Waste-to-hydrogen technologies: A critical review of techno-economic and socio-environmental sustainability.

Hydrogen is a fuel with immense potential of satisfying the need for environmentally benign energy sources, and waste-derived hydrogen is promising in diverting waste streams away from landfills and other costly treatment. Nonetheless, many waste-to-hydrogen pathways are incipient and require significant efforts to be established as an indispensable element of the path towards sustainability. This review comprehensively evaluates waste-to-hydrogen technologies from technological, economic, environmental, and societal viewpoints. State-of-the-art of five technologies was summarized, focusing on emerging trends in published literature. Several knowledge gaps, future research prospects, and possible improvements related to performance, greenhouse gas emissions, production costs, hydrogen-based transportation, and public acceptance were also identified. Fulfilling the lack of techno-economic and environmental studies of waste-to-hydrogen routes, incorporation of renewable energy into processes, and necessities of scaling-up and production cost reduction are prominent among research needs recognized through this review. Conclusions of this study will be beneficial towards sustainably integrating hydrogen into large-scale energy systems. • Hydrogen production from different types of wastes was critically reviewed. • The state-of-the-art of five waste-to-hydrogen processes was compiled. • Emissions of waste-based hydrogen production are lower than conventional methods. • Thermochemical methods perform better than biochemical methods techno-economically. • Lowered cost and improved safety increase social acceptance of waste-to-hydrogen. [ABSTRACT FROM AUTHOR]