Green Hydrogen Production: Energy and Economic Modelling of Self-sufficient Solar-powered Electrolyser Based on Seawater Desalination

Growing energy demands and increasing concerns about climate change have spurred new approaches in both policy and industry, with a focus on transforming current energy systems in modern energy hubs. In this context, green hydrogen produced through electrolysis process powered by renewable energy sources emerges as a highly versatile and promising solution for decarbonising sectors and provide alternative fuels for process and transportation. This study models and simulates an integrated system comprising desalination, brine treatment, and electrolysis to generate green hydrogen, fuelled entirely by solar energy. The desalination unit produces demineralised water suitable for electrolysis, while alternative brine management strategies are explored for scenarios where brine discharge back to the sea is restricted. An economic analysis further evaluates cost-effective system configurations by varying component sizes. To demonstrate the model potential, a case study for green hydrogen production based on seawater desalination was conducted for an Italian port city and extended to three other sites with different annual solar radiation. The objective is to determine configurations that minimise hydrogen cost and identify required incentives. The economic performance of the system, in terms of the Levelized Cost of Hydrogen, ranges from 5 to 8 €/kg, while the required incentives, to make green hydrogen competitive with blue hydrogen production systems, vary between 7 and 12 M€ across the analysed configurations. Furthermore, the analysis provides valuable insights into the potential of coastal areas to serve as critical hubs for green hydrogen production, given the abundant availability of seawater. Ports, with their existing infrastructure and proximity to maritime transport, represent ideal locations for integrating renewable energy sources with hydrogen production facilities.