Chapter 01 · Climate & transitionEnergy & Transition
Anion exchange membrane (AEM) electrolyzer
Definition
An electrolyser that splits water using a solid anion exchange membrane, which conducts hydroxide ions between electrodes in an alkaline environment. By combining the low-cost, non-precious-metal catalysts of alkaline systems with the compact, membrane-based design of PEM systems, AEM technology aims to deliver cheaper and more flexible hydrogen production.
References
TRL status (4→6 vs TRL 9 incumbents); technical bottlenecks; durability demonstrations; IRENA targets.
Technology shares of installed capacity; market context for emerging types.
Overview
What it means
AEM is the least mature of the four main electrolyser types: the IEA rates alkaline and PEM at technology readiness level 9 (market uptake), while AEM rose from TRL 4 (small prototype) in 2021 to TRL 6 (large prototype) in 2022. Key bottlenecks are membrane durability and ionic conductivity, catalyst stability, and scaling beyond demonstration units; projects above 100 MW remain in development.
How it is used
Research focuses on non-precious-metal catalysts (nickel-iron based) and more stable membranes, with some laboratory systems showing industrial-grade durability (for example 12,000-hour operation in one reported test). IRENA has set techno-economic targets for AEM to become cost-competitive by mid-century.
Why it matters
If AEM matures, it could undercut both incumbent technologies on cost while handling variable renewable power — potentially lowering the cost of green hydrogen. Tracking its readiness level matters for realistic hydrogen deployment planning.