From Laboratory Performance to Industrial Reality: A Review Fuzing Proton Exchange Membrane Electrolyzer Component Degradation and Impact on Levelized Cost of Hydrogen

The long‐awaited Hydrogen Economy needs to be fueled by affordable hydrogen that is produced at a large scale from green, sustainable energy sources to reduce our dependency on fossil fuels and global CO ₂ footprint. This review shows how specifically PEM electrolysis stack technology was developed to deliver high purity hydrogen over the last 20 years, and which component iterations made an actual difference to the levelized cost of hydrogen (LCOH) by improving capital expenditures, operational expenditures, and lifetime. Scale‐up and industrialization are needed to deliver an affordable stack product to the projected GW market, but require consolidation first. This route will fail without addressing standardization of MW‐size stack platform, an appropriate “design‐for‐manufacturing” production process, and affordable cost of goods sold (COGS). Hydrogen technology cannot dominate the market and replace the status quo, as long as manufacturers keep manually assembling their own bespoke prototype stacks. The community must think big. Critical to success is the material selection to sustain functionality, stability, and longevity within an operational window that is continuously pushed to higher current density to increase stack output capacity, whilst compromising on availability and cost. The application of the right amount of catalyst loading or membrane thickness can be complemented by adjusting the startup/shutdown protocols and balance‐of‐plant (BOP) system workarounds to boost compromised stack properties. Many laboratory experiments are conducted only on small screener cells (5–25 cm ² active area), which give best‐in‐class results when compared with industrial stack hardware. Smalscale tests show overly optimistic performance data due to ideal conditions one can achieve on a single cell, while in practice, megawatt stacks, there is very likely a statistical distribution of non‐uniform/non‐optimal conditions that contribute to lower performance and variation behavior. Here in this review, we provide a report on the claimed achievements relevant to LCOH, or absence thereof, accelerated stress testing, in comparison to what is actually applied and observed in larger stacks in the field. Of course, the stack behavior is extremely dependent on its local environment within the BOP system. We estimated the cost‐efficiency of investing into enhanced thermal management solutions, corrosion mitigation, high‐quality water purification, and power supply control to mitigate well‐known component degradation mechanisms and avoid non‐uniform stack failure modes altogether. Our focused overview of publicly available information in the public domain shows the data is non‐conclusive, but clearly highlights the technological gaps and their prioritization in implementation to guarantee a sustainable business case from an industrial viewpoint. The technology development cycle takes about 3 years before the next iteration delivers an improved stack to market, so it is more important to understand degradation and control a design lifetime to optimize the business case for hydrogen.