Catalyst with Shayle Kann - How to Save a Planet: Spark Tank! How Do We Solve the Energy Storage Problem?

Episode Date: July 1, 2022

It’s shark week! Or ‘spark’ week? Today we’re bringing you an episode of How to Save a Planet, in which Shayle steps into the shoes of a Shark Tank-style judge. This episode is all about (drum-roll please): Storage! ...Exciting, right? Ok, we’ll prove it to you. Each day, more and more of our electricity comes from intermittent renewables like wind and solar. To balance out our electric grid in the future, we’ll need new ways of storing extra energy, so we can still turn on our lights when the wind isn’t blowing and the sun isn’t shining. This week, with help from Dr. Leah Stokes and Shayle Kann, we explore the wild world of energy storage, from a hidden underground lair to a piping hot thermos full of poison. And did we mention it’s a gameshow? Guests Dr. Leah Stokes, Professor of Climate and Energy Policy at University of California, Santa Barbara Shayle Kann, Climate Tech Investor at Energy Impact Partners Len Greene, Director of Government Affairs and Communications, FirstLight Power Curtis VanWalleghem, CEO of Hydrostor Dr. Cristina Prieto, Professor of Engineering at the University of Seville Calls to Action Learn more about energy storage Pumped Hydro Compressed Air Molten Salts And for a really wild one: check out Energy Vault Learn more about our electric grid, with our episodes How We Got our Grid and How We Get a Better One and Party Like It’s 2035 We still want to see your climate Venn diagrams! For inspiration, check out ClimateVenn.info. Post your diagram to Instagram and tag us at @how2saveaplanet. We’ll be reposting examples listeners share with us. Check out our Calls to Action archive for all of the actions we've recommended on the show. Send us your ideas or feedback with our Listener Mail Form. Sign up for our newsletter here. And follow us on Twitter and Instagram. This episode of How to Save a Planet was produced by Daniel Ackerman. The rest of our reporting and producing team includes Kendra Pierre-Louis, Rachel Waldholz and Anna Ladd. Our supervising producer is Matthew Shilts. Our editor is Caitlin Kenney. Our intern is Janae Morris. Sound design and mixing by Peter Leonard with original music from Emma Munger. Our fact checker for this episode was James Gaines. Catalyst is supported by Antenna Group. For 25 years, Antenna has partnered with leading clean-economy innovators to build their brands and accelerate business growth. If you're a startup, investor, enterprise, or innovation ecosystem that's creating positive change, Antenna is ready to power your impact. Visit antennagroup.com to learn more.  Solar Power International and Energy Storage International are returning in-person this year as part of RE+. Come join everyone in Anaheim for the largest, B2B clean energy event in North America. Catalyst listeners can receive 15% off a full conference, non-member pass using promo code CANARY15. Register here.

Hey, everyone, it's Shale. We'll be back with our normally scheduled programming on Catalyst next week. But in the meantime, one more really cool crossover episode for you, this one where I'm actually a guest. So having watched the TV show Shark Tank and been involved in a few Shark Tank like things myself, I can tell you it's not how most venture capital transactions take place. But nonetheless, it is an interesting way to look at a variety of technologies or companies all at once. and see how they compare against each other. And I was recently afforded the opportunity to be a panelist on a Shark Tank on another podcast that I really like, the folks over at How to Save a Planet from Gimlet Media and Spotify. It's hosted by the journalist Alex Bloomberg, of whom I've been a fanboy from a podcast perspective

since about 2007 when he was producing a show called Planet Money, which was tracking the daily meltdown of the economy. It's basically the podcast that, got me into listening to podcasts in the first place. Now he's doing the show where he and his self-described crew of climate nerds talk about big issues in climate change. Their show is geared a little bit more toward folks who are newer to climate tech and want to understand it through interesting, fun, inspiring stories. But he invited me on a couple of weeks ago, along with Leah Stokes, who many of you will be familiar with, to look at a few different non-battery

long-duration energy storage technologies. And look at how they compare to each other, think about which of them might have the most promise and where the big risks are going to lie. And it was really fun. So I think you'll enjoy it as well. We talk about things you'll be familiar with here, compressed air energy storage,

molten salt storage, pumped hydro, all the good stuff. And we did some shark tank like judging. So have a listen. I think you'll like it. If you do, of course, then highly recommend checking out how to save a planet in general. You can find more info on the show in the show notes here or go find them wherever you get your podcasts.

And we'll see you back next week. Welcome to How to Save a Planet. I'm Alex Bloomberg. And this is the show where we talk about what we need to do to address climate change and how to make those things happen. Hello, everyone. Today, I am joined by How to Save a Planet producer, Daniel Ackerman. Hello, Dan. Hey, Alex.

And you're here because we have to take a visit. visit to the future. All right, here we are, through the magic of podcasting. We are now a decade or two in the future. And Dan, we explained to listeners what the future looks like. First of all, there are just wind turbines everywhere. As far as the eye can see, out in the ocean, onshore, it's beautiful. There's solar panels out in the fields.

Solar panels that make a sound. And most of our electricity is coming from wind and solar. It's wonderful. It's a beautiful future. It's clean here. It's quiet. There's like way less pollution. Fewer people have asthma. And oh, there's a flock of sheep over there grazing in the gentle shade of a solar panel.

But Alex, there's a big obstacle standing between us and this glorious renewable future. And that obstacle is storage. Ah, yes, I'm familiar with this problem. Storage. See, there's one key difference between this clean, renewable future and our dirty fossil fuel present. And that is, in the future, it is harder to match demand for electricity with supply. And for a quick explainer here, our electricity use today in the present generally follows a really predictable pattern. So on a super hot day in New York City, for example, in the afternoon, demand for electricity spikes.

It goes way up because the afternoon is when people get home from work, they crank up their AC and maybe fire up an episode of How to Save a Planet. And right now, with the power plants we have today, so that's lots of fossil fuels, some nuclear, some hydro, the electric utility can meet that spike in demand by just firing up more electricity generation. So they might turn on more coal or gas power plants to meet that afternoon demand spike. But in the future, it won't work that way. The utility can't call up the wind and ask it to blow more or demand that the sun shine on a cloudy day. And in fact, solar panels are generating the bulk of their electricity in the middle of the day when demand for that electricity is low. And so that is where storage comes in. In our glorious renewable future, we're going to need ways of storing all that excess energy created by our renewables so that we can use it later when we need it. All right.

So, Dan, in the future, what will that storage look like? You know, that is a lot less clear than the wind turbines and solar panels. It's a safe bet that renewables like wind and solar are going to generate much of our electricity but as to what technology is going to store the excess electricity that is still up in the air. Dan, short little aside, I know we're in the middle of the podcast here, but don't we actually know the answer?

Isn't the answer batteries? Isn't that what we're going to have a lot of batteries? Alex, that is a rookie assumption. Yes, batteries are part of the solution. Batteries are great for things like your car, or your house, or maybe even your neighborhood, but with our current battery technology, it would just be way too expensive to back up the entire electric grid.

Plus, it would require more materials like lithium and cobalt than we have sitting around right now. So with batteries, it's a yes and. Yes, we will have lots of batteries nestled into the electric grid of the future, and we'll need all kinds of other non-battery technologies for storing massive New York City-sized amounts of energy. And lucky for you, Alex, I have been on a deep dive into those other myriad and fascinating technologies

that people are inventing and building to store energy in the future. And it's taken me to a secret layer hidden deep inside a mountain. It's also involved Greek mythology and a giant thermos full of poison. You know, we figured we could just tell you about this, like sometimes we do on the program. Just lay out all the stuff that you've uncovered, Dan. But we decided it would be exciting to add some stakes here. And so we are turning our podcast today into a game show.

A game show complete with real, and by that I mean fake, money. We are going to present three of the most interesting storage ideas you've discovered, Dan, to two experts, one of whom is an actual investor in renewable technology, Shale Khan, who also hosts the amazing podcast, Catalyst, And the other longtime friend of the show, professor, author, all around climate smarty pants, host of her own podcast, Matter of Degrees, Dr. Leah Stokes, they will have to decide which of the three technologies they would put their actual slash fake money into. It's sort of like Shark Tank, but instead of pitching Throx, that is Sox sold in sets of three

in case you lose one, which is a real Shark Tank pitch, by the way. Instead of pitching Throcks, we're pitching a more resilient, renewable electric grid. And we're calling our game Spark Tank. Get it? Spark, electricity? All right, so Spark Tank is coming up after a break. When utilities need flexible capacity they can count on, they turn to Energy Hub. Energy Hub works with more than 170 utilities, coordinating over 2.5 million devices to manage 3.4 gigawatts of flexibility, built for the moments when utilities can't afford

uncertainty. Energy Hub builds and operates virtual power plants that utilities actually stake their grid planning on, coordinating EVs, batteries, thermostats, and more through a single platform built for utility scale. Predictive, verifiable, and designed to perform when it counts. Learn more at energy hub.com. Trillions of dollars are flowing into clean and critical infrastructure, but those investments aren't driven by technology alone. They're shaped by markets, by policy, by capital, and by the institutions that connect them. I'm Alfred Johnson, CEO of Crux, and host of a brand new podcast, Critical Capital. Each episode, I talk with people deploying capital, shaping policy, and building the clean economy.

Tune in as we unpack how progress is actually made. Listen to Critical Capital on Spotify, Apple, or wherever you get your podcasts. Welcome back to today's episode of Spark Tank, Shark Tank, but for energy storage. I now have the distinct honor of introducing our Spark Tank Climate Sharks. Dr. Leah Stokes, Professor of Environmental Policy at the University of California, Santa Barbara. Welcome, Leah. How are you? I'm good, but am I a shark or am I a spark if I'm on the spark tank? That's what I'm confused about. What am I? It's existential.

That is a good question. I think you're a spark shark? It could be. You are joined by another spark slash shark slash spark shark, Shale Khan. Shale hosts the climate podcast Catalyst, and he's an investor in climate technologies as a partner at the firm Energy Impact Partners, which means what we're about to do in this game show he actually does for a living. Welcome, Shale.

Thanks. It's great to be here. I have to say, though I like Shark Tank, I prefer that, you know, there's a British version of that game show and they call it Dragon's Den in the UK, which I think is actually better. It's also the Canadian version, just so you know. It's also Canadian. I'm so very sorry, Leah, to have left out Canada.

So, but be. Before we get to the game show, before we have you react to the different ideas for energy storage that Dan has dug up, I just want to hear your thoughts in general because you both think about energy storage a lot, way more than I do. I guess, Leah, do you think this is actually worth its own game show? I think so. I remember, wow, how long ago was it? I guess 12 years ago, I was taking an energy policy course when I was starting my PhD. And what I learned in that course was that the most important gap in terms of what technology we had was storage. This was the missing piece in the puzzle. And it's been 12 years and it still seems to be a missing piece. So I think it's very worthy of investment, focus, even a game show.

And Shail, do you see lots of pitches for different storage solutions in your day job as an investor? Yeah, tons. I mean, there's probably more going on from a technology standpoint in energy storage than maybe any other space in energy tech or climate tech, because it crosses over. I mean, we're going to talk about a bunch of technologies to store energy on the grid. But if you think about all the innovation that's going on in electric vehicle batteries, which is like a different area of energy storage, it's just like Cambrian explosion of different ideas and approaches.

So there's just a really wide and burgeoning universe that's pretty exciting. exciting. All right. So are you guys ready to start the game? Mm-hmm. Always. So I'm going to start by handing each of you a stack of 10 million fake dollars. Don't spend it all at once. Thank you, Alex. I always knew you would invest in my dreams. And you are going to use your fake money to invest in the grid of the future. you're about to hear three different ideas, three pitches for energy storage technologies.

After you hear those pitches, you get to decide how to invest your $10 million among those technologies. So you can invest all $10 million and one. You can spread them out across all three. You can choose to not invest in any of them. However you want to deploy your capital, you can. Does that sound okay? Any questions? Nope, this is literally my job.

All right. Okay. How to Save a Planet producer, Daniel Ackerman. You will be our MC for today, guide us through the three pitches. And for pitch number one, Dan, you actually visited an energy storage facility in western Massachusetts. It was a place called Northfield Mountain. And the energy storage technology being used there is called pumped hydro. You want to take us there and tell us what you saw? Yeah, so to get to Northfield Mountain, I drove about an hour and a half west of Boston. And when I got there at the base of the mountain, it looked to me just like a standard issue Massachusetts Mountain. If it were out west, it would probably just be called a hill. It was about 1,200 feet tall. It's got boulders, trees, birds singing. But then I hopped in a pickup truck with Carter Wall and Len Green. The two of them work at the mountain, or I guess I should say, in the mountain. We're about to go into the Into the tunnel, into the mountain itself.

As you can see, there's a big... Yeah, so like this huge metal door right into the side of the mountain just raised up. We rolled inside, the sunlight behind us disappeared, and we were suddenly just driving down this long, dark tunnel. It actually goes right down, about half a mile down into the center of the mountain itself. Do you ever do any, like, drag racing down here? No. No. No.

What about when you're not on the record talking to the media? Do you do any drag racing down here? Absolutely not. Okay, so as we proceeded cautiously into the bowels of Northfield Mountain, I got the distinct feeling we were entering the layer of a Bond villain. Len and Carter referred to it affectionately as the Batcave, so that is another option for your imaginations there. So we got to the end of this long tunnel, hopped out of the truck,

and we were just in this dark, dank passageway. Like, there was literally water dripping from the ceiling. And there was this door in the rock. We opened the door, walked through, and then suddenly stepped into this just, like, humongous, empty space. Like, this artificial cavern blown out of the inside of the mountain. It was like the size of a football stadium, but just, like, surrounded by rock.

I watched the Lord of the Rings movie, The Desolation of Smog not that long ago. And you're like describing to a T-smoked layer. I was ready for like orcs to pop out. I wasn't sure this podcast could get geekier, but you guys really proved me wrong. Okay, so on the floor of this huge cavern inside the mountain, there were these four green boxy-looking machines. Each one was like the size of an SUV. And these were pieces of electric generators and specifically hydroelectric generators.

So another thing to know about Northfield Mountain is that right above where we were standing like up through hundreds of feet of solid rock at the very top of the mountain sits a five and a half billion gallon reservoir. And Len told me that all that water up there comes from the Connecticut River all the way down at the base of the mountain. We actually pump that water up through the inside of this mountain here, just about a thousand feet up to a large reservoir which sits atop the mountain. We store that water for when it's actually needed by the grid. So pumping the water all the way to the top of the mountain, that is how they bank energy that they can turn back into electricity later.

It's how they charge their mountain-sized water battery, if you will, when energy is plentiful. So they store the water up in that high-up reservoir until they need it for the electric grid, like at night, say, when solar panels are not generating. And when that happens, they basically pull the plug on the mountaintop reservoir, all that water comes rushing back down through the bowels of the mountain, through a set of pipes running just below our feet, and that water spins the turbines connected to those loud green

boxy generators to make electricity. And just a quick explainer on electricity generation, because it's going to come up a bunch today. One of the most effective ways we know of to make electricity is actually very, very simple. We spin a bunch of wires inside a magnetic field. That is literally probably the way all of your electricity that you're using right now is generated, unless it's solar. But most of the other energy generated is just wires spinning inside a magnet. The wires are in a thing called a turbine.

The turbine spins really fast. The fact of it spinning creates the electricity. That's all it is. It's all super fancy, but it's basically that. And that is all that's happening here. The water comes down from its reservoir on top of the mountain through these pipes in the mountain. As it comes down through the pipes, it spins the turbines. The turbines spinning is what generates the electricity.

All right. Explain her complete. Thanks, Alex. So back at Northfield Mountain, that energy storage technology, pushing water uphill and letting it run back down again to generate electricity, that is called pumped hydro storage. And when I was in the Batcave inside Northfield Mountain talking to Len Green about it, something that struck me about pumped hydro storage is that it is appealingly simple.

I'm not super up on my mythology, but is Sisyphus the one who like pushes a rock up and down the mouth? Yes, he is. Yep. This is a, this is Sisyphean, if you will, but in a good way. We're quite literally pushing water up a hill and then releasing it down a hill over and over and over again. This is the Sisyphus of the electric grid. I got to start using the adjective Sisyphian more. I'm not sure why the cavern was quite so gigantic, but there was a lot of machinery in there. because of smoke. Because of smoke.

Weird not to lead with the dragon. I'm going to figure out a way that every one of these technologies is dragon related. Once we get to energy storage with heat, you might have some easy options there. Oh my God, this is so good. I never thought of this.

Okay. Staying with pumped hydro, Len told me that when the reservoir at Northfield Mountain is pumped full of water, it can be used to power about a million homes for eight hours. And I should also note that pumped hydro-like

pretty much every energy storage technology is not perfect. It's not 100% efficient. So that means energy does get lost over the course of this Sisyphian task. Of the energy that it takes to run all the pumps and stuff at Northfield Mountain, they get about 75% of it back. Right. So it takes more energy to pump it up than they get letting it back down and turning the turbines. Right. And just to kind of compare, a battery could be somewhere in the 75% range in efficiency as well. Okay, gotcha. All right. Pumped hydro storage. This is our first spark tank pitch. Judges, what are your reactions? What do you like about pumped hydro and what are your concerns about it? Well, pumped hydro is great. So lithium ion batteries, the type of batteries using your watch that we're

going to put a bunch of on the grid, they're really great for. short duration energy storage, right? So think of like, what's going to happen to bridge that evening period that you describe, Daniel, where the sun sets but peak load shows up. Lithium ion's great for that. The problem with lithium ion is that the cost scales pretty directly with the duration. So if you want four hours of energy storage, it's great. But if you want 40 hours of energy storage, it's very expensive. It costs 10 times more to get 40 than it does to get four. Yeah, like rough order of magnitude, that's generally true. Pump hydro, not true at all, right?

Because you could just store the water up at the top of the reservoir, basically as long as you need to, you're not going to lose any of it, and then you let it down whenever you want, you run the turbine. So the duration is kind of infinite, basically, in principle, which makes it really attractive for these longer durations. We have a lot of it. So pump hydro is awesome. It's cheap.

It works really well. It's proven. The problem is we can't find that many places. to do it. You described the situation in which you found yourself, which is you're in a mountainside, there's water flowing, and you could permit this thing, and you could build this big cavern. Just think about, like, how common that is, and you pretty easily figure out what the challenges are. Yeah, like a flat desert city like Las Vegas, for example, I'm imagining there's not a lot of options for pumped hydro storage. Well, and you also just need a lot of land to do it,

no matter where it is, irrespective of the height issues. And you also need water. And, of course, in California, where I live, water is becoming more and more of a scarce resource. And this idea that it would still be there over the long duration is not necessarily true. We have lots of water storage right now just for water, and we're finding that there's less and less actually in those reservoirs over time. Right, because the water is evaporating. And by the way, when we talk about reservoirs, creating reservoirs, we're often talking about damning a river, which has lots of environmental consequences. It can sort of destroy these ecosystems in the valley.

It can impact fish populations, all sorts of things. Which is why we have not built a lot of new hydropower in the U.S. in the past few decades. Right. And when I was researching this, I should say there are some projects where it's moving ahead. the Kauai Island Utility Cooperative in Kauai County, Hawaii, they are making a pump storage facility because they have a ton of renewables on their grid

so it just makes sense for them to build more energy storage. But to the points that you've just been making, Kauai, of course, is blessed with hills, mountains, and a lot, a lot of rain. So they've got the topography and they've got the water. Right. All right. Okay.

Should we move on to, contestant number two. All right, let's do it. Next up is compressed air energy storage. Woohoo! I feel like he needs some dramatic sound effects or something. I actually think I know the perfect sound effect for representing compressed air and air horn. You've probably heard that on the podcast before, right?

And to explain this technology, let me introduce contestant number two, Curtis Van Wallacham. He is the CEO of HydroStore, that's an energy storage startup. And Curtis told me that for their compressed air facility, they basically dig a mine shaft straight into the ground, down into the bedrock. They blast out a big, empty cavern inside that bedrock, and they fill it with water. And then Curtis says they pump a bunch of air into the cavern underneath the water. And as the air goes in, it lifts the water out, and then that's storing energy. in compressed air. So that compressed air is now sitting underground. It's underneath the water.

The air has pushed the water up to the surface, and that water is really heavy. So the weight of all that water is what's keeping that air down below pressurized. So if you could picture this, now we have these two layers, water sitting up top, the air deep down below underground in the cavern, and that air is pressurized to six times the pressure of Earth's atmosphere at sea level. And then where the air is, there's a valve, and you can pop open that valve and release the air. And when you want electricity, we let that air come shooting back up, and it spins a fan that makes electricity. So it turns a turbine blade. See, I told you there'd be more turbines.

It's all about spinning turbines. Also more caverns. This is a very common theme. I just want to say the air getting sucked in is what the dragon does before it breathes. it's fire. The first thing it has to do is suck the air in. That's right. So do you have any like dragon-related conflict of interest that you'd like to disclose at this point to our audience? I can neither confirm nor deny any dragon-related investments that I've made. So basically, you pump the air down. It goes under all this water. The water is putting tremendous

pressure on the air. It's sort of like blowing up a gigantic balloon, holding it closed. And then when you want the electricity, you open up the balloon, the air comes shooting out, it spins a turbine or a fan, and again, spinning, that's what generates the electricity. Yeah, that is basically it. Another big selling point that does not, as far as I'm aware, relate to dragons that Curtis laid out about compressed air energy storage, has to do with the just transition, which is something we talk about on this show somewhat often. Yeah, the just transition is this idea that as we move away from fossil fuels to renewables. We want to find ways to repair the harm that fossil fuels have done in certain communities, often communities of color. And we also want to support the people whose

livelihoods depended on the fossil fuel economy. We want to ditch oil and gas, but we don't want to leave behind all the oil and gas workers who need to make a living. Yeah, that's exactly it. And Curtis told me that hydro stores facilities, they can actually use the skills and expertise of those workers who are exiting the fossil fuel industry. All of this equipment is from the oil and gas industry. So the compressors move natural gas down pipelines. The turbines are used in liquid natural gas processes. And the caverns are used to store typically natural gas.

So we're keeping that workforce in those factories, just they're still doing the same thing they've always done, put together in a unique way for us under our patents, to serve the clean energy economy. So that is compressed air. And I should say that this technology is not quite as well established as pumped hydro. It's a little more experimental. And Curtis told me that their compressed air facilities are about 65% energy efficient.

So it doesn't quite hit that 75% mark of pumped hydro. But Curtis did tell me that one of these caverns pumped full of air could power about a million homes for a day or so. So similar to pumped hydro. And where is this company based? They are based in Toronto. Uh-huh. That's why I asked. I didn't actually care the answer. I could recognize the Canadian accent. That's why I asked. I'm also from Toronto. So I know a Torontoian when I hear one. Yeah. Okay. So judges, reactions, questions, concerns.

Well, I must declare my conflict of interest, which is as a Canadian, I may be biased towards this guy. You know, he's really tugging at my heartstrings. But, you know, I think this is an interesting concept. It would be interesting. interesting to think about where do we have storage facilities that can store this underground. Maybe there's more available land, right? Because you're not taking up area on the above ground. You're not taking a lot of surface that you need for other things. You're just going underground. And I think it's also interesting to think about how oil and gas technologies could be repurposed and the workers and the sort of specific expertise that those companies have towards this kind of technology. So in those ways, I think it's quite promising. Yeah, what are your thoughts? Yeah, yeah.

Yeah, so compressed air energy storage is cool. It has the promise of much better sightability than pumped hydro. There's actually lots and lots and lots of places we could do this. And to Leah's point, it doesn't use as much above-ground land. And I like the sort of usage of the oil and gas infrastructure and talents and all that kind of stuff. I think that's all important and real. Historically, the challenge with compressed air energy storage has to do with this. trade-off between efficiency and cost.

The basic challenge is when you compress air, you create heat, right? And if you let that heat dissipate into the atmosphere, you're just going to lose a lot of energy in the process of storing it. So most of the innovations around compressed air energy storage have to do with what do you do with this heat? Right. So for hydro store specifically, Curtis told me that they capture that heat and then use it to survive the long cold to Canadian winters.

Just kidding. He said they use it to improve the energy efficiency of their facility. Got it. All right. Let us move on to our third and final contestant. Okay, quick review, though. So we've heard pitch number one for pumped hydro that is storing energy by pushing water up and down a hill.

We've heard pitch number two about compressed air that's pressurizing and releasing air in an underground cavern. And up next, contestant number three, our final contestant, has a pitch for storing energy as heat. All right. Heat. It was a problem in pitch number two,

but it's the solution in pitch number three. Who is contestant number three? Contestant number three is Dr. Christina Prieto. She is an engineer at the University of Seville, so that is located in sunny southern Spain. And Christina's journey into energy storage actually started a couple decades ago when she was working, of all places,

in the petrochemical industry. I started working in refinery. And as I like to explain, suddenly I saw the light. And I changed. Is this literal or metaphor? 50-50. So it's a half metaphor.

Yeah. So here's why Christina, seeing the light, is only half metaphor. Christina took a job at a renewable energy company. It was a company that used sunlight to generate heat, and they used that heat to make electricity. Remember, Alex heat boils water, steam, spins a turbine, and that makes electricity.

But sometimes when the sun was really shining, remember this is southern Spain, they ended up with way more heat than they needed for the electric grid. So Christina helped figure out how to store all that extra heat to be used later. And just so I understand this, you have extra heat, and what you want to do is heat something up that will cool down very slowly so that you can sort of basically hang on to the heat, which is like a little bit of a hard thing for me to get my mind around, because I don't really think of like heat as something that you can store.

Yeah, like you want to find a specific object that you can heat up and that will hold that heat rather than letting it just disperse into the air. You heat it up and then it stays hot. Right, and Christina looked into a bunch of different ways to do this. She looked into cooking blocks of concrete, and that worked okay, but was not so efficient at really high temperatures. She looked into cooking a tank of water, but the problem there is that water boils at a relatively low temperature, and that would cause the tank to explode, which is no good.

So she settled on a storage solution called molten salts. Mm, classic. Molten salts, which sounds like maybe either a spa treatment or a torture device. I'm not sure which, but what are molten salts exactly? So salt like on the dinner table? Not quite. So this is mostly nitrates, a little different than dinner salt. You would not want to eat this stuff.

Listeners do not eat molten salts. But these molten salts, these nitrates are another kind of relatively cheap and plentiful salt. So it is an easy-to-get material. and what's really good about these molten salts is you can get them super, super hot, like more than 500 degrees Celsius, and even then these molten salts will stay molten, they will not try to boil

and explode your tank like water wood. And that seems important, right? Because if you want to store the heat, you want to get the liquid as hot as possible, and if it turns into a gas that sort of blows the whole thing apart, basically. Quite literally. Yeah, gotcha. Okay.

Okay, I get it. Seems a little complicated. What's the big selling point? here? So there were two selling points that Christina pointed to. The first is that to make electricity from a super hot tank of molten salt, you can actually hook it right up to infrastructure that already exists. So this again actually relates to the just transition. Like you might have a power plant today that burns natural gas or fossil gas to boil water and spin a turbine and make electricity. Well, you could just swap the fossil fuels out of that equation and instead use a renewably heated

tank of molten salt to boil the water and spin a turbine and create electricity. All right. So it could make an easy pivot away from fossil fuels, kind of like for compressed air. And what's the second selling point? So selling point number two for molten salts is that when you have energy stored up as heat, you can do a lot of different things with that heat. You can use it to make electricity for the grid like we've been talking about, and that's awesome.

But you can also just use that heat directly. Like you could transfer that heat from your tank of molten salts through a set of steam pipes and into homes to heat them in the wintertime. Or you could use that heat for industrial processes like making pharmaceuticals or paper. And here's why that's important. Right now, industry accounts for about a quarter of the greenhouse gas emissions in the U.S. And most of that is not to keep the lights on in the factories. It's because they need heat for chemical reactions and to melt and transform materials. Now, Christina told me that these molten salt tanks can hold a ton of energy. A big old tank of hot molten salt could back up a mid-sized city of about 200,000

people for a few hours. Okay. And these molten salt tanks, they are quite efficient. You get back about 80 to 90% of the energy you put in. So that is the best of our three pitches, and that is way better than fossil fuels. Yes. And when you talk about big old tank, is that a technical term, big old? How big is big old? So Christina said one of these tanks would take up most of a city block, and it'd be about like three or four stories high. Oh, okay. So bigger than like a train car, I guess, which I was sort of imagining, but still much smaller than a Massachusetts mountain housing a pump hydro facility. Basically, I'm picturing sort of one of those big cylindrical tankers that you see at a refinery or something.

That's exactly what these look like, yeah. Yeah. And one of those could power all of like a mid-sized city like Grand Rapids or something for half a day. Yeah. That's amazing. That's amazing. All right, I'm in. I don't have any money. But, like, this is, like, quickly gone from Dark Horse to my favorite guy. Judges, what are your thoughts? Well, you know, this is used already in some applications. There is a concentrating solar power project, which I've driven by in the desert. Basically, what it does is you use solar panels, more like, think of it like a mirror. And they are reflecting the sun's light. and then putting it towards the tower. So when you drive past this,

you'll often see these huge beams of light going towards the tower. And what they're doing is the tower is this molten salt, and then the energy gets stored there. So you focus all the sun's rays back onto a single point, and that gets super, super hot,

sort of the same way that you can sort of cook an ant with a magnifying glass. It's just like that. And you can see the beams if you drive by this site. It's quite dramatic. That's crazy.

I just want to say, I swear this is just working out this way. But that project, if you've ever driven by it or if you've ever flown over it, it is really distinguishable and it looks a lot like Eisengard, the tower in the Lord of the Rings. They're looking for a visual, I swear, exactly what it looks like. Also, molten salt storing as heat, this is what is inside the dragon's belt before it. I mean, obviously, it's just science.

It's just science. I didn't plan it out. I should offer a bit of disclosure. We are not investors in pumped hydro storage in the moment. We are not investors in compressed air energy storage. We are investors in a company that does thermal storage, storage as heat, albeit not molten salt. So we're investors in the company called Rondo Energy, which has what they call a heat battery, which uses a different medium besides molten salt, but same principle.

And in their case, specifically to deliver it as heat for industrial uses. As you said, I think that's actually one of the really, really key important points to understand here, which is in high-temperature heat is a huge portion of global energy consumption and of greenhouse gas emissions. It's what we use in cement-making and steel-making and all these other industrial processes, petrochemical production. It creates a ton of emissions because the only way we can generate that really high-temperature heat. Otherwise, right now is using a boiler to burn fossil fuels. So actually being able to store, you know, clean, cheap electricity as heat and then deliver it as heat may have as much, if not more value than turning that heat back into electricity to put it back on the grid. So specifically for the industrial heat application, I really love thermal energy storage.

Great. All right. So we've got 10 million fake dollars burning a hole in your real pockets. So let's spend it after the break. Virtual power plants are becoming a reliable way for utilities to manage capacity, but enrolling devices is just the start. What really matters is confidence, knowing those resources will perform when dispatched and being able to prove it, from the control room to the living room. Energy Hub's platform handles the full picture,

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Listen to Critical Capital on Spotify, Apple, or wherever you get your podcasts. All right, everyone, welcome back to Spark Tank. are at the moment of truth. Shale Khan, Dr. Leah Stokes, you've heard the pitches. Now you have to decide where to spend your money. Pumped hydro, which is sort of like a big high lake. Compressed air, which is a giant underground balloon under a lake.

And then molten salts, which is sort of like a gigantic thermos filled with really, really hot liquid. So, without further ado, how are you going to spend your money? Shail, you go first. How are you going to spend your fake $10 million? Well, much as I love pumped hydro storage, I just realistically don't think we're going to add a whole lot more of it, certainly here in the U.S. So I'm not going to put any of my money into that solution, though it is probably the most mature and maybe the cheapest, ultimately it solves a lot of problems. I wish we could build more. On the other two, I'm going to go two-three-three-three-three-three-old.

of my money into the compressed air energy storage. Oh. I think it's actually a, it's a really promising long-duration energy storage technology. We have to solve these, you know, waste, heat, integration, and capital cost challenges that I described. But I think there's a lot of interesting innovation going on there. And if we could solve that, then it's a cool piece of the puzzle. And then I'll put the other third into molten salt energy storage.

they're the only reason I'm not investing more is that I think molten salt specifically has some real challenges we didn't really talk about like the environmental and permitting challenges of molten salt which is uh itself kind of toxic and corrosive if it leaks so not to say that it's going to but it requires a fair amount of like permitting and environmental engineering and all that to get anything built not every thermal storage medium is like that so there are some that i think i have the promise of being potentially both cheaper and just easier to build and again And it solves a problem that none of these other ones do, which is how do you deliver high-temperature heat for industrial processes.

Right, right. I also, by the way, I want to say these are all interesting and promising. There are a bunch of other, you know, types of energy storage as well. We haven't talked about batteries like electrochemical batteries, like what you have in your watch, but with different technologies. There's a whole universe there, too. Huh. All right.

So, to recap, Shale, you are putting two-thirds of your fake $10 million into compressed air, and then one third into molten salt, although if the molten could expand beyond salts, beyond nitrates, you would maybe change the allocation a little bit, put more of your money into the molten stuff. You got it. Leah, what are you doing? Well, my answer was going to be pretty similar,

which isn't very fun. That's fun. So I just come up with a different one because it sounds more fun. I'm also not putting any money in the pumped hydro for the same reasons we talked about. It's not really scalable. You know what? I've decided other people. are all excited about molten salts.

I'm not going to give them any money either, and I'm going to go with the Canadians. All right, growing with compressed air. And I'm going to give them all $10 million. And you know what else? It's going to go even farther because those American dollars converted to Canadian just give you extra cash.

So I'm really excited about it because I feel like it is scalable. And it takes engineering knowledge and really human resources and uses them for a new end. So I think it's super exciting to think about, for example, there are these massive underground storage tanks, not too far from where I live,

that leaked huge amounts of gas, which was terrible. The Porter Ranch leak. People had to leave their homes. They got really sick. But it's an example of an underground cavern, basically, an underground storage tank that you could think about putting air into. And those kinds of facilities are all over the place. So to me, if the cost isn't there,

yet that's okay because I think that this is a scalable enough idea that as we engineer it, you know, as a thousandth and one project it's built, the cost will have fallen. So that's really why I'm excited about that technology. Awesome. All right. Well, this was really, really fabulous. We now have a better sense, hopefully, of all the ways we are going to hold on to the wind and solar energy that we will be producing in our glorious renewable future. Thank you both so much for being such good sports for playing our ridiculous game show with us. I had a lot of fun. I hope you did as well.

And I hope our listeners did too. Thanks for having us on. It was super fun. Thank you so much. I just want to say for the record, I'm not that big a Lord of the Rings fan. To be honest, it just, this just happened. It's too late, man. I'm realizing now how I've portrayed myself.

Yeah. I don't know if it was a good plan for the long time. long-term viability of your business. I think the disclaimer at the very end of the podcast is not going to undo all the, all the work you've already put in there. One energy storage technology to rule them all. And that brings us to our calls to action. If you want to learn more about any of the energy storage technologies you heard about today,

we will put links in the show notes. We'll also link to a couple of really out-there storage ideas that Dan, you came across in your research, like building a brick tower hundreds of feet tall and then unbuilding it over and over and over again. Also, you can hear way more about the history and future of our electric grid. We've covered this before. Those episodes include how we got our grid

and how we get a better one, and party like it's 2035. Those are also in the show notes. How to Save a Planet is a Spotify original podcast in Gimlet production. It's hosted by me, Alex Bloomberg. This episode was produced by Daniel Ackerman, rest of our reporting and producing team includes Kendra Pierre Lewis, Rachel Waltz, and Anna Ladd.

Our supervising producer is Matt Schultz. Our editor is Caitlin Kenney. Our intern is Junae Morris. Sound design and mixing by Peter Leonard with original music by Peter Leonard and Emma Munger. Our fact checker for this episode is James Gaines. Special thanks today to David Bissell, CEO of the Kauai Island Utility Co-op, which is building that big pumped hydro facility to store uddles of clean solar energy on Kauai. And thanks to all of you for listening. See you next week.