Hydrogen bulk storage areas: How advanced consequence modelling can inform a safer design and help reduce the risks from explosions

Hydrogen is expected to play a big role in the transition toward a more sustainable energy system, with numerous projects already underway along the entire value chain from production through storage and distribution, to a wide variety of end-user applications.

Although the use of hydrogen in industry is not new, the energy transition is leading to many novel applications.

Hydrogen is being located and used near the general public, whose lack of safety awareness and specialist training runs the risk of potential accidents occurring. This would result not only in the loss of public support but also the license to operate and possibly delay the introduction of new technologies.

If hydrogen is to fulfil its promise in the energy transition, safety is of paramount importance.

The importance of understanding risks associated with hydrogen

Every player in the hydrogen value chain needs to understand the hazards associated with the introduction of hydrogen, carefully evaluate the risks, and put in place sufficient mitigation measures to reduce these risks to tolerable levels.

This includes the hydrogen bulk storage areas.

The design and operation of hydrogen storage and handling facilities must consider the unique explosion characteristics that hydrogen possesses compared to other fuels such as natural gas.

Due to its greater reactivity and ignition sensitivity, the explosion overpressures generated in the case of an ignited release, have the potential to cause significant damage in the surrounding area of the facilities.  

An ignited event involving hydrogen has a higher likelihood of undergoing a deflagration to detonation transition (DDT), which would result in very severe overpressures and potentially catastrophic damage to equipment and structures.

Potential effects of hydrogen explosions must be assessed from the early stages of a project and adequate prevention and mitigation measures evaluated as the project progresses.

Currently, there is only limited guidance and standards (e.g., COP  CP33,  NFPA  2)  for the design of hydrogen storage facilities, and while certain separation distances to occupied buildings and equipment are provided, nothing is mentioned regarding layouts and recommended distances between banks of hydrogen tanks.

It is also thought that the outlined safety distances could be underpredicted in some circumstances.

At the 2022 Gastech Conference and Exhibition, Dr Karina Almeida Leñero and Pablo Giacopinelli presented a study of several explosion scenarios in a hydrogen storage facility, conducted using the CFD consequence modelling tool, FLACS-CFD.

In their presentation, Karina and Pablo discussed the effect of different layouts, storage tank configurations and levels of confinement/congestion on the maximum overpressure, likelihood of DDT and the flame path. They also talked about the discrepancies between currently available guidance and the results from this study being discussed.

Finally, they presented potential recommended mitigation measures to ensure that facilities storing large amounts of hydrogen can be designed safely.

Would you like to learn more about this topic?

Watch a webinar where you will be presented with an investigation of the discrepancies between the currently available guidance and the results from our case study on safety distances for hydrogen application.