Curious Conversations, a research podcast

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Travis

When it comes to excess carbon, is one solution to simply bury our problems?

While it may sound a little far -fetched to you at first, and is in fact not at all simple, geologic carbon sequestration is a possible solution that Virginia Tech's Ryan Pollyea has been exploring for years. So I was curious what all this entails, what some of the challenges are, and what some of the potential could be, both from an environmental and an economic standpoint. And thankfully, Ryan was kind enough to answer all my questions and more. Ryan is an associate professor in the Department of Geosciences, as well as an affiliate faculty of the Department of Mining and Minerals engineering and the Virginia Center for Coal and Energy Research. Ryan explained what all goes into geologic carbon sequestration, including some of the challenges of not only locating a geologic formation that can hold carbon, but making sure that it's secure for the long term, meaning thousands and thousands of years. We talked about some of the types of rocks that are currently known to be good for this type of storage, as well as some of the work he and his colleagues are doing to explore the use of other types of geologic formations for this work, which could possibly expand this to other regions of the country and even regions of the world. He also shared a little bit about his journey into this space and what gives him hope for the future. So needless to say, this podcast rocks. I'm sorry, I felt like I had to say that. I'm Travis Williams and this is Virginia Tech's Curious Conversations.

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Travis

But yeah, I guess just to start off, what is carbon sequestering? What should I have in my mind when I hear that term?

Ryan

Well, carbon sequestering is a way to reduce the carbon that is coming from basically anywhere. I mean, nature sequesters carbon in oceans and trees and that sort of thing. But when we talk about carbon sequestration sort of from a science and engineering perspective, we're talking about a mechanism or technology to reduce the CO2 emissions from, in my case, industrial sources. So energy plants, electricity plants, coal plants, gas, fire, power plants, they produce carbon dioxide as an emission. And cement factories produce carbon dioxide and steel and ammonia and lots of large industries are stationary sources of enormous CO2 emissions. The same thing is true of cars and trucks. When we burn fossil fuels for transportation, We're putting a byproduct of that is carbon dioxide. But when I talk about carbon sequestration and the kind of work that I'm doing, I'm talking about capturing and sequestering, storing CO2, trying to reduce the CO2 output from an emissions point source emission stream, like a big factory or power plant.

Travis

Okay. How do you capture carbon?

Ryan

At a point source, something like a factory, a gas -fired power plant, a coal -fired power plant, a cement plant, whatever it might be, they have...big flue stacks. They have an industrial process, whether it's combusting coal or natural gas to make energy or heating limestone in a kiln to make cement. The process generates CO2 and basically it's like an exhaust. It's a giant flue stack coming off the factory and it's vented into the atmosphere. So in order to sequester it in the context of geologic carbon storage or geologic carbon sequestration, you first need to capture the CO2.

That's a big chemical engineering problem. And so there's ways to retrofit these flu stacks, the giant exhaust pipes of a factory. There's ways to retrofit instruments or equipment on there that will remove the CO2 from the flue gas and purify it. So, you know, flue gas might be 18, 17 % CO2 from a power plant. And you want to get that up to, you know, 98, 99, 95%, whatever it might be, some higher concentration of CO2 for storage. So there's different technologies to do that absorption methods and membranes and separations. But at the end of the day, the idea is really to just take a dilute gas of exhausts of CO2 and other things and concentrate it to pure CO2 and then we can do something with it from there.

Travis

You mentioned the geological part of this. What exactly, where exactly do you or are you working on trying to store this?

Ryan

Yeah, well, so backing out just a little bit from the geology side of it, before we even put the CO2 into, before geology comes into play, we can ask the question, are there other things we can do with the CO2? So we capture all the CO2. Well, a big part of carbon management or CO2 reductions is try to utilize parts of that CO2. Can we use the CO2 for some beneficial use before we even have to deal with why I'm working on the geology? And the answer is in some cases, yes. We use a lot of CO2 for food stocks. So things like your carbonated water, your fizzy water, soda water, your beer, things of that nature. they require CO2. So, you know, we can use captured CO2 in other places and that's probably the ideal situation because then we're kind of closing the loop on that CO2 emission stream. Rather than getting to the atmosphere, we're getting to the products we call that utilization. Sometimes carbon capture and sequestration is called carbon capture utilization and sequestration. So the U is a big challenge you want. A lot of folks are working on that. Now, once you get through the utilization part of it, you start talking about the storage or the sequestration to use the fancy word.

Now we generate so much CO2 that we can't make enough. I mean, we generate more CO2 than we can produce beer and Coca -Cola, right? So we got to have to do something with all this excess CO2. We don't want it going into the atmosphere. So one technology that we are working with and that a lot of folks around the country are now working with is to take that captured carbon dioxide stream and pump it into deep geologic formations. So we're talking much deeper than groundwater aquavers.

We think about oil and gas reservoirs right there. They've been geologic formations that have been holding liquids and gases for millions of years. The idea with geologic carbon storage is that we're looking for geologic formations that can potentially store our CO2 at many kilometers deep. So, three, two, three, four kilometers underground is where we want to try to put the CO2. And the idea being we pump the CO2 into these geologic formations and then it gets trapped and it gets stored down there. Just like oil and gas is stored for millions of years, we want to try to store the CO2 down there so that it won't escape and go into the atmosphere. So this is a technology to capture at the plant, pump it back into the earth, and keep it out of the atmosphere. And so at the end of the day, that's what geologic carbon sequestration is. It's putting the CO2 back in the earth.

Travis

Okay, wow. I'm glad you mentioned the part about utilizing some of it because I think that was a part that I'd never really...talked about or really read about and but I guess if I was to summarize that we produce a lot of carbon and we'd like to use a lot of it but we simply cannot drink as much soda and beer as there is carbon so we kind of do something else with it right? So we have to do something else with it?

Ryan

yeah that's exactly right.

Travis

So when it comes to putting it back in the earth are there certain types of rocks or certain areas of the country that that where this is going on that have proven better for that?

Ryan

Well we know you know there's if for those listeners that maybe go back to their geology classes and maybe you've taken an earth science class in eighth grade or in college or something on those. In Virginia, it's in middle school and then you might get it again in college. But if you go back to your geology class, you might remember that there are three basic types of rocks. There's sedimentary rocks, there's igneous rocks, and there's metamorphic rocks. The sedimentary rocks are things like sandstone. It's basically sand like you would think about at the beach, beach sand, except it's been what's called lithified. So it's kind of been turned into a rock. So you wouldn't get a pile of loose sand, you'd get a rock, it's a bunch of little cement grains or a bunch of little sand grains with little things holding it together. So sandstone is a really good what we call reservoir rock. Sandstone is one of these types of rock that we get a lot of oil and gas from. And when sandstone and shale are put next to each other, the shale does not allow fluids to flow, the sandstone does. So the oil will...oil and gas will get trapped in a sandstone and sit below a shale. We call that a trap, like a structural trap or a shale trap or something along those lines. And so those are the types of formations that we know can trap fluids for long periods of time. So when we talk about carbon storage, the sandstone formations in what we call sedimentary basins tend to be the ideal kind of case. And there's a lot of folks working on this in the Gulf of Mexico, which are these huge sedimentary packages of rocks. They're looking at it and...Texas and Oklahoma and places where there's a long history of oil and gas because the geology is well explored. We know it can hold gas and oil. And so, you know, the idea is that we think it can hold CO2 as well. Now, that, when you start talking about that type of geology, you limit the geography of where you can implement carbon storage. And so, the things that we're working on in my research group and many others around the country, but sort of one of the things that I think were...getting pretty interested in and making a compelling case for is that there are other geologic environments where this might work. And so we've been looking at places like carbonate platforms. So big limestone packages like you would get down in South Florida. We're thinking about fold and thrust belts, which are kind of mountain ranges where the rocks are really complicated. These are a little bit higher risk, you know, kind of operations, but, you know, they're potentially a very high reward because you have in fold and thrust belts, you tend to have a lot of industry think like Appalachia is a fold and thrust belt. They're in Europe. They're out West you tend to get industry concentrated in places where there's resources and these places tend to have resources, right? So so we're studying these kinds of rocks as a potential place to put co2 and one of the most interesting ones and I've been studying this for some time is what we call basalt so if we go back to our three basic rock types sedimentary metamorphic and igneous Basalt is an igneous rock. Now. This is a rock. There's basically cool lava that's been cooled And this rock is fascinating because the CO2 can go in the water, it will acidify the water just a little bit, and that will dissolve some of the iron and calcium and magnesium ions from that rock. They'll go into the formation and then they'll help that CO2 turn into a carbonate mineral, like lime scale in your pipes. So it's basically using the fractures in the basalt rock like pipes that we want to scale up with lime scale and store the CO2 in a mineral so it's no longer mobile. So.

To answer your question, a very long -winded answer, we typically think about sandstone formations because they're great and we know they're going to work, right? We have high confidence that they're going to work. But we're looking at lots of other places around, lots of rock types, which takes us to lots of places around the world. So, very long answer to the question, but there's just a lot to unpack there.

Travis

Thank you for explaining it that way, as somebody that probably took Earth science in about ninth grade.

I think at this point, I know there are different types of rocks and that they're probably in different types of places. So being able to break it down like that is awesome.

What is the greatest challenge when it comes to trying to figure out if carbon can be stored in these different types of rocks?

Ryan

Yeah, I think that's a great question. I think one of the biggest challenges is that we're talking about kilometers underground.

Ideally, CO2 storage reservoirs occur below about 800 meters depth. Presumably, one to two kilometers. The deeper you go, the more expensive you go. Let's say one to two kilometer depth. We're talking over a mile. When you get down that deep, what can you see? You can't see very much. The geologic uncertainty is very large.

So when we think about the big challenges and sort of unlocking some of this new kind of geology, one of the biggest challenges from my perspective is, you know, we can't see very much. There's methods we can do, like geophysical methods, you know, geophysics from the surface of the Earth that, you know, we send some energy waves down, they bounce off the rocks. We can try to image the Earth a little bit, kind of like an Earth MRI, so to speak, you know, like an imaging method. We can drill holes, which are incredibly expensive, but then you get some, data kind of along a line, a vertical line going down through the geologic formation. So, understanding what the geology looks like is probably the biggest challenge because if we can't store, if we can't ensure secure carbon storage, we spend a lot of money on something that's not going to work and by not working, we're not really contributing to, you know, the benefits of keeping it out of the atmosphere. The Department of Energy has long said 1 % leakage over a thousand year period is what is you know, sort of considered a successful less, if you want to keep successful carbon storage products is less than 1 % of the CO2 leaving your target formation within a thousand years. So that's a, you know, that's a pretty high bar and we have to try to, and the geology is what makes it possible. So seeing the geology, characterizing it, understanding it, I think is the biggest challenge.

Travis

Yeah, that does sound super challenging. So you're working on trying to figure out some of these other geological formations. What is the potential if...We can unlock some of that?

Ryan

I don't have the storage estimates just fresh off the top of my head but the kind of a you know, high altitude a very high level kind of discussion of potential is that we're talking about You know gigaton scale, right? So so very large scale amounts of co2 But we're talking about opening up other parts of the so let's just think about the United States for a minute the

We have sedimentary basins in the central United States. And so if we know that sedimentary basins are the most attractive, lowest risk places to do this, we've kind of isolated ourselves to the central United States. But we have a big basalt province up in the Pacific Northwest. We have the Columbia River Plateau, along with the East Vancouver Plain. These are the basalt rocks. And if there are CO2 sources up there where we want to try to trap the CO2 in like a basalt formation, well, we need to unlock that basalt rock just to see if it's going to work. And so there's folks that are doing that.

In fact, part of my PhD was kind of looking at one part of that problem up in the Pacific Northwest. So that's one region. We're also looking at these carbonate rocks. And so carbonates occur, you know, kind of in some similar places to the, you know, the sandstone formations. But in our case, we're looking at, you know, kind of the Florida area as a place where there's plenty of industry. Of course, if you have a lot of really good high grade limestone, you also have a lot of cement, right? And so cement factories, cement plants use limestone as their feedstock.

So if you have a lot of limestone, you probably have some cement factories, and that's a place where cement is one of these, what we call hard to abate sectors for carbon production, right? It's very hard to reduce the carbon footprint of a cement plant. So we're looking at South Florida, where also, as I mentioned before, we're looking at Fulton Thrust Belt, particularly in the Appalachian Basin. Well, the Appalachians, the kind of geology we have right here in our backyard, would it work?

And so we've been doing some modeling to try to understand based on the geometry of the rocks and what we know about them, which isn't a whole lot at the depths of interest that we need for carbon, will they work? So when you talk about, you know, what is the potential, the potential is leaving the high -confidence, low -risk regions and really expanding out to where you have a lot more CO2 to capture and store because you can't pipe this stuff all over them, you can pipe it, but you can't take CO2 from California and put it into a reservoir in...I mean, that's just too expensive, right? So you want to try to keep the CO2 storage close to the CO2 source. And so matching source and sink becomes a really important part of this kind of problem of, can we capture and store CO2 in this way? If I'm understanding you correctly, it would be really great if we can expand because then we can store carbon closer to where we're actually making carbon.

Travis

If we're able to do that, will that in those areas, will there be some type of job creation component that goes along with that?

Ryan

I think so. I think that when we talk about carbon storage, we're talking about a sort of a burgeoning, a new industry, carbon management kind of writ large is a new place, a new economic, I don't want to say sector, but it's a new part of the economy that there's a lot of effort going into growing and understanding. And so there's, from the jobs in the field to jobs in the C -suite, there's a lot going on in terms of job creation. So I'm most interested in kind of local effects. If we put a carbon storage hub, let's just say in a rural community that's got maybe a factory or two making a lot of cement or plastics or steel or something along these lines, and you put a carbon storage facility in there, what does that do for community benefit? And so we try to think about the halo around what a carbon storage complex could do to the first order, the jobs is a big one. If you think about somewhere, for example, like Appalachia, this is a region where there's a long history of underground subsurface workforce, particularly around the coal fields. So we have a lot of people around here that understand subsurface work. They understand geology and things of that nature because there's a long history of coal mining and coal exploration. So if we now have this workforce that maybe doesn't have the same...prosperity as it once did because the coal has been in decline for some time. And we started thinking about carbon storage. Could some of that skill be repurposed and retrained to work on carbon? I think the answer might be yes. I mean, we're not going to be digging mines and putting people underground for carbon storage, but there's a lot of ancillary knowledge that goes with the history of coal mining in this region in particular that could be useful. Now, the same is true In other places, right, we have a skilled workforce that, you know, the economy has maybe, you know, slowed down a little bit. Can those folks be retrained for carbon? I think the answer is yes. So that's, you know, that's kind of your labor, you know, kind of market. Now you start to think about, well, what about your, you know, your scientists, your engineers, that kind of folks, right? Maybe the consulting type of industry. But I think they're going to be supported by carbon management as well. I mean, one of the important parts of carbon management is the fact that, you know, if it's going to work, we need to have to some extent, some kind of a market driven approach behind it, that market's going to come from the form of carbon credits. And, you know, there's people that have been talking about various forms of trading, you know, these 45, it's called 45Q tax credits is the buzzword right now. You know, it's a federal incentive, a tradeable tax credit. Well, markets are going to build up around that. So now we need to certify these credits. And so I'll say, what's that going to do to, you know, kind of the classic geologic and environmental consultants? Well, they're probably going to start getting interested in, well, how do we certify carbon credits? And so you may have an economic sector kind of building up around around that. Now you have a product that you can trade and you can trade it on the open market. So you better believe that the traders are going to start getting involved. So now you're going to have a whole kind of whole sphere of, you know, kind of financial folks that are knowledgeable about carbon management and carbon storage because they want to get their hands on these credits and trade them around it. So you can kind of see like the halo effect around this becomes pretty substantial, you know, from boots on the ground workforce, you know, to Wall Street. And we're starting to see some of that kind of pop up.

Travis

Wow, that's really cool. And I like that you have thought through a lot of those, like how much this could ripple out. Well, the last thing I want to ask you, and you've touched on pieces of this as we've talked, but I'm really curious, in this space, what gives you hope?

Ryan

Well, there's a couple of things. So I've been, I guess I'm going to go into a little bit of a biographical answer here. So I'm certainly not a first mover. I started studying geologic carbon sequestration in about 2007 when I went back to grad school after spending some time as an environmental consultant.

And then people had been looking at for 20 years before that. So, geologic carbon sequestration, the idea has been around for a long time. But I can remember trying to get papers published when I was first kind of getting into this, particularly looking at putting carbon CO2 into basalt rock, right? This is the igneous rocks that you have stored as a mineral form. And I'll get review comments back saying, we would never do that. Why would we do that? This paper doesn't make any sense because that's never going to happen. And so, there's always been this, and there still is you know, some skepticism around whether or not carbon storage is going to work. Now, what gives me hope is that in the last three years, there has been a tremendous amount of movement in the space. I mean, we spent decades just kind of studying the rocks, studying the fluids, you know, study, study, study, study. But in the last few years, there has been this enormous kind of upwelling of industry, of interest from industry to move the needle on this. And there's a couple reasons for that. Well,

Two of the specific reasons, one is the Inflation Reduction Act and the other one is a bipartisan infrastructure law. So these have the bipartisan infrastructure law sets aside substantial funding for industry to university with university partners and other interested parties, but basically it sets aside money for industry to develop pilot projects, to study the rocks, to do the R &D with a focus on the development part of the research and development.

And so BIL had $12 billion set aside for carbon management and carbon storage projects. That's a billion with a B, right? So now you're talking about if you're an industry, if you're an operator, if you run a business, you're looking at, okay, if I can get some of this federal funding to, you know, that offsets my capital expenditures for actually developing site. But you can't, you don't want to plan on developing a site, which could be a 10 year period, all right, to develop the full capture and storage unless you have a way to project the economics of it going forward. And so that's what the Inflation Reduction Act comes in. The Inflation Reduction Act increased the tax credit to $85 per ton of CO2 stored securely. So imagine a million ton, you have a plant that puts a million tons of CO2 in the atmosphere every year and you can capture a good chunk of that. You'd be looking at $70 to $80 million a year in tax benefit. So...

So now you're, now that's OPEX, right? Because that's moving forward. So now you have operating expenditures. So you've got CAPEX and OPEX and the feds are subsidizing that for the next, you know, probably five to 10 years, depending on, you know, how things can go. So now that has pushed industry into it in a big way. And we have, you know, the big oil companies, Chevron, Exxon, Shell, they're looking at carbon management and carbon storage as a growth opportunity because they can repurpose their skills in underground exploration for gas. They're good at pulling stuff out of the ground. Well, they're saying, well, we're probably just as good at putting it back in. So this is a growth opportunity for big oil. You also have these hard to abate sectors like the cement plants and things of that nature. And they're starting to say, well, we don't have any other options because our process naturally makes so much cement. We can't go to solar fuel and cut our CO2 footprint by that much. That's why we call them hard to abate sectors. So they're saying this is really our only option for carbon management. So they're getting involved.

So we're seeing projects popping up all over the country that spurred by this kind of federal incentive, the projects are coming. There's a lot of money and brain power going into this and a lot of interest that I think we may be coming to a point where we go from research to development to operations and we kind of go through this rapid growth curve of climate tech and carbon storage to where it's kind of like, okay, this is just now a part of what we do and we might be 10 or 15 years from that, but there's going to be a huge installed base of new projects over the next five to 10 years. And I think that that's where I see hope. I think that carbon storage, geological carbon storage, isn't the answer to the climate problem. There's no single silver bullet that's going to solve it, but I think it's an important technology that can help us move the needle in a positive direction.

Travis

Yeah, that's got to be really cool, too, to see some of the research that you did years ago finally start to move into becoming actionable.

Ryan

It's very, yeah, it's satisfying to know that the stuff that we are working on, you know, 10, 15, 20 years ago is now becoming, you know, an important part of, you know, what I hope is a solution, right? I've always, I've built my career around wanting to be part of solutions, right? We know scientists, you know, we tend to be pretty good at identifying problems. But, you know, the solutions is the other side of that. And I like to be part of solutions. And I think this is one of those areas where, Yeah, it's not a perfect solution, but I think it's a pretty good one. And I think it's something that we can do to make a positive contribution now. And so we're training our students and we're contributing to projects that are helping to do that.

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Travis

And thanks to Ryan for sharing his expertise related to geologic carbon sequestration. If you or someone you know makes for a great curious conversation, email me at traviskw at vt .edu. I'm Travis Williams and this has been Virginia Tech's curious conversations.