In this episode of Hardware to Save a Planet, Dylan is joined by Claudio Spadacini, Founder and CEO of Energy Dome, to discuss the revolutionary technology Energy Dome develops for large-scale and long-duration grid energy storage.

Claudio is an innovator and engineer with a track record of developing disruptive technologies to combat climate change. He is also an experienced entrepreneur who founded several businesses in the climate tech space, including Cavaglio Hydropower, Exergy ORC, SEBIGAS Srl, and Agripower SRL.

If you want to discover more about the technology behind Energy Dome, check the key takeaways of this episode or the transcript below.

Key highlights

  • 9:16 – 15:38 – The Energy Dome’s Technology – The company uses a technology based on a closed thermodynamic transformation that enables efficient and cost-effective energy storage by manipulating CO2 between its gaseous and liquid phases. The CO2 is drawn from an atmospheric gasholder, the Dome, compressed at about sixty bar. Due to compression, the CO2 hits and exits the compressor at about 350 degrees Celsius and then enters into a thermal energy storage system, which cools down the CO2 from 350 to about thirty degrees. The CO2 is then stored under pressure at ambient temperature in a high-density supercritical or liquid state. When energy needs to be released, the CO2 is evaporated into a turbine and then returned to the atmospheric gasholder, ready for the next charging cycle.
  • 15:38 – 20:32 – Energy Dome’s Advantages – The strength of Energy Dome’s CO2 battery is that it works fully site and ambient temperature independent, which means that the system offers the same performances in various parts of the world. This is not only an advantage in terms of supply chain cost reduction but also access to the low cost of capital. In terms of renewable energy, the solutions available to us are solar and wind primarily, which are land intensive on their own. But Energy Dome’s batteries take about ten percent of the land that a total solar farm would charge. And because they’re higher efficiency, you need a smaller number of solar panels to charge the same capacity battery.


Dylan Garrett: Hello and welcome to Hardware to Save a Planet. We got to talk today about long-duration grid energy storage with Claudio Spadacini, the founder and CEO of Energy Dome. Grid energy storage is a key enabler in our transition to clean electricity generation. Renewables like wind and solar have ups and downs that don’t line up with energy demand fluctuations. We need storage to even out the supply.

This has been front of mind for many of us in California during this recent September heatwave here as the state has had to enforce blackouts and other emergency measures to reduce demand in the afternoons, as our solar farms stopped producing. This is a very timely topic. Energy Dome’s technology uses compressed CO2 to store energy. It looks really promising in terms of some of the key metrics like efficiency, cost, and lifespan. I’m excited to learn more about it.

I’m also really excited to get to know Claudio better. He’s an engineer with a track record of developing disruptive technologies to combat climate change and he’s an entrepreneur. He’s responsible for what looks to me like several careers worth of technology inventions and businesses founded in the climate tech space, including Exergy, the company focused on heat to electricity using Claudio’s invention of the radial outflow turbine and a company that drills tunnels in rock for hydroelectric power plants. Welcome Claudio. It’s an honor to have you. Thank you very much for being on the show.

Claudio Spadacini: Thank you very much, Dylan . It’s a great pleasure for me to be in this podcast and thank you very much for inviting me. It’s a great opportunity to speak about Energy Dome and our technology, the CO2 battery that we are very proud of.

Dylan: Awesome. I appreciate that and look forward to the conversation. I’d love to start actually just hearing more about your background and your path to climate tech and any major inspirations that got you here.

Claudio: Yes, thank you. I’m a professional engineer with 25-year experience in the energy sector. I started my career back in 1995 in a startup company, which developed the gasification technology for municipal solid waste to produce synthetic gas and hydrogen out of municipal solid waste. It was a high-temperature oxygen gasification process. I spent almost five years there. We built plants around the world, in Japan, in Germany, and in other places. A great opportunity to learn how to establish a brand new technology and a brand new quite sophisticated process.

Then I spent several years in the gas turbine and combined gas turbine sector. Then, in 2008, I started my first company, SEBIGAS, a company which developed a technology for biogas production from organic waste and energy crops. We deployed more than 80 plants around Italy, Europe but also in the Far East, in Thailand, and also in Brazil. Then, in 2011, I founded– I started Exergy, the company which you already mentioned, a company which developed a brand new technology for radial outflow expander used in organic Rankine cycle. Exergy has been able to deploy more than 500 megawatt of geothermal plants ranging from 10 to 25 megawatt each. This has been a great opportunity.

I left Exergy in late 2019. Together with my former CTO in Exergy, Dario Rizzi, and my former business development manager, Francesco Oppici, who are my co-founders, I started the Energy Dome. We started operation in February 2020, one week in the office and then back home due to COVID. Then we had a lot of time just to engineer our first system, which you see in the background, which is our first commercial plant that is now up and running.

Very proud that we’ve been able in less than two and a half years to start from a vision, from an idea and convert that into reality, which is a plant, which is not a demo. It’s a commercial plant which operates daily in the Italian grid and has demonstrated a technology that we feel very confident we will be able to deploy commercially in the next month, so we are on a fast track.

The best approach to identifying a good and breakthrough technology to me is just brainstorming and trying to identify something. And as soon as you get the idea, try to destroy it as much and fast as you can. If you can destroy it, you just succeed because you just save time. If you don’t, maybe you have something good to work on.

— Claudio

Dylan: That’s amazing. Yes, incredible speed to get to that point. Before we get deeper into Energy Dome, I’m just curious because you have such a diversity of innovations and businesses and places you’ve made an impact in climate tech. I’d love to know what your process is. Do you start by looking at problems in climate change, climate change challenges, and then look for technology solutions or do you start with the technology? How do you go about it?

Claudio: Thank you for this question because it’s very interesting and I can get this question from many corners. From a business perspective, I would say that the actual space, the actual market, which is energy storage is not really by accident. I was looking for a market with a potential big market, because I spent the last 10 years in geothermal, I feel we did everything very well. We have been able to develop a very strong technology, but geothermal is just difficult. It takes time to be developed. It is very difficult to be standardized. It is very difficult due to the geological risk and it’s very difficult to get scale. Geothermal will never get access to low cost of capital.

I said the next challenge– the next company I want to try to start is a company that has to participate in a potential big market like solar, like wind. When I heard about energy storage as the missing piece in the puzzle of energy transition, because there is no doubt that energy storage is the missing piece in the puzzle of energy transition, I said, “Yes, I have to look into that. I have to try to see if I have some ideas and if I can find something to participate in that space.” This is the business perspective.

From the other perspective, how to identify a good idea, how to participate in some space, my process is always to try to challenge myself as fast as I can and try to destroy my idea as fast as I can. I’m following philosophy. The best approach to identify a good and breakthrough technology to me is just to brainstorm and try to identify something and as soon as you get the idea, try to destroy as much as you can, as fast as you can. If you can destroy, you just succeed because you just save time. If you don’t, maybe you have something good to work on and go ahead. Every day just trying to identify a way to make it better and the day after, to destroy that idea.

Then if it can survive quite fast, you can just land to the right arrangement. That is what we did and together with my team that is just working in the same way. Me with Dario and all the team of engineers, we are just brainstorming, putting together ideas, and then going through and very fast. We have been able to convert a vision into a real plant just due to this and that’s the way we used it. This is our secret, if you like, our secret sauce.

Dylan: Yes, thank you for sharing the secret sauce. I appreciate it. Let’s talk a little bit about what– if you could just run through what the process is, what your technology does, step by step so people have that baseline understanding of it.

Claudio: Yes. Our process is a thermodynamic transformation, which is CO2. We store atmospheric ambient pressure and ambient temperature CO2 into a gasholder, which is a dome that keeps the CO2 at ambient temperature and pressure. From that, the compressor sucks the CO2 and compresses it to about 60 bar. The CO2 which is delivered by the compressor at 60 bar is also high temperature because due to compression the CO2 heat up and exit the compressor at about 350 degrees C, and then enter into a system, which is a thermal energy storage, which cool down the CO2 from 350 to about 30 degree by storing heat inside the thermal energy storage.

After cooling down, the CO2 is liquefied by condensing and releasing the condensation heat to a water basin. This water basin is a kind of thermal energy storage, which is an ambient-temperature thermal energy storage, which is just cheap, safe because it’s a water basin. No consumption of water, just store some heat. After that, the liquified CO2, which is very high density and low volume, can be stored in a very cheap, high-pressure carbon steel vessel, pressure tank.

In that case, this is one of the main reasons why our technology is very competitive. That is that we can store a large amount of liquid CO2 in very small carbon steel vessels, which are very low cost and simple to be manufactured. In the discharge mode, we just follow the same way, the other way around. We will evaporate back the liquid CO2 into gas by taking back the heat stored into the water tank.

Then, after being vaporized, the CO2 goes back to the thermal energy storage where the heat is released back to the CO2, which warms up to a temperature which is a bit less than the temperature during charging, so it can be a bit less than 350 degrees. Then the pressurized CO2 enters into the turbine, into the expander, which produces the power which is injected back to the grid.

The total round-trip efficiency of the system is 75% at full scale, which is best in class. I would say it is very close to the lithium ion battery’s efficiency because even if lithium ion batteries are higher in efficiency at the beginning, if you consider the full life cycle, end of life, normal lithium ion battery are changed when they reach 67%, 65% efficiency, so as an average are very close in the lifespan, which is between 3,000 and maybe, someone say even more cycle, 4,000 cycle in the lifespan. The average efficiency is not far from 75, but together with that we combine much lower CapEx in the lifespan, which is in the range of 30 years.

Dylan: You’re using CO2 and when I first heard about this, I thought, “Oh, this must be a carbon sequestration play.” It sounds like maybe it’s just a coincidence that CO2 is the villain in climate change so often, but in this case it happens to have the right physical properties for your application. Is that the case or is there some kind of carbon–

Claudio: That is just the case. It is just ironic that the fluid which is ideal to store energy because it has an excellent thermodynamic behavior and then it’s a very common fluid. It’s really nontoxic. Obviously, it is. We could also use other gas like N2O, which has the exact same thermodynamic behavior of CO2. Exactly the same. Unfortunately, that is a fluid which is a bit forbidden, let’s say.

Dylan: Yes.

Claudio: Especially, because it was used for other use in the past. Again, it’s just ironically the same fluid which is causing the problem which could be a solution for that. In terms of embedded emission, I’d like to stress a bit that our system, first of all, is done only by steel and we need some water, no continuous consumptions, just a first filling. Then we need just a first filling of CO2. No rare earth material, no rare metals. That is a huge advantage.

Then, in terms of embedded emission, we have embedded emissions which are much lower than lithium. Moreover, we aim in the future to charge our system with CO2 which is coming from direct air capture or maybe capture beyond the geothermal plant. Using these as a negative, we want to start with a negative emission of CO2 in this system on top of the CO2 reduction that we will cause by storing renewal.

Talking about the carbonization of the planet, we can approach the issue in two different ways. The first could be nuclear fusion, which, in my opinion, is good and will happen somewhere in time, but definitely not tomorrow. The second solution is renewable. But the missing piece of the puzzle is energy storage.

— Claudio

Dylan: Interesting. You mentioned total round-trip efficiency, lifespan, I’m curious about all these metrics that are really important to this type of storage, how it compares to other options. I guess another thing that seems like an advantage is site specificity. Is there any restriction on where this could be built? Whereas some of these other options do have site specificity, like I’m thinking pumped-storage hydro or compressed air uses underground storage, how does that look for Energy Dome?

Claudio: Our strength and the strength of our product, the CO2 battery, is that we are fully site independent. Moreover, very, very important, we’re ambient temperature independent. It means that the system can work exactly with the same performances in summer in Texas or Arizona or in winter in Alaska. This is key to unlock the possibility to deeply standardize the system. We can exactly deliver exactly the same catalog. From the same catalog, the same product, we are developing one size of CO2 battery right now. The second will be available in six months and then the next year we will maybe have a catalog of five or seven different models, like a wind turbine OEM.

We compare ourselves to a wind turbine business. We want to offer a machine and the CO2 battery which can be deployed exactly in different areas. This is not only an advantage in terms of supply chain, cost reduction, which is indeed a big advantage in terms of cost reduction and supply chain, but is also potentially a big advantage in terms of access to low cost of capital, which has been the key to success for solar PV and wind.

The issue that we have is the decarbonisation target. We can reach that target in two different ways, in my view. The first could be nuclear fusion, which in my opinion is good and will happen somewhere in time, but it’s not tomorrow. It’s definitely not tomorrow. The second solution is renewable, but there is the missing piece of the puzzle, which is energy storage. We need energy storage. We need energy storage to produce baseload wind power. If you look at our system which is not, again, best in class on length of usage, but we have very high efficiency.

If you look at the space you need to install the solar PV plant that you need to charge our system, it’s much smaller. Let’s consider that we want to build a system which discharges, I don’t know, 20 megawatt for 10 hours. Having 75% efficiency, we need a solar PV plant which is 27 megawatt for 10 hours, for example. If you compare us– and that system is big, I don’t know, 25 megawatt, 27 megawatt of solar, how many acres or hectares?

If you compare us with another technology like CAES, which declare 60% in some case or Highview, which declare something like 50% or Malta, which is something like– with other solution, which have a lower round-trip efficiency, they need more than 50% more solar PV space than the space we need for the CO2 battery is just 8% of the space you need for the solar PV which charge our system.

Obviously, we are not the technology that is best to be installed in the center of the city, but since energy transition is about a lot of deployment of solar PV plants and wind farms, and we need a lot of space to deploy that generation because renewable is a distributed way to produce power. Inside that infrastructure, there is 10x the space. We need just 1/10 of the space or less to install the storage device which is needed to transform that peaking generation.

The energy market is just technology constraints. The breakthrough technology to unlock that market could open huge opportunities.

— Claudio

Dylan: Yes, that makes a lot of sense. Maybe just the last way to look at it, I guess, would be in terms of the levelized cost of energy storage. Is that a metric that’s important to know when looking at this?

Claudio: Yes, obviously, those parameters are always very, very much dependent on the assumptions. We have always to be very careful to say, including the cost of capital, which is not really something which is merging into that. Our technology, we want to achieve a levelized cost of storage, which is below the 5 cent per kilowatt hour, let’s say 5 to 6 cent per kilowatt hour based on the assumption that we will be able to deploy several dozens at least of unit per year, which will allow us to get access to the right capital. I think that this is just a process we are undertaking.

We have been able in two and a half years to have a commercial plant, which is not good size, but it’s 2.5 megawatt and 4-megawatt hour. Now, we have already issued the purchase order for the turbo machinery for the full-size commercial plant, which is 25 megawatt, and do 200-megawatt hours. We see that there is plenty of potential opportunity. Again, we are bidding based on the price, efficiency, and the lifespan. We leave our potential customer to run the business plan for their case study.

The feedback we are getting is that there is an incredible interest because they really see that with our technology, many projects which were simply not feasible are becoming potentially very remunerative. This is the competition. The competition is versus the business plan of projects which are not feasible today due to constraints and to the available technology.

Dylan: Right. Let’s talk about the business model a little bit. It sounds like your plan is not to build and operate these plants yourself. You’re selling to energy operators. Is that right?

Claudio: Our business model is we don’t intend to own and operate the plant. We intend to try to deploy in the market as many CO2 batteries as possible, which are all identical in order to get that scale to the standardization, which again will allow us to benefit from an economy of scale. In this respect, I want to say we don’t chase an economy of scale to become competitive. We are already competitive with the first-of-a-kind.

The first-of-a-kind CO2 battery based on the existing price of off-the-shelf components, which we receive from the supplier, results in the total cost if fully PC, fully installed cost of the CO2 battery, which is at least 30% less than the turbine combined today. Then to economy of scale, we are envisioning to reduce that cost and our price even further and very fast. When we reach an economy of scale of just 10 plants per year or 12 plants per year, our supply chain will be available to deliver at much lower cost and shorter delivery time. This is very important.

There is another important parameter in that. As soon as we are able to deploy several dozen plants, also the cost of capital associated with that asset will be much lower. This is a very, very important parameter because maybe 2% or 3% difference in the cost of capital makes the difference over 30 years. We are concentrating ourselves on this and we see our customers in companies like large IPP or utilities. We are bidding on quite a lot of projects right now. Also in the US, we are just trying to enter into the US market. Yes, this is our approach.

Dylan: On the technology side of things, where have you had to innovate? It sounds like you’re able to use a lot of existing supply chains and off-the-shelf compressors and things like that. Have there been any big technical engineering challenges you’ve had to overcome?

Claudio: I think that the process itself that we have identified has a lot of features. The control of the process has a lot of features. The detailed design of all the components have been done and done very successfully. We can say because now we have all the tests and reports also from third parties of the working plant. We have been able really to best sell the heat exchangers, the compressor and expander, valve, piping, electrical motors. Everything exists, but you have to make them to match in the right way.

We have plenty of intellectual property applications because we have identified a new process, which is proprietary. New control of the process, which is proprietary. A way to combine the component and to design the component that realizes that process which is proprietary and is working really very successfully. The strength we have is that we have been fast and been able to achieve that point in just two and a half years.

Now, we have a technology which is working commercially, is protected, is proprietary, and has a very huge potential to start from very competitive costs, but through economy of scale and penetration in the market, it can achieve extremely low cost, keeping very high efficiency and long lifespan. That’s the itinerary that we have in front of us. We see in the US and North America a very nice opportunity that we can– and we want to be there. We’re just raising additional money. We are in capital raise mode because the company is growing. The company is really going fast.

Dylan: What do you think Energy Dome will look like in– and I don’t know if it’s 5 or 10 years out when you get to that steady state vision, what does that look like?

Claudio: My idea and my target, the dream is to have the dome to be the icon of the energy transition space. If you Google right now renewable energy, you see a three-blades turbine, that is the symbol of renewables. We aim to be impactful. We aim to be everywhere. We aim to have the dome, which is quite an icon, to look like an iconic symbol of the energy transition. To be that missing piece in the puzzles of the energy transition.

Dylan: That’s awesome. I have to say, and we’ll put some links to pictures of everything because it is a really iconic design and visual. I love the dome. I also love that it has a tie to your background in biogas. It’s really interesting how those things tie together. Just quickly on that, is it important that it’s a dome? Mechanically, does it serve a certain purpose as that dome shape?

Claudio: It’s important because it’s cheap, and is very fast to install. We can install these in a few days. It is relocatable, fully based on prefabricated and renewable foundation. If we have to move– It looks like we use the reactors of a plant. If we have to dismantle all the foundation of the dome or just relocatable, let’s say preassembled and prefabricated, so no problem. It’s a smart solution. It’s cheap, is safe, and is symbolic. I have this feeling and also talking to people that the new generation really cares about the environment, about pollution.

If you have something, which is also visible, but you know that that is important, is impactful to make the world greener, this will be accepted by the new generation. If it is big, it’s not important. It is what it’s there for and is that for producing baseload wind power? That is something that the young generation just understands. I got a lot of bad words about wind turbines in the past. Here in Europe, a lot of people are against it due to visual impact. Now, there is no one in the new generation which takes care of that. “Okay, this is a wind turbine. This is green. This is good.” That’s it. I feel that when I speak about an icon in that energy transition it’s because we need to recognize which technology in the asset which can enable that transition. I feel that the dome could be one of those.

Dylan: Yes, I love it. You mentioned fusion earlier. Do you think there’s a future? I don’t know how far out it would be that we don’t need energy storage like this because we have some clean renewable baseload energy like fusion or geothermal or something?

Claudio: I think that the progress, that the innovation now there is an incredible deployment of not only capital, of good people, which is trying into that sector. I don’t think that there is a reason why not to succeed. It is quite a long path because, again, simplicity is the arrival point. At the beginning, nuclear fusion is not simple because you have something like 4,000 degrees C or 5,000 degrees C to be contained in a space. Cannot be done simple. I think that it’s just a matter of– It will take some time. I thought for quite a long time, but I don’t know.

My opinion is just that now the transition is really urgent because a decision has been made, all the financial institutions don’t deploy any more money to people who want to invest anymore in coal or things like that. The transition is just urgent and we need to give answers now. The CO2 battery is a solution today. Nuclear fusion can be a solution in 20, 30 years. As an engineer, I like to build up my opinion. I spent some time looking into the different nuclear fusion technology, to build up my opinion, and this is my opinion.

Dylan: If there’s anything I’ve learned talking to everybody about climate change it’s that we don’t have time to wait, we need solutions now. It sounds like you’ve optimized for that in a really smart way. That makes a lot of sense. I think that’s a good transition to the last few closing questions. How optimistic or pessimistic are you about the future of our planet and why?

Claudio: I’m a bit skeptical about the real capability to get to the target, which has been set by 2030 and 2050 to be very realistic, but it’s also worse to have a target, which is a bit beyond what I feel is the real target. I feel that to get there we really have to be very straight and we just need to deploy renewable and long-duration energy storage. Quite frankly, obviously, I have an interest in that because I believe that we have the right technology, but I don’t see any other possibility to get the transition to happening.

On the other hand, I’m positive because I really see that all the world is moving really fast in that direction. All the financial institutions are putting a lot of money and a lot of effort. I really feel that we are in an acceleration phase. I’m quite positive. I feel that we will not get the target, but we could be close if we don’t lose time.

Dylan: Who is one other person or company doing something to address climate change right now that’s inspiring you?

Claudio: I don’t want to mention a specific company or a specific– There are few which I have in mind, which I really like, but I wouldn’t like to mention one or the other.

Dylan: Sure.

Claudio: I just think that there are incredible investors which are putting money and which are taking some risk. It’s even at this moment in time where the financial market are very difficult. I see a lot of investors which are very much interested to support those verticals like us, long-duration energy storage or like hydrogen, which are the main verticals that have to be financed to find solutions to accelerate the transition.

Dylan: That capital is really important. The last question is, what advice do you have for someone who’s not working in climate tech today, who wants to do something to help?

Claudio: Is to try to be really impactful and to think big, because everything is changing and the transition is really deep and is really something which is going to change very deeply the way we are doing things. The only way to make an impact is really to think big. We have to try to get to something which is really 5x better than before. I always like to demonstrate that the circle is round. I never accept from anyone that by definition it is like this, just to challenge everything which is maybe just said, “Okay, this thing has to be like that.” Just try to find a new solution or understand why it’s done like that. If you understand why it’s done like that, then maybe you find another way to do it, which is better.

Dylan: I love that. Think big. I think you’re setting a really great example of doing that yourself. Claudio, I really appreciate the opportunity to talk with you. I learned a lot today and I’m inspired by what you’re doing. Thank you very much.

Claudio: Thank you very much, Dylan, for the opportunity. It was great to talk today. Thank you.

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