Power to Hydrogen and Repsol Complete 1,250-Hour Durability Test of AEM Electrolyzer
en.Wedoany.com Reported - On September 8, Power to Hydrogen (P2H2) and Repsol announced the completion of testing of hybrid anion exchange membrane (AEM) electrolysis technology. The test was conducted through the All4Zero industrial innovation platform with Repsol's participation, using a 5-cell short stack composed of P2H2 commercial-size electrolysis cells, accumulating more than 1,250 hours of parameter and durability testing, and repeatedly performing dynamic load operation under simulated renewable energy fluctuation conditions.
The test load cycled between 40% and 100%, with operating pressure covering 2–30 bar. During the test period, the system continuously verified electrolysis efficiency, dynamic response, hydrogen purity, and durability under different load and pressure conditions. Results published by P2H2 show that at an operating pressure of 30 bar, the hydrogen purity directly produced by the electrolysis stack reached a maximum of 99.9%; the system also experienced an unexpected facility power outage during the test, and after power supply was restored, it restarted and continued to complete the test.
This test used a 5-cell short stack composed of P2H2 commercial-size cells, not a complete megawatt-scale electrolysis system. During the 1,250 hours of operation, P2H2 recorded an irreversible voltage degradation of approximately 2 mV/1,000 hours, with average cell voltage changing little before and after the test. Based on this, the company estimates that the technology corresponds to a system lifetime of more than 50,000 hours.
P2H2's hybrid AEM pathway does not use iridium and adopts a PFAS-free material pathway. Its system uses lower-cost materials such as stainless steel to construct the electrolysis stack, while completing the water electrolysis reaction through its proprietary catalyst and electrode system. P2H2 currently applies this technology to industrial hydrogen production systems designed for fluctuating renewable power operation, and has developed a 250 kW-class modular AEM electrolysis stack.
This test also conducted model-based calculations of hydrogen production cost. Using operating input parameters provided by Repsol and combining them with the U.S. Department of Energy's H2A-Lite analysis framework, P2H2 calculated a levelized cost of hydrogen of approximately €3.86/kg, about 16% lower than the existing electrolysis technology benchmark it selected; under a scenario using optimized renewable energy supply and a hybrid power purchase agreement, the calculated value could drop to approximately €2.82/kg. The above data are model-based calculated values formed on the basis of this test's results and specific energy cost assumptions.
After completing short-stack validation, P2H2 and Repsol are studying the next phase of a complete 500 kW to MW-scale system demonstration. The next phase will scale the currently validated commercial-size cells into a complete electrolyzer system, to continue testing the equipment's engineering performance under higher power, long-term continuous operation, and dynamic renewable energy load conditions.
P2H2 is already advancing deployment of industrial equipment at the same level. In August 2026, the company delivered a 500 kW AEM electrolysis system to the Port of Antwerp-Bruges in Belgium; the equipment consists of two 250 kW electrolysis stack modules and has entered the on-site installation stage; another 500 kW system is used for SINTEF's PYROCO₂ project in Norway.
Repsol has proposed a target of forming 600–800 MW of renewable hydrogen production capacity by 2030. After the completion of this 1,250-hour AEM test, the next clear technical milestone for both parties is a complete 500 kW to MW-scale system demonstration.
