Food Waste-to-Energy Conversion: A Critical Review of Pathways, Performance and Deployment Constraints

Abstract

Food waste constitutes a major biodegradable fraction of municipal refuse and is increasingly viewed as a recoverable energy resource rather than a disposal burden. This review critically examines the principal routes for converting food waste into useful energy, including anaerobic digestion, gasification, pyrolysis, hydrothermal liquefaction, and direct combustion. The analysis compares process severity, feedstock tolerance, energy yield, environmental performance, and downstream utilization options such as combined heat and power and solid oxide fuel cells. Across the literature, anaerobic digestion remains the most mature option for wet, source-separated waste because it tolerates high moisture content and enables simultaneous biogas and digestate production. Thermochemical pathways provide broader product flexibility and higher energy-density intermediates, but they generally require tighter feedstock conditioning and more complex gas-cleaning or upgrading steps. Life-cycle and techno-economic evidence indicates that food waste valorization can outperform landfilling when collection logistics, pretreatment, and policy support are adequately addressed. The review also highlights recurring commercialization barriers linked to feedstock heterogeneity, contamination, pretreatment cost, and fragmented regulation. Overall, the evidence favors integrated food waste-to-energy systems that combine robust preprocessing, appropriate conversion selection, and digital process control to improve recovery efficiency while limiting environmental impacts.