Integrated techno-enviroeconomic and life-cycle assessment of a solar–green hydrogen hybrid system with industrial wastewater reuse

The dual pressures of climate change and industrial water scarcity demand integrated solutions that jointly decarbonize power supply and reduce freshwater dependency. This study presents a site-specific, techno-enviroeconomic and life-cycle evaluation of a closed-loop Solar-Green Hydrogen Hybrid System (SGHHS) co-located with Gul Ahmed Textiles in Karachi, Pakistan, integrating 22.75 MW solar PV, a 2.25 MW PEM electrolyser, 450 kg hydrogen storage, and a 1 MW PEM fuel cell to deliver dispatchable, round-the-clock clean electricity under reduced nighttime demand. Unlike most SGHHS studies that assume freshwater inputs and decouple water treatment from system economics, this work quantifies an integrated wastewater-to-ultrapure-water loop (MBR→RO→DI) with fuel-cell condensate recovery within a unified TEA-LCA framework. A novel configuration treats 4,050 L/day of textile effluent to produce PEM-compatible ultrapure water while recovering and recirculating clean water for reuse within the facility, leveraging a broader on-site effluent availability of ~ 400,000 L/day. Over a 25-year project horizon, the integrated water loop reduces the Levelized Cost of Electricity (LCOE) from USD 0.10/kWh to USD 0.0866/kWh through avoided freshwater procurement and effluent-management costs. Life-cycle assessment indicates the potential to avoid over 157,000 metric tons of CO₂-equivalent emissions. The proposed framework supports multiple Sustainable Development Goals (SDGs) and provides a replicable, data-driven pathway for circular water-energy integration and industrial decarbonization in semi-arid, resource-constrained regions.