James MacNaghten: 0:03

If you look at global energy usage, half of all the energy used in the world today is used to produce heat, and half of that is used for industrial heat. So if we want to decarbonize, our world and our society, we have to be able to tackle industrial heating.

Tom Raftery: 0:21

Good morning, good afternoon, or good evening, wherever you are in the world. This is the Climate Confident podcast, the number one podcast showcasing best practices in climate emission reductions and removals. And I'm your host, Tom Raftery. Don't forget to click follow on this podcast in your podcast app of choice to be sure you don't miss any episodes. Hi everyone, welcome to episode 141 of the Climate Confident podcast. My name is Tom Raftery. Before we kick off today's show, I want to take a moment to express my gratitude to all of our amazing supporters. Your support has been instrumental in keeping this podcast going and I'm really grateful for each and every one of you. If you're not already a supporter, I'd like to encourage you to consider joining our community of like minded individuals who are passionate about climate. Supporting the podcast is easy and affordable, with options starting as low as just three euros. That's less than the cost of your latte, and your support will make a huge difference in keeping this show going strong. To become a supporter, simply click on the support link in the show notes of this or any episode, Or visit tinyurl. com slash climatepod. Now, without further ado, with me on the show today, I have my special guest, James. James, welcome to the podcast. Would you like to introduce yourself?

James MacNaghten: 1:44

Thanks Tom. My name's James MacNaghten. I'm the Chief Executive of Caldera. And we are a company developing large scale industrial heat storage.

Tom Raftery: 1:53

Okay. Large scale industrial heat storage. Can you tell me a little bit more about that, James?

James MacNaghten: 2:01

I certainly can. So if you look at global energy usage, half of all the energy used in the world today is used to produce heat, and half of that is used for industrial heat. So if we want to decarbonize, our world and our society, we have to be able to tackle industrial heating. And within industrial, and it's about, so it's about a quarter of all energy. It's about 20% of all carbon emissions. And within industrial heat there are some, there's a, there's a whole range of temperatures and processes, but you might say, first of all, what do you use industrial heat for? So, it's used from everything from at the very top end, making steel, making cement, to brewing your beer, making your cheese, pasteurizing your milk, you know, sterilizing instruments in hospitals. So, there's a very, very big range of applications it can be used for, and in a lot of ways people tend to sort of talk about industrial heat as one homogenous sector. It's actually got some very different and distinct, to our view, distinct sort of market segments depending on the temperatures you're interested in.

Tom Raftery: 3:09

Okay. Can you actually, before we get into the detail of that, can you take a step back and talk to me about the kind of the origin story of Caldera? You know, why did you wake up one morning and say to yourself, I, I think I'll start a industrial heat company and I'll call it Caldera.

James MacNaghten: 3:30

Okay, so sort of going back to the dim and distant past, we, I originally, I was CEO of a company looking to store electricity by converting it to heat and cold using large thermal stores. This was going back almost 15 years now when lithium ion batteries were unbelievably expensive. We were just starting on the journey for solar. Solar was still expensive. Wind was expensive, so it was very much on the journey at that point. And we were looking to develop a process where we took electricity, we converted it to heat and cold, stored it in these big tanks and then converted it back later. So that sort of started me on the journey and we were far too early. We were probably a decade earlier than we should have been. It's well you might say in terms once it's been mostly right, but we, we were just far too early. It's even now today, systems like that would only just be starting to be deployed, but I'd always, so I knew quite a lot about heat storage, but I'd always, for a long time, thought it wasn't particularly valuable. I thought storing electricity was actually much more important. And then we started to do some modeling and we had a, we had a sort of project we were interested in where one of the options was you get certain losses that appear as heat, and one of the options was to put the losses into a district heating network. And so we were doing the modeling on the system, and the aim was that you could charge the storage from electricity, from from wind, and we'd store it. And then we, any losses you'd put into the district heating network and you'll get paid a little bit for them. So the actual system efficiency would be very good. And we used optimizers, so, so, they're optimized is quite good because they can, they run through all the possible solutions and they can often find solutions that are not obvious. They don't always, you need to sort of bracket them and we hadn't constrained the optimizer properly. And when we said we can sell heat to the district heating network, it said, don't build any storage at all. Just sell the heat. Because actually, even though you're being paid a small amount, it added more value than building lots and lots of capital equipment that doesn't run very often. So that for me was a, it was a bit of a shock I'd always and, and, and the reason it was a shock is actually storing heat is much, much easier than storing pretty much anything else. Your hot water tank in your house. Good example of a thermal store, and as I said, if you're of a certain age, you'll remember night storage heaters where you used to take an off peak rate overnight, you'd heat up some very dense bricks inside a insulated container. You wake up in the morning sweating and hopefully by evening there'd still be some heat left to give you some heat in the house. But, you know, these are sort of easy examples to understand, but storing heat is actually much, much simpler than pretty much storing electricity, anything else. And so the sort of realization from this was actually storing heat has got a real place to pay. And then when you take a step back and look at the best places to go for storing heat, you sort of go, well, it could store heat and deliver it for under a hundred degrees Celsius, but you're always gonna be competing with heat pumps.

Tom Raftery: 6:28

Right.

James MacNaghten: 6:29

So, so to me that's, that's never been a, you know, that's always the risk is you, you know, at the top end of the temperature range, maybe 80, 90, a hundred, we compete well. But if somebody wants heat at 30 or 40 degrees Celsius, you'd always use a heat pump. Well, I would tell you always to use a heat pump. So between about 100 and 200, heat pumps now start to run into trouble. Very hard for them to work from ambient. It's actually quite an easy temperature range for us to deliver. So there's a very, very big sector of very big sector of the sort of heat usage. It's about a fifth of all industrial heat is used in this 100 to 200 celsius range, and it's normally used as steam and you probably won't notice it, but lots of hospitals have steam networks, factories do, and they're these sort of big insulated pipes that run around the site. And they basically use the steam to move heat everywhere around the site. And sort of to take a, so, to take a step back. So the realization came that heat storage was important and actually decarbonizing heat was important. The breakthrough happened about five and a half years ago when we worked out how to store. We worked out this thermal storage material, which I'm happy to explain a little bit more about, which we make from recycled aluminum and rock. And it's an amazing material. It's just so easy to use. It's really easy to you know, to, to make into different sized units. So we developed this material and on the back of it we're like, this is the business because you know, having built high temperature heat stores before and done it, there were lots of issues and this sort of seemed to solve all of them. So we pretty much pivoted business overnight to focusing on the aluminum and rock material, and we've been at there ever since. We've built some domestic units you may know about, so we originally started going smaller into homes. For fairly good reasons to do with off the price of off peak electricity, we decided that was not a good place to stay. And we've really moved the business onto industrial. But if you wanted to ask about it, it's basically we, once we had the material, we're like, this is something we can build a business around.

Tom Raftery: 8:31

Okay. And. Talk to me about the, the rock and the recycled aluminum because how did you happen upon that and why is it, or how is it such a good store of heat?

James MacNaghten: 8:47

Okay, so, when you have solid materials you know, if you want to go, so, so, The issue is normally how do you get the heat in and how do you get the heat out? So if you have, a lot of people want to have what we call, you know, piles of gravel or maybe sand where you can blow hot air through them and blow it back the other way to get the heat out. But you need a mechanism of getting the heat in and the heat out. And what the aluminum does, the element's really, really conductive. So it, it's a hundred times more conductive than rock. And what we do is we take a, a container of rocks, we heat them up, so they're now hot. And we then buy the lowest grade scrap aluminum we can find, and we melt it and we pour it over the rocks and it runs down between all the holes and it sets and it holds everything together. And I mean, the analogy I often use is if you cut it in half, it looks like a rocky road cookie the, you know, the rocks in the middle and the aluminum running around everything. And because the aluminum's so conductive, I can put heat in pretty much anywhere in that block and it will transmit it all over the block really, really quickly and without getting too hot. If you try and, and generally the cheapest things in and, and we add the rocks because they're just a low cost filler. So they have the same density, same heat capacity as the aluminum, but they're much, much cheaper. So, so you end up with this block of material that on average has the same conductivity as a block of steel. For every kilogram it stores twice as much heat. It's easy to make, which a a big block of steel isn't. and particularly the aluminum. one of the key features is the aluminum is very ductile in the temperature range we use it in. So if I took a large block of steel and I aggressively heated a couple of small bits, the block of steel would probably shatter.

Tom Raftery: 10:34

Wow.

James MacNaghten: 10:34

It will probably tear itself apart with thermal stresses, you know, very, very, very high loads you can induce in, in materials when you heat one bit and you don't spread the heat evenly. So the aluminum is both very conductive, so that move the heat around, we don't have a completely homogenous structure, so the, there's always little gaps, so everything can move and so, so the aluminum's really, really important to actually managing how you get heat in and out quickly. So, so if we didn't have the conductivity, you then end up not being able to put the heat in quickly. So, you know, there are lots of, you know, if I had a, a lump of concrete, if I tried to heat that, we, we put electric elements into our blocks. They work really well. If I did the same thing with lump of concrete, the elements would burn out in seconds because locally it would be like you're insulating them, so they'd be over a thousand degrees Celsius and they would die very quickly. So by putting them in something that's very, very conductive, everything works really, really well.

Tom Raftery: 11:36

Okay. And is it just that you connect both ends of the container full of aluminum and rocks to electrodes and you get resistive heating? Is that how the heat is generated?

James MacNaghten: 11:49

We just, we put resistors in them in the block, so that's how we generate the heat. And then when you want to take the heat out, we embed a steel coil in the block and we squirt a small amount of water in. It then turns to steam and we take the steam out and we take the heat outta that. And basically the more heat we want out, the more water we inject.

Tom Raftery: 12:09

Okay. Okay. And these are kind of barrel shaped pods full of aluminum and rocks. How much heat or energy can you store in them and where is that energy coming from?

James MacNaghten: 12:26

So the latest versions, which are about four and a half tons each, they store 200 kilowatt hours. They're 1.2 meters wide and they're about two and a half meters high. So that gives you a sort of nice feel for size them, and you put them in banks, as you said. So if you wanted four megawatt hours, You will put 20 in a, 20 together. So that that's, that's what they are. So can you remind me the second question

Tom Raftery: 12:53

Yeah. Where? Where's the energy coming from?

James MacNaghten: 12:55

Oh. So the energy coming from, so in the longer run, there are two places the energy can come from it's electrical energy. We don't, we don't do heat recovery. So we look to take surplus renewable generation or onsite renewable generation. So there are two. In the near term, we are very, very clear. The, the best business model we see is where you build a large solar farm alongside the factory. Y have to be, You know, it could be half a mile away, kilometer away. And you take a, what's called a private wire, you feed it into the factories network behind the meter. So the grid doesn't see this. You don't have to pay any of the grid charges and effectively, we provide the factory with both, and this is an important point. It's both electricity and heat. So this works for factories. You know, like a food producer, you might use one megawatt of electricity and five megawatts of heat, and what you can do is build a actually very large solar array to supply them with both electricity as heat. And we're also able to store heat to carry them through the night. For example, if they wanted to run 24 hours a day. The business case for that works. This is the weird thing, the business case for that works in the UK, which is about the last place it should work because we're not, we're not very sunny country. So if you go sunnier countries, it gets, it gets better. And the reason is, is that you are avoiding all of the grid charges and all of the, you'd have to upgrade the, there's no export. You don't have to upgrade the grid. And I think that the bottom line is, Solar pv electricity is now so cheap at utility scale. It's cheaper than most companies are paying for gas, so they don't care if they displace gas with their own electricity. It's, it's a lower cost and you sort of, you put this system in and you displace electricity and gas, and then after maybe 5, 6 years you've paid for it. They've now got 30, 40% of their energy free for another 20 years. So it's a really, really good way to decarbonize, I would say, large quantities of energy rapidly because you don't have to upgrade the grid and you can literally go in and tackle it overnight. So that's where we see in the short term. In the longer term, what we're expecting is lots of renewables on the grid, and you are also able to buy you know, at night when it's windy, you'll also be able to buy electricity from the grid at a low price and also charge. So we sort of say in the near term, it's behind the meter solar combined with our system. In the longer term, it's anything, it's behind the meter, it's from the meter. But the bit that we've still missed today is the market structure because even when the wholesale price of electricity, which is what the people that own the power stations, the generators, the wind turbines get paid when that's zero. As a customer, you would probably still have to pay eight or nine or 10p for that electricity. There's a whole lot of charges that have been added onto it that mean, and the problem with charging someone 10p when they can buy gas at, let's say 7p a kilowatt hour, is they'll stay on gas. So we end up with this very perverse situation where we pay people to turn wind farms off when there are plenty of people that might buy the electricity. Because the market structure, and this is in the UK, doesn't incentivize people to try and switch to using it.

Tom Raftery: 16:12

Sure, sure, sure, sure, sure. In terms of space, how much space would be required for a, as, as you said, a factory that uses one megawatt of power and five megawatt hours of heat, just roughly in terms of solar and in terms of the storage space?

James MacNaghten: 16:35

So for that sort of system, you'd probably want somewhere between seven and 12 megawatts of solar. In terms of land usage depending on how you do the solar, and there is both low density and high density arrays. We're, we're a big fan of high density, but you're probably talking in that scenario anywhere from 10 if you went for if you go for high density racking, you might get it into 10 acres. If you go for low density, you might want 30 or 40 acres. So there's, there's a, there is a, you're gonna need a field, you're gonna need land available. It's almost certainly too big for the factory roof. We very rarely see a factory roof that can take more than a megawatt.

Tom Raftery: 18:28

Okay.

James MacNaghten: 18:28

So that, that would be my, so, so you will want access to a friendly farmer from whom, you know, land might be available. Second question is how much storage? It depends on how much you want to decarbonize. So what we see in the short term is you would probably be looking for less than 10 megawatt hours of storage. We don't, at current pricing, you are unlikely to go and put in what you would need for overnight, which would be 60 megawatt hours. You could do it, but the payback is longer. So we have a sort of very clear view, which is you want, you need some storage when you do the, when you do the modeling, but you don't need huge amounts. But it's a sort of a question of how much do you want to decarbonize?

Tom Raftery: 19:08

Hmm.

James MacNaghten: 19:09

Pretty much as in all these things, the further, the more you want to do, the longer the payback. So the first bit always gives you the best payback, but then really, but it doesn't have much impact. So you sort of, so there's always a question when you're talking to people, which is, it's not so much what's, what's your hurdle rate? What's your return on investment for your business? What sort of payback do we need? And we size the system to what the customer wants to invest in that respect. And I, it, it's a sort of tricky one because we could probably get them to 80 or 90%, but it would be a very, very long payback. And that's, I'm I'm talking very UK specific.

Tom Raftery: 19:46

Sure.

James MacNaghten: 19:47

If we were in somewhere like the south of Spain, the economics are much better because the solar produces much more energy in the winter period and even a bit more in the summer, but you don't get this seasonality. So in, in, in somewhere like Spain, I might have a very different answer where actually we could go and put 40 or 50 or 60 megawatt hours in on day one because we can cycle it every single day. If I put the same system in the uk, I can pretty much guarantee you the thermal storage wouldn't do anything for the winter, six months at this moment. So, to me solar gets you a probably, let's say 30 to 50% of the way there maximum in the uk. It can get you further if it's a sunnier country. And for the UK we really need access to grid electricity. So I think you would build it out further when you can now buy offshore wind at night and you can actually bring it in. So, so there's solar is very, very challenging in the UK because it generates almost the majority of the electricity in June and July, the biggest months, and it almost nothing in December and January. So whenever I model it, you can never, you know the amount in December and January is tiny.

Tom Raftery: 20:59

Sure, sure. But to, to your point, you can pull in grid electricity at that point and heat the, the Caldera system that way.

James MacNaghten: 21:07

Exactly, so, so we are sort of like, now let's tackle the, let's tackle the bit that we can do rapidly, which is the summer heat load and the summer electric load. And we will then build the system out when the grid is there and the tariffs are there. Now, if it wasn't UK, if it's somewhere sunnier, we might go the whole way in a single hit.

Tom Raftery: 21:25

Okay, and what are you typically displacing? Is it gas?

James MacNaghten: 21:30

Gas, always gas. I say yes it is. I think we have not yet seen, there might be a little bit of LPG. There is meant to be a bit of oil, but they generally tend to be more rural and smaller. Pretty much all the big factories we go to run on natural gas and they, you know, they'll have three or four big boilers that tower over you that generate steam and you'll probably have, you know, one of them, one or two of them running, one of them on standby. And one of them, just in case, you know, there's, they need to strip it down for maintenance. They've, they've always, and it's really important, these businesses cannot afford to not have heat. You know, from a production point of view they always want to run with extra capacity, so, we would not say to any of them. We say to all of them, keep your gas boiler. We'll just take a huge chunk out of your energy bill, but you still have your gas boiler there if it's not sunny for a week, if you need to for whatever redundancy. Because when you're running these processes, if, if the steam goes off and the heat goes off, things might set in molds. They might, you know, suddenly you have to strip machines down. It, it's a, it's a bit of a disaster. So, so we often, when we go in, you tend to find they run more machines and they have a lot of redundancy because it's so expensive if something goes wrong.

Tom Raftery: 22:48

Okay. And I mean, you mentioned maintenance there. What are the kind of safety and maintenance implications of your system versus a a gas boiler?

James MacNaghten: 23:01

So ours is much we expect ours to be much lower. Gas boilers have certain risks associated with them, especially steam generators. You've got a combination of high temperatures from the flame and high pressures from the steam and lots of what is effectively superheated water. So the water is probably about 180 degrees Celsius and it stopped, it, it sort of boils at that temperature because it's kept at sort of 10 times normal pressure. So, our system tends to use very little, very small amounts of water. So it's inherently much safer because most of the energy is not stored in the water. It's actually stored in metal. You know, it's non-combustible inside a vacuum. So our expectation is long-term maintenance is much less than a boiler. But to be honest, boiler maintenance is not a very big part of. Almost all the running cost is fuel. So I think that's probably the key point to make is the operational cost is dominated by your fuel cost. Even if there's slightly more operational cost on our system or less, it's completely blown away by how much you pay for your energy.

Tom Raftery: 24:10

Okay. Okay. And in terms of the potential climate impact of this technology. Can you kind of quantify how much that would be? You know, how much carbon emission reductions we're looking at

James MacNaghten: 24:25

So if we can help decarbonize the space, we're interested, which is a hundred to 200, that's 4% of global carbon emissions. So, I think it's highly unlikely we'll do all of it, but that's the, but if we can help bring that sector down to zero, we've knocked 4% off. And I give you, you know, it's the better analogy I sometimes use is all the cars in the road in the world are 10%. So that's a bit like if we can do this, we can remove 40% of all cars from the road

Tom Raftery: 24:55

Okay, cool, cool. And what's your kind of vision for the future? Where do you see Caldera in the next 5-10 years and you know, what kind of obstacles are, are there to stop you getting to that widespread adoption?

James MacNaghten: 25:10

So where do I, so I see us growing to be a much larger company. We want to have offices in Europe and the USA. Those are to us, are the two sort of key markets. In Europe, you've got relatively high gas prices and we think they will stay high now 'cause we don't see people returning to being dependent on Russian pipeline gas. So sunnier parts of Europe we think would be very, very good. United States has got the Inflation Reduction Act, which makes, pays for a massive proportion of the capital of both the solar and our thermal storage. So again, we see that that offsetting the fact that the United States has much cheaper gas. So it's almost like if it, if it wasn't for the Inflation Reduction Act, actually the United States would be a very difficult market because gas is quite expensive. The one place it's not that cheap is California. So that would be, you know, even within that, I think we'd still find California interesting. So those are the markets we're looking to go to. We're looking to grow the company to in that period about the next seven years to about 400 people. We're at 20 today. And we want to be installing, you know, megawatt hours of systems. We want solar developers to be calling us up saying, you know, we fitted a megawatt to this factory, but now we've realized with your system we can fit 10 megawatts. Will you supply us with the equipment and we'll be going, yes, we'll let you go and arrange all the solar, the permitting, the planning, and, and the key point I think that you said what would hold it up, it's really how quickly can you deploy solar? We think our system has a sort of, because you don't need to export, you don't need to change your grid connection. We think it's probably planning related, but actually, can we, can we deploy? Is there a field nearby? Can you get the consents? These processes realistically are gonna take, you know, six to 18 months, so, you know, we think there's a relatively long, medium term lead time on a project, but those are the sort of things that would slow us down or speed us up. If someone comes to me. I mean, to give you an idea of where you could go scale-wise, alumina refining,

Tom Raftery: 27:14

Mm-hmm.

James MacNaghten: 27:14

I know this 'cause I've done the numbers you would want to put in over a gigawatt of solar.

Tom Raftery: 27:21

Wow.

James MacNaghten: 27:21

And something like 2,300 megawatt hours of thermal storage and, and some electrical storage as well. So that's, that, that would be, and there are 80 alumina refineries in the world, and they all use, basically 80% of their energy usage is steam.

Tom Raftery: 27:37

Wow.

James MacNaghten: 27:37

So,

Tom Raftery: 27:38

Wow.

James MacNaghten: 27:39

so there's anything from the small, putting a few units into actually a really big, big project.

Tom Raftery: 27:44

Nice. Nice. So are they in the same kind of 100 to 200? They must be higher. What's the the melting point of aluminum?

James MacNaghten: 27:52

No, no, no, it's not. They use the, so it's the processing of the alumina. So what they're trying to do is they're trying to separate the alumina out from the other ores. They make it into a sort of a liquor. They add it, they add various chemicals to it. And normally that's between 200 and 300 Celsius. We can do it, and for that sort of project, we would go to the higher temperature. And actually it's relatively, if it's a big project, that's not an issue for us. It just tends to be more of an issue on the smaller side. So that's, so you basically want heat in the sort of 200 to 300 C range.

Tom Raftery: 28:24

Wow. Okay. Okay. Talk to me a little bit as well about your, your funding, because I know you've gone through a couple of funding rounds and how are, how are you being funded and how is that going?

James MacNaghten: 28:36

So, thank you for asking because we are, we have, we, we went out and we fundraised a couple of times in the past, but the last time we raised around one and a half million on a crowdfunding website called Crowdcube. This was in 2021. We're back out there on Crowdcube again. So I have to say there are some risk warnings associated if you, if you assume there are risks associated with investing in companies, you know, at our stage on Crowdcube, then I've done my bit for, for, you know, the the compliance side, but we are there if you want to join us. We've got 1300 investors. We're looking to raise a similar sum to last time. And I love the fact that we've got so many investors, you know, a lot of them I know. We can have conversations. They're interested in this space. And you know, you also get the, you also get leads. People say, I get emails saying, you know, I've got a factory. We use a bit of heat, it's got a big roof. Do you wanna come and talk to us? So, so to me it's sort of, it's both a source of funding, but it's also a source of, you know, support, contacts, introductions.

Tom Raftery: 29:34

Okay. And talk to me a bit about the offering on CrowdCube. How much can I invest? What's the minimum, what's the maximum and what do I get for that?

James MacNaghten: 29:44

The minimum is 10 pounds. I'm pretty sure there isn't a maximum. Although, although if you, if you, if you invest over, I think if you invest over 20,000, we hold the, you have your shares held directly in the company. If you're 10 pounds, it's held through the CrowdCube structure. So, but in either case, if you were over 20,000, I'll be on the phone to you going, let's have a conversation. So I think, and the most, you know, I think it's rare that people go into the hundreds of thousands, I would say.

Tom Raftery: 30:13

Okay.

James MacNaghten: 30:14

But that's, that's just from experience. But, but it's, it's, we're, we're likely to go live. I think when this comes out, we'll be just about going live on CrowdCube for people to start investing properly. At the moment, you can just express interest.

Tom Raftery: 30:26

Okay. Okay, cool. Cool. And are you kind of set in stone now, pardon the pun, in terms of your technology, or do you see more technological advances in the coming years, which will, I don't know, make your product cheaper, make it more energy dense, or you know?

James MacNaghten: 30:47

All of all of that, there is a, all of the key technology bits have been solved, but when you manufacture stuff, you have learning curves. In fact, I think it's an achieve, it's, it's almost an achievement for you not to have cost reductions as you improve your manufacturing. I mean, it's, it's natural because everybody goes, you're doing this way, and they go, well, why don't we do it this way? You know, so why do I need this part? So, I would completely expect energy density to creep up. I expect cost to go down. I expect bits to be removed. You know, I expect reliability to increase. All of these things are just natural, but we are really comfortable that the core technology works and that's on what we're basically going forward from that base.

Tom Raftery: 31:32

Okay. A bit of a left field question for you. A lot of industrial things, for want of a better word, come in like 40 foot containers. Is that something you're thinking of working towards containerizing your, your batteries? They're not batteries, but they are batteries in 40 foot containers.

James MacNaghten: 31:57

No, we, we want them to be modular and transportable. We put a, we put vacuum. So one of the points we, we have both the material, we also put vacuum insulation around ours, so, and for the reason we think it's much cheaper and it's much more compact, and we found it really easy. It's worked really, really well. The sort of vacuum installation we use doesn't go into squares. It wants to be circular. So there is a very good reason these are sort of cylindrical in shape from a structural point of view. So, and what we've looked at is if you put them inside the container, you actually make your life really difficult from a servicing point of view, and you actually add cost. So while they might be transportable in a container, we're not gonna leave them in the container.

Tom Raftery: 32:40

Okay. That makes sense. That makes sense. Great. James, we're coming towards the end of the podcast now. Is there any question I haven't asked that you wish I had or any aspect of this we haven't touched on that you think it's important for people to be aware of?

James MacNaghten: 32:55

Probably just the sort of, well, I always think it's quite useful people is to understand, so we talked a bit earlier, but you know, when you look at industrial heat, there are, there are really just to say there are, you know, people ask, why don't you go hotter? So there are two other, there are two higher temperature bands that are interesting. One's at 900 and one's at 1500. 1500 is steel making, 900 is cement. And both of those temperature ranges are very technically very challenging. To store heat at and then deliver it out. So we are really, and, and then so, so there's sort of just to say there's a really clear reason. So we basically pick this range, which is above heat pumps, but easy to deliver still. And it's just a very big chunk of the market. But we aren't trying to go miles hotter. So for the 900 1500, because actually they're very, very hard to do technically.

Tom Raftery: 33:44

Okay. Okay. Fair enough. Cool. Great.

James MacNaghten: 33:47

And it's the one area steel. Steel making is the one area I think hydrogen could be very useful.

Tom Raftery: 33:53

Fair. Yeah. No, that's true. That's true. Cool. James, that's been fascinating. If people would like to know more about yourself or any of the things we discussed on the podcast today, where would you have me direct them?

James MacNaghten: 34:05

So I'd have you direct them to our website. It's Caldera, so ww.caldera.co.uk. And if you're interested in Crowdcube, there is a link on the front page of our website, or you can go straight to Crowdcube and you could register interest there. But Tom, thank you very, very much for chance to be on the show today and also to tell everyone a bit about what we're doing.

Tom Raftery: 34:26

Thank you, James. Thanks for coming on the show today. It was fascinating.

James MacNaghten: 34:30

Thank you.

Tom Raftery: 34:33

Okay, we've come to the end of the show. Thanks everyone for listening. If you'd like to know more about the Climate Confident podcast, feel free to drop me an email to tomraftery at outlook. com or message me on LinkedIn or Twitter. If you like the show, please don't forget to click follow on it in your podcast application of choice to get new episodes as soon as they're published. Also, please don't forget to rate and review the podcast. It really does help new people to find the show. Thanks. Catch you all next time.