Status and Q&A regarding the Kjørbo incident

Nel received a report of an incident involving a fire at the Kjørbo hydrogen station outside Oslo, Norway, at 17:40 CEST on June 10, 2019. The fire was contained just after 20:00 CEST. Immediately upon receiving notification, Nel mobilized its crisis response team in Norway and Denmark.

Current status

The root cause of the incident has been identified as an assembly error of a specific plug in a hydrogen tank in the high-pressure storage unit. This led to a hydrogen leak, creating a mixture of hydrogen and air that ignited. The investigations will continue into the specific source of ignition.

Nel held press and investor conferences on Friday, 28 June, to share all relevant information publicly. Both events were live-streamed and available as recordings for the remainder of the day for anyone who wasn’t able to join at the time.

We will continue to assist our customers in getting stations safely back into operation as quickly as possible.

Going forward, Nel will share all findings with the hydrogen industry and other stakeholders.

(Published: 27 June, 2019; Updated: 29 June, 2019)

Q: What caused the incident and what is the current status?

The root cause of the incident has been identified as an assembly error of a specific plug in a hydrogen tank in the high-pressure storage unit. This led to a hydrogen leak, which created a mixture of hydrogen and air that ignited. Investigations into the specific source of ignition continue.

Together with the authorities, Nel and Gexcon have finalized the off-site examination of the high-pressure storage unit. With the root cause now identified, Nel will conduct an inspection and integrity verification program for the high-pressure storage units with similar plugs. Additionally, Nel has initiated a program outlining new assembly, verification, and documentation procedures.

(Published: 27 June, 2019)

Q: What went wrong with the assembly of the plug?

Due to human error, the inner bolts of the plug had not been adequately torqued.

(Published: 03 July, 2019)

Q: How sensitive is the torqueing?

The bolt calculations show that the torqueing is not particularly sensitive. If the bolts are tightened to nominal torque, they will be tight with a safety factor of more than 3 (against separation).
Nel has very clear specifications for the proper torqueing of bolts in the high-pressure storage unit. Unfortunately, in this case, the torqueing requirements weren’t met due to human error.

(Published: 03 July, 2019)

Q: What caused the ignition?

This is still not clear. Further investigations and data simulations will look into the source of the ignition.

(Published: 17 June, 2019)

Q: What is the likely source of ignition?

The source of ignition is still being investigated and it is possible it will never be known with certainty. However, the investigations by Gexcon have indicated that either auto-ignition and/or the movement of the gravel underneath the unit are the most likely sources.

(Published: 28 June, 2019)

Q: Could this happen again?

While our ambition is to have zero incidents at sites with Nel technology, there is always the possibility of an incident at fueling or charging stations of all kinds; this includes conventional fueling stations. That said, we recognize how serious such incidents are and we are continuously working to prevent it from ever happening again.

To help ensure an incident like this doesn’t happen again, we have introduced a dual-witness torque procedure, whereby first one fitter torques to nominal torque in a 3-step procedure and marks each specific bolt with a green line after torqueing. Afterwards, a second fitter performs a control by re-torqueing each bolt, marking it with a red line. This procedure is performed on the inner bolt holding the bush and on the outer bolts holding the plug.

Both fitters must sign-off in the Assembly Quality Control chart, noting the specific cylinder serial number, that they have been torqueing the bolts, stating the torque value, and noting which torque wrench – all of which are calibrated – was used.
While all Nel employees handling our equipment are expected to meet Nel specifications in the work they do, having a dual-witness procedure will provide an extra level of assurance against mistakes.

(Published: 28 June, 2019; Updated: 03 July, 2019)

Q: Was it Nel’s equipment that caused the incident?

The high-pressure storage unit involved is not part of Nel’s core technology, however it is a part of Nel’s scope of supply. It consists of steel tanks and components sourced from sub-suppliers and was assembled by Nel. The solution has been certified by a third party.

(Published: 27 June, 2019)

Q: Was Nel responsible?

Nel takes responsibility for the situation. We have allocated substantial resources towards the investigation and are satisfied that the root cause of the incident has been uncovered. All the learnings will be shared to help the industry become even safer. The allocation of legal and financial liabilities related to the incident will be concluded at a later stage.

(Published: 27 June, 2019)

Q: Can vandalism or terrorism be ruled out?

We have no indication of either vandalism or terrorism. We anticipate that the final report from the investigations carried out by the authorities will provide a definitive answer.

(Published: 14 June, 2019; Updated: 17 June, 2019)

Q: When do you expect to reach a conclusion in the investigation?

The authorities are conducting a formal investigation and have stated publicly that this will take time. In addition to contributing to the formal investigation, we, together with Gexcon, will continue our own investigations into the source of ignition. We will provide updates on a regular basis.

(Published: 12 June, 2019; Updated: 27 June, 2019)

Q: Was the fueling dispenser unit involved?

No. Gexcon has completely ruled out involvement of the customer-facing unit, i.e. the fueling dispenser.

(Published: 13 June, 2019; Updated: 27 June, 2019)

Q: Was the on-site electrolyzer involved?

No. Gexcon has completely ruled out that the electrolyzer was involved.

(Published: 13 June, 2019; Updated: 27 June, 2019)

Q: Was there an explosion?

No unit exploded at the site. Based on our current information, hydrogen gas that had leaked caught fire in open air. This created a pressure wave.

(Published: 13 June, 2019)

Q: What caused the hydrogen to leak?

Investigations indicate that an assembly error of a specific plug in a hydrogen tank in the high-pressure storage unit caused the leak.

(Published: 27 June, 2019)

Q: Were there any injuries or fatalities?

According to police reports, three people were taken to the hospital and treated for minor injuries due to airbags deploying in their cars nearby the site. There were no fatalities and no on-site injuries.

(Published: 12 June, 2019; Updated: 27 June, 2019)

Q: Are any other stations affected?

As a precautionary measure following the incident, Nel recommended its customers put stations within the same product family on a temporary standby until the root cause was identified. This included stations both in Europe and in the US. Some operators also independently decided to put stations on standby as an additional precaution.

With the root cause identified, we are actively working with our customers to bring stations back online.

(Published: 12 June, 2019; Updated: 27 June, 2019)

Q: When can the stations reopen?

The Nel team is working on plans for reopening stations. The older generation stations as well as the US and Korean stations have a different high-pressure storage design, and should be able to reopen relatively soon.

(Published: 27 June, 2019)

Q: If Korea and the US use different plugs not subject to the same kind of error, why aren’t those plugs used in Europe, too?

The difference in plug design has to do both with suppliers and certification. The European cylinders are from a particular supplier and certified for use in Europe. The cylinders used in the US and Korea are from a different supplier and certified for use in the US and Korea. Both designs are sound so long as assembly is done correctly and there is no technical reason for changing the plug used in Europe.

(Published: 03 July, 2019)

Q: As a hydrogen customer, can I refuel during the temporary standby?

When a station is in temporary standby, it means that you cannot fuel at that station. We empathize deeply with the hydrogen customers who have been affected by this and are actively working to help our customers be able to reopen stations as soon as possible.

(Published: 12 June, 2019; Updated: 27 June, 2019)

Q: What is the position of suppliers of hydrogen vehicles?

An official statement from Toyota Norway says that the company has not stopped sales. For the time being only deliveries have been put on hold, as refueling is currently not possible in the country. It is our understanding that other suppliers have taken similar positions.

(Published: 13 June, 2019)

Q: Are hydrogen fueling stations safe?

The hydrogen refueling stations designed and manufactured by Nel, known as H2Station™ are as safe as conventional fueling stations. They are built according to the highest level of safety and comply with codes and standards that meet the same safety levels as the oil and gas industry. The stations in Europe, the US, and Korea comply with national codes and standards, as well as international standards. The European H2Station is approved by industry-leading third parties, and complies with all relevant European and international standards, as well as applicable directives.

(Published: 12 June, 2019)

Q: Will learnings from the incident be shared?

We are committed to sharing learnings from this incident with the rest of the hydrogen industry in order to make the industry even safer than it is today.

(Published: 27 June, 2019)

Q: How much will this cost Nel?

Nel has deployed all relevant resources for the Kjørbo incident, which will entail extraordinary costs during 2019. The costs are related to investigations, station inspections, site clean-up, station replacement, and other potentially unforeseen costs. The eventual insurance settlements and other issues may impact the final costs as well. We expect to have a clearer picture of the costs to be presented along with the Q2 report on 28 August 2019.

(Published: 28 June, 2019)