Comparison between green hydrogen production from ultrapure water and seawater: modeling and energy efficiency assessment

The objective — and simultaneously the design constraint — of this thesis is the annual production of 500 tons of green hydrogen in Morocco, a country offering favorable conditions thanks to high solar irradiance and abundant access to seawater. The proposed system is based on the conversion of solar energy via photovoltaic panels, which generate electricity used to power both electrolyzers and a desalination unit. Any excess electricity is sold directly to the grid. The system includes two types of electrolyzers: one operating directly with seawater and the other with freshwater, obtained through the desalination of seawater. This dual configuration enables a comparative analysis of hydrogen production from both water sources, with a specific focus on maximizing the efficiency of the seawater-based electrolyzer, which, despite being less mature, holds promising potential in terms of water resource sustainability. An integrated energy model was developed and implemented in MATLAB to simulate the energy flows, water balances, and system performance. The goal is to identify the optimal configuration capable of meeting the fixed hydrogen production target while minimizing the energy consumption of desalination and maximizing overall conversion efficiency. Results provide valuable insights and practical guidelines for the implementation of green hydrogen systems in coastal and arid regions.