Interview with Chris Stern of CarbiCrete on the Process and Challenges of Obtaining CO2

Hello everyone. Welcome to this episode of Conscious Design. I'm Ian Peterman, your host and author of the book Conscious Design. And with me today, I have Chris Stern, CEO and co-founder of Carbocrete. Welcome to the show.

Thank you very much, Ian. It's great to be here.

Yeah. So, You guys are doing some really great work in replacing concrete or improving it. So that's, that's a huge task. That's, that's a huge undertaking. So what I'd love you to start with, what is your journey like? How did, how did you arrive on this particular problem as something you wanted to solve?

Well, interestingly enough, I, um, I was coming off the heels of my last startup. I was in solar power before, and I was a co-founder at a company called Pure Energies, which was a residential solar provider, which we sold in 2014 to NRG Energy, an electric transmitter in the United States. And after several months of not doing anything, I I was looking for something to do, actually. And I was introduced to the folks at McGill University, where I learned about cement. And I learned the difference between cement and concrete, because they're different. Cement is the glue and concrete is the form factor. It's the stuff you see that's being poured or put into bricks and things like that. And I learned that cement is actually extremely carbon intensive, which I had not known. You know, like if cement were a country, it would be number 3 in terms of carbon emissions. So cement's responsible for about 8% of CO2 emissions every year. And it's impossible to stop that because you can use different fuels to convert the limestone into the—

Cement.

into clinker. But the issue is, is that as you're doing that, as you're cracking the calcium carbonate, CaCO3, you're tearing off CO2. And the only way to stop that from happening is to either capture the CO2 or use a different material. So the folks that I met at McGill had discovered that you can use an industrial waste byproduct called steel slag, which is, you know, about 12 to 15% by weight of steel production. So if you have, you know, a ton of steel being made, 120 to 150 kilograms of, of, uh, slag is produced. And it has to be produced. That's— it's part of the process, and it actually makes good steel. But it is something that, you know, is basically just a byproduct. Um, and a lot of times this byproduct is, um, it's actually landfilled. It's not dangerous. I think it's just— it's just very calcium-rich, uh, minerals. And so the—

mostly it's just like an inert but kind of useless material to the steel industry.

Yeah, a lot of times, other than landfilling, what they use it for is to— is as aggregate underneath roads. So it's an inexpensive gravel, as it were. But now we've repurposed it to replace cement as the binder in concrete. It's very rich in calcium silicates and calcium oxides, which lend themselves very well to reacting with CO2. So we do 3 things. We eliminate the need for cement, which is highly carbon intensive. We find a new use for an industrial waste byproduct, which is typically landfilled, called steel slag. And by the way, the only way to cure this steel slag-based concrete is to react it with CO2. So the CO2 is uptaken by the slag and it's forever, forever part of the concrete, you know, to never leak out.

So you're reducing— you're making it so you don't create any off-gassing and then you're actually absorbing it.

Exactly.

You're actually pulling it back out of— and does it just do it naturally when it— when you cure it, it just pulls it straight from the air? No.

No, it's not, it's not that. I mean, over the course of time, yes, it's a natural product, like it's natural.

Got it. And are you, are you able to cap— like, what, how are you getting that CO2? Is it other industrial waste that you're collecting?

So currently, yeah, currently we get it from one of the gas producers. And in fact, you know, in our first plant here, uh, it's being collected at an ethanol fermentation plant. So it's a biogenic source. So we're not burning fossil fuels to make the CO2. It's as a result of ethanol fermentation. And then it gets inserted into the curing system where it reacts with the steel slag.

So you're taking 2 industrial wastes and putting them together into this material.

Yeah, making a very useful building product that you can explain to your grandmother. You know, everybody understands what a brick and a paving stone is and concrete blocks. So that's why it's a unique solution to climate change. It's one of the solutions that's easily explainable to a lot of people, because a lot of these solutions are difficult to explain. Like, you're taking CO2 out of the air and you're sticking it into the ground, and people have a hard time with that. This is— we're taking CO2, the other industrial waste, put it all together in a box, and out comes concrete blocks that you can use to build a home.

And so your process, so you mentioned making, making the bricks, right? Cinder blocks, essentially. Is that the primary? Is that, you know, for the material, is that the best use? Could it— can it be poured? Is it kind of— what, what can you do with your material?

Um, well, there's, there's, there's several different types of, uh, of concrete. Um, what we're talking about is masonry, which is dry cast. So when you, when When it's formed inside of a concrete machine, I mean, it's not dry, but it's not liquid. You can't pour it. It's like wet sand, you know, like, and that's called dry cast materials. And so like, what is a dry cast material? A concrete masonry unit. So a cinder block, it's a paving stone, it's a retaining wall, the things that you would buy at Lowe's or Home Depot, you know, for your backyard or for your driveway or for—

Okay.

Then you've got precast materials, and precast materials are like Jersey barriers that you see on the roads. They're like, you know, precast balconies that you would see on a condo. Those are precast materials. And then the final thing is ready-mix, which is the trucks that you see rolling around that pour into formwork. And those are, those are the 3 basic types of concrete. So right now we're working on the dry cast portion, which is masonry, and we're also doing research and development on wet cast. for wet applications like Jersey barriers and other things like this.

Got it. And so is there any difference material-wise? Is it able to, you know, are your cinder blocks able to handle similarly? Is it, you know, material strength and things like that similar? Is it better? Kind of what would be the comparison if someone was looking between, you know, Yeah, I mean, sustainability side, right?

It's similar or better. I mean, we really design the strength according to the application, so we can turn up the strength or turn down the strength depending on what we need to do. And the interesting thing is that the more stronger the material or the concrete, the more CO2 is actually captured. So it's, it's like, yeah, it's like a positive feedback, right? So You make a really strong piece of concrete at 75 MPa, it's really soaked up a lot of CO2.

Oh, interesting. Yeah, that's a really good benefit then.

It's one of those too good to be true situations, right? Like, we're getting— like, we're doing 3 things, right? Getting rid of industrial waste, CO2, making concrete, and capturing CO2.

And making it stronger makes it absorb even more. Even more CO2, which usually that's where you would see the opposite. You're like, well, where's the drawback?

Yeah, there aren't actually— there aren't any drawbacks, you know, to this product, actually. I mean, the fact remains is we're scaling up and people are going to start using this material, you know, anywhere within 150 miles of a steel plant. You know, our product is going to be the product of choice.

Got it. And so are you, you know, long-term, you say you're scaling. So is that, are you scaling based on, you know, basically just going where a steel factory is? Because I mean, obviously it keeps your transportation low. You're not shipping heavy waste across, across the country to make something. Is that, is that what you're looking at or how, how are you looking at scaling? Scaling this up.

So there's a couple of things there. The first thing to look at is, first of all, we license our technology to existing concrete producers. So we're not out there, we're not building Carbocrete plants, we're licensing the technology. And the concept is to create clusters of companies or clusters of licensees that are not too far from steel plants, you know, to obviously minimize the amount of fossil fuels burned to bring the things all around. But also the cost that's associated with it. So all those things coming together and where we decide where to go next. Got it.

And as you're licensing it out, what is the general response? Or is it— are there any? Is it too cost prohibitive or people really willing to go? What's the reception been?

The cost, actually, the, the materials cost is lower, um, because we're using it better. Um, you know, when you factor in, obviously there's some CapEx involved, it's about the same price. Um, you know, so people are actually contacting us. Um, you know, so it's, uh, it's, it's not something that we're out, you know, we haven't done a lot of outward marketing directly towards companies. People have been coming to us, to us based on what they've read in the news or Heard on podcasts.

Right, right, like this. Well, that— so there really are no drawbacks if it's, if it's cheaper and better or similar and better in every single way. There's really— there's really— it's really a no-brainer at this point.

It is a no-brainer. Yeah, 100%.

Why wouldn't you use this? And, and because you're the same strength, you're able— any application that somebody would have, you know, a regular cinder block or anything, you're You're able to meet, meet that. And is, is there any— how is scaling like volume? Is there— is the production pretty similar? Is there, you know, specific challenges around producing a ton of these, or is it pretty much the same process? Are you able to use like the same equipment to mold it, for example?

Yeah, for the molding equipment, it's exactly the same. The batching equipment— the only thing that changes is the curing system. So, you know, the curing system's got to contain CO2. The standard systems today use heat and steam, and they're not hermetic. So we need a hermetic system because you're putting CO2 in there. So that's the biggest difference. So scaling is not that difficult. It's just that you need to have different curing systems installed in the plant.

Right. But you're talking about only one piece of equipment rather than a whole— you don't need to— if you wanted to convert your entire production facility to this material, you would be replacing one type of equipment rather than a whole system-wide kind of gut and replace.

Hence the licensing model. All the equipment is already out there already, so why not just leverage all that? We don't need to build our own masonry plants because they all exist out there.

Right.

And the sales channels, all that, you know, everybody is— it's a business that's been going on for hundreds of years, right? So, so we don't do, uh, that. We just need to upend how things are done.

Got it. And as you're, as you're going through this, so you mentioned a little bit kind of your, your long-term research that you're doing. You're, you're looking to get into the next zone. Is there, as you've been doing this, is there any similar products? Is it kind of what's your long-term goal here with this material, what you plan to do with the company?

Yeah, so I mean, my long-term goal is to, uh, is to utilize every, every extra piece of steel slag that we can find and turn it into concrete. So that, you know, if we do that based on today's numbers, we can make a billion tons of carbon-negative concrete, uh, you know, and with process improvements and, and, uh, and reclamation of old slag, you know, we could get that to 2 2 billion tons of carbon-negative concrete per year. So that's the endgame for us. That's our North Star and where we're headed.

And how does that line up with the global production of regular concrete? Is that enough to totally replace it, or—

No, it's not. I mean, the global usage of concrete right now, it's the second most used material in the world after water. And so there's about 30 billion tons of it made every year. So that's why I said we're part of the solution to climate change. And a billion tons of concrete is a lot of concrete. So regardless. Yeah.

Got it. And so is it the only— is this steel slag that you're talking about, is that the only source of it then is the processing. So you have your, I guess, your cap, so to speak, is the output of the slag. Is that—

Yeah, I mean, there's that and obviously process improvements. We've already invented a new way that'll see us have a, I would say, a 40% decline in the amount of slag that we need. But like, there's— so all those things will allow us to, you know, be a bit more conservative with the slag usage and therefore be able to make more concrete. So that's an ongoing R&D.

Right. Well, that's good. So there's obviously ways for you to be able to optimize that slag usage and still make a concrete that's usable. Is there— I mean, you talked about there's many different kinds of Use for concrete. Does this— is this something that would ever be able to apply to like roads? Because there's still concrete roads, concrete sidewalks. Is that, is that an end goal, or are you sticking with more of the molded?

There are some opportunities for us to get into other markets like that, but I think what we'll see our company do is cover the masonry market and then get into the know, the precast market, like, like, like Jersey barriers and things like that. Pipes, um, you know, there's a lot of concrete pipes made, um, you know. So I think probably in the precast world, after masonry, I think pipes will be our next, uh, our next invention or, um, scale-up.

Got it. Well, that's still— there's a lot of pipes. I, I've done some projects on, on the pipe end of things, and there's, there's a lot of concrete pipes. that we put in the ground. So that's a huge piece. And so that's great. That's still a huge amount of— if you can produce 1 billion tons, that's a lot of concrete.

Well, look, we're trying to take 150 million tons of CO2 off the table, and it's something that we can do. And it's not 40 or 50 gigatons, but it's on the path to getting there. And like I said, there's many different solutions to climate change, and ours is a no-brainer. It's not direct air capture and sticking it into the ground, which costs $1,200 per ton. This is not a cost center. This is something that makes money for somebody.

Right. Well, and not only does it make money for someone, it is replacing at an equal cost a material that is a problem and replaces the one that undoes some of, some of the problem by itself, which I— yeah, I have no idea why anybody would be able to say this isn't an easy no-brainer to just pick this material.

Yeah, this is like— not to use a cliché, but it's low-hanging fruit, right? This is— it's—

yeah. Well, that's great. I mean, it's great to see that there are low-hanging fruit because I think that's one of the things people are so— they want change. I recently heard a report that 80% of Americans all agree climate change is a problem, which I think is the only thing we agree on that majority of as a country. So that was impressive alone. And it happened to be over climate change. But there's— even when I talk to people, there's still this— idea of everything is still more expensive. There's not solutions that are equal cost that are actually better. And such low-hanging fruit, this is an easy swap. It's great to hear that there's— Well, there are low-hanging fruits.

People say that this will cost more, it's going to cost that in the end, but what is the cost of not doing it? And secondly, to create all the things that we have these days, like the interstate system in the US, the electric grid, all these things required some input from the people. Once it's done, it's done. When the infrastructure is done, it's done.

Right.

I think people need to look at it like that, and that it's an investment, yes, but in the end, you get something that can last a long time and changes the way people do things.

Yeah, I love the highway analogy because that's— I don't know anybody that remembers or thinks about the fact that we didn't used to have an interstate system. That was a huge undertaking to interstate all of the US. And it was just like, we're all so used to it because we live in it. We just hop on a highway and I can go to any part of the country. I can leave to Canada, Mexico on interstates. that have been built way before I was born, and it's just, they exist, right? They just do. And we kind of take it for granted, and we don't remember that it took a lot of time and money and effort to make that happen. But now it's, you know, it's great.

Well, the same thing for years, the same thing with railroads, electric grid, uh, you know, water infrastructure, all that. You know, we take it for granted, but it was paid for. And now people just use it at will. Same thing with internet. Internet is something that's happened in our lifetimes, and we take that for granted. But there was a huge cost to get fiber optics everywhere.

Those cables in the ocean didn't just appear.

Yeah, exactly. So you can call it more expensive, but I mean, it's like solar panels. Once you've paid for them, you just set them up, and the electricity flows. You don't have to feed natural gas into it. You don't have to feed oil or coal. It just kind of happens, right? Through the photovoltaic effect.

Right.

Photovoltaic effect, sorry.

Yeah, exactly. Well, this is super exciting for me. I've talked to people that have more complex solutions for concrete, but they're They're long-term. They're not— they require a new factory or they require a lot of investment. So it's great to see that there's these options where you go, no, we can just swap out a material, keep your plant, replace one machine, and you are now— I mean, if you do it right, I feel like you're carbon negative or close by the time you're—

We are carbon negative. Yeah. That's— I mean, we make a carbon negative product. It's been reviewed by 2 different agencies, our lifecycle analysis is carbon negative. So we actually, we consume more CO2 than we emit.

That's amazing. Well, that's, that's, that is so amazing. It's such an easy— it's a low-hanging fruit and it's carbon negative. Like, that's a— yeah, such an easy win, I feel like. So kudos to you guys figuring out how to do that because that's very helpful.

Yeah, I mean, like, look, I didn't figure it out. I met the inventors at McGill. So the, you know, My business partner, Veerad, had been working on it since 2012, and then I met him in 2015, and we incorporated in 2016. So he worked a lot on this in the meantime. He set out with the goal of replacing cement, and then he came upon this and then realized that you can't hydrate steel slag. So the process of making cement hard is you hydrate it, and when you hydrate it, you know, becomes— gains strength. We cannot hydrate our material. We need CO2. So, like, you know, 20 years ago, people would be like, well, I'm not going to do that. Nobody wants to use CO2 to make concrete. But nowadays, everyone wants to find a home for CO2, right? And we've got this— we've got this distributable way of storing CO2 all over the world.

Right. Yeah. Now we're— now we're trying to use it as much as possible. Yeah, great, great. You guys have found a use, a use for it in concrete.

Yeah, exactly.

Well, this has been— I, I've learned a few things, so this is, this is great. I really appreciate you taking time to share what you guys are doing, and it's really exciting. I, I will be following what you guys do for a while, and hopefully you guys keep licensing more and more because it's It seems like such a no-brainer to swap your factory over and have a carbon-negative product. And that's—

Yeah, well, I appreciate your time, Ian, and, and, uh, and you following us. Thanks very much.

Yeah, and for anybody that's watching that, you know, listens to this podcast and wants to contact you guys, what, what's the best place for people to find you and, and make that contact so they can You can go to our website, www.carbocrete.com.

You can also email me at chris.stern@carbocrete.com.

Perfect. And we'll make sure those are in the description for anybody who wants to just copy and paste. So perfect. Well, thanks again. Appreciate your time. Thank you, Ian.

Take care and have a great day.