creating missed opportunities for climate mitigation.

To combat this, the University of Leeds researchers have developed and evaluated an integrated biochar production system that processes straw and manure separately through parallel pyrolysis lines – systems which convert waste materials into valuable organics.

Biochar is produced by heating biomass in a low-oxygen environment, creating a stable carbon-rich material that can be applied to soil.

The material has been utilised by some Australian initiatives to reduce environmental impact.

The research team’s biochar production design allows farms to comply with existing land application regulations, which currently prohibit the mixing of certain feedstocks, while improving energy efficiency through internal heat recovery.

Using the University of Leeds Research Farm as a case study, the team conducted a cradle-to-grave life cycle assessment and techno-economic analysis to evaluate environmental and financial performance over one year of operation.

The research team found the proposed system could produce 300 tonnes of biochar annually, sequester approximately 350 tonnes of carbon dioxide equivalent, and reduce manure management emissions by 75 per cent.

Surplus heat generated during the pyrolysis was also found to potentially offset further emissions, avoiding an additional 30 tonnes of carbon dioxide equivalent per year.

“Biochar is often discussed as a promising carbon removal solution, but real-world farm implementation has been limited,” said University of Leeds lead research author Yuzhou Tang.

“Our study demonstrates that a regulation-compliant, farm-based system can simultaneously reduce emissions from manure, sequester stable carbon in soils, and improve energy use efficiency.”

Another key innovation of the study was the separation of straw and manure processing.

According to the research team, manure typically contains high moisture levels, making it energy-intensive to treat.

However, by using heat generated from straw pyrolysis to dry and process manure, the biochar production system reduced energy penalties while maintaining operational flexibility as residue availability changed over time.

The study also identified straw availability as the most influential factor affecting system performance.

Variations in crop rotation and annual yields significantly impacted both carbon removal potential and cost effectiveness. When straw supply was insufficient, purchasing additional straw emerged as the most effective strategy for maintaining environmental performance.

Despite the strong environmental results, the system’s economic analysis revealed challenges.

The carbon abatement cost was estimated at £226.00 (AUD $428.87) per tonne of carbon dioxide equivalent, primarily driven by capital investment, labour, and electricity costs. Producing biochar costs approximately £754.00 (AUD $1430.82) per tonne under current assumptions.

However, the researchers noted that technological optimisation, modular system design, supply chain improvements, and operational integration into farm management could substantially reduce costs over time.

“Our findings provide a realistic framework for scaling biochar within the agricultural sector,” Tang said.

“With continued innovation and supportive policy, farm-based biochar systems could become a meaningful contributor to net zero targets.”

By addressing both regulatory and technical barriers, the study offers a practical pathway for integrating biochar into modern farming systems and highlights the trade-offs between cost, carbon removal, and system design decisions.