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To save others the clicking and scrolling (if you're mainly interested in the conclusion, as I was), the summary at the end says that the risk of fire starting

by kelnos 2y ago

To save others the clicking and scrolling (if you're mainly interested in the conclusion, as I was), the summary at the end says that the risk of fire starting in your battery energy storage (or in your EV) is lower than that of your average house fire (or in your ICE car). They liken the risk of a fire starting in the battery storage to that of fire starting in a clothes dryer. But, depending on the placement of your batteries in/around your home, the severity of a fire, if one should happen, could end up being worse than a fire that starts in some other household appliance. I was pleased to read that the risk of fire is reasonable and low; I wasn't sure what to expect, but was afraid the conclusion would be that they're higher-risk. I suppose I expected to see the result that a fire that included large batteries could be a much worse fire. Li ion battery fires can be pretty bad, and those batteries are much larger than what you'd find in your phone or other small electronics. I still would like to add rooftop solar to my house (even though California's metering system is all kinds of anti-rooftop-solar now). When I last looked into it a couple years ago, battery storage seemed like it was a little too pricey to be worth it, but it seems like that's been changing.

Sayrus 2y ago
> The fires in HSS in Germany were determined using web crawling for the year 2023 because no other data was available. All other probabilities were calculated using researched data. HSS may also be underrepresented in the scrapped data due to the method used. The document sections Discussion and Limitations and Outlook touch about this. The authors highlight a lack of common categorization of fires types and count as well as the need for a standardized reporting framework. Another warning made by the author is that their document investigates the number of fires but not how much damage was done.
mindslight 2y ago
Note that the research is centered on Germany, where there is a bit more of a default-deny approach to electrical safety. Here in the US, some of the pictures I've seen of sample finished installations that the installer is proud of have been downright scary. Like giant wall of 2V batteries with terminals coming out horizontally, open bus bars tying them all in series to make 48V, and then the leads going to the inverter just draped over the entrance to a wiring trough with a rough edge! There was probably a fuse as part of the inverter itself, but no protection for the batteries themselves. I'm guessing it has to be a case of code inspectors not particularly caring or knowing about the DC side? Although with that kind of current capacity, perhaps the wiring itself is considered a fuse...
- gottorf 2y ago
  > I'm guessing it has to be a case of code inspectors not particularly caring or knowing about the DC side? I don't know what you saw, but it could have been a "homeowner's special", or some kind of proof-of-concept? Professionals are certainly capable of hackjobs, but I have a hard time thinking that a client would be satisfied enough to pay for what you describe. You don't have to be an electrician to know that some stuff just looks dangerous and poorly done!
  - mindslight 2y ago
    No. It was a Faceboot page of a decently popular solar installation company showing off their completed works. There could have been some anti-abrasion thing I couldn't see in the picture, but the lack of fusing was still concerning. (And FWIW I did check the battery datasheets to make sure there weren't internal fuses). I suppose those particular installations might have gotten a pass on inspections due to "off grid", but still.
- neither_color 2y ago
  >I'm guessing it has to be a case of code inspectors not particularly caring or knowing about the DC side? I'm inclined to agree with this. US electrical code, especially in recent years, is pretty robust and has gotten to the point where people groan about excessive safety features(tamper resistant outlets required in all new dwelling spaces, arc fault circuit breakers, whole home surge protection all make wiring a house significantly more expensive than 15 years ago). Inspectors are pretty good at catching grounding and other issues. That said we don't yet have generational knowledge of PV and battery systems. A lot of installers are still learning by doing, it feels. Are you sure it wasn't just DIY un-permitted work, though?
  - ssl-3 2y ago
    It is always important to remember that the National Electric Code isn't national. It is up to the states or other (more-local) AHJs to adopt it (or not). And many simply have not done so. For example: A person building a single-family home in Meigs County, Ohio, has no electrical code to follow, nor any electrical permits to pull, nor any government inspections of any electrical work. (Lacking code, there's no standard by which to permit nor to inspect the work.)
devjab 2y ago
It will be interesting to see what it does for fire fighting if we start adopting batteries on large scale in our homes. EVs already pose a significant challenge in European cities. Easy enough for electric cars which can be put into some sort of container to handle the fire, less easy with electric busses. I’m not sure we have a good strategy in place yet here in my city. So far the strategy seems to be “well, it was lucky it caught fire outside the main streets”. I imagine it’ll be wild if a fire breaks out in a line of town houses with battery storages. If it’s as difficulty to put out as EV’s then you’re probably going to have a hard time containing it to just a few houses.
- thebruce87m 2y ago
  > If it’s as difficulty to put out as EV’s EVs do not all share the same battery chemistry. Many have LFP batteries, and these are common for home batteries too. You can go on YouTube and see people drilling into an LFP battery with only a little smoke to show for it.
  - giobox 2y ago
    Right exactly. Any discussion about this topic that doesn’t separate LFP (lithium iron phosphate) based batteries from the wider discussion about lithium ion is missing one of the biggest changes to battery tech in recent years. Not all lithium based batteries share the same fire risks - there are enormous differences now. Increasingly EVs and especially backup batteries use the LFP tech - you can charge it to 100% without harming the battery unlike previous lithium ion batteries, and they don’t really catch fire. This paper even acknowledges LFP is significantly safer, mentioning it once, but doesn’t dive into the significant improvements. Again, many EVs (including brands like Tesla etc) already use LFP packs in many cars, and the usage is only increasing. Tesla’s generation 3 powerwalls (home backup battery) are LFP too, its really taken off for home power storage for very obvious reasons - they don’t really catch fire, and you don’t need to worry about charging to 100% harming the battery over time.
- ZeroGravitas 2y ago
  I wonder if the reduction in entire houses being reduced to a rubble filled crater by gas pipeline explosions will counterbalance these home battery fires as we electrify homes.
WalterBright 2y ago
I'd prefer to have the battery outside the house, with a concrete wall between it and the house. Or just have it 10 feet away, like where you'd put a generator.
- 1970-01-01 2y ago
  Most generators are installed within 4ft of the exterior house wall.
  - WalterBright 2y ago
    Seeing how hot a battery fire is, I'd want it 10 feet away. Or a concrete wall between. None of that is expensive. And you can sleep safe!
    - gerdesj 2y ago
      A genny does not have a Li-Ion battery.
      - Dylan16807 2y ago
        "it" in that sentence refers to battery banks and not generators.
      - WalterBright 2y ago
        A genny: https://en.wikipedia.org/wiki/Curtiss_JN_Jenny#/media/File:Flying_jenny_cropped.jpg https://en.wikipedia.org/wiki/Curtiss_JN_Jenny#/media/File:F...
  - gerdesj 2y ago
    A genny has a 12V car/lorry battery to start it. My work one is basically a lorry diesel motor on a floor bolted chassis. It is the other side of an external wall (double skin of brick). Ironically enough the genny is inside the same room as the hot water boiler which is gas powered. The original heating was a coal fired boiler which was converted to a weird oil squirting "hair dryer". That's all gone now. The fire risks that I worry about do not really include the genny. The fridge in the kitchen is potentially far worse. I have, of course, put in a fire detection and suppression system inside the computer room. At home I actually have a more involved fire risk assessment than at work. My wife does dog boarding at home and one day I will stop her leaving a cloth to dry on the cooker ... sigh. Anyway, making sure that humans and dogs get warned and get out safely is quite involved. As we all know there are three ingredients required for fire: a source of ignition, a combustible material and finally: oxygen. Remove one and fire does not happen. Unfortunately some reactions will generate copious amounts of heat and oxygen, ie all three requirements for combustion and become self sustaining. Lithium batteries for example can do this. It's a bit of a nightmare but techniques are being developed to deal with "self igniting metals" and the like. I drive an EV.
sidewndr46 2y ago
Isn't this entire discussion academic? You could just not mount it on the structure you live in.
- alias_neo 2y ago
  Where do you propose people mount their home battery storage?
shadowpho 2y ago
>even though California's metering system is all kinds of anti-rooftop-solar now How do?
- ericd 2y ago
  Eh I'd revise that to say it's anti-rooftop-without-storage. Basically, the CA grid now has a massive glut of solar generation at midday, and so they changed net metering to not pay anywhere near 1:1 on backfed power (it's a really bad ratio, but I don't remember, maybe like 1:5). On the literature around this change, they noted that it's to encourage people to install storage and do time shifting on the power they generate, to help even things out for the grid.
  - shadowpho 2y ago
    >Basically, the CA grid now has a massive glut of solar generation at midday, and so they changed net metering to not pay anywhere near 1:1 on backfed power (it's a really bad ratio, but I don't remember, maybe like 1:5) 1:5 isn't "anti-solar" though, it accurately reflects the fact that power is worth significantly less at that point in time. >it's to encourage people to install storage and do time shifting on the power they generate, to help even things out for the grid. Yep makes sense. Someone has to bear the cost of providing power when it's expensive to do, and it makes sense to more accurately price the solar energy.
    - ericd 2y ago
      I’d agree with you that it was accurate pricing if they sold power for similarly cheap at that time, such that you could just install storage and profit off of time shifting by backfeeding when there’s not a glut. But I’m pretty sure they still charge their absurd rates at noon on a sunny day.
mmooss 2y ago
> To save others the clicking and scrolling (if you're mainly interested in the conclusion, as I was) Thanks. Another solution is to read the abstract at the top.
pjc50 2y ago
I do think this stuff would be better off at utility scale, but there's another kind of regulatory arbitrage going on there: some people will accept much lower safety standards in their own houses, while other people are keen to clobber anything with any sort of risk attached in the public sphere. (climate change is of course not seen as a "risk" in the public sense, more of a "business as usual", because it's too diffuse for blame to attach)
- nkrisc 2y ago
  My suspicion is that people simply overestimate their ability to asses risk, thus are tolerant of increased risk in their own home as they’re responsible for it, while other people are responsible for risk in the public realm.

by kelnos 2y ago

Sayrus 2y ago

> The fires in HSS in Germany were determined using web crawling for the year 2023 because no other data was available. All other probabilities were calculated using researched data. HSS may also be underrepresented in the scrapped data due to the method used. The document sections Discussion and Limitations and Outlook touch about this. The authors highlight a lack of common categorization of fires types and count as well as the need for a standardized reporting framework. Another warning made by the author is that their document investigates the number of fires but not how much damage was done.

mindslight 2y ago

Note that the research is centered on Germany, where there is a bit more of a default-deny approach to electrical safety. Here in the US, some of the pictures I've seen of sample finished installations that the installer is proud of have been downright scary. Like giant wall of 2V batteries with terminals coming out horizontally, open bus bars tying them all in series to make 48V, and then the leads going to the inverter just draped over the entrance to a wiring trough with a rough edge! There was probably a fuse as part of the inverter itself, but no protection for the batteries themselves. I'm guessing it has to be a case of code inspectors not particularly caring or knowing about the DC side? Although with that kind of current capacity, perhaps the wiring itself is considered a fuse...

gottorf 2y ago
> I'm guessing it has to be a case of code inspectors not particularly caring or knowing about the DC side? I don't know what you saw, but it could have been a "homeowner's special", or some kind of proof-of-concept? Professionals are certainly capable of hackjobs, but I have a hard time thinking that a client would be satisfied enough to pay for what you describe. You don't have to be an electrician to know that some stuff just looks dangerous and poorly done!
- mindslight 2y ago
  No. It was a Faceboot page of a decently popular solar installation company showing off their completed works. There could have been some anti-abrasion thing I couldn't see in the picture, but the lack of fusing was still concerning. (And FWIW I did check the battery datasheets to make sure there weren't internal fuses). I suppose those particular installations might have gotten a pass on inspections due to "off grid", but still.
neither_color 2y ago
>I'm guessing it has to be a case of code inspectors not particularly caring or knowing about the DC side? I'm inclined to agree with this. US electrical code, especially in recent years, is pretty robust and has gotten to the point where people groan about excessive safety features(tamper resistant outlets required in all new dwelling spaces, arc fault circuit breakers, whole home surge protection all make wiring a house significantly more expensive than 15 years ago). Inspectors are pretty good at catching grounding and other issues. That said we don't yet have generational knowledge of PV and battery systems. A lot of installers are still learning by doing, it feels. Are you sure it wasn't just DIY un-permitted work, though?
- ssl-3 2y ago
  It is always important to remember that the National Electric Code isn't national. It is up to the states or other (more-local) AHJs to adopt it (or not). And many simply have not done so. For example: A person building a single-family home in Meigs County, Ohio, has no electrical code to follow, nor any electrical permits to pull, nor any government inspections of any electrical work. (Lacking code, there's no standard by which to permit nor to inspect the work.)

devjab 2y ago

It will be interesting to see what it does for fire fighting if we start adopting batteries on large scale in our homes. EVs already pose a significant challenge in European cities. Easy enough for electric cars which can be put into some sort of container to handle the fire, less easy with electric busses. I’m not sure we have a good strategy in place yet here in my city. So far the strategy seems to be “well, it was lucky it caught fire outside the main streets”. I imagine it’ll be wild if a fire breaks out in a line of town houses with battery storages. If it’s as difficulty to put out as EV’s then you’re probably going to have a hard time containing it to just a few houses.

thebruce87m 2y ago
> If it’s as difficulty to put out as EV’s EVs do not all share the same battery chemistry. Many have LFP batteries, and these are common for home batteries too. You can go on YouTube and see people drilling into an LFP battery with only a little smoke to show for it.
- giobox 2y ago
  Right exactly. Any discussion about this topic that doesn’t separate LFP (lithium iron phosphate) based batteries from the wider discussion about lithium ion is missing one of the biggest changes to battery tech in recent years. Not all lithium based batteries share the same fire risks - there are enormous differences now. Increasingly EVs and especially backup batteries use the LFP tech - you can charge it to 100% without harming the battery unlike previous lithium ion batteries, and they don’t really catch fire. This paper even acknowledges LFP is significantly safer, mentioning it once, but doesn’t dive into the significant improvements. Again, many EVs (including brands like Tesla etc) already use LFP packs in many cars, and the usage is only increasing. Tesla’s generation 3 powerwalls (home backup battery) are LFP too, its really taken off for home power storage for very obvious reasons - they don’t really catch fire, and you don’t need to worry about charging to 100% harming the battery over time.
ZeroGravitas 2y ago
I wonder if the reduction in entire houses being reduced to a rubble filled crater by gas pipeline explosions will counterbalance these home battery fires as we electrify homes.

WalterBright 2y ago

I'd prefer to have the battery outside the house, with a concrete wall between it and the house. Or just have it 10 feet away, like where you'd put a generator.

1970-01-01 2y ago
Most generators are installed within 4ft of the exterior house wall.
- WalterBright 2y ago
  Seeing how hot a battery fire is, I'd want it 10 feet away. Or a concrete wall between. None of that is expensive. And you can sleep safe!
  - gerdesj 2y ago
    A genny does not have a Li-Ion battery.
    - Dylan16807 2y ago
      "it" in that sentence refers to battery banks and not generators.
    - WalterBright 2y ago
      A genny: https://en.wikipedia.org/wiki/Curtiss_JN_Jenny#/media/File:Flying_jenny_cropped.jpg https://en.wikipedia.org/wiki/Curtiss_JN_Jenny#/media/File:F...
- gerdesj 2y ago
  A genny has a 12V car/lorry battery to start it. My work one is basically a lorry diesel motor on a floor bolted chassis. It is the other side of an external wall (double skin of brick). Ironically enough the genny is inside the same room as the hot water boiler which is gas powered. The original heating was a coal fired boiler which was converted to a weird oil squirting "hair dryer". That's all gone now. The fire risks that I worry about do not really include the genny. The fridge in the kitchen is potentially far worse. I have, of course, put in a fire detection and suppression system inside the computer room. At home I actually have a more involved fire risk assessment than at work. My wife does dog boarding at home and one day I will stop her leaving a cloth to dry on the cooker ... sigh. Anyway, making sure that humans and dogs get warned and get out safely is quite involved. As we all know there are three ingredients required for fire: a source of ignition, a combustible material and finally: oxygen. Remove one and fire does not happen. Unfortunately some reactions will generate copious amounts of heat and oxygen, ie all three requirements for combustion and become self sustaining. Lithium batteries for example can do this. It's a bit of a nightmare but techniques are being developed to deal with "self igniting metals" and the like. I drive an EV.

sidewndr46 2y ago

Isn't this entire discussion academic? You could just not mount it on the structure you live in.

alias_neo 2y ago
Where do you propose people mount their home battery storage?

shadowpho 2y ago

>even though California's metering system is all kinds of anti-rooftop-solar now How do?

ericd 2y ago
Eh I'd revise that to say it's anti-rooftop-without-storage. Basically, the CA grid now has a massive glut of solar generation at midday, and so they changed net metering to not pay anywhere near 1:1 on backfed power (it's a really bad ratio, but I don't remember, maybe like 1:5). On the literature around this change, they noted that it's to encourage people to install storage and do time shifting on the power they generate, to help even things out for the grid.
- shadowpho 2y ago
  >Basically, the CA grid now has a massive glut of solar generation at midday, and so they changed net metering to not pay anywhere near 1:1 on backfed power (it's a really bad ratio, but I don't remember, maybe like 1:5) 1:5 isn't "anti-solar" though, it accurately reflects the fact that power is worth significantly less at that point in time. >it's to encourage people to install storage and do time shifting on the power they generate, to help even things out for the grid. Yep makes sense. Someone has to bear the cost of providing power when it's expensive to do, and it makes sense to more accurately price the solar energy.
  - ericd 2y ago
    I’d agree with you that it was accurate pricing if they sold power for similarly cheap at that time, such that you could just install storage and profit off of time shifting by backfeeding when there’s not a glut. But I’m pretty sure they still charge their absurd rates at noon on a sunny day.

mmooss 2y ago

> To save others the clicking and scrolling (if you're mainly interested in the conclusion, as I was) Thanks. Another solution is to read the abstract at the top.

pjc50 2y ago

I do think this stuff would be better off at utility scale, but there's another kind of regulatory arbitrage going on there: some people will accept much lower safety standards in their own houses, while other people are keen to clobber anything with any sort of risk attached in the public sphere. (climate change is of course not seen as a "risk" in the public sense, more of a "business as usual", because it's too diffuse for blame to attach)

nkrisc 2y ago
My suspicion is that people simply overestimate their ability to asses risk, thus are tolerant of increased risk in their own home as they’re responsible for it, while other people are responsible for risk in the public realm.