Biochar is gaining traction as a negative emissions technology due to its ability to store carbon in the soil. This research, the first of its kind, comprehensively assesses the sustainability of large-scale biochar production and application in Malaysia using five abundant agricultural waste feedstocks: palm oil empty fruit bunches, fibres, fronds, shells, and rice straw.

Key findings include:

• Biochar production from all feedstocks resulted in negative global warming potential (GWP), ranging from -436 to -2085 kg CO2 eq./t biochar and -660 to -933 kg CO2 eq./t CO2 removed.
• PyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More temperature significantly impacts sustainability. Higher temperatures generally lead to lower GWP but higher impacts in other categories.
• FeedstockFeedstock refers to the raw organic material used to produce biochar. This can include a wide range of materials, such as wood chips, agricultural residues, and animal manure. More choice also plays a role. Shells have the lowest GWP and straw the highest, while fibres are generally the best option for most other impact categories.
• The pyrolysis process is the main hotspot, contributing 66-75% to life cycle costs, which range from US$116-197/t biochar and US$60-204/t CO2 removed.
• Utilizing all available feedstocks could remove 6-12.4 Mt of CO2 annually, reduce national agricultural emissions by up to 54%, and save US$36.05 million annually on fertilizer imports.

This study highlights the potential of biochar production from agricultural waste in Malaysia as a sustainable solution for negative emissions, soil improvement, and economic benefits. The findings can inform policy decisions in Malaysia and other regions with abundant agricultural waste, promoting the adoption of biochar as a climate change mitigation and soil management strategy.