Low cost, high efficiency PEM electrolyser stack

One of the major challenges associated with green hydrogen produced via electrolysis of water is the investment cost (CAPEX), which leads to a high price for green hydrogen compared to that produced via non-renewable, carbon-based energy sources. For green hydrogen to become competitive it is therefore crucial to achieve a significant reduction in CAPEX. In HYSTACK-II, the CAPEX of Hystar’s world-leading electrolysers will be reduced by 50%, without loss of efficiency. One of the largest contributions to the total cost of an electrolyser comes from the use of expensive and rare precious metals like iridium and titanium. The CAPEX reduction will be achieved through techniques for better utilization or replacement with alternate materials. Replacement of electrolyser components with less costly and more sustainable results like stainless steel bipolar plates and hydrocarbon-based fluoride-free membranes, will be investigated. In the Net Zero Emissions by 2050 Scenario, a production capacity of 170 GW/year in 2030 is outlined. As the currently planned capacity does not cover this, it is important to secure that the technology developed in HYSTACK-II is scalable up to industrial scale. Hystar’s technology is already developed and designed with mass production in mind, and HYSTACK-II emphasizes investigations of how the introduced changes affect efficiency, safety and scalability, as well as potential for integration into Hystar’s own GW production line which will be operational from 2026.

Hystar’s patented PEM electrolyser stack technology, realised in the previous HYSTACK IPN project has resulted in great product value proposition: • World’s most efficient PEM electrolyser, safest system design, and mass-produced stacks • Easily customizable plant sizes due to modular product offerings (stacks or stack modules) • Competitive price due to higher current densities and lower materials costs. Hystar stacks still have a huge potential for further minimisation of the use of raw materials impacting the overall cost of the stack. Based on preliminary results, from own experimental activities, research partners, component suppliers, and literature it is estimated that a further 50% stack CAPEX reduction is achievable by: • Reduction of Ir loading with optimal catalyst layer utilization • Replacing PGM coated Ti based BPP with non-PGM coated stainless steel BPP • Replacing current PFSA-based membranes with HC-membranes However, it is already foreseen that considerable R&D effort is required to determine and better understand the effect of these new materials on the lifetime and performance of Hystar PEM electrolysers. SINTEF’s Norwegian Fuel cell and Hydrogen Centre and Hystar’s Innovation Centre, which combined are by far the most advanced and complete PEM electrolyser testing facilities in the Nordic countries will be utilised during the project.