new analysis approach for analyzing environmentally friendly multigeneration system used in the biogas production complex

Urban sludge management is increasingly recognized as both a climate liability, due to uncontrolled methane and co₂ emissions, and a resource opportunity for renewable energy and water recovery. conventional waste-to-energy and multigeneration systems improve efficiency but rarely achieve full integration of environmental mitigation, multi-utility production, and reliability evaluation. this study develops a novel biogas-driven multigeneration system that simultaneously delivers electricity, refrigeration, freshwater, upgraded biomethane, and captured co₂. the plant configuration integrates brayton and inverse-brayton cycles, a supercritical co₂ cycle, dual organic rankine cycles, an absorption refrigeration unit, and two thermally autonomous desalination modules, achieving sequential recovery of low- and medium-grade heat. a unified 4e framework is combined with hybrid ann–nsga-ii multi-objective optimization and serial–parallel reliability modeling to identify pareto-optimal strategies and long-term resilience. results show high thermodynamic efficiencies, competitive product costs, and a net-negative ghg balance with co₂ capture credits, with availability aligned to industrial practice. the novelty lies in jointly linking sludge valorization, multigeneration, co₂ capture, optimization, and reliability into a single framework. beyond immediate findings, the proposed methodology offers a transferable tool for designing other sustainable energy–water systems, providing the scientific community with an integrated optimization–reliability platform and supporting prospects for scalable, carbon-negative urban infrastructures.