Addressing the material gap in GW-scale Proton Exchange Membrane (PEM) electrolyser deployment is key to meeting the global green hydrogen ambition

Electrolytic hydrogen produced using polymer electrolyte membrane (PEM) is expected to be a key enabler for global decarbonisation efforts. This study investigates the challenges associated with rising demand for platinum group metals required in PEM electrolysers. We develop a dynamic approach that integrates material flow analysis with life cycle assessment to assess the role of reduced catalyst loading and improved circularity to manage primary material demand and the associated GHG emissions. Supply challenges are less pressing for platinum compared to iridium – provided waste streams are efficiently managed - due to significant global reserves relative to future PEM demands and future secondary supply from conventional vehicle catalytic converters as light-duty road transport electrifies. We identify a “material gap”, where plausible availability of iridium is likely insufficient to meet projected deployment of PEM electrolysers under future energy scenarios - even with optimistic reduction in catalyst loading requirements. To meet PEM electrolyser deployment targets without constraining iridium supply, an 89-97% decrease in overall iridium use is required by 2050, with near-term reduction in iridium loading from 0.64 kg/MW to 0.07 – 0.02 kg/MW by 2030. A reduced catalyst loading could also mitigate overall GHG emissions by up to 65% due to a lower demand for primary materials. The study calls attention to the material gap in an ambitious green hydrogen ambition and highlights the need for a more efficient use of the world’s limited resources through newer technologies and the creation of a circular economy.