Fire Science Show
Fire Science Show
225 - Battery Energy Storage Systems with Noah Ryder
Demand for the energy storage is as high as ever, and is about to triple-quadruple. The development of technology is at unprecedented phase, and even within a single project you may face different cell, battery or container generations. This pace reshapes how we think about battery energy storage safety, from enclosure design to emergency response. We sat down with Noah Ryder from the Fire and Risk Alliance to unpack how BESS has evolved from walk-in containers to dense, modular “refrigerator” units—and how the move to liquid cooling, tighter layouts, and higher amp-hour cells impacts both opportunity and risk.
We explore the real jobs batteries do for the grid: shifting solar and wind, replacing peaker plants, stabilizing frequency, and powering microgrids. Then we zoom into the fast-growing edge case: AI-hungry data centers integrating batteries at the rack level for modularity and speed. That flexibility has a cost. Less free airspace and larger cells mean faster gas accumulation, higher heat flux into insulated enclosures, and a credible explosion hazard from a single failure. We walk through the failure timeline—monitoring anomalies, venting, immediate versus delayed ignition, sustained fire, and potential propagation—and identify practical interventions at each step.
Noah lays out the tradeoffs many teams avoid: accept that a damaged unit is a write-off, or try to save modules at all costs? Should we prefer a known flame over an uncertain blast by using intentional spark ignition? How should NFPA 855’s push toward gas-triggered mechanical ventilation and deflagration venting influence spacing, panel placement, and vent direction? We also dig into enclosure construction—non-combustible insulation, steel skins, coolant flammability—and how better insulation can safely cut spacing by slowing heat penetration and reducing internal temperature rise.
Looking forward, stacking feels inevitable. The smarter approach is to treat batteries not just as a cause but as a fuel, borrowing tested methods from high-rack storage: quantify heat release and radiant exposure, model gas evolution and overpressure, orient vents to manage flame jets, and define acceptable loss before design begins. If you care about real-world energy storage—utility sites, microgrids, or data centers—you’ll leave with a clearer framework to make informed, defensible choices.
If you would like to learn more about Noah and the Fire and Risk Alliance, you can find them online here: https://fireriskalliance.com/
Enjoy the conversation, then subscribe, share this episode with a colleague, and leave a review to help more engineers find the show.
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Hello everybody, welcome to the Fire Science Show. I've just came back from Hong Kong where I've attended the fourth International Lithium Battery Fire Safety Symposium. What an excellent conference that was congratulations to Professor Xinyan Huang and his team at the HK PolyU for organizing this fantastic, fantastic conference. I've learned a lot about battery fire safety and also while being there, I've picked some interesting topics or interesting presentations that were shown that I thought could be of high use to the fire science show community. Some I've recorded on place, some of I've got the speakers agreed to give me an interview in future. But regardless, I'll be releasing them because battery fire safety is one of the most interesting parts of fire safety right now. If you like it or not, it's something coming for all of us and we need to be prepared and need to be aware of what's happening. While there was a ton of talks about electrolytes, uh separators, uh chemistries, modeling, etc. I was looking for talks that are practical and directly useful to our craft. And today, first of such talks, my interview with uh Noah Ryder from Fire and Risk Alliance who was talking about battery energy storage systems, BSS, and those are popping like crazy everywhere. I had a skewed idea of what a battery energy storage system looks like. I had some ideas how to give a safety to the ones that I had in mind, but as the structure evolves, as the idea, the concept of a storage system evolves, uh and the solutions must evolve as well. In this talk, I've tried to pick Noah about how those storage systems are constructed, what drives their design, what drives the way, what shapes them, how people decide how to construct them and how to join them into bigger, larger energy storage parks. Because all of those are important considerations when we want to provide the fire safety of such a storage system. An important question that a fire engineer has to ask what is considered a safe storage system? At what point we believe we have provided safety for those devices because this will also also determine how we will construct the safety systems within the cells, batteries, modules, or entire devices. So well, anyway, I've talked enough and let's give the microphone to Noah. This is recorded in live at the Hong Kong Polytechnic University campus. It was a great discussion, and I hope it's a nice listen for you. Let's be an intro and jump into the episode. Welcome to the Fire Science Show. My name is Wojciech Wegrzynski and I will be your host. As the UK leading independent fire consultancy, OFR's globally established team have developed a reputation for preeminent fire engineering expertise with colleagues working across the world to help protect people, property and the planet. Established in the UK in twelve sixteen as a startup business by two highly experienced fire engineering consultants, the business continues to grow at a phenomenal rate with offices across the country in eight locations, from Edinburgh to Bath and plans for future expansions. If you're keen to find out more or join OFR consultants during this exciting period of growth, visit their website at OFR Consultants.com. And now back to the episode. Hello everybody. I am joined today by Noah Ryder from Fire and Risk Alliance. Hey Noah, good to have you in the podcast. Good to be here. Thanks for having me. Yeah, thanks for agreeing to do it the live. Yay, we're live in Hong Kong at the beautiful um Fourth International Symposium on Battery Fire S afety. Are you enjoying it so far?
Noah Ryder:It's been great. It's been great. City is lovely and uh a lot of good technical presentations. So uh enjoying my first trip here, actually.
Wojciech Węgrzyński:You know, I really love how when I go for tunneling conferences to Germany because the Swiss German guys are the ones who are building tunnels and have good technology, you learn from them. And I can say the same thing about uh going for a battery conference to China.
Noah Ryder:There are definitely quite a lot to learn, and uh, I think you know, just from what we've seen in terms of the sheer number of papers here and high quality ones, it's uh a lot obviously a lot of the manufacturing is happening here, so it makes sense that there's quite a bit of uh good information coming out.
Wojciech Węgrzyński:Manufacturing investment, you know, they it feels really strategic in here, and I think they are doing it on a purpose, and I think they understand the purpose very well. And I mean, it's also highly we're gonna talk about battery energy storage systems, so but this is so relevant. Like I see the developments happening in here because they understand the sheer amount of battery energy storage that we would probably like. What do you think?
Noah Ryder:Uh 100%. I think the you know, as you kind of pointed out, there's been some very, I'd say, high-level strategic thinking and planning in terms of the battery development and just the industries that the batteries can serve. So obviously there's the EV side of it. I'm more focused, or today we're going to talk more about the energy storage side of it. But you know, the amount of effort that's going into improving technologies, manufacturing, safety across the board, I think is pretty impressive. I think for them, it's such a critical part of their infrastructure and you know products that they're selling worldwide that they have an inherent interest in safety in a way for the industry in a way that other maybe standalone companies or countries may not have. So it's it's it's it's neat to see. Yeah.
Wojciech Węgrzyński:If we talk about battery energy storage systems, uh, how many batteries do we need? Like what scale are we even talking about? Because I I see numbers in megawatts, gigawatts, uh, gigawatt hours. It's like a very abstract unit to me. How big is that?
Noah Ryder:Yeah, no, I mean it's it's a great question. So I mean, I think in terms of the the of how many we need, I I think the short answer is if we could snap our fingers and have as much as we need today, we would. Um, but when we when we look at that in terms of actual quantities, you know, there's if you start at the base level, just to give some idea, there's we're producing probably in the order of about 10 billion new battery cells each year. Not all of those obviously are going towards energy storage, but an increasing number is. And so right now within the US, we're sitting at around probably close to about 80, maybe 90 gigawatt of installed capacity. China is uh around 230 or so. And over the next three to five years, they're expecting that to probably triple the kind of the baseline case. And if we kind of push expectations, you may get to you know four or five times uh more installed capacity than we have today. So you might be looking at a terawatt hour of uh installed capacity in China by you know 2027.
Wojciech Węgrzyński:So when we define this in gigawatts or or watt hours, the gigawatts reflect to how much you can instantaneously take out of it and what hours means how much it contains?
Noah Ryder:Yeah. So I mean generally the way you'll see it is you'll hear like a if you talk about an energy storage system, they'll say, oh, this is a hundred megawatt site, or it'll be uh uh 400 megawatt hours. And so really the key is is like what is your duration of operation and then what you can simultaneously discharge to the system. So some cases they're looking at like a four-hour system, in some cases it's a one-hour system. It really just depends on kind of the use case that's there, but that's why uh almost always uh a specific energy storage site will have two numbers associated with it. It'll be you know a 100 megawatt, 400 megawatt hour or so for if they're you know, those kind of things.
Wojciech Węgrzyński:Okay. Um a power bank is like 50, 60 watt hours, a car is like kilowatt hours.
Noah Ryder:Yeah, I mean a car battery, like for a big car, you know, battery pack is a hundred kilowatt hour pack. Okay, that's a big car. Yeah.
Wojciech Węgrzyński:Um that's the one that gives you 600 kilometers or 400 miles.
Noah Ryder:This is like top of the line, go as far as you can, kind of thing. And then by scale, right? I mean, not that many people have them anymore, but you know, your standard incandescent light bulb is 100 watts.
Wojciech Węgrzyński:Yeah.
Noah Ryder:So, you know, when you start looking at scales, um, these are massive systems that we're talking about. Obviously, they have to be because they're supporting entire grid infrastructures and homes. So most of the ones that we talk about today in terms of size are sufficient to power tens of thousands of homes, sometimes up to you know, a hundred thousand homes, just depending on on where it's at.
Wojciech Węgrzyński:What was the purpose of those? What the role do they play? Because we we didn't have them 10, 20 years ago and we were just fine. Like I know we store the energy in mountains. Like you have build a water tank on top of a mountain, you pump water up, then it goes down. I I understood that it's it's to conserve some energy when it's cheaper and then spend it when there's a peak. What what role do those devices play now?
Noah Ryder:So, in some regards, they play a similar role as kind of your hydraulic uh type systems that were storing in based on water or flywheel type systems and more mechanical basis systems.
Wojciech Węgrzyński:Oh, I love those. I love those.
Noah Ryder:Yeah, so I mean the the concept of energy storage is not new. Yeah, yeah. What has changed over the past 20 or 30 years, I think, one is is our is our needs, our power needs have skyrocketed and the grid infrastructure has generally not kept up. So we haven't been building uh, you know, quite as many power plants and everything else. But what has happened is we've built more uh wind and solar power, which is great. And the the biggest or one of the bigger challenges I'd say is that if there was excess power that was generated, it just literally went to ground. And so energy storage in particular batteries kind of fills that gap. And so it can take all that extra. It helps you uh not need to spin up like a peaker plant. Um, in some cases, you may not have to build the plant at all. So it really kind of fits this gap in needs where if there's excess power generation, or well, and that's typically at night or you know, other low use times, then you can store all that for later. And so that's really where it's kind of filled in. Um, the other big use case that we're seeing now is for entities that want to be more energy independent. They're doing their own microgrids. And so they they may have a tie and get power from from the made infrastructure, but they have the ability to basically island themselves and they can operate for anywhere from several hours to, in some cases, several days without any outside uh uh uh energy needs. So that's kind of a pretty wide range, but yeah.
Wojciech Węgrzyński:In your from your talk, I captured that a lot of this development. Obviously, the renewables, like you mentioned just before, is is one of the drivers, but also the data centers and AI, which are extreme uh power consumers. What role does play in in those resiliency uh or yeah?
Noah Ryder:So I mean data centers are an interesting one because we see, you know, I I think I I saw a recent uh uh number just the other day that the kind of the big guys, if you will, that they spent 400 billion dollars on AI infrastructure in 2025 alone. Like a hardware, yeah, yeah, just everything. And it's just so I mean I think a lot of it's been the most of it's or a good chunk has been on the hardware because it's it's really expensive.
Wojciech Węgrzyński:I know I bought one GPU for computation, it's like just one.
Noah Ryder:Yes, yeah, exactly. Yeah, sometimes you know it's like uh it's tough.
Wojciech Węgrzyński:But um I preferred the times when Bitcoin was driving it, you know. They those guys needed less.
Noah Ryder:Yeah, yeah, and it it was bad enough then, but no, it's definitely it's kind of uh order of magnitude and um they're power hogs. Yeah. So we kind of see two things happening in the data center space. I'd say one is is kind of still kind of the the you know standalone energy storage systems, kind of your standard boxes that are outside, or replacements for your lead-acid batteries that are kind of in your mechanical rooms or wherever, your your UPS applications. The other it that's happening that is, I think, frankly, more interesting from a fire safety standpoint is almost everybody is integrating them directly into racks. Um so it's you may have a a rack that's half filled with GPUs and then half filled with batteries.
Wojciech Węgrzyński:Okay.
Noah Ryder:And they're scaling those out as the as the data center is being filled in. So the white space might take a year to fill in, and the stuff that uh gets built first may use one battery design, and by the time they get to the end, it may be a different one. So uh yeah.
Wojciech Węgrzyński:I mean, uh that goes a little bit uh away from the subject of this interview, which I hope to be the battery energy storage. But it is interesting. It's very interesting uh what drives this need. I I mean I am of a belief, um we we are talking for the first time. I'm of a belief that the fire engineers need to very well understand the reasons why people do things because that allows them to do fire engineering efficiently, and otherwise we just ban stuff to people and they hate us. So I I would love to understand why such uh dispersion of the net why put it on the rack? What's the benefit of putting it on a rack versus having a container outside of your building? Because for me as a fire engineer, hey, your computer is like pretty expensive, like, and this is like pretty fiery. Uh how about the move it outside?
Noah Ryder:So I think there's the pros and cons discussion. Yeah, I think the other aspect is that there's the knowledge and what information they have. So I think one of the challenges and one of the things we've seen is is sometimes there's really not a whole lot of thought given to, oh, we're just gonna do this because why not? Okay. And and so the potential that it may increase the risk to their facility is kind of has been glossed over. Okay. Um, and and this is going a little bit far afield, but not entirely. I uh so if you look at the history of what kind of the cost of the IT equipment has been as you put it into these facilities, if you look 10 years ago at a standard kind of search type of of equipment, it was nominally $10,000 per square foot. Okay. Assuming you had an eight to ten foot tall rack. Okay. Now it's three hundred to five hundred thousand dollars per square foot. So we we've seen two orders of magnitude increase in the cost of the equipment, but the risk in the thought process in terms of how we approach it from fire safety and what the kind of the concerns are hasn't caught up yet. So I I think as far as an industry goes, they're they're starting to get up to speed on that. I think that's there. And I think that will actually help drive it. And there may be some push to do uh some more outside. But to answer your the the the original question, part of it is if I put a box outside, I think nobody would would disagree that it's safer. However, it means that I'm stuck with that box and whatever it can do for the next 20 to 30 years. Okay. And I have to pay that infrastructure cost up front. I gotta do it, I gotta have it all installed. If I can build it out within my white space, I can build out something today for my use today. And if my needs change six months from now, I can build that out to address that. And I can continue to do that. And so, you know, if a project takes three years to complete, what was installed day one may look very different than what was installed day three year year three. So it gives them a lot of flexibility uh to adapt to you know, ultimately what their very modular design. Yeah, it's it's I I have a fondness for Legos. Yeah, and so I always like to think of things in terms of like, hey, this is this is modular, it's blocky. Can I put it together and take apart easily? And I think that's kind of how they're approaching it. Um it's a big benefit too.
Wojciech Węgrzyński:I I thought there will be more direct answer, like, oh yeah, the cable cost is like this, or something, but it's it seems multifactual.
Noah Ryder:I I think it's yeah, I think it really comes down to as opposed to a utility type architecture where they're looking at a 30-year time scale for this piece of equipment, they may install it, run it for two or three years, and rip it out and replace it with something new.
Wojciech Węgrzyński:Yeah.
Noah Ryder:Uh so they're I don't want to say they're not cost driven, but cost is the secondary or tertiary level you know thing.
Wojciech Węgrzyński:I I mean, I'm sometimes uh not very optimistic, and what they see here is the steam engine case, you know, when the the first industrialization came up, you had the massive steam engine in the middle of your plant, you built everything around the steam engine, then those stuff those things started burning and you start losing a lot of money, and here comes factory mutual and sprinklers and everything, you know. So I wonder if this is the same pathway. I hope not. Uh okay, let's move to the battery energy storage systems. In your talk, you gave an overview of topologies. I must say, for me, if I think about battery energy storage system, I see a container to which I walk in. There are like racks of devices on the walls. From your talk, I already know I'm I'm antique. Uh so uh let's perhaps walk the listeners through the existing uh technologies and generations of technologies in energy storage systems, how they evolved.
Noah Ryder:Yeah, so that's a great question. Um so I think if you if you go back, you know, say a a decade.
Wojciech Węgrzyński:Oh, that's ancient times.
Noah Ryder:It is, it is, but 10, you know, 10 years was you know, kind of the the state of the art was what you just talked about. So it was kind of a a walking container, maybe a building, right? So I mean, obviously, most folks that have some knowledge on on energy storage, they're aware of the the surprise Arizona, the McMicken incident. That was a building. Um, and we can talk about that later a little bit if need be. But but in short, there were structures that you could walk into that, as you said, they had batteries lining the walls and for accessibility, maintenance, HVAC purposes, everything, you know, it had some open space and so forth. As things started to develop and real estate became more valuable, and in particular, as it transitioned from, say, like utilities building these to more development, you know, type of uh operation. So, you know, private equity-backed uh organizations or or whomever that are basically building utility scale, they they kind of looked at it and said, well, why am I wasting you know, effectively half of my space, my surface area?
Wojciech Węgrzyński:So it really matters from a cost perspective.
Noah Ryder:Uh tremendously, yeah. I mean, if you have unlimited cheap land, it it doesn't really matter.
Wojciech Węgrzyński:I mean, I again it's my distorted image of a data of a data center of something being built in like desert Arizona, like you know, with nothing around.
Noah Ryder:So there certainly is some of that, but I think you know, the the locations are also have to be paired with substations and things that are going to support the grid. And they increase in density build around them, it's a small city now. Yep, yep. So so the the you know, your your density per square foot matters a lot, which is why, you know, during this conference, if you see, you know, some people have talked about it a little bit, but you'd see like battery density and what does that translate into in terms of energy per square meter or things like that. So what happened was is that you know, I think partly because on on market needs, partly due to manufacturing and transportation, and everything kind of came together and people started moving away from the walk-in style enclosures to self-contained, kind of more reach-in, where it's it may still have been an ISO container, like generally a 20-foot ISO, but they loaded it up with racks, and you could open the doors and reach in, but you can't be occupied.
Wojciech Węgrzyński:So you open it from outside, and there's immediately your batteries.
Noah Ryder:Yep, exactly. It basically you could think of it just like you know, they almost look just like server racks, and you just have a fully popular thing. Yeah, exactly. And so the only way to access it is by opening the doors and and pulling the modules in and out. So that that started really happening probably six, seven years ago, and is pretty much the default today. What we've seen over the past several years is a little bit of a migration uh with more companies moving towards instead of your 20-foot or whatever shipping container style into more modular. So I kind of call them the refrigerators. And so they're all self-enclosed, but I can take three, four, five, ten, whatever it is, refrigerators, sandwiching them together, and that becomes my unit. Um so that is where a lot of entities are moving today. If you see some of the new products that are coming out, you know, over the past year or so and and stuff that's been announced. Yeah.
Wojciech Węgrzyński:Is this uh refrigerator unit uh a wholly self-contained battery energy storage system? Like does it have management, cooling, everything?
Noah Ryder:They do, yeah. So generally speaking, they they may be linked with the other units or the refrigerators next to them, but they are fully self-contained. Um, they may share like an inverter. Um, so depending on who makes it, there may be some shared resources that are like a master unit and and and storage units. Correct, yeah. And uh so it really just depends on how the OEM is configured it. But generally speaking, they have at the kind of refrigerator level, they've got the full insight from the BMS controls, they can shut it down, they can do whatever else, independent of the other ones there.
Wojciech Węgrzyński:Uh how did uh free airspace inside evolve? I mean, I obviously decreased, but to what extent?
Noah Ryder:Well, obviously, so I mean if you had the walk-in enclosure, you you may have had 50, 60, 70% free airspace. The systems that we're looking at today are nominally 20% free airspace. And so it's uh dropped drastically in terms of uh how much is there, and and that obviously impacts the safety system and anything else.
Wojciech Węgrzyński:I mean to start with cooling, did cooling change significantly also in those? So yeah.
Noah Ryder:So I mean, basically, there's you can either do air cooling or liquid cooling. We've seen an increasing number of folks actually move away from air-cooled systems to liquid cooled systems. And so, you know, depending on what approach you've taken uh from a cooling perspective, then obviously the free airspace will impact that as well. That's almost entirely on the operational side. And one of the key things is that even if you were using an air-cooled system, it's technically supposed to be independent of any mechanical ventilation system you may have for safety. But you know, it it's I'd say largely dominated by liquid-cooled systems these days, and they've kind of moved away from the HVAC chiller and kind of approach.
Wojciech Węgrzyński:And the casings themselves, the technologies that we work with, uh what's the material of all of the casing? Is it just like a sheet of metal? Is it like insulated? I mean, it has to be weather controlled and weatherproof, but probably has to have some specific characteristics.
Noah Ryder:Yeah, no, that's a good question. So most of them are you know steel structure externally. They at this point in time almost all have some level of insulation. So not driven through safety, uh, but through operations you know, want to keep the temperature and the environment pretty consistent. So most of them will have a couple inches of of some type of insulation, like a rock wall type insulation or something else that's there. Uh, there was a period where folks had some like polyurethane insulation and things like that. Um, fortunately, we've seen a lot of that go away.
Wojciech Węgrzyński:Uh you need to add like a cavity to it, just maybe cover with ACP. You're gonna have a very beautiful system. Yeah, yeah.
Noah Ryder:No, it's something that just, you know, if you just want to make the incident as big as possible, go for it. A CLT roof.
Wojciech Węgrzyński:Uh that would be awesome. It'd be great.
Noah Ryder:Um yeah. I mean, we could have a lot of fun with it designing something that would uh you know really burn well. But no, no, fortunately, I think they they have moved towards kind of the non-combustible uh insulation. And and that generally is covering you know all the walls and in the roof deck for the most part. And but that does have a really important impact on the safety calculations uh that they come downstream as well. Um, obviously, it's kind of like your oven. If I've you know if it does a good job of of insulating and it's gonna keep the heat out if we've got insulating, yeah.
Wojciech Węgrzyński:Well, that's the real reason why I'm asking. Also, you know, uh the air cooling. I I in my image, like the the device has like some sort of fans on it. So I assume there must be to vent out some air from inside, which obviously when you have uh an event inside of the of the thing will be the place where it vents out, you know, the flames, right? Uh and and uh the casing. If you will consider spread from unit to unit, that's the first thing that's protects the unit. If it's just a thin aluminum foil, it's gonna give you a completely different performance than it if it's like a five centimeter sandwich panel with and non-combustible insulation in it. So so though those are tremendously different uh characteristics, and again, I have a feeling that those would be driven by other needs rather than fire itself. Is the coolant in in liquid systems combustible or a lot of times it is.
Noah Ryder:So a lot of times it'll be you know, another layer of uh yeah, you know, wet or glycol mix that usually has some flammability to it, so that can add to it for sure. I think you know the the insulation aspect actually what we're seeing is is a little interesting is that safety is starting to slide into it a bit because they need it primarily for operations. But when you do an analysis and you say, okay, we're gonna assume this unit is on fire, regardless of cause, but we're gonna assume it's on fire. And and and the big question is is it going to propagate to another unit? The incident heat flux to a target unit is actually pretty easy to establish, right? There's been plenty of tests, there's models, there's all kinds of stuff. And so we we can do that pretty well. The big question is what happens once it strikes that surface? And so uh we're under a wind detector. Yeah. Oh Lord, we give it a second to die down here, but it came out of nowhere.
Wojciech Węgrzyński:Yeah.
Noah Ryder:So uh before we got attacked by the wind, what what's happening from a safety standpoint is when we're trying to evaluate whether propagation from one unit to the next is going to happen, the insulation plays a critical role. Yeah. So early systems, we looked at, and in many cases didn't have a whole lot of insulation. And so, as you can imagine, steel plate, basically thermally thin, that heat just rips right through it. And and so the inside of the container heated up pretty quickly. And so propagation was was realistic. That's not a good outcome. At the same time, they wanted to maintain the spacing between these units. So if it was six feet or 10 feet, they really wanted it from an energy density standpoint. If you told them they had to be spaced 25 feet apart, that you know economically makes a project not viable. You just changed the entire design to fit more inside and now you're spacing them further.
Wojciech Węgrzyński:Correct.
Noah Ryder:Right. So so you you're defeating the purpose. So what's happened is that instead of moving out 25 feet, they both from an operational standpoint, but then also from a fire safety standpoint, the insulation is playing more of a role because if I do a better job of insulating it, you can oh yeah, I can now put it at six feet or ten feet safely when I couldn't before. So there's more analysis being done on that. And I think we're seeing you know more OEMs and every everybody kind of look at that as a as a contributing factor, which is which is kind of cool because you know there's interesting work to do there.
Wojciech Węgrzyński:Yeah. I'll put forward a challenging thought, and do you feel free to disagree with it? Was if I was thinking about uh a safety of a whole like park of those of those systems, and I had a fire within one of those, I mean, if any kind of fire happened to one of those, I would consider this this refrigerator or this container lost, and that's it. I I probably would be okay with losing one, I would be very not okay with losing uh the whole field. Maybe I would be okay with losing a few. Is this kind of risk-driven thinking a part of the design process for this? Or the efforts is to save like all the cells within the one of them?
Noah Ryder:Great question. And this is really interesting because we've seen I I I think the the thought process varies depending on who you talk to.
Wojciech Węgrzyński:Okay.
Noah Ryder:So we've seen some efforts by OEMs and others, and and I think even if it's at the uh the conference here, you know, there's a lot of focus on how do we stop thermal runaway propagation within a module or something to try and even the cell. Even the cell. Uh I always kind of am like, look, you know, the the cell's a gimme, but that that's you know, that's a different topic. But really the propagation within a module or within the unit itself or externally to other units. The reality from what we've observed is that, you know, whether it's from heat, whether it's from the smoke, whether it's from the the vent gases that come over firefighter operations, firefighter operations, generally speaking, that unit is a gonna be a write-off. Like the insurance company that is insuring it is not going to pretty much allow it to stay in operation. So even if in small events, even where there's only been generally like a single module involved, they generally come in, they take that unit away, whatever the size of the enclosure is. And this may be one of the benefits of having kind of the refrigerator size versus the 20-footers, is that gets taken away and they replace it for warranty purposes, liability, whatever, there's a whole host of stuff. So there is, I don't want to say there's no value in trying to mitigate it, but sometimes I think the thought process is that, oh, this is the panacea. We, if we can do this, we've solved the problem. This guy, like, well, you didn't fundamentally change the end outcome, which is I'm taking that container away. You may have changed PR, you may have changed fire size, so forth. So um, depending on kind of who's approaching it um and what their thought process is, they may have different answers to that. But generally speaking, I like to say that it's not my job to say what's acceptable. My job is to tell you what's going to happen. It's your facility, it's your insurer. You have to decide whether that's okay or not. Most people are gonna say one container is fine, some damage to the ones around it. The field absolutely is a loss, uh, or is a, you know, cannot be a Total loss. And we've seen pretty good kind of agreement around that, both from the insurance companies as well as you know, developers and everybody else.
Wojciech Węgrzyński:Yeah, I guess it also will uh change with the change in energy density, it will change with the, let's say, uh technical sophistication of the device. If you're using like uh reused car batteries for some reason, yeah, versus new uh super high-tech tells that that give you a completely different performance that's gonna probably matter. And also if we move to the centralized, as in the battery storage being on top of a rack, then perhaps it's like this the intervention should be at a smaller scale.
Noah Ryder:Yeah, so the use case is critical. Yeah. For sure. And I think that's you know, the from the talk you've seen, but you know, I always like to focus on analyzing the risk so we understand, and the risk is really going to be impacted by where this thing is installed. And so, you know, you put something out in the middle of a field remote from everything, and you can have a large event, nobody really cares, but you put that in a more urban environment, that's the same fire size and everything, and across some a daycare or whatever, that that profile changes. And then if you move it into a data center, it's even worse.
Wojciech Węgrzyński:That's good. So, in your talk, uh let's maybe move to what's happening when it goes wrong, or maybe no, maybe uh one more thing about the technology. Yeah. So the cells that are used in those storage systems, are they like the same as we see in uh e-cigarettes and electric vehicles? Are those different cells?
Noah Ryder:So they often will have uh a similar chemistry. And so, you know, but I it my analogy around that is uh I uh cakes, right? Um, and and that is that you know, everybody's got their own recipe for say a chocolate cake, but they still call it a chocolate cake. And so battery cells are somewhat similar in that you know, most manufacturers will have an LFP cell or an NMC cell or whatever, but um, and they're all siloed into those kind of chemistries, but they they they will be different. Um, so when we look at e-cigarettes or we look at e-bikes and everything else, they may have you know a similar chemistry nomenclature, but the recipes may be different. Uh the specific size obviously is going to be different. If it's got to fit in an e-cigarette, it's got to be small versus you know, you could support a larger cell in an EV. And then finally, the form factor itself. Um so you can have the button batteries or you know, your standard cylindrical or prismatics. So you will see differences across the board from the more consumer-focused type of products versus energy storage.
Wojciech Węgrzyński:So I guess for energy storage, again, is optimization for the space and and capacity. So probably larger, right? Better fitting.
Noah Ryder:Yeah, larger. And so what we've seen is it's kind of crazy. You know, four or five years ago, a you know, nominally a 100 amp hour cell was kind of typical for an energy storage system. A couple years after that, it was uh, you know, 200, and then last year it was 300. We're now seeing 500 amp hour cells in products, and uh a number of companies have just released products that are a thousand amp hours. A thousand looks exciting. Yes. So we've we've got a thousand amp hour products that are that are coming out for sure. So that that that's gonna be a game changer a little bit.
Wojciech Węgrzyński:Wow, okay.
Noah Ryder:But from a perspective, chemistry, it's like the same like out cathode just how do you pack it, right? Yeah, the basic architecture is gonna be similar. Um, you know, at a conceptual level, it's all the same. Yeah, it's just really the details that are gonna change, and you know, you'll see because everybody has patents, so everybody has to do something different. Oh, yeah. So you can't have identical things no matter what, just just because of the patents.
Wojciech Węgrzyński:Well, that that that's an interesting driver, yeah. Yeah. Uh anyway, uh let's move into the um uh the cascading failures. Uh, you had this uh this slide on your talk where you were talking about the things that happen, the events that happen, cell-driven events, uh where you mentioned uh cell monitoring, I assume that's where you detect venting, then immediate or delayed ignition, and then perhaps unit propagation. They were also indicating that we have opportunities at each of these steps along the way. So maybe you can give me an overview of this timeline and then we can talk about the interventions.
Noah Ryder:Yeah. So if we start out assuming that the initiation of an incident starts with the cell, which isn't always the case, and we could talk about that maybe a little bit later. But um if if we look at it from that standpoint, then we have kind of a standard event sequence that you kind of ran through. And if everything is operating normally, we're monitoring the cell, the state of health of the system overall. If we start to see anything that's abnormal, then ideally we can correct it as soon as possible, right? So that's why having a VMS system is really critical, getting as much information as you can down to the cell level, because you may be able to uh basically isolate it, you may be able to discharge. Uh, so there may be actions that you can take to do, you know, kind of cut it off. Assuming you can't stop the incident then and the cell continues towards failure, then generally the next step is going to be that the cell is going to vent. What do you mean by that? Well, so exactly that. Yeah. So, so, you know, there's a number of different failure mechanisms that are there. It can be contamination, it can be mechanical, it can be overcharge. But in essence, generally what it winds up with is you're going to have an exothermic reaction that is going to start to drive the temperature and the pressure associated with it. And most modern batteries actually have a vent on the top of the cell, if you want to call it that. And so when the pressure starts to build up, it literally opens up. It's basically like a valve releasing and the gases that are formed from um the cell electrolyte and and the breakdown of the separators and whatever happens there. And there's a lot of details that folks can read about. But in essence, at the end, you're going to vent those gases.
Wojciech Węgrzyński:They're not necessarily burning yet, right?
Noah Ryder:It can no, and so what I was gonna say is it's so they are they are flammable and it's measured in like the 9540A tests and things like that, where you'll you'll get the flammability range, but it doesn't necessarily auto-ignite. So certain chemistries, uh, certain form factors and things like that may auto-ignite more commonly than others, but uh we have yet to see a chemistry that does not produce a flammable gas. Um even though a lot of folks will be like, ah, sodium ion never ignites, they still produce a fair amount of flammable gas and a good amount of hydrogen in particular. So that gas is venting and it's venting into a volume, and this is where your immediate or delayed ignition could occur, right? So we can either have auto ignition, in which case the the gases are just they're they're burning off, and now you have a sustained flame for however long the vent gas is there and then it could propagate. But if if you don't have an immediate ignition, you may get into a delayed ignition type of event where maybe it's 10 seconds or 30 seconds or a minute or two minutes later, in which case you've got a larger gas volume built up in a confined space, it ignites, and we've had an overpressure or an explosion. And uh, depending on the nature of the event, kind of the the where it would go from there is if we have sustained flaming, either from the immediate ignition or the post-explosion type of event, then we may have a fully involved BES fire. And then the real question gets back to what you asked uh a couple minutes ago, and that was, you know, kind of what's an acceptable loss.
Wojciech Węgrzyński:Yeah.
Noah Ryder:Right? Is it one container or is it more? If we have a developed fire condition following that kind of event sequence, then we get into is this going to propagate or not? And that's kind of start to finish. And generally speaking, at each of those stages, we have the opportunity to do something, either through technology, through better product design, uh, in some cases, it may be manual intervention, but to kind of mitigate the the next steps and maybe stop that sequence.
Wojciech Węgrzyński:What one thing that felt really surprising to me in one of the talks, one of the speakers mentioned spark igniters as a safety feature. Yeah. Uh as in making sure that the gas is actually ignite and they don't accumulate and explode. So it's an interesting trade-off about like, would you rather have a bad outcome that you are certain about or a low probability worse outcome? I'm I'm not sure if fire and explosion, you can rank them as worse or better. I guess it's case by case, but yeah, no, it's a good.
Noah Ryder:So I mean, we've we've seen obviously one major manufacturer, so Tesla has been doing this for years. We we know of others that are pursuing it. And to me, it's a uh it's a really neat concept because to your point, you pretty much know the outcome. And if you are going to write off your box regardless, then I would kind of make the argument that, well, we're not fundamentally changing the outcome, which is replacing the box, but we are ensuring that we keep the incident to something that is manageable because we know what's going to happen. So if you yeah, introduce the sparkers, and obviously it requires you to do the analysis and design it appropriately and everything like that. But if you've done that, then you pretty much guarantee that there's going to be a minimal quantity of gas involved that you would then ignite. And then you have a known event. And if you know what's going to happen, then you can plan for it and you can design around it. It's it's the uncertainty that's really tough. Yeah.
Wojciech Węgrzyński:Yeah, you exchange uh a known uh enemy versus unknown, uh, potentially worse, potentially bad, better.
Noah Ryder:And and I think, you know, from an engineering and insurance standpoint, if you have the knowledge, then you can make informed decisions. So I think an insurance company, even that says, like, I know what my loss is going to be, even if it's bigger than you would hope, if I know it's something, then I can price the premium accordingly and I can still operate. Yeah. It's, you know, and uh same thing on the engineering side. If I I know what it is, I I can put in mitigations to make sure it doesn't get beyond that.
Wojciech Węgrzyński:Okay, uh let's go this a little bit. I I you also covered this in your in your presentation, so I'm gonna get this a little deeper. Let's assume you don't have the spark ignite, or perhaps you want to understand if you need one. Let's assume you have a cell going into some sort of event, one cell within the battery, it ventilates combustible flammable gases. Is uh this already an explosion hazard in the unit, or you have to have more involved than one?
Noah Ryder:Yeah, great question. And so if you'd asked me that question five years ago, I would have said you absolutely need more than one. Okay, and and you probably need a good number of them.
Wojciech Węgrzyński:Okay. Uh 100, 200, uh 500 well hours, now a thousand ampersand. Yeah, exactly.
Noah Ryder:Right. Uh they grew a bit. So yeah, the the the hundred the hundred amp hour cell into now the thousand amp hour cell, that risk has changed significantly. So what we're seeing now is is that you know, the explosion hazard from a single cell is now very real.
Wojciech Węgrzyński:Okay.
Noah Ryder:To the extent that before, maybe you had one or two or three cells and you could hit the lower flammability limit within the enclosure, but it'd be pretty tough to get to stoichiometric. Now we're in a situation where you may need for systems that are kind of out there today, you may need maybe two cells to hit stoichiometric. And the ones that are being designed and sold with the, say, the thousand amp hour cells, one cell is sufficient. So all I need is this failure of one really big cell, and I can have a stoichiometric mixture.
Wojciech Węgrzyński:Yeah, we we and we just established a few minutes ago that also the free space is uh is smaller. You perhaps replace your ventilation with uh liquid cooling, which also changes, you know, the dilutions and everything. So everything uh everything promotes that. And I also saw a lot of talks on the conference about these explosion prevention measures like uh relief valves and stuff like that. Do they have a role in fire spread? I mean, they look to me like a pathways for jet flames, right?
Noah Ryder:Yeah, so great, great. There's there's a there's a lot to dissect there. So NFPA 855 kind of is the governing standard for for stationary energy storage systems. So there's actually a pretty big change that came up, uh, and this is a roundabout way to get to your question, but is in the the newly re released edition, the 2026, that is making a strong push to have mechanically ventilated systems, similar to an NFPA 69 type of system.
Wojciech Węgrzyński:As in uh constantly ventilated or mechanic discharge on event?
Noah Ryder:On event. So upon gas detection. So generally it's gonna, you know, whatever the number of gas sensors are that's needed, trigger it 10% with the goal of uh ventilating the space and keeping it.
Wojciech Węgrzyński:So like preventing explosion.
Noah Ryder:Yep, explosion prevention, yeah, and keeping it below 25% of the lower flammability limit. Previous to that, a lot of the systems had used the deflagration panels. So it allowed the gas to build up, assumed it ignited, and then you tried to vent the overpressure. So when we look at it from a fire spread standpoint, it really becomes a question of one, which system or approach is used, and then where they're placed. So if you have the panels for mechanically, or or you know, the vents for mechanically ventilated systems, then yes, those are clear pathways out. And if it's on the sides of the unit and may directly impinge on on another one and and so forth. So your you know, total surface area that can be burning and act as a basically a radiant panel, if you will, starts really to come into play when you look at the propagation aspects of it. And this is why there's a lot of work that's looking at, okay, what happens if if there is a flame coming out of those? What happens if the deflagration panels are open and there's flames coming out of there? Because it really changes the exposure significantly. But what we're seeing is that even with mechanically ventilated systems, the partial volume of gas that remains, even once they're active, is still generally sufficient that you need to put deflagration panels in anyways. So you oftentimes wind up with both.
Wojciech Węgrzyński:And uh I guess it also matters where you direct the flame. Okay, when it's when it's explosion deflagration, I I'm happy it just gets relieved. Yes. Yeah, but when it's fire, I would perhaps like it to point upwards, not sidewards, maybe. So I guess it's a lot matters where do you place them and how do they look?
Noah Ryder:Yeah, so the the challenge is that for both systems, honestly, yeah, ideally you'd put them on the roof and vent upwards.
Wojciech Węgrzyński:Yeah.
Noah Ryder:Unfortunately, from a weather standpoint, uh, that's not necessarily always ideal, right? So these are IP-rated boxes, and we like to keep them that way. They also need to be able to operate during snow, wind, uh, a whole range of different conditions. And so if you have the ventilation on the roof, a lot of times that can pose a challenge. So generally, we'll see the supply and returns for these systems mounted on doors or sidewalls or things like that, which inevitably means they they oftentimes are pointed at targets as opposed to away from them.
Wojciech Węgrzyński:Well, um, but yeah. I have a brilliant idea how to increase the value per square meter. It's a black and lie. It's it's I I stole it from your presentation. Yeah. Are we going to stack them?
Noah Ryder:Yeah. So um, so I think the short answer is that it's inevitable. It's inevitable, yes. Um even if it's a challenge from a safety standpoint, I I think eventually you get to the point where it's going to be required. And honestly, I think there's a lot of work to be done, but I kind of look at it as if I can have uh basically a warehouse stacked 40, 50, 60 feet of highly flammable goods, there's no real reason why we shouldn't be able to do this with batteries. There may be challenges that we need to overcome. And and I think uh Yi's presentation uh from from FM yesterday. Yeah, you know, and and he made a really good point, which is how we think about it as well is batteries are they may be a cause, but they're also really just a fuel.
Wojciech Węgrzyński:Yeah.
Noah Ryder:And so, you know, he made the analogy to to rolled paper storage and things like that. And so I think if you kind of change the the thought process from viewing it just as kind of the ignition source and start looking at it as how does this burn? How is it able to propagate, and how can we analyze and understand it, then you can start designing mitigation for it as dense as it is and as tall as it may go.
Wojciech Węgrzyński:I brought that point because you know, everything we've discussed so far in this interview, uh, I've tried to build a narrative of goal, reason, solution, you know, like uh what do you want your objective, what you try to achieve, what can it cause, and how we can prevent or mitigate it. And uh a lot of things that made sense so far, as soon as you put them on one on top of each other, you're gonna figure out a different thing.
Noah Ryder:Yeah, I mean, I I think the you know, the the fun thing about engineering, at the end of the day, we're problem solvers.
Wojciech Węgrzyński:Yeah.
Noah Ryder:And if you give us a problem, we can probably give you a solution to it. It may not be the most cost effective or it may not, you know, happen in a time frame that you're looking at, but we can do that. And so I think, you know, when we look at batteries as well, um, if you move into stacking it, yes, the dynamics change, some of the the things that you could count on when they're basically a two-dimensional problem if you're moving into three dimensions. If you look at it from a holistic viewpoint from fire safety, are there some differences? Yes. But I think fundamentally the hazards that we're trying to protect against are the same as anything else. We've got thermal or fire hazards, we've got overpressure hazards, we've got toxicity hazards, and and you know, that's not really different than other fire problems, if you will.
Wojciech Węgrzyński:What do you think will be the main driver for future change? That's the last question. What will be the main driver? Is it standardization, uh energy density increase, investment? I would say I would put my money on where the money is.
Noah Ryder:Yeah, I mean, I if I was a a betting man, I'd I'd say, you know, putting your money where the money is is always a good choice. Um so I you know, I I think in this particular case, because of how quickly the industry is evolving, you know, I think it's a little bit of a race between kind of market needs and technology development. But you know, certainly the money is there to build as quickly as possible, as densely as possible, and and uh, you know, short of something drastic happening, I don't really see that changing. So yeah.
Wojciech Węgrzyński:Well, no, I think thank you very much, one, for your uh inspiring talk tiers in the conference, and two for sharing this with the audience of the fire science show. And uh well, let's perhaps meet in two, three years and see uh if any of our predictions made sense and how how tall we stacked them on each other. Yeah, sounds great. Thanks very much. I appreciate it. This was uh this was a great time. Thank you, mate. Thank you very much. And that's it. Those in-person interviews always have a different dynamic than the ones recorded online. During this one, we've tried to find a silent place at the campus, and we were attacked by at least three different highways, then by birds chirping very loudly, then by construction workers, then by random moving students as we sit down in uh one of the main pathways, people taking photographs after graduation, and in the end by B. So quite a journey through the campus this interview was, but uh in the end we've made it, and I hope we've uh provided you with some valuable content. Regarding the battery energy storage systems, I think the design is evolving as the needs of the industry are evolving. It's very important to recognize the drivers of change. People are building them as close as they can to the massive uh power uh receivers like AI centers, people are using them to stabilize grid, where there probably be different drivers for for for growth. There will be different types of batteries, different chemistry used, depending on if you need to have very high capacity or if you need to release this energy very quickly or take it very quickly. So a lot to consider is no one general guidance for battery energy storage system that would solve all your problems. But I think in this interview we've highlighted different aspects of construction of such a device, and through this those different aspects you will be able to take your engineering judgment and design something that in the end is is fire safe, makes sense for your client, and in general provides the level of safety that is expected from your facility. I hope this interview gave you a lot of ideas on how to design fire safety of those systems, and I'm sure if you reach Dinoa, he will be of some help. It was quite a nice person and a very nice interview. Anyway, that would be it for today's Fire Science Show episode from the Hong Kong Polytechnic University. Next week I'm actually flying for another battery conference. I'm flying to Lisbon in Portugal, where we have the SFPE symposium on battery fire safety where we will be discussing similar matters with like-minded engineers. Again, three days of excellent talks and presentations, cherry-picked speakers. I am proud to say I'm one of them, so if you are in Lisbon, I hope to see you there. And that would be it for today's podcast episode. Have a great day and see you here again next Wednesday. Thank you. Bye.