 Good afternoon and welcome to today's Energy Seminar. It's my great pleasure to introduce Andrew Ponett, the co-founder and CEO of Antora Energy here today. You may remember when we last met a long time ago last week, we had four excellent presentations by student researchers who had won the awards for the best technical presentations. But I think we said at the end of that that sometimes people like that that are not much older than you go out and start new companies and win research prizes and change the world. Well, Andrew's kind of at least halfway, maybe more than even though he's still pretty young, halfway down that road. He was a student here, took some time off, did a very successful startup. Fortunately for Stanford, he came back after that and then he went out after he graduated and did another startup called Antora Energy. I hope you find the story about that in the individual technology interesting. I worked with the GSAP project for 10 years and we thought we had seen everything. In this particular technology, we had not seen that it looks very exciting and very promising. So without further ado, I'll turn it over to Andrew to tell you how he did it and how you might be able to do it too. Thanks. All right, well, thanks so much for the introduction. Welcome everyone as you're sitting there. I used to attend this seminar all the time when I was an undergrad. So I was a class of 2017. I did take a little bit of time off, but yeah, I hope you enjoy this talk and all the rest this quarter and beyond. It's a really wonderful speaker series. Yeah, so I'm Andrew with Antora Energy and I'm just gonna go through a little bit about what Antora does, kind of the larger context of the area of energy that we're focused on and then a little bit about our specific solution. So the first is really to talk about the challenges in decarbonizing industry. And this is about one third of all global emissions come from industry, from making stuff. And so it's certainly a sector that can't be ignored. And then we'll talk about what Antora is doing about that. So I think the first thing to talk about is why is decarbonizing industry hard? Just like everything else, it has its own challenges. But I would say that one of the biggest challenges in decarbonizing industry is that about two thirds and maybe as much as three quarters of the energy used in industry is in the form of heat rather than in the form of electricity. And at this point, you're probably all pretty familiar with the fact that we have good alternatives to fossil fuels to generate electricity, still some problems that we can talk about, particularly around variability. But electricity in some ways is an easier area to decarbonize than heat. And so even if we've decarbonized the grid, a huge chunk of those industrial emissions won't have been solved yet. And the real reason that decarbonizing industrial heat is so problematic is that heat is really cheap. Heat from fossil fuels in particular is very inexpensive. And so it's not so much a technical challenge. It's not that we don't know how we could generate high temperatures or steam or anything like that with electricity, for instance, that might be decarbonized. But it's just a problem of techno-economics. And I'll just make one kind of larger point here before moving on. techno-economics is everything in energy. Most of the things that are being sold in the energy industry are commodities. And so it really, really matters what your costs are. And so if somebody has a demonstration that shows, hey, I can take air and water and turn it into gasoline or something like that, which would be a wonderful thing. The demonstration alone is not actually that valuable. You really need to be able to show all the way through the techno-economics, not only that it is possible to do what you're saying, but that it is possible to do it at a low cost. So heat, again, is very, very cheap. And that's why it is so challenging to show how to decarbonize it. So one of the ways to look at this is to focus on the cost of heat in a unit that probably many of us are more familiar with, which is US cents per kilowatt hour. So one of the things I've noticed across the energy industries, people often don't like putting different sources of energy on the same axis. There's for gas, for natural gas dollars per MBTU, lots of people talk about dollars per kilogram hydrogen, electricity's all in cents per kilowatt hour or dollars per megawatt hour. Oil is dollars per barrel. So all of these different units make it very hard sometimes to figure out where are the challenges? And again, where are the challenges in the techno-economics of these areas, not just in the technology? And so with the caveat that these slides were actually made before the recent spike in energy prices, which we can talk about, natural gas in the US has typically, for the last 10 years or so, been about one cent per kilowatt hour. Natural gas in Europe has usually been a little bit more expensive, but not that much more expensive between one and two cents. So you may or may not have a sense in your mind of what that means, but you may have heard that some of the best solar and wind resources are getting down into the two or three cents per kilowatt hour range. They're variable, but they are that cheap. But this shows that natural gas is even cheaper. So even if you had a perfect way to turn electricity into heat and you had the best solar resource in the world, it still is hard compared to natural gas, say, in the US right now or in the recent past. So one thing that a lot of people talk about is hydrogen and what can you do with hydrogen? Hydrogen is a great thing can be used in a lot of different ways. But I think putting hydrogen on an energy basis on the same sort of cost axes is a bit sobering, because if you look at gray hydrogen, so hydrogen made from steam, methane, reformation of natural gas. So fossil fuel based hydrogen right now is about a buck 50 a kilogram. A lot of people are out there saying, hey, can we make green hydrogen that is the same price or even cheaper than fossil hydrogen and then use that. And certainly there are places where that might be useful, but you can see here, even if you were able to beat fossil hydrogen, you put on the same axis as natural gas in the US over the past 10 years, you're still missing the mark by a lot. And so by just showing that you could decarbonize a certain industry by burning hydrogen instead of methane to generate your heat, doesn't necessarily mean it's going to take off and provide the sort of decarbonization we need. So one thing that many people would look at this and say, okay, okay, but there's no carbon price on the natural gas. And so obviously there are some extra amounts, which is very important. And if we do add about a $100 per ton carbon price, that matters a lot. It really increases the effective price of natural gas. Maybe to the point where some of these other things like hydrogen would work, but you can still see it's still a very, very challenging problem to meet the cost that people are used to with an industry for this heat. By the way, coal is typically even a little bit cheaper than this, and even though we're mostly moving away from coal for industrial heat in the US and Europe, lots of other places are still using coal. So this same kind of argument applies there as well. So one of the things that we've looked at at Antora is, well, we talked about maybe a really good solar power plant or wind plant might be able to produce two or three cents per kilowatt hour levelized cost of energy. So the kind of the average price. But one thing that's interesting is because of the variability, you often get big swings in price. Some of the time the electricity price on the grid will be much more than that and sometimes much less. And so if you actually look, even in the US right now, SPP is the Southwest Power Pool. So this is the utilities that are, or the grids that are sort of in the wind belt. So I think Texas, Oklahoma, Kansas. If you look at the 25th percentile of electricity prices there, right now on the grid, you're actually seeing something that's pretty competitive with natural gas. So you can immediately say at least 25% of the time, electricity is cheaper than natural gas and so could be a good replacement for heat. If you somehow were able to look just at the 10% of the time that the energy is the cheapest, it's definitely cheaper than natural gas. So immediately you start to look at this and say, if we wanna decarbonize industry, if we wanna be able to compete with natural gas on price, a good starting point may be to take the cheapest electricity when there's an excess, say from over generation of wind or solar and then try to convert that into the heat that industry needs. Of course, some way to store that, we'll probably add some adder on. These are kind of our own numbers for what that looks like. But we think that even the conversion process and potentially some storage for that electricity in the form of heat can still beat natural gas. So a few things just to talk about, these are some of my pet peeves. So I'm sorry, I have to share them all. It's just that people don't always go through these unit conversions. These are approximate for sure, they're not exact, but they're close enough to get by. So one thing that I feel like is really easy to keep in your head, there's kind of two factors of three between dollars per kilogram hydrogen cents per kilowatt hour and dollars per MBTU, which is what everybody in the gas industry uses. So a dollar per kilogram hydrogen is about three cents per kilowatt hour. Electricity is equivalent to $9 per MBTU natural gas. So just having that in your head when you hear someone talk about like, hey, I'm gonna make hydrogen at $2 per kilogram, you can go, okay, that's six cents a kilowatt hour. Maybe that's good, maybe that's bad, depending on the circumstance, but at least you'll be able to compare it. Another one that is pretty useful is, a lot of people are talking about putting carbon prices on natural gas. There's even a larger kind of conversion, or a more favorable conversion factor if you're looking at coal because it has higher carbon intensity, but for natural gas it's about a factor of 20. So if you take, let's say someone says, well, we're gonna slap $100 per ton tax on carbon dioxide, you can say, well, that would be about $5 per MBTU adder onto natural gas, which again, you can see is pretty large because natural gas is usually about that price or in many cases cheaper. So we're talking about $100 per ton tax on natural gas doubling the effective price of that gas. And then one last one is that one watt for one year is about a dollar. So that's whether you're generating it obviously or consuming it, that corresponds to an electricity price of about 11 cents a kilowatt hour, which is usually within a factor two, very few people are paying less than half that for their electricity or paying more than double that. So again, just some really simple rules of thumb, they're not exact, but that allow you to start getting a gut feel for some of these things. Again, in techno economics, which I'm claiming here is really like what you should always be thinking about with when looking at energy technologies. Okay, so the opportunity that sort of I mentioned before in the Southwest Power Pool and looking at the kind of variability of these renewables and the sometimes very low prices, it all comes from what we know is a huge change in the energy ecosystem, which is really cheap solar and wind and a few different place of estimated different numbers, but there's probably tens of terawatts of renewable solar and wind generation capacity that's gonna come online in the next few decades. And then obviously, the big challenge that we're all working on or that many of us are working on and very interested in is how to tackle the approximately 50 gigatons of CO2 or equivalent that we're emitting each year. So somehow combining those two, using one to solve the other is what we should be aiming for. And the problem is variability. If it weren't for the variability of solar and wind, this would actually be a relatively easy problem. We could decarbonize a lot of different sectors of our economy quite rapidly. So if you look at the typical ways people are storing energy like lithium ion batteries, we do get a problem of them being too expensive for certain use cases. So this is a German renewable generation plot over a couple of weeks, I think last November. And you can see that there's about 50 or 100 hour gaps sometimes where there just isn't that much wind blowing because a lot of this is pretty wind-heavy grid. So typical lithium ion battery installations right now discharge for about four hours, that's where they're very competitive and we're quite bullish actually on lithium ion batteries and what they're gonna do in the future. But you can see that there's still kind of an order magnitude gap between what lithium ion can do economically right now and what is needed. And one thing I'll mention right here, I said what lithium ion can do economically. There's nothing that prevents you from discharging a lithium ion battery slowly. You can take a four hour lithium ion battery, four hours just being the ratio of power to energy. You can just discharge that slowly and cover that whole gap. But if you do that and your lithium ion battery is only ever discharging very slowly, it means it's gonna go through fewer cycles of charge and discharge over the course of a year and it won't make as much money and it won't pay back the high capital cost of those batteries. So again, the problem with long duration storage, if you hear people talking about, oh there's a problem with long duration energy storage, it is entirely a problem of techno-economics. We have plenty of technologies that could cover that gap. They just can't do it in an economically competitive way. So this is a big problem. We think lithium ion is gonna solve a lot of the problems. It's gonna solve a lot of these short duration problems. But a few days is sort of out of reach for what lithium ion can do comfortably. And the way we've looked at this problem and the different approach we've taken is to look at storing energy in the form of heat rather than in electrochemistry. So storing energy is heat has a couple of advantages. One is that you can use very, very inexpensive raw materials. Lots of different things can get hot. We have our favorite material, but there's lots of options out there. And then the other thing is you have the potential for very high energy densities. And energy densities are incredibly important because while sometimes techno-economics just focuses on the unit itself, it's very easy to forget all the stuff that goes around it. The shipping, the land, all of the pumps and steel that have to go around, whatever your battery is or whatever the energy storage itself is. So it's really easy to forget sometimes if you have a low energy density solution, you're gonna pay penalties in other areas. And so again, so thermal has the potential, not always realized, to see energy density similar to that or even better than that of lithium ion batteries while being able to be made from very, very cheap raw materials. So let's go into what that looks like in Enforis view. So in our system, we take energy, electricity that could come from the grid or directly from solar or wind or any other source and we actually put it into a thermal battery. So we're actually resistively heating material to very high temperatures. At those very high temperatures, our material is actually glowing. It's glowing hot. And so what comes out of the side of this unit is actually a beam of high intensity light. It's this very bright glow coming off this very hot object. And so once you've converted the energy of the electricity into this kind of stored energy and heat and then to this very bright light, you can do one of two things with it. One is you could directly address industrial heat. So you could turn that into steam by putting that light on a steam pipe. You could put on something higher temperature like calcination of minerals like are used in cement. The other thing you could do with it is actually turn it back into electricity using a photovoltaic cells. So photovoltaic cells are already very good at turning light into electricity. So this gives us something that's pretty interesting, which is that not only are you very flexible in what kind of input you're taking, you're also flexible in the output that you're providing, whether that's industrial heat or electricity. So looking a little bit closer at what this system looks like, we have this core gray box, which is about 100 megawatt hours of storage and that's stored in the form of solid carbon. And then what you have are these kind of discharge modules, these shiny boxes on the side, which are the power modules. So they kind of bolt onto the side of this unit and they accept the light that is coming off of this and turn it either into a useful form of heat or into electricity. What's between those two is essentially a shutter. So when you don't want energy coming out of the system, you close a shutter that's right at the interface there, no energy's coming out. When you do want the energy, you open it up and then you're discharging. So there are a lot of different ways that you could approach this. So when we were starting out, we had this sort of luxury, we didn't have any existing technology or any kind of preconceived notions about what this had to be. So we were able to start pretty technology agnostic and look at all the different aspects of the system. So the first is you have to choose what material you're gonna use to store heat. We chose carbon out of a number of ones that we investigated. The second thing you need to do in a thermal energy storage system is think about what is your heat transfer mechanism? Actually most thermal energy storage systems use some sort of convective heat transfer. You actually pump a fluid of some sort through your thermal storage and then bring it somewhere else where you need the heat. We chose something a little bit unusual which is to use thermal radiation, the glow coming off of a hot object. And then finally you have to choose if you want some of that energy to come back in the form of electricity, which we do in many cases, you can choose what heat engine you want. And there are many options, many different heat engines out there and we chose photovoltaics which has a few advantages. And each of these three materials are heat transfer power conversion methods. They all have drawbacks. But one of the things that was really interesting is we found that the combination of these three worked really, really well together. They solved some of each other's problems. So I'm gonna go through a little bit about how that works and why this is a good parent. So the first one is why carbon? A few things, one, it's very, very inexpensive. And one of the reasons it's very inexpensive is it's used in steel and aluminum. So huge quantities of solid carbon, often in the form of graphite, are used as electrodes in aluminum and steel. And so there are huge supply chains that make very, very large quantities of these. Another thing that's really nice about carbon is that you have access to very high temperatures and you have a high specific heat. And so if you look at this plot, that sort of combines both the specific heat and the temperature range. So you can see the kind of energy stored is the area underneath these curves. And so graphite or carbon has the ability to go to these high temperatures and it has a high specific heat. So you end up storing a lot more energy than you would in something like steel or in kind of ceramics, metal oxides. And then finally, it has a high thermal conductivity which is always very important in a thermal energy storage system because that's just helpful in getting the heat out. This is just compared to a lot of other different companies that are looking at thermal energy storage. You can see the energy density, again, because of the carbon having that huge area under the curve there, it is quite high. Another way to look at it, which is going away from the numbers and everything is just a picture like this. These are electrodes that are used in the aluminum smelting industry. So you can see they're made in absolutely enormous quantities. They're very, very, very cheap. And what you're seeing here is about a gigawatt hour of energy storage potential in that carbon. So these are some of the reasons why we really like carbon. So the next thing is why radiation? So what heat transfer mechanism do we want? So using light in the form of thermal radiation to move the heat is a very simple way to do it. It has a lot less moving parts, things that can fail compared to, say, pumping a fluid around through it. So what's important here is that thermal radiation as many of you probably know, is very temperature dependent. So it's actually proportional to the fourth power of temperature. So if you have twice the absolute temperature, you're getting 16 times as much power transferred through radiation. So this is a very powerful effect, which means if you're at cold temperatures, you don't get much thermal radiation, and so this would be a really poor heat transfer mechanism. So this kind of explains a little bit why people haven't looked so much at radiation as heat transfer in thermal energy storage before, because most thermal energy storage has been at relatively low temperatures, often because the input source of that heat is something like concentrating solar or combustion or something else that's temperature limited. And so if you were limited by your heat input to low temperatures, you had bad thermal radiation, this was a bad idea. Once you move to charging with electricity, once you say, hey look, we have this opportunity with cheap solar, cheap wind, to have tons and tons of cheaper noble electricity, now you can charge up to whatever temperature you want. And again, this is where carbon sort of solves one of the problems of this. Carbon can go up to very high temperatures, which allows radiation to be such a good heat transfer mechanism. So again, it's kind of enabled by this different, you know, temperature range that we're working with, and then a few other things that's interesting. So you might notice that the geometry is here, here is kind of unusual, which is that your thermal storage is kind of in the shape of this U, your power module, which is where you're extracting the power is on the top there, and then you have this big void. And that void is actually really important. If you didn't have the void and you just filled the whole system up with carbon, then you'd have to conduct that heat all the way through a lot of carbon before it gets to the power module, and that would limit the rate at which you can extract power. And this is actually one of the reasons why people usually don't use solids as thermal energy storage unless you have convection as well, because it's just, conduction through a solid is not good enough. But here again, by using the fact that we're at high temperature and light, thermal radiation carries that heat so effectively, adding this cavity means we can discharge heat from very deep within the system. And so kind of a fun factor here is if you set yourself to say, I wanna be able to pull this heat out within a hundred hours. I wanna be able to fully discharge all that heat that was in that carbon. If you look at it without any cavity there, you would get a certain amount of energy that you can extract. By adding the cavity, you actually get more energy that is extractable during that period of time. So it's kind of counterintuitive to say like, hey, here's the amount of usable energy stored in the system. What if I remove a whole bunch of the thing that's storing energy? That should reduce the amount of energy that's stored. But in this case, you're increasing the amount of energy that at least you have access to because you're drawing it from sort of deeper within the system. Again, another kind of advantage of light here as I mentioned is that you can have a very simple mechanism to control the discharge, which is to put a shutter between the power module and the thermal storage. And then finally, it gives you a lot of flexibility because it's in the form of light, you can make either electricity or heat out of it. I'm actually gonna skip that one. So let's talk about how to turn heat into electricity with a photovoltaic cell. So we said this is hot, it's glowing, light's coming off of it. We put a PV cell in front of it, it turns it into electricity. That's an easy thing to say, but if you take a traditional solar cell and put it in front of this glowing hot object, you're actually gonna get really terrible efficiency, probably less, certainly less than 10%, probably less than 5% efficiency. That's not good enough for thermal energy storage like this to be competitive. So there's one thing though that you can do a little differently. So here's our kind of black body spectrum. You can see that you have your carbon and your semiconductor. If you're talking about high energy photons, photons above the band gap of the semiconductor, then the photon will immediately create an electron, that's how PV works and that's what you wanted. So that's all fine and good. The problem is that at these temperatures, most of your photons are in the infrared and they're below the band gap of the semiconductor. So all of those photons would otherwise be lost in a traditional PV setup. In this case, we put a very, very good reflector behind the semiconductor and reflect those infrared photons right back to the carbon where that energy is reabsorbed and recycled rather than being lost. So let's talk about why this is possible in this system and not in solar. The reason is because it's a closed system. If you reflect photons back to the sun, nobody gives you credit. You don't get to say your efficiency was any higher. You weren't really recycling them. You were just kind of putting them somewhere else, losing them in a different way. In this case though, because it's a closed system, all of these photons that you're sending right back to the carbon, that energy stays in the system and so that increases your efficiency overall. So that's the key to how Antoria is getting higher efficiencies and just to provide a little bit of a sense here. Over the past few years, thanks to the work of many, many folks on our team, we've been able to take TPV from under 30%, actually the best TPV that had ever been demonstrated before we started working on it was in 1980, here at Stanford by Dick Swanson before he had left to start Sunpower. So it's a sort of Stanford invention through and through. But so previous best was just under 30% and then we've been able to get to over 40%. And that's really just about making better mirrors behind the cells to reflect that light and then using some of the higher quality PV materials that we have access to now that Dick Swanson didn't have 40 years ago. Last thing I'll mention here is about size. You may be familiar with, solar panels are kind of big and bulky. I showed this very small unit and I said it was a megawatt. It's really because of this. When you're very close to a hot object, you get a lot more light from that hot object. It's really because if you imagine yourself as the PV cell, your entire sky is bright. Your entire sky is this hot carbon. Whereas here on earth, the sun is just a very small dot in this guy. So even though this is cooler than the sun, it's much closer than the sun is. So you get a few hundred times as much power out of these cells than you would a traditional solar cell. Okay, so we've gone through kind of the carbon, the heat transfer in the form of radiation and the PV as a way to convert some of that power back into electricity. And so this is just kind of recapping. Not only are they kind of nice ways to store thermal energy because they solve some of each other's problems, we also have the ability to draw on existing supply chains. So again, the materials used like carbon, very, very inexpensive. The thermal hardware, if you want to say, take that light coming out of the system and turn it into steam, also pretty easy to do. There's plenty of steam tubes from the oil and gas industry that are meant to operate based on radiative heat transfer, OTSGs. And then the last is the photovoltaic power conversion where we can leverage a lot of work that's been done to improve photovoltaics over the years. Okay, so I'll just tell you a little bit about where Antor is at. We're currently working with a small prototype. It's about the size of an elevator here, 500 kilowatt hours that we've been operating for over a thousand hours. We're able to leverage a lot of experience in the high temperature furnace industry as well as PV manufacturing to prepare ourselves to go up quite a bit in size. Our next system is a 100 megawatt hour pilot that we're working on near Fresno and that's funded in part by the California Energy Commission that we're very grateful for their support. So just looking at the system again, a few hundred kilowatt hours thermal and we were able to build this system very, very quickly and relatively cheaply exactly because of all the other stuff we mentioned in this presentation which is it's very cheap raw materials and it's pretty standard industrial engineering. This was actually an off the shelf furnace that we modified to become a thermal energy storage unit. This is a little bit about that next site which is again funded by the CEC which should be about one of those blocks that we've shown in those renders. By the way, that's about the same size that we imagine the commercial product would be so if you want more than a megawatt you would just tile those one megawatt blocks together. All right, so a little bit about just the economics because again I was saying techno economics is everything and you should not take my word for any of this and if you were an investor you should say hey I wanna go look at all your spreadsheets and see where all this comes from but for now you will have to take my word for it. This has the ability to be very inexpensive and if you look at sort of what an industrial customer typically pays for electricity and heat today you're talking somewhere around here if you were to sell, there are different ways you can sort of structure the money here but here I'm just saying let's imagine you're selling your heat for the same price as heat today you're now able to deliver them electricity at a much, much lower rate. So again that's because you have one box that is taking solar or wind electricity in and then providing power and heat to the industrial customer every hour of the year and this is what we're saying is we could beat the natural gas grid and the electric grid which is the other way they could get that energy with our system plus on-site renewables. Okay, this is just talking about the market which is very large but I think the more important thing is that we can address it due to the very inexpensive system that we have but this is the real fun which is the amazing team. There is someone from the audience who is in this photo so you can try to figure out who that is and this was our ribbon cutting this summer. It's a really, really wonderful team. For any of you that are looking at internships in the future, we absolutely love interns. We have taken many interns including from the Tomcat internship program so I'd highly recommend that. If you're interested at all or if you know someone that you think would be interested we are hiring quite a bit right now and so please send an email to hiringedantora.energy to get in touch with us. So that is everything I have. I would love to hear what questions you have. All right, what's the biggest roadblock you guys are currently facing? Is it scaling, manufacturing? Just curious. Yeah, I think one of the biggest roadblocks is actually in project finance. So after this first units which itself is a relatively large unit we have to figure out how to pay for that one. Kind of the next step is what we think is gonna be one of the hardest things because you're in this weird in-between zone. You're talking about amounts of money that are larger than a company like ours can just put out itself. We can't just build it on our own dime. We have to get someone else to pay for it but it's also still gonna be a relatively untested technology at that point. So if you go to a bank and say hey, I want a loan to be able to build this next unit they may say whoa, whoa, whoa, I've never heard of Antoria, I've never seen this unit. Like how do I know it's gonna last 20 or 30 years? And so we think that's gonna be one of the biggest challenges. How do we show as soon as possible that this is a very, very simple, very reliable system so that immediately after that first one we can go to customers and we can actually get a bank or someone else to finance that system rather than having to pay for it ourselves or force the customer to pay for all of that themselves. So it's really a matter of how do you kind of put the risk in the right place. Yeah, so the question was about kind of financing. We have raised some venture and we will be raising more and we have also raised a fair amount of grants. We're really, really happy with the supporters we have there. We have ARPA-E, the California Energy Commission, other funding from the DOE, the NSF. We've raised about $17 or $18 million in grant funding so far. Thanks so much for an interesting presentation, Andrew. I was curious, what are some of the key trade-offs that your team is thinking about when designing the system, thinking about metrics like energy density, round trip efficiency, self-discharge? Yeah, how do you manage all of those different trade-offs? Great question, great question. The trade-offs are where all the interesting stuff lies. So I'll mention a few of them. One is on the system itself and the design. So I mentioned that cavity which is really allowing the heat to get out. There's a lot of interesting optimization to do around. How big should that cavity be? Obviously the endpoints don't make any sense. If you make the whole thing cavity, there's no carbon, there's no energy being stored. And as I said, if you make no cavity, then you can't get the heat out very effectively. But the size and shape of that cavity are something that we have to figure out and that we're working on. It also, the optimum cavity varies depending on how fast you want the heat out. So if you want the heat out really fast, you probably want a bigger cavity so the extraction happened faster. If you are okay with it coming out really slowly, you'll have a smaller cavity because you just want more of the energy stored. So not only is there that, we wanna kind of find a happy medium so that we don't have to change every installation is going to have a different geometry. Maybe that's possible at some point in the future but we wanna find something that we think is gonna cover the bases well enough to sort of meet everyone's needs. So that's certainly one that we're thinking about. Another one that I think we've mostly settled on now but there was an interesting optimization was the size of the system. So any thermal energy storage has the trade off around heat leakage. So you want the system to leak as little heat through the insulation as possible. That's just self-discharge, that's loss. And so one way to do that is to put a lot of insulation around it which we definitely do. The other way to do that is to make it really big and then your surface area to volume ratio is better and better the bigger you go and so you'll leak less heat percentage wise that way. But on the flip side, if you make these really big systems, you run into other problems like can you ship it? Is it bigger than a certain customer would need? So we kinda wanna make the smallest system that we can to make it kind of shippable and meet the market needs so be able to be kind of modular while still being big enough that it doesn't leak too much heat. And so one of the things we've done with the system is trying to make it modular in different ways so that it can be shipped in parts and then would have very limited assembly on site. So that allowed us to get kind of bigger than any one piece that could get shipped while still not having to move into a mode where every bolt and whatnot is being done on site because on site construction is way, way, way more expensive and failure prone than assembly in the factory. Yeah, great question. Thanks Andrew, this is really great. Given your emphasis on techno economics, can you talk a little bit about the breakdown in unit costs from the carbon storage to the thermal radiation transmission and the photovoltaic modules? Kind of how did the unit economics break down and could you have done this a decade ago when before photovoltaic module cell prices had sort of precipitously declined? Yeah, great question. The, you could say very roughly the breakdown of the system is about a third, a third, a third between the power components like the PV itself, the energy components, which is the carbon blocks and the insulation and then about a third is maybe the kind of everything else category, you know, all of the site work, the structures, kind of the balance of plant. You know, the, as far as could we have done this before? Yes and no, actually the PV technology that we use is not silicon PV. The, we're using three or five semiconductors, which are the type of semiconductors typically used in like space applications, for instance. Now these are much more expensive, like at least a hundred times more expensive than regular silicon PV. However, as I mentioned earlier, you're getting so much more power per area that it's okay that it's a hundred times more expensive, you're getting a hundred times more power up. So the cost per watt ends up being pretty similar. So the question though, like could we have done this before, actually the cost of those three five semiconductors has also come down over time. Obviously the whole thing has been shifted up versus silicon PV, which has been coming down, but from a much lower starting point than these very high efficiency cells. But so that's why it's sort of a yes and no, yes, but not for the reason you think it's not because of silicon PV dropping in price that makes it so available to us. Yeah, I'm sorry about this earlier, but who would you say is your primary customer base? And a second part of that question is, assuming you get the project financing that you would need, what is, how long would it take for you to scale it to commercial application? Yeah, great questions. So the customer base that we're focused on is industrial customers. So there's absolutely applicability of this for the grid. And we actually have a number of partners that we've been talking to or working with that just want this for the straight electricity storage. You take electricity in from the grid, output it later when the sun's not shining or when it's not blowing. So there is something there, but we found the industrial customers to be a really interesting area for a few reasons. One is that they value some of the resiliency benefits of having the energy on site. Even if the grid goes down, they can keep going. As you might imagine after some of the PSPS here and the Texas freeze, people are very interested in those benefits. But the other side of it is their energy prices are typically higher. So kind of like solar PV on rooftops can kind of displace very expensive electricity at the end point. You get something kind of similar with industrial customers. Industrial customers are very large, so they get pricing that's a lot better than you would at a home. But they're still not paying quite the same price as the sort of wholesale price on the grid that a utility would be buying and selling at. And so that helps as well. And then the third factor really is the fact that they can use the heat. And so that's where the economics of the system become really, really good. And there's kind of a big differentiation between Antora and what other solutions can provide. So a few examples of where you might do this, you might do this at a mine that is both needs electricity to like crush the rock and maybe need some heat in order to drive some process that extracts the mineral. You might do it at something like an ethanol plant that uses both a lot of heat for distillation and then also electricity for everything else at the plant. Paper, pulp, chemicals, there's a lot of different areas. Again, about a third of emissions come from this sector in general. A lot of that is heat from all of these different areas. I guess one last one I'll mention is food and ag. That's a really big area where they use a lot of heat in addition to electricity. The second part of your question is about your project finance and scalability. So there's kind of, if we had all the money that we wanted, we actually think we could scale up very rapidly. We think that probably project finance is gonna be the limiting factor for us because sometimes you just need to see years go by before people get comfortable with a system like this. After project finance, everything else is much more solvable problems. There are existing supply chains for the different components of this. Of course, there'll be some aspect of us just having to get used to building this, overseeing the building of this, the development of these projects. Sometimes you'd be limited even just by finding a customer who has a need like this, working with them, working with the plant manager to make sure they understand how this is gonna integrate into all of their systems. So there are certainly steps other than that, but that one really is the main one. You said, do I have an estimate for how long? Ah, yes, yes. So from the time that we have project finance in place, we think we can install a full project in less than a year. And that's, again, largely because of the modularity of the system, which allows most of it to be built in the factory and then just kind of minimally assembled on site. Andrew, this is an interesting question. Can you put up your slide where you show carbon and steel and concrete and other storage media for a second? Yeah. Oh, that's it. Now, these materials are not doing a phase transition in. And traditional thermal or solar thermal energy generation, part of the way they do the load shift in the storage is they use a material with a big phase transition and so they store it. Now, they don't go to the same temperature you do, but the energy density is good. And if you thought about some kind of hybrid where you use a phase transition material, maybe you don't take it out as radiative energy, but you take it out at a lower temperature through some more conventional mechanism. So I'm curious, phase transition materials, where would they fit in this plot? Yeah, phase transition is super interesting. So the main reason we haven't done phase transition, and we've certainly looked at it with a few different materials, is just the complexity of having liquids in the system and then the actual freeze thought cycles. It's very difficult to get a system that you're gonna be sure is gonna last for decades when it's undergoing contraction and expansion, freezing and thawing, but then also just the containment. Once you have a liquid and you have to contain it in some sort of tank, you have to be really careful about, is it gonna leak? There's pressure at the bottom of the container. So just to explain why we haven't done it, that's the reason. Why we would like to do it is what you just said. You can get very high energy densities. One of the best materials actually is silicon, which has a phase transition at 1414. There's actually a company called 1414, which was founded around the idea of using the silicon phase transition as a way to store thermal energy at high temperatures, very energy dense. And so yeah, there are people looking at this absolutely. We've seen kind of the practical challenges with that, not worth it. One thing I will mention actually, if you look at this, I do have 1414 up there. So you can get very high compared to everybody else kind of in energy density. We're able to match or even exceed that, largely just because we do have that enormous range of sensible heat temperatures to go through. But if you look at like how much energy we store between 1500 and 1600 C versus what a silicon phase transition would do at 1414, like you're getting way more energy out of that phase transition. We only make up for it by going to extremely high temperatures on the hot end. So they might beat you on volume. It would be pretty close on volume, yeah. Thank you. Thank you so much for your presentation. I was just wondering, are there some unavoidable losses that would maybe cause like an existing limit on how high you could go with the efficiency even with advances in technology or materials? Yeah, yeah, so a lot of limitations. Unavoidable losses, certainly just heat conduction through the insulation, just leakage is an unavoidable loss. Typically, we keep that very low again by making a reasonably sized system and putting a lot of insulation. But that's actually one of the things that sets our upper end temperature. Insulation gets more expensive and its performance is worse as you go to higher and higher temperatures. And so both of those things are hurting you. And because of that, at some point above 2000 degrees Celsius, we sort of have had to draw a line and say it's just not worth it anymore to pay for the amount of insulation we'd have to put to keep those losses under control. So that's absolutely a sort of limiter. One other kind of limiting factor on the PV side is PV is a heat engine, just like lots of other heat engines. It has Carnot limitations and then there's practical limitations far below that. So we think that even with kind of a perfect TPV cell, you're probably not gonna ever see more than 70% efficiency, heat to electricity, which would be very, very good. And we'd love to have that, but to give a sense like that's kind of a practical limit, even though it's not the theoretical limit. And then we're looking at sort of more near term, hitting about 50% efficiency with those cells. And so that's a limit that does matter. Round trip efficiency does matter, but what's interesting is in some of these applications, like very long duration storage, the cost matters a lot more than the efficiency because you're not necessarily using this system that many times over the course of a year. You're using it for continuous amounts of time, long periods per time, but not that many times. And because it's a very long duration system, you can be sort of choosy with when you're charging it. You can charge it only sort of at the peaks of the day when there's a lot of solar that would otherwise be spilled or at really low price times with wind. So all of those things kind of push efficiency to be a little less important than it would be, say, for a lithium ion battery and makes cost even more important because you're basically trying to make a big bucket of energy compared to a lithium ion battery. So there's a few limitations that we're always thinking about. Any final questions? Actually, I had one comment. Even since you've left, one of the big new things on campus, I think the newest initiative is the Sustainable Finance Initiative. So I think on this finance ability question, there might be some synergies there. So there's a few people we could talk to. I've actually studied technology diffusion a lot, not at the depth that you would need, but it is often the case that it's, can we get people to want to buy this and you beg them to buy it and then it becomes the big new idea and then you can't keep up with the math for it. So I'm hoping for all of us that that is exactly what's gonna happen and I'm pretty confident that you can pull it off, partly because you're looking at it this in such a flexible way with many often on ramps, which I think is a key thing in innovation in general. So with that, I'd like to thank Andrew for an absolutely inspiring talk full of numbers. You explained a lot of really complicated things in a pretty easy to understand way, even for all of us who aren't that well versed and the audience for asking some great questions that allowed Andrew to expand upon those. So thanks again. And I'll let you, I mean, let me put you down here. Thank you.