Months of anion exchange membrane (AEM) electrolyser testing has produced data that suggests the technology could provide the durability and performance required for industrial applications while retaining the cost advantages that could underpin its role in the future renewable energy mix.
US-based Power to Hydrogen (P2H2) worked with European energy company Repsol on a rigorous pilot designed to validate P2H2’s hybrid AEM electrolysis technology for large-scale green hydrogen production.
Conducted through Repsol’s All4Zero industrial innovation hub, the pilot evaluated P2H2’s commercial-scale AEM stack across more than 1,250 hours of parametric and durability testing, including extensive operation under simulated load profiles. The test results show that the system met or exceeded key performance targets across efficiency, flexibility and durability.
Testing of P2H2’s commercial-scale cells in a five-cell short stack produced several results that exceeded conventional proton exchange membrane (PEM) benchmarks. The system recorded irreversible degradation of around 2mV/kHr over 1,250 hours, with average cell voltage changing little over the test period. As such, P2H2 says the results point to potential system lifetimes exceeding 50,000 hours.
Dr Paul Matter, founder and CEO of P2H2 says that these are the results the market has been waiting to see from AEM.
“That degradation rate is important, because it puts the technology in line with established technologies such as (PEM) and alkaline electrolysis. To be bankable, the degradation rate need to be proven in full commercial-scale systems for thousands of hours,” Matter explains.
Cost benefit analysis
Using Repsol-specific inputs and the US Department of Energy’s H2A-Lite methodology, P2H2 estimates a levelised hydrogen cost of around €3.86/kg – approximately 16% below incumbent electrolyser technologies. Under optimised renewable power scenarios using hybrid PPAs, costs could fall to around €2.82/kg, moving closer to commercially attractive levels for industrial hydrogen.
The pilot also tested whether the technology could handle the variable operating conditions associated with renewable power. The system was subjected to repeated cycling between 40% and 100% load and operation across pressures of 2–30 bar.
Testing also achieved hydrogen purity of up to 99.9% directly from the stack at 30 bar, while maintaining performance across the full 2-30 bar pressure range.
And the system demonstrated rapid load-following capability and resumed operation without apparent impact following an unplanned facility power outage.
Real-world reliability
Discussing this variable facet of the work, Matter says: “These are the types of events that happen in the real world, so a controlled lab test without such events would be less credible. We believe AEM has an advantage for integration with renewables because it can cycle more reliably than conventional alkaline systems. Compared with PEM systems, the stacks can be run more efficiently at lower currents without a huge CAPEX penalty, thus improving efficiency and lowering operating expenses for hydrogen production.”
Following the pilot, P2H2 and Repsol are now researching pathways to a larger-scale demonstration at the 500kW to MW level – an important step in supporting Repsol’s target of 600-800MW of renewable hydrogen capacity by 2030. P2H2 is already deploying systems at this scale, including ongoing projects at the Port of Antwerp-Bruges and with SINTEF in Norway.
And if the promising test results from the pilot are replicated at full commercial scale, how does Matter predict they could change the economics of green hydrogen?
“This technology can lower the CAPEX for hydrogen production with equipment that can operate when electricity prices are low and turn off when they are high. We believe this will be crucial for lowering the cost of green hydrogen as much as 50%,” he states.
