Thermo-environ-economic analysis and multi-criteria optimization with grey wolf optimizer for a biomass-fueled power, hydrogen, and desalinated water tri-generation plant

Abstract This study presents a comprehensive thermodynamic, economic, and environmental assessment of a novel biomass-fueled tri-generation system designed to simultaneously produce electricity, hydrogen, and desalinated water. The proposed configuration integrates a Biomass Gasification Integrated Gas Turbine (BGI–GT) as the topping cycle with three bottoming subsystems: a vanadium–chlorine thermochemical water-splitting cycle (TWSC) for hydrogen production, an organic Rankine cycle (ORC) for heat recovery, and a humidification–dehumidification (HDH) unit for freshwater generation. The gas-turbine exhaust waste heat is sequentially recovered to drive these subsystems, improving overall energy utilization and reducing exergy destruction. A detailed thermodynamic model based on the first and second laws is developed and validated against published experimental data, while economic and environmental performances are quantified using the levelized cost of products (LCOP) and a CO₂ emission index. An ANN-assisted multi-objective Grey Wolf Optimization (GWO) coupled with TOPSIS is then applied to identify optimal operating conditions considering exergy efficiency, LCOP, and CO₂ emissions. At the TOPSIS-selected optimum point, the exergy efficiency, LCOP, and emission index reach 47.67%, 15.51 $/GJ, and 0.658 kg/kWh, representing improvements of 6.05%, 6.17%, and 12.4% over baseline conditions. Overall, the results highlight the proposed system as a promising solution for integrated clean power, hydrogen, and freshwater production from biomass resources.