Safe Design for Large Scale H2 Production Facilities

To contribute to a more diverse and efficient energy infrastructure, large quantities of hydrogen are requested for industries (e.g., mining, refining, fertilizers…). These applications need large scale facilities such as dozens of electrolyzer stacks from atmospheric pressure to 30 bar with a total capacity ranging from 100 up to 400 MW and associated hydrogen storage from a few to 50 tons.
Local use can be fed by electrolyzer in 20 feet container and stored in bundles with small volumes. Nevertheless, industrial applications can request much bigger capacity of production which are generally located in buildings. The different technologies available for the production of hydrogen at large scale are alkaline or PEM electrolyzer with for example 100 MW capacity in a building of 20000 m3 and hydrogen stored in tube trailers or other fixed hydrogen storage solution with large volumes.
These applications led to the use of hydrogen inside large but confined spaces with the risk of fire and explosion in case of loss of containment followed by ignition. This can lead to severe consequences on asset, workers and public due to the large inventories of hydrogen handled.
This article aims to provide an overview of the strategy to safely design large scale hydrogen production facilities in buildings through benchmarks based on projects and literature reviews, best practices & standards, regulations. It is completed by a risk assessment taking into consideration hydrogen behavior and influence of different parameters in dispersion and explosion in large buildings.
This article provides recommendations for hydrogen project stakeholders to perform informed-based decisions for designing large scale production buildings. It includes safety measures as reducing hydrogen inventories inside building, allocating clearance around electrolyzer stacks, implementing early detection and isolation devices and building geometry to avoid hydrogen accumulation.