Thermochemical conversion of municipal solid waste to energy: challenges, advancements and future prospects – a review

Municipal solid waste (MSW) presents an escalating environmental and economic challenge due to rapid urbanization and population growth, yet it remains a largely untapped resource for renewable energy and nutrient recovery. This review critically evaluates thermochemical conversion technologies, including combustion, pyrolysis, gasification, hydrothermal liquefaction, and torrefaction for transforming heterogeneous MSW streams into energy-dense fuels, biochar, and biofertilizers. This review employs a systematic and quantitative synthesis approach, integrating bibliometric analysis, statistical evaluation, and critical synthesis of recent challenges, advancements, and future outlooks in experimental and pilot-scale studies. This approach highlights technical performance and operational challenges. Key challenges identified include feedstock heterogeneity, high capital and operational costs, and regulatory constraints. Emerging solutions, such as integrated biorefinery approaches, catalytic and hybrid conversion systems, AI-driven process optimization, and Techno-economic analysis, are discussed for their potential to enhance energy recovery, material valorization, and overall sustainability. The findings offer actionable insights for researchers, policymakers, and industry stakeholders, promoting circular bioeconomy strategies and advancing the United Nations Sustainable Development Goals on affordable and clean energy, sustainable cities, and climate action.