Electric buses withdrawn in south London after fire | Hacker News Reader

Electric buses withdrawn in south London after fire

bbc.com

46 pointsantongribok40 comments

I saw this on the BBC the other day, it made me go look up how many bus fires there are.

242 over the past couple of years (although it seems these are mostly diesel or hybrid rather than battery), there’s reasonable detail in the summaries further down the page by cause: https://www.gov.uk/government/publications/investigation-int...

I couldn’t find a way to estimate fires per miles driven.

It also doesn’t include all bus fires, only those reported to the DVSA. London Fire Brigade reports a bunch more in their publication.

It would be interesting to see if there was some weighted way to compare bus fires in non-electric ones vs electric ones. To check if either have bigger probability for the fire being a bigger issue.

I don't really see a link between electric bus fires and diesel fires. The safety issue is that electric vehicle fires are far more difficult to control than their combustion counterparts.

"Electric Vehicle Fire" by "South Metro Fire Rescue Centennial, Colorado"

https://youtu.be/itGeAq9rBeY

We had electric buses for many, many decades. They are called trolley buses and they are awesome. Why they see so little use is crazy to me.

All these low carbon plans but instead of just investing in infrastructure, they invest in all these fancy new technologies that really aren't an advantage.

What was the chemistry of the battery? I'm guessing it wasn't LFP, but then again I've heard that LFP isn't quite as fire bulletproof as it was advertised.

I have never heard that LFP would be fire safe. Just safer compared to other lithium cell types.

Correct. That energy stored in the battery needs to go somewhere. Failing fully charged LFP is no less dangerous than any other chemistry.

The electrolyte in lithium ion batteries is very flammable. It combusts on contact to air which is why batteries if punctured. LiFePO4 batteries don't have super flammable electrolyte; they can burn but not easily and violently.

It’s is less dangerous, because LFP has lower energy density that other lithium chemistries so which means either less energy to dissipate per kg of battery, or more surface area to dissipate the energy per joule.

Also LFPs don’t contain components with negative temperature coefficients of resistance (I.e. stuff that gets more conducive as it heats up), which reduces the risk of thermal runaway because LFPs increase their resistance as they get hot, reducing their max output power. Rather other chemistries that reduce resistance as they get hot, increasing their output power.

Edit: See comment below. The first fire was a fully electric bus, not a hybrid.

> "The vehicle utilises a 32kWh capacity energy storage system, comprising third generation lithium nickel manganese cobalt battery technology"

I think it might be this hybrid but I could not find a confirmation [0].

[0] https://www.alexander-dennis.com/alexander-dennis-enviro400e...

The article is actually about two bus fires - one in west london, south of the thames:

> a double-decker caught fire on Thursday [...] The fire started during the morning rush hour in Wimbledon [...] the operator, London General - a subsidiary of Go-Ahead London - and the bus manufacturer, Switch

And also one a day later, in east london, just north of the thames:

> On Friday, a hybrid double-decker bus was destroyed in a fire [...] in North Woolwich. [...] the operator, Go-Ahead, and the manufacturer, Alexander Dennis [...] we have no reason to suspect that this fire on a hybrid bus was linked to an earlier incident on an electric bus

Almost certainly one of these: https://en.wikipedia.org/wiki/Switch_Metrodecker , based on the details in the story. Full battery bus, not a hybrid. Been around for 10 years, so probably unlikely to be LFP.

You're likely right. Here's a site that lists the vehicles used on the specific route mentioned a few days ago [1] and now [2]. All the ones starting Me appears to be Metrodecker's (click through the vehicle number). Notice how they've been replaced by "SE" (which appears to be ADL Environ200's) and others.

https://bustimes.org/services/200-raynes-park-wimbledon-mitc...

Thanks. I haven't heard of Switch Mobility before.

Where have you heard that? I've seen videos of people actually sinking axes into LFP cells which just vent a bit compared to say NMC which burst into flames.

We have had quite a few "unexplained" electric and hybrid bus fires here in Barcelona the last few years.

Tail risk is simply outright difficult to get through folks' head.

Oslo in Norway had massive problems due to the cold affecting the amount of charge the buses would hold as well as the charge speed leaving them unable to recharge them fully over night.

Oslo can't have been surprised by the existence of cold weather. Did they not contemplate any countermeasures, like heaters at the charging location or better insulating the batteries so the heat from discharging them and then recharging through regenerative braking keeps them warmer?

Bus developers probably weren't based in Oslo

Toyota isn't based in Oslo either but they know how to make a vehicle that runs there, and the companies that don't generally don't do a lot of business there.

Electric buses in Oslo Norway (of all places) is a dictate of politics, not practicality. The people implementing the politics were likely warning about such oversights, but were rebuffed. They will gladly see it all fail, so that they may say: We told you so.

The temperature does not affect to charge stored in the batteries, right? However, you have to use the battery to heat itself as well as heat the bus (unless you got diesel heater or something for the cabin).

Batteries produce electricity through a chemical reaction. When it is colder, that reaction creates less electricity.

If you fully charge a battery, freeze it, then warm it back up, it will still be close to fully charged.

It’s pretty well known (in industries that use batteries) that temperature affects the capacity of batteries.

It’ll impact the usable charge because the colder temps will decrease the ability of the battery to produce high currents. Effectively setting the floor for a “useful” charge level higher. Below that useful level, current supply is too low to power whatever it is you’re powering.

A universal problem for all EVs in cold climates

That's one reason to not switch to EVs. But muuuh local emissions free...

This appears to be an exaggeration that’s making its way around less scrupulous news sources. From https://www.euronews.com/my-europe/2023/12/30/was-oslo-paral... :

a spokesperson called the allegations “an extreme exaggeration… We cancelled, on average, between 50 and 100 departures, out of more than 4,000 daily departures, for a few days.”

The company did however admit they had a few “challenges with the range of the buses being shorter in cold weather."

"We solved this by changing the charging shifts. And also by fixing the charging infrastructure."

Ruter [the bus operating company] claims the issues have since been fixed and the fleet of electric buses continues to run as usual.

That not right at all. Norwegian news say something very different and is probably more reliable.

https://www.nrk.no/stor-oslo/kaller-inn-byrad-i-oslo-pa-grun....

Reached 1000 cancelations at the worst in a single day it seems.

They managed to resume traffic by using emergency diesel replacement buses.

Why the big fuss? Fires happen occasionally. Is there something about the fire that was avoidable? There are really no details given - a real non-story.

Perhaps this part of a PR campaign to signal how government takes this sort of thing very seriously?

They've withdrawn the electric buses on one specific route, which a later paragraph suggests is a specific type, while figuring out if there's a specific issue. It's posted in a regional sub-section for London rather than in their national news. That doesn't sound like a big fuss to me.

Your second point is probably the correct point, but hopefully we find out more with time.

Battery fires are actually very hard to tackle so my guess is that these busses were built to avoid catching on fire as much as possible so when one does happen, they need to investigate to make sure there isn't a major design flaw.

This article is in the BBC's local news section for London. It's a run-of-the-mill public transport local news story. It's not national news. Why it has been posted here, I don't know.

I posted this and can answer your question.

I don't live in UK, and don't generally read the local news section of BBC, so this was displayed on the side when I was reading a story about the volcanic activity in Iceland.

I clicked on the story, because it was about electric busses, a subject I'm interested in, since we don't have any where I live.

After clicking on the story, I was a bit disappointed with the lack of detail.

I decided to post here, because I figured if it got any traction, someone on here would post a bit more detail.

The top comment on here currently is exactly what I was hoping to see, and I'm glad I posted the story.

It seems to be part of the current "culture war" in Britain — at least judging by the promoted Facebook posts I see.

Over half of London's buses are electric (11%) or hybrid (44%) so it's not surprising that fires are now affecting these.

Promoted FB posts are a very bad measure of what is happening. They are designed to provoke people and get reactions - it is all about engagement.

I do not know what the motive is (some way of making money no doubt) but it is clear to me that these are mostly just trying to get comments and reactions.

I strongly suspect a lot of what I see on FB is not even human written - lots of jokes that do not quite make sense, minor variations on things I have seen before that also do not quire make sense.

There's also reporting like "Officials today launched an investigation after one of Sadiq Khan's electric buses exploded during today's rush hour". [1]

"A huge blast ripped off the back of an Optare Metrodecker 1050 bus"... yet the picture shows the back of the bus is intact. [2]

Daily Mail nonsense like this was enough to influence the Uxbridge byelection (over LTNs), but I'll admit I'm too far away from Britain to know the situation.

[1] https://www.dailymail.co.uk/news/article-12950765/London-ele...

[2] https://www.dailymail.co.uk/news/article-12955781/Wimbledon-...

It seems like a _bit_ of a non-story, absent any other info; bus fires are more common than you might think.

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