Safety in a green hydrogen plant: what can go wrong?

There is little experience with the safety risks associated with large-scale production of hydrogen. The ISPT project ‘Green Hydrogen Inherent Safety on a large Industrial scale’ should provide more insight into this. Carol Xiao, Director Business Development, explains in an interview with Europoort Kringen: “Despite the design, something can go wrong with this water electrolysis technology because there is little data available yet.”

In the beginning of 2022, ISPT presented a design for an innovative and advanced green hydrogen plant at 1 GigaWatt scale. “When we met in the working sessions, participating parties told us that safety is an important common subject that deserves to be developed,” says Carol Xiao. ISPT took the initiative and started the project Green Hydrogen Inherent Safety Practices on a large industrial scale, as part of the Hydrohub Innovation Program.

Risk of explosion

“Hydrogen is a well-known substance,” says Xiao about the project. “But little is known about safety in a green hydrogen plant with regard to hydrogen. The two main technologies for water electrolysis are PEM and AWE. In both technologies, water is split into hydrogen and oxygen in an electrolyser – also known as stack. The hydrogen is separated from the oxygen by a membrane. But due to gas transport or if something breaks, tears of leaks, the two substances can come together. Despite the design, there is a risk of explosion in exceptional scenarios. In view of process safety, a safe workplace and the environment of the plant, you have to adjust measures accordingly.”

Despite the design, there is a risk of explosion

Lack of historical data

Because no data is available yet about the safety of large-scale water electrolysis with multiple stacks and modules, everyone is extremely careful. “We cannot afford incidents. There is a need for guidelines, standards and protocols; everything is new! Suppliers, industry and licensing authorities therefore remained stuck in the cycle of setting requirements and designs for a long time.”  

The safety project focuses on two aspects: improving the assessment methodologies and options for inherently safer design. “Our findings can be included in every new project, so that the wheel does not have to be reinvented every time.” Electrolysis is a well-known process, says Xiao, but it is unknown how it behaves in large-scale production processes under variable loads. “We are analyzing credible scenarios, but we don’t know yet how often things can go wrong.”

There is a need for guidelines, standards and protocols; everything is new!

1 gigawatt plant

The focus of this project is on 1 gigawatt plants. But according to Carol Xiao, largely the same safety risks can also arise at smaller hydrogen productions. In the light of the long term, Xiao considers a 200 MW green hydrogen plant, as Shell envisions at the ‘Tweede Maasvlakte’, as an intermediate step. “You have to imagine that a 1 GW plant only produces one 10^th of the amount of hydrogen we will need in the Netherlands in a future hydrogen economy.”

Standards

Xiao favors an open dialogue with asset owners and suppliers. She was initially afraid that suppliers would not want to communicate about risks because of damage to their image. “However, I was surprised by their open way of sharing knowledge,” says Xiao.

Hydrogen safety program

ISPT is working on a hydrogen safety program. This is because safety still has many aspects to work out. For example, standardization is necessary for the realization of a safe plant. In collaboration with asset owners, suppliers and NEN, in addition to the technical aspects, work is also being done on aspects relating to policy-making and permit provision issues. “You have to know what to approve. If you don’t have standards, it remains subjective and it is difficult to guarantee safety. The production process also needs to be standardized. Asset owners need to know how to operate and maintain the stacks.” A follow-up project on standardization is expected to start this year (2023), focusing on testing and experimentation for failure probabilities and inherent safe design.

Momentum

“Safety comes naturally. I notice that our partners want to take it even more seriously together than I expected. That is very positive.” Carol expects that the results from this project can be used in the construction of new green hydrogen plants. “It is important that we take the lead in safety in the Netherlands. In Egypt, Canada and China they are already starting to build 100 MW hydrogen plants. So let’s keep the momentum going here.”