Direct seawater electrolysis technology for distributed hydrogen production

SWEETHY will develop an advanced technology for direct seawater electrolysis that will be able to produce H2 and O2 under intermittent conditions accounting for the coupling to renewable power sources (especially wind, PV).  The electrolyser will be based on an anion exchange membrane (AEM) operating in natural or alkaline seawater, and the SWEETHY technology will be developed along three dimensions:

a) Materials optimization to meet the specific requirement of seawater environment: A focus will be made on corrosion resistance and selective PGM-free electrocatalysts for hydrogen and oxygen evolution reactions, on AEM with high selectivity for transporting hydroxide anions and anti-fouling properties as well as on novel anti-corrosion coatings for bipolar plates and porous transport layers prepared by plasma spraying and electrodeposition.
 

b) An electrolyser stack prototype based on a novel stack architecture applying hydraulic cell compression is developed to host the advanced materials to produce H2 at high pressure. Beneficial functions of the targeted unique stack are related to scalability and maintainability that will be tremendously improved in comparison to conventional AEMWE stacks.
 

c) Sustainability analysis studies not only for the electrolyser system but also for its integration into renewable-power systems and for efficient by-product utilization in industrial symbioses, feeding back to materials optimization and stack development early on. Complementing LCA, social LCA and techno-economic analyses/optimization by qualitative work ensures both environmental, economic, and social sustainability.

Combining these three dimensions, SWEETHY will utilize Mediterranean seawater feed in Messina, Italy, to withstand more than 2000 h of operation to produce 20 gH2/h with a degradation rate lower than 1%/100h. In addition, SWEETHY will demonstrate how the operation of the electrolyser can ensure an optimized revenue concerning by-products and grid services.