In the quest for sustainable energy solutions, EarthEn stands out with its approach to energy storage. Co-founded by Manas Pathak, EarthEn has developed a novel thermo-mechanical energy storage system that leverages carbon dioxide (CO2) in a closed-loop cycle. This innovative technology promises to store energy efficiently and at a low cost, with the flexibility to scale from 4 to 100+ hours of storage.
In a recent interview with TechNews180, Pathak provided insights into how EarthEn’s technology works, its advantages over traditional battery systems, and the potential impact on various sectors.
Neil: Could you just provide an overview of how EarthEn pods work and explain the role of carbon dioxide in your energy storage facility?
Manas: In simple terms, our systems are called thermo-mechanical energy storage. There are two terms here, thermal and mechanical, and you will know why we call it thermo-mechanical. If you look at the physics, the way the battery, call it CO2 battery or just thermo-mechanical carbon dioxide battery works is you take a lot of CO2 and you compress it when you want to charge our system.
As you compress the CO2, the temperatures and the pressures of CO2 go up. The temperature goes up and that's called thermal, and the pressures go up, that's called mechanical. That's why the name, ‘thermo-mechanical’ CO2 based energy storage.
When the sun is shining and the wind is blowing, you would want to charge the system by compressing a lot of CO2.
When the sun has set, the wind is not blowing, and you want the energy back to the grid or to the factory floors, the pressurized CO2 picks up the heat, becomes hot again, and then the pressure and heat differential spins a turbine, much like how steam turbines are spun. The spinning of the turbine, this is a CO2 turbine, produces power that goes to the grid. CO2, in turn, never leaves the system, but goes to the low pressure tank. It's a closed loop CO2 cycle.
Neil:You mention that Earthen pods outperform traditional battery tech. Could you elaborate on how they do this and how this translates into real-world applications?
Manas: One, the round-trip efficiency for systems is close to 78%, which is a reasonably high number compared to the other technology types in this segment.
Number two, the main value proposition for our customer is that our systems can grow with the increasing requirement of durations in the grid. What it means is a customer can sign up and have a product delivered to them, say, at a one megawatt, 10-hour system. If they want to go from 10 hours to 20 hours in two years, because they have more solar and wind in their portfolio of generation, and now they need a longer duration energy storage battery, you don’t have to buy two of those. In typical batteries, if you're going to go from a 10-hour to a 20-hour system, you just buy two of those 10-hour systems. In our case, when you want to go from 10 to 20 hours, a longer duration, you just pump more CO2 into the system.
That's it. You just bring a few more tanks and retrofit an existing installed product, and now a 10-hour system becomes a 20-hour battery. This ability to future-proof the requirements of the customers, serves the key pain point where in the future the longer duration would be required, but the same technology you're installing today cannot fulfill that longer duration, so you have to buy many of those or something different.
The fact that we can go and retrofit and upgrade those systems to a longer duration is the biggest value proposition that we have.
Neil: One of the other unique features of the tech lies in its ability to scale energy independently. Can you explain how and why that's important?
Manas: Yeah, so the other benefits of our systems are it's very compact because the CO2 in our systems is not gas. It's a liquid to supercritical form. That is the kind of CO2 which has water-like densities, a very dense form of CO2. This density of CO2 being higher translates to higher energy density, which in turn translates to being a lower footprint on the ground.
So now we have these compact systems in something like shipping container form and being modular, you can just replicate and install many of those as the demand increases in the future. For example, there is no geographical constraint to our systems. If you look at compressed air energy storage, when you compress air, you need to have these large caverns under the ground in order to store the compressed air. That’s not scalable.
We don't have those problems. We store our CO2 in tanks. So the geographical constraint is not present.
Neil: How does using carbon dioxide in a closed loop contribute to environmental sustainability and what are the long-term benefits of deploying the pods widely?
Manas: CO2 is a public enemy right now. What we are doing is using CO2 to help curb climate change, turning OC2 into a public good. So the CO2, which in the atmosphere is creating a problem, but putting it in our systems is actually helpful because it's a carbon utilization play. So one megawatt hour uses several tons of CO2.
This CO2 is locked basically for the lifetime because these systems last 30 years and then you can keep reusing the same CO2 upon decommissioning.
And so there are two benefits. Number one, being any energy storage system, you are enabling more renewables in the grid. That's common for everybody, whoever is an energy storage player.
Because if you can store energy in the day and use it in the nighttime, now you're enabling more renewables and more solar and wind to come online. But the fact that we have on top of just enabling renewables is the scalability, the modularity, and then you can site these systems anywhere. So now you don't have the constraint of like having to have a hilly region in order to install a pumped hydro system.
And then lastly, we do use CO2 in a closed loop So the fact that the CO2 can be used in a closed loop system and it's locked away is a carbon utilization play that helps with further elevating the concerns of having carbon dioxide in the atmosphere, which you are putting into better use.
Neil: What challenges and opportunities do you foresee in terms of market adoption for your solutions and which sectors are showing the most interest?
Manas: Long-duration energy storage is still a sector that is just getting started. There are not many pathways of revenue generation as it stands today. They are limited. However, the market is quite rapidly shifting and we see specifically in the markets where you have commercial and industrial customers wanting to have the ability to be not reliant on the grid, to have the ability to generate and store their own power. For example, it's the same scenario that you look at when you have a residential solar up your rooftop. You know, the sun is shining, you have it, but what do you do in the nighttime? You've got to install something in your garage as a battery. These big commercial and industrial customers have the same problem. They can rely on solar and renewable grid in the times when they're active, but not in the times when they are not active. So we foresee a C&I space as being one of the early users of long-duration energy storage.
We also foresee what's called the 24-7 renewable PPAs (Power Purchasing Agreement). There's a new trend in the market where the big enterprise customers who have the mission of getting net neutral in foreseeable years and decades are asking for 24/7 green PPA. You can't have a 24/7 green PPA where every hour you're getting a green energy, unless you have long-duration energy storage.
The utility sector is also very keen and interested in piloting many of these long-duration energy storage technologies today, because everybody is understanding that come 2030 and 2035, there would be a strong and a very imminent need of longer-duration energy storage. At EarthEn, we have flexible duration because we can do small-duration and long-duration, which is what our key value proposition is. But in general, the market for long-duration storage in the utility sector is growing. You see these RFIs and RFPs coming out from the big utility customers in the U.S.
Now, we have one additional unique market just for our product. And that market is the oil and gas, CCUS hubs, and hydrogen hubs. Let me explain how. The reason is because what our technology is, we have a two-tank, a low-pressure and a high-pressure tank, and we toggle the CO2 between these two tanks to charge and discharge the system. It just so happens the low-pressure tank can also be replaced with a CO2 pipeline. So, everybody who owns a CO2 pipeline, we can treat it as a low-pressure tank, retrofit our systems onto it, and now you have a CO2 pipeline being converted into an energy storage asset.
Our oil and gas customers have CO2 pipelines today. There are CCUS hubs in the U.S. which are coming that have CO2 pipelines in the horizon, and all blue hydrogen developers would have CO2 pipelines as well. All of these CO2 pipelines can be converted to energy storage to power the very assets the CO2 is coming from, or use the power anywhere in the vicinity of the pipeline. Or send it back to the grid. This market is only earthen-specific because nobody else can basically do what we are doing and can convert a pipeline into energy storage.
There are a few more customer segments like solar and wind farm owners or wind farm developers that are looking to install a longer duration energy storage versus just a four-hour or six-hour lithium-ion battery. But in a nutshell, these are all the segments which are opening up for us.
Neil: Looking ahead, what are the next steps in terms of technological development and expansion?
Manas: We have proven our systems and labs, which means the physics works. We will have yet another demonstration at a slightly higher 10x scale-up coming end of this year in a national laboratory here in the U.S. The Department of Energy National Laboratory is called Oak Ridge National Lab down in Tennessee. And then beyond that, we have two pilots that we are working towards. These are megawatt-scale pilots that will be installed and constructed in 2026.
Neil: What do you envision your impact on the energy landscape in the next decade to be?
Manas: So what EarthEn is, we are an electrification company. We are starting off with energy storage. What we are really after is harnessing the power of sCO2 or supercritical CO2 molecules to electrify every opportunity of electrification.
For example, you have heat coming from geothermal, heat coming from nuclear, heat coming from waste heat. All of this heat can be converted into electricity using a supercritical CO2 power cycle. The first go-to market for us is long-duration energy storage, but that's not it.
So we foresee making two parallel impacts by the end of the decade in the energy landscape. Number one is bringing our safe, flexible duration, geographic agnostic energy storage system that is very highly efficient, modular, and ready for scale to the market at the scale that is needed, which is 100 megawatts and beyond. That will help enable a more renewable grid, not just in the U.S., but across the globe.
And also, decentralizing the electricity by enabling every heat pocket; waste heat, geothermal, nuclear, wherever there is heat, you would electrify it using SCO2 cycles. So you will have basically a decentralization of the grid because the heat pockets are already decentralized and you are converting them into electricity. So a decentralized electrification is the need of the hour and this is what we would enable in the second parallel effort.
And our first effort, which is energy storage, would enable and add to the second effort.
Conclusion
EarthEn's cutting-edge energy storage solutions represent a significant step forward in the transition to a more sustainable and resilient energy grid. By utilizing CO2 in a closed loop, EarthEn addresses both energy storage needs and environmental concerns. As Manas Pathak envisions, EarthEn's technology will not only support the growing demand for renewable energy but also pave the way for a decentralized and electrified future, harnessing every opportunity for sustainable power generation.
