Techno-Economic Assessment of Membrane Distillation for Green Hydrogen Production in Australia

As global momentum builds toward decarbonisation, green hydrogen has emerged as a key pillar in Australia’s transition to a net-zero emissions future. However, the freshwater demands of large-scale electrolysis poses a significant social hurdle, particularly in a nation facing acute water scarcity. The SeaHydrogen approach, developed in the Netherlands, offers a potential solution by using waste heat from the electrolysis process to desalinate seawater via membrane distillation, enabling hydrogen production without drawing on limited freshwater supplies. This paper investigates the techno-economic feasibility of using membrane distillation as the desalination method for green hydrogen production, when compared to conventional reverse osmosis. The Arrowsmith Hydrogen Project in Western Australia was used as a case study to link the investigation to real world applications. Hydrogen electrolysis requires significant volumes of purified water, posing challenges in water-scarce regions such as regional Australia. Eight scenarios were modelled using brackish aquifer and seawater sources to evaluate capital expenditure, operational expenditure, levelised cost of water, and net present value for both desalination technologies. Results showed that membrane distillation achieved lower levelised cost of water values than reverse osmosis across all configurations (with reductions in cost between 15–37% for the cases considered). This was primarily due to its ability to utilise low-grade waste heat from electrolysers, substantially reducing energy demand and operational expenditure. Aquifer-sourced membrane distillation emerged as the most economically viable configuration. Integrated membrane distillation also presents other potential benefits, including lower energy intensity, reduced-liquid discharge, improved waste-heat recovery, and the option to produce a limited volume of surplus distilled water, either for on-site use or to supplement small local communities. The findings highlight membrane distillation as a promising alternative to reverse osmosis for sustainable hydrogen production, consistently delivering water for lower cost for the Arrowsmith site. Moreover the analysis shows that both methods can be used to generate excess potable water at prices that are competitive with existing water supplies.