Several fires in ferry battery compartments: “No effective way to extinguish lithium-ion batteries”

24. august 2022 kl. 09:51
Several fires in ferry battery compartments: “No effective way to extinguish lithium-ion batteries”
This is what the battery compartment of MS Brim looked like after the fire. Illustration: Statens Havarikommisjon.
Despite battery-powered ferries having been around for 10 years, the strategy is still to let the battery burn out and ensure that the gases do not cause the whole ship to explode.
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The fire hazard in a battery-powered vessel is roughly the same as in a diesel-powered vessel.

But while we know how to effectively extinguish a fire on a diesel-powered ferry, we still do not know how to effectively extinguish fires on battery-powered ferries. And that poses a significant security risk.

This conclusion is based on, among other things, two Norwegian incidents in which a fire broke out in the battery compartments of MF Ytterøyvingen and MS Brim ferries.

In July, the Norwegian Safety Investigation Authority published the MS Brim investigation report, which once again concluded that there is currently no proper solution on the market for extinguishing fires in lithium-ion batteries.

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“The investigation has shown that the fire extinguishing agent Novec only had a small effect on the fire behaviour, and that there are no effective fire extinguishing agents that prevent fire and propagation in lithium-ion batteries available today. It is a safety risk that there are no effective fire extinguishing agents for lithium-ion batteries,” the authority concludes in the investigation report.

As more battery-powered ferries are built, older ferries are retrofitted to use batteries, and the share of electric cars increases, the risk of fires also increases.

That is why the lack of a proper fire extinguishing agent is the biggest safety risk, according to several experts that Ingeniøren has talked to.

“Every time a fire takes place, we learn more about how we can prevent fires and avoid new ones breaking out on ferries. But when it comes to the fires that occur in lithium-ion batteries, whether on water or on land, the challenge is that we still don’t have a proper method to control and extinguish them,” says Sverre Eriksen, certification engineer at DNV.

Long extinguishing process

It is not like battery compartment fires on ferries are monthly or annual events, not even if we look at the entire Nordic region.

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But in Norway, there have been two particularly noteworthy fires, namely those on MF Ytterøyvingen in 2019 and MS Brim in 2021.

On the former, the fire broke out due to a leakage from the battery’s cooling system due to a defective gasket. Firefighters reacted quickly, but they withdrew due to difficult access conditions and let the battery burn. The gases from the burning batteries created a particularly dangerous atmosphere, and after just over 12 hours there was an explosion of such force that it damaged the fire engines in the vicinity.

The incident evokes memories of the 2014 accident in Copenhagen, in which a second officer in one of the city’s harbour buses was badly burned after faulty batteries had leaked gases overnight. The gas ignited when he connected a starter cable to the battery.

Lessons from Ytterøyvingen

The lessons learned from MF Ytterøyvingen had stuck with the fire brigade when a fire broke out on MS Brim last year. In this case, the fire was caused by the fact that a ventilation system designed precisely to suck out the flammable gases ended up being a channel for salt water, which was fed into the battery.

Shortly after the fire brigade had arrived at the scene, they began to examine the vessel for gases and found high concentrations of, among other things, carbon monoxide, hydrogen sulphide, and other “explosive gases”.

Watch the Norwegian Safety Investigation Authority talk about the investigation here:

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Therefore, the fire brigade decided to replace the dangerous gases with nitrogen, so a “pump truck” and “nitrogen truck” were connected to the ship’s ventilation system, and five days after the fire broke out, the ship was declared “safe” by the fire brigade.

No fire extinguishing agents

Pumps with the fire extinguishing agent Novec were installed in the battery compartment of MS Brim, despite the fact that the company behind it advises against using the agent in battery compartments. According to the report, the Norwegian Maritime Authority was aware that Novec was used in battery compartments despite the manufacturer’s warnings, but states that “there is no extinguishing system that can extinguish a lithium-ion fire available today”.

Jimmy Henningsson, technical director at Power Tech Sweden AB, a company that designs products for hybrid ferries, shares the same view.

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“Diesel engines have existed for many years, and the authorities know exactly how to handle a fire. But when it comes to batteries, it’s still a completely new field. They have now learned that, for example, you mustn't use saltwater to put out the fire, but it is an ongoing process; people need to learn how it’s done,” he says, also highlighting the problem of fire extinguishing agents.

“In the beginning, there was no market for developing systems to put out battery fires, and nothing has yet been developed that does the job properly, but hopefully the increase in hybrid and battery-powered ferries in recent years has prompted some to develop a product that works,” Jimmy Henningsson says.

Danish Maritime Authority: It is still a new field

Asked whether there are rules in place to protect Danish travellers against fires on Danish ferries, the Danish Maritime Authority admits that it is still a new field.

“This is a relatively new technology which continues to be developed, which is why standardization and regulations in this field are also under continuous development,” the authority said in a written response to Ingeniøren.

“As part of the green transition, several ferries have been built—or retrofitted—with battery systems as a full or partial replacement for traditional diesel machinery in recent years. This entails different safety risks on board, as risks associated with diesel machinery disappear, while new ones arise, including risks for battery fires, which can be difficult to control,” the agency wrote.

The authority acknowledges that no detailed technical rules have yet been introduced but claims that they are currently being prepared.

“The current statutory safety rules for ship construction, equipment, and operation therefore do not yet contain detailed, technical rules and standards that fully cover battery systems on board ships,” the authority says and states that it expects a pan-European set of guidelines to be completed in 2023.

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