CENmat

AEM vs PEM: iridium calculator

PEM electrolysers use iridium, a scarce platinum-group metal, on the anode. AEM electrolysers can run without it. Enter a capacity to see the iridium a PEM installation needs at the average loadings published by IRENA or with ultra-low-iridium OXYGN (PEM), priced at a dated reference iridium price, and compare it with CRM-free AEM.

as of 25 Sep 2026
Iridium US$8,200/oz ≈ €7,191/oz · €231/gReference price, source Umicore; € at the ECB euro reference rate, 25 Sep 2026. Iridium prices move a lot – check a current quote before you decide.

Pre-filled with the dated reference price above (25 Sep 2026). Overwrite it with your own quote.

Anode loading preset

0.053g/kW
0.2 mg/cm² at 2.0 A/cm² × 1.9 V (3.8 W/cm², IRENA 2020 Table 6 operating point) = 0.053 g/kW

PEM, typical loading today (1.3 g Ir/kW)

1.3 kg

PEM, IRENA future target (0.4 g Ir/kW)

0.4 kg

Selected: OXYGN (PEM) 0.2 mg/cm²

0.05 kg

AEM with CRM-free OXYGN / H2GN electrodes

0 kg

no iridium, no platinum-group metals

Indicative catalyst-metal estimate only, based on the average values in IRENA (2020), Table 7, and the dated reference price. Real loadings depend on the manufacturer, current density and cell design. This is not a system cost, a price or a CENmat quote. What does the full plant cost per kg of hydrogen? Try the LCOH calculator.

aem vs pem at a glance

PEM electrolysisAEM electrolysis (CENmat)
Anode catalystIridium-based; about 1.3 g Ir/kW today, 0.4 g/kW targeted (IRENA 2020, Table 7). CENmat's OXYGN (PEM) reduces iridium loading to about 0.2 mg/cm².OXYGN (AEM): CRM-free oxygen-evolution catalyst, no iridium.
Cathode catalystPlatinum-group metal; about 0.5 g/kW today, 0.1 g/kW targeted (IRENA 2020, Table 7).H2GN: CRM-free hydrogen-evolution catalyst.
Membrane / ionomerPFAS-based membranes are standard (IRENA 2020, Chapter 2).AionFLX™: PFAS-free anion-exchange membranes with matched ionomer.
Supply constraintCurrent platinum-group-metal production supports an estimated 3–7.5 GW of PEM manufacturing per year, versus around 100 GW/year needed by 2030 (IRENA 2020).IRENA notes that AEM electrolysers do not need scarce materials in the first place.
CENmat offerOXYGN (PEM) ultra-low-iridium catalyst and CCMs (0.2 mg Ir/cm²: 1.86 V at 2 A/cm² and more than 1,000 h without degradation).HYScale stacks (6 kW short stack validated), AionFLX™ membranes and ionomers, OXYGN and H2GN electrodes.

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sources

  1. IRENA (2020), Green Hydrogen Cost Reduction: Scaling up Electrolysers to Meet the 1.5 °C Climate Goal, International Renewable Energy Agency, Abu Dhabi – Table 7 (PGM loading for PEM electrolysers, p. 70); Chapter 2 (PEM membranes); key findings on PGM supply.
  2. Iridium reference price: Umicore, as of 25 Sep 2026 (US$8,200/oz; € at the ECB euro reference rate, 25 Sep 2026). PEM plant CAPEX: European Hydrogen Observatory LCOH calculator default.
  3. CENmat product information: OXYGN (PEM), OXYGN (AEM), H2GN, AionFLX™, HYScale.