Water electrolysis, a hydrogen energy production method, can generate pure hydrogen and oxygen without emitting 

carbon-based molecules; thus, it is an environmentally friendly technology. Zero-gap alkaline water electrolyzer (ZGAWE) 

can produce hydrogen economically and effi ciently. Here, we developed a ZGAWE hydrodynamic model and investigated 

the changes in cell performance according to the input power and diff erent electrode supporter structures, such as wavy 

mesh, foam, and serpentine, under actual operating conditions. Owing to its high hydrogen conversion rate and low 

operation costs, the wavy mesh supporter design had the highest effi ciency. Additionally, as the system size increased, the 

operation costs decreased; thus, the wavy mesh supporter design was also applicable for large-scale ZGAWE systems. 

Foam supporter fl ow fi eld design shows a very similar trend and can compete with the wavy mesh supporter. Conversely, 

diff erent hydrodynamic performance and high operation costs of the serpentine fl ow fi eld design made it unsuitable for 

the ZGAWE system, but it could be used for the proton/anion exchange membrane water electrolyzer. The results provide 

signifi cant insights into the hydrodynamic eff ects to operate ZGAWEs at diff erent cell voltages; additionally, the results 

can be used to develop high-performance water electrolyzer systems.