Agro-industrial Waste-to-Energy in Sub-Saharan Africa: A Review of Sustainability, Technology, Circular Bioeconomy and Implementation Barriers

Abstract

Agro-industrial activities in sub-Saharan Africa (SSA) generate substantial organic residues whose inadequate management contributes to environmental degradation and public health risks. Meanwhile, the region faces persistent energy deficits and increasing pressure to decarbonize development. This review examines agro-industrial waste-to-energy (WtE) systems as components of a circular bioeconomy, focusing on feedstock characteristics, conversion technologies, emerging innovations, multi-criteria decision analysis (MCDA), and implementation barriers. Major waste streams, including oil palm residues, cocoa by-products, cassava peels, cereal residues, timber wastes, and animal-derived wastes, are assessed based on physicochemical properties, energy potential, biochemical methane potential, recoverability, and competing uses. Anaerobic digestion, gasification, pyrolysis, and biodiesel production are compared in terms of conversion efficiency, energy yield, operational complexity, costs, and greenhouse gas mitigation potential. The review identifies key barriers, including inadequate infrastructure, high capital requirements, fragmented policies, unreliable feedstock supply, limited technical capacity, and difficulties integrating informal waste-sector actors. Opportunities include modular technologies, innovative business models, carbon finance, and inclusive governance. SWOT analysis and sustainability assessment suggest that appropriately designed WtE systems could mitigate 0.3–2.5 t CO 2 -eq per tonne of waste and achieve levelized energy costs of US$0.04–0.45/kWh. Such systems could strengthen energy security, create rural and peri-urban value chains, and improve waste management. The review recommends context-specific technology deployment, differentiated policies, regional cooperation, capacity development, and South–South knowledge exchange to advance inclusive green growth, climate resilience, and circular bioeconomy development across SSA.