Hexagon plagued by a leaky valve
Safety problems with vehicles using hydrogen tanks from the Norwegian manufacturer Hexagon Purus have been reported in two unrelated incidents, one in the US and one in Europe. Hexagon Purus is investigating.
The news website Hydrogen Insight issued a special report about the two cases this week, which it has since adjusted. Upon publication in our German edition, Hexagon Purus has wrote to electrive with its own statements.
According to Hydrogen Insight, the first incident reportedly occurred on June 10 in the Netherlands. Hydrogen infrastructure provider Everfuel said it discovered an H2 tank leaking in one of its hydrogen transport trailers in Rotterdam and cancelled all orders as a precaution. Everfuel claims this leak was caused by a burst O-ring on a valve whose bolts had not been properly tightened during assembly. After fixing this fault, Everfuel said they found a second malfunction on the same valve on eight of its 12 H2 transport trailers.
The second incident occurred last week in the USA. Tanks from the Norwegian manufacturer were also installed in an H2 bus from Canadian manufacturer New Flyer that was destroyed by a fire in Bakersfield, California. Initially, the bus operator Golden Empire Transit said the fire started when the bottles exploded during refuelling. The company has since removed the press release with that statement from its website but has not retracted the statement.
A spokesperson for Hexagon Purus confirmed to Hydrogen Insights their hydrogen cylinders were on board the bus and that Hexagon is working closely with the operator, the bus manufacturer, and the appropriate authorities to investigate the event. “The investigation is still ongoing, and it is too early to speculate on the root cause of the fire,” Hexagon told Hydrogen Insights.
Hexagon Purus has since been in touch directly with electrive. A spokesperson for the company explained that although the cylinders in both incidents are Hexagon Purus Type 4 cylinders, they are different models of cylinder designed for different applications: Everfuel received a system delivery built for hydrogen bulk hauling, while New Flyer’s cylinders were manufactured for onboard hydrogen storage on a bus. The Norwegian company clarified: “In the Everfuel incident, the root cause to the incident was not the cylinder, but a valve related to the cylinder system. These types of valves are not present in an onboard hydrogen storage cylinder.”
The Norwegian hydrogen specialist has been supplying its Type 4 model (lightweight high-pressure tanks) to New Flyer for the Xcelsior Charge FC bus model since early 2021.
Hexagon Purus opened its own U.S. plant in the state of Maryland this February for local production of the Type 4 cylinders. The plant for up to 10,000 tanks per year replaced a smaller plant in the neighbouring city that could only build 1,200 Type 4 tanks per year.
Hexagon Purus assured electrive it would issue further statements as the investigations unfold.