The accelerating climate crisis, resource depletion, and escalating global waste generation have intensified the need for integrated strategies that convert waste into valuable resources. Recent advances in waste valorization for energy and renewable fuel production are reshaping how municipal solid waste, agricultural residues, industrial byproducts, plastics, and wastewater are managed, transforming them into biofuels, hydrogen, syngas, biochar, biogas, and advanced drop-in fuels. Progress in thermochemical, biochemical, catalytic, electrochemical, and hybrid conversion pathways—together with digital optimization and systems-level integration—continues to redefine the efficiency, sustainability, and scalability of circular energy systems.

Despite these advances, substantial and interrelated challenges remain across experimental, computational, and translational domains. For instance, feedstock heterogeneity and contamination limit reproducibility and process optimization, while complex reaction networks, heat and mass transfer constraints, catalyst deactivation, fouling, and byproduct formation reduce efficiency and operational stability. Biological systems face issues of microbial inhibition and pathway regulation, whereas computational efforts are hindered by limited high-quality datasets, uncertainty in multiscale modeling, and validation gaps. In addition, scale-up limitations, lifecycle assessment complexities, and techno-economic uncertainties continue to impede reliable industrial deployment.

This Collection aims to provide a broad, forward-looking platform that captures scientific, technological, and translational progress across the full spectrum of waste valorization for energy and renewable fuel production. The Collection will feature original research articles reporting innovative experimental and computational studies, methods articles detailing reproducible and scalable approaches, and review articles synthesizing emerging trends and knowledge gaps.

By consolidating state-of-the-art developments within a unified forum, this Collection will stimulate interdisciplinary collaboration, clarify research priorities, and accelerate the deployment of economically viable and environmentally responsible waste-to-resource technologies, ultimately supporting global decarbonization and circular economy objectives.