Comparative technical analysis of different methods for green hydrogen production from humid air and seawater

Abstract The growing demand for clean energy solutions has increased interest in green hydrogen technologies. However, green hydrogen production relies on freshwater, and the global water scarcity is escalating, with 25 countries experiencing extreme water stress. Therefore, this study conducts a comparative analysis of four green hydrogen production technologies, including desalination combined with electrolysis, atmospheric water generation combined with electrolysis, direct seawater electrolysis, and direct air electrolysis, to support a sustainable energy transition while reducing pressure on freshwater resources. An integrated entropy–VIKOR (VIšeKriterijumska Optimizacija I Kompromisno Rešenje) multi-criteria decision-making approach was employed to provide a comprehensive perspective on identifying the optimal integration pathway for green hydrogen production, combining expert opinions with quantitative technical analysis across key factors such as energy consumption, scalability, and maintenance requirements. The entropy analysis identified maintenance requirements as the most critical criterion for technology selection. Although experts favored desalination (57%) due to its maturity, reliability, and established infrastructure, the VIKOR rankings ranked direct seawater electrolysis first, driven by its low energy consumption, compact single-stage design, and potential for simplified operation. This divergence highlights the trade-off between current technological readiness and future potential.