Proton Exchange Membrane Electrolysis Performance Targets for Achieving 2050 Expansion Goals Constrained by Iridium Supply

As demand for hydrogen electrolysis increases with the renewable energy transition, it is critical to ensure that the supply of required resources for these technologies is sufficient to match demand. Several studies have set forth projections for H2 production targets to achieve net-zero emissions by mid-century, where proton exchange membrane (PEM) electrolyzers feature prominently. As compared to other commercially available electrolyzers, PEM systems exhibit high current densities that favor flexible operation to utilize intermittent renewable energy sources but rely on relatively scarce iridium (Ir) for catalysis. In this work, we model the supply of Ir resources available for PEM electrolysis and compare it to the Ir required to meet plausible H2 production targets for 2030 and 2050. In order for Ir supply to be sufficient for 2030 H2 production targets, significant improvement in average operational current density or Ir loading would be required compared to today's averages of 2 A/cm2 and 2 mg/cm2, respectively. By 2050, current technology may be sufficient to meet the lower end of H2 production targets (83 Mt), with modest technological advances needed in case H2 demand exceeds these levels.