Technological Solutions for Sustainable Biochar Production in Sub-Saharan Africa: Scalability, Environmental Performance, and Socio-Economic Sustainability
摘要
This review investigates scalability, environmental performance, and socio-economic sustainability of biochar production in sub-Saharan Africa with a focus on traditional/low-tech solutions. Low-tech methods, including open pits, metal drum kilns, and earth mounds, are easily accessible and reasonably priced, but they can have high emissions, uneven biochar quality, and poor thermal efficiency. Standardizing enhanced low-technology designs, putting strong quality assurance systems in place, mobilizing underutilized biomass streams, and using digital monitoring and artificial intelligence to optimize pyrolysis operations are some of the main strategies proposed to achieve scalable and sustainable biochar production in the region. Retort kilns or sophisticated pyrolysis units with gas recirculation are considered medium-to-high technology to stabilize product qualities, lower emissions, and call for a moderate amount of capital and technical know-how. Along with evaluating feedstock possibilities such as invasive species, forestry wastes, and crop residues, the review incorporates techno-economic analysis, climate-smart forestry tools, and circular economy principles. Economically viable biochar systems in Sub-Saharan African contexts require either (i) integration with existing agro-industrial waste streams (e.g., rice mills, sugarcane processing) where collection infrastructure already exists, or (ii) decentralized production using low-cost kilns (< US$500 capital cost) that eliminate transport through on-farm processing. To align waste management and forest conservation with goals for negative carbon soil enhancement, the paper recommends policymakers support standardized low-technology designs, create frameworks for ensuring the quality of biochar, increase the use of underutilized biomass streams, and use digital monitoring and artificial intelligence to optimize pyrolysis processes.