Ferry fire in Norway

A hybrid ferry suffered fire in a battery compartment last night. The fire was extinguished using the fix fifi system, but this morning at least one of the batteries exploded:

This is the first time a hybrid ferry in Norway has suffered a fire. Since there will be at least 70 such ferries in traffic in Norwegian waters by the end of next year there is great interest in finding out the cause of the fire.
Experts from the battery supplier, the yard that did the conversion and NMA has been called in to assist and advise the firefighters and owners on the danger of further explosions and eventually the risk of future incidents of this type.

Latest as reported in tu.no:

This is also reported in gcaptain newsletter today:

Note: This ferry was built as a diesel only ferry in 2006 and converted to hybrid earlier this year only.

This will have consequences for both existing and future ferries and other vessels with battery banks on board. How much depends very much on the result of the investigation now under way on board the MF Ytterøyningen.
Whether it will slow down the development of an all 0-emission ferry fleet in Norway is left to be seen.

PS> Corvus is a Canadian company, but its main production and development facilities are in Norway:

Been there, seen that, unfortunately: http://www.professionalmariner.com/December-January-2013/Battery-related-fire-damages-famed-hybrid-tug-puts-it-out-of-service/
Foss wound up reconfiguring to isolate batteries: https://www.maritime-executive.com/article/hybrid-design-reworked-after-tug-fire

It would appear that Li batteries present fire risk whether in a dive camera, vape device, Tesla car, or hybrid boat.


Let’s hope this latest incident will cause some improvement in design and safety.
With 70 some odd battery powered or hybrid ferries due to be in service just in Norway by 2021 it should get everybody’s attention.
It also requires funds to do the necessary research and development to find solutions.

Rest assured that that rules and regulations will be developed and implemented as soon as cause has been ascertained and solutions has been found to mitigate.

According to an article on NRK, the cause of the fire and explosion have been ascertained:

Original – Machine Translation

Apparently, a misaligned seal in the battery cooling system caused a leak, which in turn caused the fire. Further introduction of seawater by way of the sprinkler system caused the explosion.

Uh, yeah. A chemist needs to speak to whoever signed off on that.


Rules will be developed.
But how many people will get killed before they are?

So far none, Who can predict anything about the future?
As the report said: The danger with battery power is no greater than with any other power source.
Sh*t happens everywhere. If you want to be entirely safe you have to hide under your bed and even then there may be dangers.

Well, since it’s the battery maker talking, I guess there are chemists somewhere in the loop. Why so sceptical? Adding salt to the mix does accelerate electrolytic separation of oxygen and hydrogen.

The received wisdom is that you can use water on a lithium-ion battery fire but not a lithium-metal one. I assumed (always dangerous) that the energy density required for a ferry boat would require use of a lithium-metal battery. Do we know what the battery composition was?



Edit: Additional thought: if it was a lithium-ion battery, and the flooding with water was according to the received wisdom, then the delayed explosion indicates a problem with the received wisdom, not the people who signed off on the sprinkler system.

Lithium-ion batteries on ships are becoming more common and is now a force to be reckoned with according to this article:

It seems that Corvus makes several types of battery packs, and I haven’t found specs on the one that went up. I did find their press release on the incident, however. It’s a bit more informative than the newspaper re-hash:

Basically, the coolant leak caused arcing that ignited the glycol component.

Several hours after the fire was out, and in a different compartment? I don’t think it sounds like a metal-water explosion. Anyhow, 1kV battery packs in an installation designed to be drenched should at least make someone think about the hardness and hence conductivity of the water.

What I get so far is confusing:

  1. It’s a Lithium Ion system, and the amount of lithium is sufficiently small that drenching with water is supposedly OK. There does not seem to be general agreement on this point; USCG apparently requires a Class D extinguisher, and descriptions of the various Tesla fires indicate people use other means of fire suppression such as water with suspended solids.

  2. The Corvus system uses ethylene glycol as a coolant; Tesla uses propylene glycol. Ethylene glycol is toxic, and this is probably what sent the 12 firemen to the hospital.

  3. The battery is asserted to have been off-line at the time of the incident.

  4. Preliminary cause determination is that glycol leaked into the cells, causing a short and a subsequent glycol-fueled fire. The Corvus control system is asserted to have prevented a thermal runaway event.

  5. Both an inert gas (Halon?) and saltwater sprinkler system were activated.

So at this point we don’t have a battery fire, we have a coolant system fire that was suppressed. Then 12 hours later there was an explosion, not of the battery, but “in the switchboard room adjacent to the battery room.” Where did the energy come from to cause the explosion? The battery was presumably still off line. I can understand how a soaking wet battery could have another short circuit and reignite a fire in the battery room, but I can’t figure out how you could manage to blow up the room next door.

This is going to be a pretty interesting event chain, if they ever figure it out.



I bet the batteries were fused at the packs, but permanently live at the switchboard. That neatly sets the stage for a hydrogen explosion.

Where would the hydrogen have come from? If the temperature of the coolant+battery fire was enough to split the seawater, why wouldn’t the explosion have been in the battery room instead of next door?

Not challenging, just curious.



When you pass DC through water, you get oxygen at the anode and hydrogen at the cathode. You get bubbles forming with a single alkaline cell (just drop one in a glass of slightly salty water), and a steady stream of bubbles at 4.5 V, or at least that’s how I remember it from playing around on the kitchen counter at age ~10. I imagine that you get quite a bit of gas forming at a kilovolt.

As for why the explosion occurred away from the batteries, there are many possible explanations. The gas may have pooled in the control room, since it is quite a bit lighter than air and doesn’t like to be contained. Alternately, the batteries may have been properly insulated to prevent this while the switchboard was not, so that’s where gas formed when the whole installation was flooded. Or gas may have been formed throughout, but only the battery room was properly ventilated.

It’s also possible that I’m entirely mistaken, but Hydrogen is where I’d put my money if I had to make a bet.


Ah, got it. Thanks, seems reasonable.



Maybe they need some of our advanced battery technology. There are plenty of US companies with extensive knowledge and experience with current battery technology. They already import a ton of Teslas.

I don’t know where you get the that idea from, but to power a car and a ferry require very different technology.

There are more than just one company competing in the market to supply battery solutions to the maritime industry and they will eventually iron out the problems that becomes evident during the process.

If Tesla have the better solution they will win the competition for a potentially multi-billion dollar market for maritime batteries. Otherwise they will stick to batteries for automotive and stationary use.

I don’t know if they are even interested in the maritime market.(??)

I had my money on Duracell. Damn.