Can This Innovative Tech Solve Our Energy Storage Dilemma?

Welcome to the CTRL+Listen podcast brought to you by Octopart. In this episode, host James Sweetlove interviews Mark Swinnerton, the CEO of Green Gravity, a company pioneering the use of gravitational energy storage to support renewable energy solutions. Discover how Green Gravity is transforming legacy mine shafts into mechanical batteries to provide sustainable energy storage solutions.

Episode Highlights:

How gravitational GREEN ENERGY STORAGE works
How reusing legacy mine shafts help solve the ENERGY STORAGE DILEMMA
Comparison with traditional battery technologies
The potential impact on renewable energy and the energy grid
Future prospects and government support for Green Gravity

Links and Resources:

James Sweetlove: Hi everyone. Welcome to the CTRL+ Listen podcast brought to you by Octa Part. I am your host, James Sweetlove. Today we are joined by Mark Swinnerton, CEO of Green Gravity. Thank you so much for coming on the show. Great to have you here.

James: Anytime. Just to get started, do you maybe wanna tell people a little bit about yourself, a bit about the company, if they may not know anything about it?

Mark: Oh yeah, look, my name Mark Swinnerton, I have a background in mining and in fact I did 25 years in mining before branching out and wanting to work much more directly on climate. And I'm the founder and CEO of Green Gravity and our business repurposes legacy mine shafts for gravitational energy storage. And what that means is we, we find legacy mine shafts and we go about lifting heavy objects up the mine shaft to consume electricity at one point in the day. And then at another point when we need it, we lower those objects again to regenerate. So typically we're able to assist solar energy at dispatching when it's needed.

James: Fantastic. So in simplified terms as kind of like a new sort of battery technology?

Mark: It is, yeah. It's a mechanical battery and you can think about a technology called pumped hydroelectricity, which has been around for hundreds of years. And where we pump water to the top of a hill during, you know, using excess energy and then lower it back down again to run a turbine when it's needed. We're very similar, but we use a legacy mine staff and we don't use water.

James: Yeah, I mean you guys kind of have an established infrastructure that you're just adding to as opposed to constructing from scratch.

Mark: Absolutely. Core to what we're doing. You know, we wanna reuse the infrastructure and there are thousands and in fact hundreds of thousands of legacy mines out there in many countries. And so we've set about a mission to try and reuse some of that infrastructure and do it in a way that's gonna support renewable energy.

James: Yeah, I think it's kind of ironic as well that's something like a mine, which is tied to fossil fuels is now being used to work with clean energy in its second life.

Mark: It's absolutely fundamental. I mean, we're working in a number of coal mining jurisdictions where those mines are still closing and what we're able to do is offer a new pathway for closure where we can create jobs at investment in that coal mining area as it's stopping its coal mining and it can come up in renewable energy ranks. And so it's, it's such a pleasure.

James: Just looking at those mines. What would be the alternative? So say, say they didn't go with something like this, what would they do with a mine like that? Otherwise they?

Mark: Fill them in. So, so ultimately in almost every jurisdiction what happens is the mine gets to a point where they go and they dig more dirt and fill the hole in and pull all the infrastructure out and scrap it. And so we offer this alternative. It says, rather than go and do all that extra work and rip out all of what was built, yeah, we just, we can keep a lot of it there and find a way to reuse it for this purpose.

James: And fascinating. And obviously with mines you've got those built in quite remote areas generally, so I'm sure there's opportunity to have renewable energy infrastructure built near that storage, like say solar or wind power or something like that.

Mark: There's absolutely that. And, and one quick point I'll make is that there are so many mines out there right there through the United States of America, but also through Australia and, and lots of jurisdictions that we're working in there are such a, a number of mines. They're actually not all remote. There are many mines that are right next to urban areas that we don't even know are there. And so for example, near Sydney, I'm in Sydney today, we have nearly a hundred mines within a hundred kilometers of Sydney. And so these things can be built, this is deployed in areas where there's large demand, but also as you say, we can, we can install the infrastructure in areas where we can add a lot more renewable generation. And what that means is we can firm the renewables at source, which means we can lower the investment needed in the transmission grid, which means we need less copper, we need less critical minerals to achieve the same outcomes. So we can have a real benefit in that area as well.

James: Yeah, I mean I know there's a lot of people who are skeptics of a green grid and I think a lot of that fear or skepticism comes from storage issues. So I think that nailing something like this would go a long way to actually winning people over to that sort of end generation.

Mark: I look, I think there's a, there's a lot of challenges in supply chains as you say, and we need more solutions and our technology is one that's, it kind of just can come back in and reuse we we've already done and we can do it at real scale. So it, it changes the dynamic on the renewable energy transition. It reduces the cost, it reduces the environmental impacts 'cause we need no new land, we don't need water resources, we don't create any waste. So this is a genuinely sustainable way of, of giving renewable energy a huge boost up to become round the clock energy. And so ultimately we can turn the coal power stations off and generate solar at night using technologies like ours.

James: That's awesome. You said that it, it can be built close to urban areas. What's the sort of scale and size that's needed of a mine shaft to be able to construct something like this?

Mark: Yeah, really significant. So right here in sort of southern Sydney area, we have about 45 legacy coal mines and those are say 500 meters deep. So they're very deep. I mean, you think of the Empire State Building isn't 500 meters tall and so these shafts are all right in the urban area. If we took two of them and we we commercialized of shafts, a pair of shafts could have as much as 50 megawatt hours of energy, which is really significant. And up there with the biggest of the, the big batteries until there's the most recent ones are coming through. So that's the kind of scaling. And if we talk about that, that's tens of thousands of powers powered through the evening peak through one pair of mine shafts. But if we get out to, to areas and it's depending on how the all bodies were, where they're deep and there in many parts of Australia that we're working with, now that the mine shaft holders where the shafts are over a thousand meters deep in that environment, we can store hundreds of megawatt hours in shafts. And so really stepping it up to firm, firm large quantities of renewable energy.

Mark: It is our physics, our physics adheres to the year 11 textbook and it's, the amount of energy we get is mass times high. And so for the same amount of money we spend on a mass, if we have a a mine twice as deep, we get twice as much energy for the same capital.

James: Fascinating. With the actual technology itself, do you wanna go maybe a little bit more into how it works exactly what, what what is moving up and down to generate that energy and install that energy?

Mark: Absolutely. The first important thing is that we, like any battery system, we operate the, the device either charging or discharging, not both. So we don't take masses up and down at the same time. That would be, that would be counter to to its purpose. So what happens is if we are charging the system, we progressively lift masses up the mine shaft, we do that using a special gripping system and very dense weights and we do it then using a standard winch. So we manufacture a winch and a regenerative electrical motor like you find in your electric vehicle. And so what happens here is we energize the motor using solar energy, could be from the grid or from a local source, and we then lift those objects up the shaft this effectively consumes the electricity, but at the same time increases the gravitational potential of the masses because they go higher. And so we sit those masses in the lay down area at the top of the shaft and then we can wait. And the good news is, compared to many other battery systems, our system doesn't reduce its capacity with it as a function of time. And so it doesn't leak the same potential energy is there tomorrow as it is today, or more importantly this evening for dinner as it was at lunchtime when we lifted the weights up when there was excess solar. Now at dinnertime there's no solar, the grid is crying out for renewable energy, the prices are higher than they were earlier in the day. And now we take those same masses and we start to lower them back down. And because we have an electric regenerative motor attached to the winding system, it's able to act as a generator. And so as we break the descent of the mass going down, it generates electrons back to the grid and now we're generating again and hence we've created this energy storage effect.

James: Wow. I mean you made it sound so simple, but it is quite impressive that you guys have come up with something like this. It's,

Mark: Yeah, done. It's simple, but we've had to do a lot of work to get to simple Of course. So there's a, there's a lot in howJames: Wow. I mean you made it sound so simple, but it is quite impressive that you guys have come up with something like this.

Mark: Yeah, it’s simple, but we’ve had to do a lot of work to get to simple. There’s a lot in how we get the engineering to function correctly, but it is something that indeed is a simple concept and people can absolutely understand it. There’s nothing hidden here. This is exactly how it works. And it’s fantastic because each of those parts we’re able to reuse. Yes, we bring in some new motors and so forth, but fundamentally the mine shaft was there and rather than go fill it in, we can now make it pay back for renewables for the next 50 years.

James: No, that’s awesome. Love that. What is the government buy-in on this sort of thing? Are they seeing the value in this?

Mark: Yeah, we’ve got really strong support. We’ve been working carefully in Australia at the federal and state levels. We’ve got strong relationships and strong support. That includes looking at the government-owned portfolio of mines because, of course, in every country the government ultimately ends up owning a lot of the old mines. So that’s one angle. But the second angle, of course, is the kind of jobs and economic benefits that we can create while we’re enabling renewable energy uptake. So we’re having really good relationships starting in Australia but also already in many countries where we’ve had excellent dialogue with the federal government of India. And I’ve been there multiple times now with a number of the key ministries and they’re very supportive of the potential to bring the technology to make a huge change in a market such as India. But we’re also currently in Eastern Europe and we recently, in recent months, announced a strategic relationship with the federal government of Romania where we’re working with the coal company CVJ in the Jew Valley of Central Romania where there are 17 mine shafts currently closing. And we’re working with the local community and right through to the federal government to find ways that this technology could change the dynamic on that, the economics, jobs investment and renewable energy for that region.

James: Wow. With the manufacturing of these parts, is that something that is done in Australia currently or is it done somewhere else and then brought to Australia?

Mark: Yeah, so some of the parts, particularly motors, we’re bringing into Australia, but most of the other components we’re able to manufacture in local regions. So we’ve got contract manufacturing partners that we’re stepping up plans with, including in North America. We’ve got some fantastic partners in North America that are specialist suppliers for elements as we do in Australia and Europe. We believe that as we scale the technology, there are so many mines and globally millions, we can create local manufacturing jobs in regions because we don’t want to have to transport the parts very far. That’s both costly and carbon-intensive to many elements of this we can produce close to destination and therefore we get manufacturing jobs, engineering jobs, operational jobs in regions that really need it.

James: Yeah, I mean I think a lot of companies are trying to do the same thing these days since Covid. Things in the supply chain have been a whole different ball game for everyone.

Mark: Exactly. It’s a big issue. Look, we don’t need the critical minerals. A lot of our parts, you know, they’re either steel-based or, you know, there’s stuff that you can get in local countries. And yes, there’s a couple of specialist things like the electric regenerative motors that we do need to think carefully about the supply chain, but we are working through that with a variety of regions and we think this really offers something in the energy security space essentially where we go through a transition, there’s a lot of need to bring these supply chains up, whether that’s lithium, whether that’s chromium, all of these areas. I think we offer a really interesting hedge to energy security where we can quite domestically support countries.

James: Yeah, I think the way it’s developing is we’re going to need a diversified grid, the more options we have in fallbacks and different operating styles, the better because it’s really hard to predict what’s going to happen in the next sort of 20 to 30 years with that energy sector.

Mark: Absolutely. And distributed energy is, there’s no doubt we’re getting a more distributed, more fragmented grid in every major electricity grid and our technology is super interesting because there are so many mining assets and so many of them are connected to the grid. This is something that I think has been very interesting. We’ve found 85% of the sites that we’ve been to and examined are grid-connected, often with a latent grid connection doing nothing in a world where people are screaming out to get connected to grids. And actually what we have is thousands and thousands of connections sitting idle at mine sites. So we’re able to repurpose the grid connection itself and connect back in and make a distributed energy effect by putting five or 10 megawatts maybe rather than huge quantities, which we can also do, but we can actually have a distributed set of storage assets through the grid, which helps reduce volatility and increase reliability.

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James: What are you looking at sort of roughly as a construction or setup cost for one of these sites?

Mark: It’s really effective cost because we’re able to effectively get a subsidy for a lot of the bits and the construction because a lot of it’s there. And so, you know, it’s competitive today with lithium from a capital perspective already. And we think we’re going to, over the coming years, despite the fact that we know lithium-ion costs are going to come down and that’s what’s the leading proponent for energy storage in the main grids today. We know its costs are going to come down. We think ours are going to come down at the same rate or faster than lithium-ion because we’ve got a learning curve as well. We’re early on our journey and we’re going to get better and better. So I think because we are able to see a capital subsidy from the reuse of infrastructure and also because we’re able to have a very long asset life that doesn’t degrade, we’re able to see a really, really attractive cost. So materially lower costs on a levelized cost basis, so a total economic cost basis than other competitors because of that real long life. So we can just sort of pump electrons through for many, many decades.

James: Yeah, that’s awesome. And you can kind of just swap parts out as you need to, I guess. You don’t have to actually absolutely take out a battery or something that degrades over time like that. They’re so complicated and expensive.

Mark: So, and it’s waste for those ones, right? So you want to degrade the chemicals, you’re then going to deal with the chemical at end of life. If we were to swap a bit out, maybe it’s a rope and we say, look, okay, the rope’s now worn to a point where we’re going to switch it out like any lifting gear. Go and find a crane at some point in its life you’re going to change this rope. We just bring another rope in and change it out and then we can recycle the old rope because we’ll still go back into a steel furnace. So I think we’ve got this amazing ability to change the waste dynamic here and not create wasted end of life that someone, a future generation, you just worry about that waste. No, we’re already embedding the ability to have no waste and to generate no progressive waste because we have no fuel, 'cause gravity is our fuel.

James: Right. I think it is interesting because it’s kind of being a look back at technology, we said we don’t need that anymore. That’s now coming back. I saw they’re looking at putting massive sails on ships but like advanced sail technology again. Yeah, that’s awesome. Using gravity again. So I think the technology’s at a point where we can harness things we’ve already had for a long time but make it more effective and more efficient.

Mark: Well, absolutely. Like the 1600s that had a grandfather clock sort of, you know, appeared and it effectively used gravitational energy storage through the pulley. You pull these weights up and it slowly declines and runs the clock overnight. So, you know, the concept isn’t new, we’re not able to patent the concept, but what we can do is patent the components that are really important and the technologies that we’ve brought to bear. I mean, we’re working extensively with Nvidia and, in fact, we were featured in their CEO’s address a couple months ago in Santa Cruz as one of the startups that is taking advantage of the Nvidia omniverse to be able to rethink the way we do our engineering, get our performance up and our costs down. And so we’re taking cutting edge technology and applying it to what is nominally an old concept. And then we’re able to use the state-of-the-art regenerative motors and technologies in the electrical space to bring this to life in a modern world where we can now bringing renewable energy down the cost curve and bringing it up in the quantities that are there.

James: Right, exactly. It's one of those things as well. If you tie this in with what's being generated, you get a truly green grid. Because at the moment if you are using a battery system that's not fully renewable, that's got waste, that's got recyclable components, you're using rare earth materials, but yours is genuinely green.

Mark: Yeah, absolutely. I couldn’t agree more. We work extensively on how to make sure that we don't accidentally create a problem by thinking we're solving one problem but creating another. You could easily put so much carbon dioxide into the technology that the amount it saves through turning coal off doesn't help, and so that's not us. What we are doing is working carefully to have low amounts of carbon in the process, low waste streams, so that we are extremely stable and extremely scalable. With nearly 900,000 legacy mines in the United States, it's an extraordinary potential to be able to connect across the entire country and to realistically produce long-duration storage that runs renewables through the night reliably.

James: I think that's sort of been the issue that the electric vehicle industry's been facing is that yes, energy is much more eco-friendly and green than fossil fuels, but the manufacturing and recycling of those components is where we're entering a whole different range of issues.

Mark: I think we're gonna go through waves of this and the first wave is we're getting these technologies forward, but there's some downside to them. Now we're gonna get another wave where new technologies like ours are coming through to say we can supplement or replace certain components to make it even more sustainable. So that when the end point is here we go, this isn't just an industrial revolution on change, this is a complete change to the way our energy economy works and it's something we can be proud of. We know that it's going to be sustainable going forward and our kids aren't gonna go, "What did those guys do?" They're gonna go, "Thank you very much for the effort that was put in to get something that's sustainable."

James: So I'll ask a question then. Do you think that the goals that we've set, the net zero goals, do you think that's achievable by the dates that we have put in place?

Mark: It's gonna rely on a lot more effort from here, James. I am genuinely concerned that we're not on track. We need to see companies like Green Gravity and our peers and future companies that we don't yet know about get a lot more support. Governments need to pay a lot more attention to smaller emerging technologies rather than handing money to big companies. I can see it in every country we go to. There’s a lot of work to do. It’s eminently achievable. We have a lot of smart people out there working on this, but there's a lot more investment, a lot more effort needed and it needs to happen fast.

James: Do you think the idealism that we will just scrap fossil fuels right away is realistic or do you think that's gonna be more of like a gradual transition?

Mark: No, I don't subscribe to that. I think we need a managed transition. Shooting ourselves in the foot by turning the electricity off before we're ready doesn't build support from people around the transition to a better, more sustainable grid. We need to do it in a way that everybody comes along the journey and that includes progressively making change as it makes sense. It means supporting the right technologies and changes to become economic and not supporting them forever, but to make them economic and come in and then increase the cost of doing business the wrong way. Price the externalities; carbon should be priced and it should be a penalty for generating it, but it shouldn't just be mandatorily turned off. We need to use the economic levers we have and the technical levers we have to create a transition where we get sensible costs, sensible reliability, and sensible environmental outcomes.

James: That’s one of the most reasonable answers I've heard to that question, so thank you. We had a guest on a few weeks back called a company called EN fco. Have you heard of them?

James: They work in the combustion and energy generation space, but it’s called cold plasma energy combustion. What they do is fit panels into existing combustion engines that burn over a certain temperature and it actually reduces the required fuel burn by something like 30%. So I think technologies like that in the interim are gonna be really helpful.

Mark: Absolutely. Improvement in small steps is still progress. I grew up in the steelmaking industry and mining industry, and there was always a philosophy of improvement in small steps. You’ll get there, but it doesn't have to be one giant leap. Let's just get on and get going. If we can reduce emissions by 30% in one sector while we're doing other things, absolutely fantastic.

Mark: Exactly. We still have to get to the end and we need more technologies to get there, but ultimately we have to ensure that when we reach that destination, the cost position in aggregate is lower than it is at the starting position. Therefore, there’s greater value overall both environmentally and economically. That’s critical. In that intervening period, we’ve got to be careful as well. We need to make sure technologies are supported but not indefinitely. This isn’t about creating a welfare state for technology. The IRA has been an excellent injection of funds and it's got to be done in the right way in the United States to get the right outcomes.

James: Definitely agree. Speaking of changes and trends, have there been any trends in the energy sector that have stood out to you in the last 12 months or so that have stood out to you?

Mark: Well, probably one, one that has stood out in Australia and in the storage space in Australia along with sort of Texas and California as some of the most advanced storage markets in the world, is the clear movement in the duration of energy storage assets being put forward and they've been surprisingly short duration in the first, let's call it decade or less than decade of, of installation of the new forms of energy storage. And we've seen them focused on quite short durations.
.

That has radically started to change. We’ve seen nearly a doubling in the storage duration of assets being put forward in any one year. I think we’re seeing that in many markets with some eight-hour duration assets now being put forward. This is an important signal and I think it’s something that’s going to keep changing. We need to diversify the storage base. We need to see longer durations and much larger scales. That’s really starting to hit the market quickly.

James: Do you think that trend started really ticking up when interest in battery technology became prevalent with Tesla? Because I think there’s definitely been a swing since those have hit the road in public knowledge.

Mark: Tesla’s a game changer. They’ve created such an ability to break out of traditional thinking and look at new solutions for how to radically change the grid much more quickly. We’re actually seeing an acceleration in the rate of change in my view. Even though there's all these challenges, there's inflation going on and there's wars in Europe. Tesla’s one of those companies leading the thinking and enabling today’s eight-hour batteries at scale in California and Australia, which five years ago no one would have thought possible. I’m excited about what’s going to happen in five years’ time. Hopefully, it’s going to include a lot of green gravity technology making a difference to the grid.

James: That’s awesome. I hope so too. I love that Tesla made a lot of their technology available to the public, which is really cool.

Mark: We would love to see schemes like community batteries. We’re speaking with local councils about the fact that they’ve got a thousand mine shafts in their local government area. Some are at the end of the street for some people. We might be able to put clips of storage capacity in that could be sustainable long term and community-owned. Distributed energy can include lots of ways of participation, including many schemes that are emerging on community battery systems.

James: That’s awesome. Could a really small mine shaft support a town of a couple hundred people easily?

Mark: Yes, certainly for its round-the-clock needs. You could use rooftop solar locally in distributed locations and use the mine shaft to store your evening energy.

Mark: And it wouldn’t need chemicals. It doesn’t need something that’s got to be replaced every five or ten years. It can go in like we used to think about the grid. You build the transmission or the coal power station and it’s there for the next couple of generations. Our assets will be the same sort of flavor. Once you get them there, they’re there, and if we can just reuse something a prior generation built, all the better.

James: For remote towns, which Australia's full of and America's full of, there’s so much opportunity there.

Mark: And think about emerging countries that haven’t yet built their grid. We can reduce the grid investment. This transmission investment that everyone’s so uptight about—fair enough, I used to be involved in copper mining, there’s a lot of copper needed to run that grid out—we can incrementally see that reduced with the right strategies and storage at the right locations.

James: Wow. I only have one more major question for you. What are some of the key areas you think we as a society can improve to reduce emissions and energy wastage?

Mark: Firstly, energy efficiency is still so low. We produce a lot of energy and then it gets wasted. We keep missing a trick on reuse or reduction in efficiencies. If you look at a carbon abatement curve, which stacks up all the ways you could reduce emissions and says how costly each one is, there’s still so abatement that could be done that's MPV positive. It doesn't, it's not even gonna cost you, it saves you. And so I think that we don't do enough to focus on the stuff that's just low ag in front of us. That's the first thing. And secondly, I think that there is not enough fundamental economic thinking being done on how to penalize bad and incentivize good out there in the energy system. You know, so there's, there's
too much of just this ability to get away with doing something that's not sustainable and having no consequence to it. I think if we just stretch it up a little bit of consequence and ratchet up a little bit more support, we can, we can reduce the total costs of everything and we can tip the scales in the way that's actually something that you just progressively the economy will fix. And so I don't think we're doing anywhere near after that.

James: No, I completely agree with you. There's some companies out there doing things that are outright dangerous and negligent where there's very little repercussion for their actions as well.

James: No, I fully agree. So last question for you I guess is if people wanna check out your technology and learn about it, what's the best place for 'em to go to do that?

Mark: Yeah, so www.greengravity.com, we've got a heap of material there about the technology. We've got a learning site there and you know, we're actually gonna start to upgrade that soon with a a lot more about what locations we're doing different things, we're testing the technology in different minds, we're working with different locations globally about how do I, how to bring this technology to commercial, you know, scaling more quickly. And so I think that's the best place to go. We've also got a great news and media section there. We've got podcasts and stories and everything else to, for people to learn about what we're doing. We've got a, an info line for people who wanna reach out. We do. We we speak to lots of people. We work with schools, we do, you know, all sorts of things. We're a small company. We
can't be flooded, but we try and do our bid in all the communities that we're working in.

James: Oh, that's awesome. And as far as social media goes, people wanna just keep up with you guys.

Mark: Oh please follow us on LinkedIn. Yeah, so we, we really, we really enjoy the LinkedIn platform. We find that we can reach to the stakeholders that, that are ones that, that either our customers are our supporters and so forth. So we are very, we're very active on LinkedIn so please do follow us on LinkedIn to to hear the stuff we've got. We've got so many cool things about to happen in the next year with this technology. o if you get onto LinkedIn, you'll know all about it.

James: Fantastic. Well for anyone listening we will have links to that website and all that stuff. More info about the company listed in the description. So check that out and give them a follow. Fascinating stuff going on here. Really exciting. Mark, thank you so much for coming on the show. It's been absolutely fascinating chatting with you.

James: Anytime. You're welcome back. Anytime. Thanks. And for anyone listening, tune in next week.We will have another guest for you. Thank you.