Abstract
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.