One of the many challenges facing the world in the coming decades to reach carbon neutrality – in order for climate change to stabilize – is the challenge of both capturing and sequestering carbon dioxide that is emitted from power plants and putting it underground. This is what is called Carbon Capture Utilization and Storage. And accomplishing this on a large scale will be necessary all across the world to meet carbon emissions reduction goals laid out by the Paris Climate Agreement.
It turns out that Utah has some high potential to become a reservoir for captured CO₂. A number of state and federal agencies, and research institutions like the University of Utah, have been exploring this possibility for a few decades already. And one person involved with this work is Liz Mahon, a Wilkes Center Postdoctoral Scholar in the Department of Geology and Geophysics at the University of Utah. I recently had the chance to sit down and talk with her about her work. (Featured image: The Arizona Wave, a famous geologic rock formation in Pariah Canyon, Utah.)
Listen to the Interview:
Transcript:
Ross Chambless
Well, Liz Mahon, welcome to the show.
Liz Mahon
Thank you.
Ross Chambless
Well, before we kind of just talk about your current research. Could you just fill us in a little bit about your background as far as where you have been in your journey as a scholar and researcher before you have arrived here in Utah?
Liz Mahon
Sure. So, I’m a geologist specifically a sedimentary geologist, and I’m interested in ancient environments. I kind of initially became interested in that through an interest in environmental science. I actually originally wanted to be a park ranger when I was a kid because I like camping. But I ended up going down the geology route in my undergraduate degree. I studied a Bachelor of Science and took a geology class and loved it. So, I kind of consider these days that I research ancient environments rather than modern environments. So, after I finished my undergraduate degree, I went and worked in industry. So, I worked for Chevron on the CO2 Gorgon Project in Australia. And then after that I went and did a Ph.D., something I’d always wanted to do at the University of Melbourne in Australia. I was looking at ancient coastal plains and shorelines in the Gippsland Basin in Victoria.
Ross Chambless
So, what is it about geology that you came to really love or appreciate? You know, where did that interest come from?
Liz Mahon
You know, I’m not sure. It’s kind of like modern environmental science, but for me, it’s just a bit more interesting. It’s a little bit more mysterious. You know, there’s life forms that don’t exist anymore that are preserved in those sedimentary rocks. I think it’s really interesting to see the way ancient environments are preserved. So, you can look at, you know, sandstone and mudstone and work out that that was a river 100 million years ago and that sort of thing. So, it’s kind of a puzzle, problem solving sort of thing.
Ross Chambless
Yeah, absolutely. Well, so now to shift to your current research focus here at the University of Utah within the Department of Geology and Geophysics. You’re looking at the potential for CO2 storage in roughly this area, in the Colorado Plateau. Can you talk about that?
Liz Mahon
So, this project is looking at the Glen Canyon Group. So that’s a geologic group which is approximately, I think 210 to 170 million years old. So, from the Mesozoic. And it is composed of really beautiful sandstone. I think a lot of people have probably seen lovely big sandstones in Utah in a lot of the national parks and things. So that particular geologic group is what we call an aeolian sand or a desert deposit. During the late Triassic Jurassic time, Utah and a lot of the other states around here were a massive desert dune field, what we call an erg in geologic terms. They think it was probably one of the largest ergs, definitely one of the largest that we have preserved in the rock record, probably one of the largest on Earth. So a huge, huge sand sea.
And the reason that’s important for CO2 is sandstones make really great reservoirs. So, they have lots of little spaces between the sand grains, the porosity and permeability, which are really good for storing fluids. So, I’m looking at the Glen Canyon Group from you know, a depositional environment perspective and how it can be used to store CO2 in the future.
Ross Chambless
Interesting. So, I was looking at your initial proposal for this project. And it was interesting to read that for a lot of the global climate change emissions or greenhouse gas reduction goals, that carbon capture, utilization and storage seems like it’s going to be essential for meeting those goals. And there seems to be abundant CO2 storage resources globally that are identified, but how it’s going to be stored and sealed needs more research. Is that true?
Liz Mahon
Yeah, basically yeah. We’ve identified that there’s a lot of really great sandstones around the world and not just sandstone. In fact, you can store CO2 in other lithologies, but, what needs to be done is like a really good geologic analysis. So, you need to look at things like how will that CO2 move through the sandstone? Is there any faults that might cause leakage? Is there a rock unit above it that will seal it? And, you know, fluids and gases and things are constantly moving through our rocks. They’re not static. So, you know, over the timespan of hundreds to thousands of years, we have to do forward modeling of what kind of behavior will that CO2 plume in the earth kind of do. So, yeah, there’s lots of geologic work that needs to be done before we can kind of successfully store lots of CO2.
Ross Chambless
Right. And I understand the federal EPA is requiring essentially these potential reservoirs to be tested and basically thoroughly inspected before any sort of large-scale efforts happen?
Liz Mahon
Yeah, that’s correct. In fact, CO2 storage, the Paris Agreement was to limit our average global temperature to 1.5 degrees Celsius by 2100. But in order to do that, we need to get to net zero by 2050. And in order to do that, we need to be storing CO2. So, it’s actually an integral part of that kind of forward plan of the Paris Agreement. So yeah, it’s an essential aspect. As far as a way, I don’t think we can meet those targets without it.
Ross Chambless
Interesting. So, with this particular project who are the partners you might be working with? I’m guessing, are there any state agencies or federal agencies or other university partners focused on this project?
Liz Mahon
Yeah. So, there’s actually multiple kind of CO2 investigators projects underway in Utah right now. The State Geologic Survey, the EGI at the University of Utah, and then industry as well. So, there’s a lot of interest and there’s a lot of focus in Utah, and to be honest, globally. It’s understandably receiving a lot of focus because it’s just so important.
Ross Chambless
Yeah. When you say industry, I’m guessing we’re talking about industries that release a lot of carbon dioxide in the in their processes. I mean, are we talking power plants?
Liz Mahon
Yeah, that’s right. So, there’s been some work done on trying to work out how to capture that CO2 that, for example, coal plants are releasing to try and capture that and then store it in the ground. Similarly, for example, the project I worked on in Australia, CO2 was a component of the natural gas. So rather than just releasing it into the air, we can try and store it in the ground. So, CO2 storage has actually been undertaken for quite a while, decades at this point. In the past industry have used it for what they call EOR – enhanced oil recovery. They inject CO2 into their hydrocarbon reservoir and it kind of flushes out the oil. So there is some pre-existing experience with industry companies with doing that. But we’re kind of shifting the focus now to instead of, you know, trying to maximize our hydrocarbon input, we’re trying to store that CO2.
Ross Chambless
And to clarify, I mean, your work specifically is looking at the sort of long-term storage potential and not necessarily the capturing of the CO2, correct?
Liz Mahon
Yes, that’s correct. I think the capturing is actually quite a tricky part. And hats off to the people researching that, because I think that’s quite complex and I’m kind of relieved I’m not researching that bit.
Ross Chambless
Right. But given that those folks trying to figure that out are successful in some way, then it would come down to your work, of how we actually take that CO2 and keep it underground for a long time?
Liz Mahon
Yes, that’s correct.
Ross Chambless
And so, what are you learning about CO2 – Carbon dioxide? Once it is deposited underground in certain areas, are there chemical changes that occur? What happens to it down there?
Liz Mahon
Yeah, so it can be a little bit complicated. It’s a bit of a geochemistry involved. So, we have to take into account things like the minerals that are in the rock that you’re injecting the CO2 into. So, CO2 can make water acidic. So, it will dissolve in the water. So once your groundwater becomes a bit acidic, it can just start dissolving minerals like calcite or other minerals that are particularly susceptible. And that can have actually an upside. So, by dissolving minerals, you increase your porosity and permeability, which is your storage capacity. But you also then consider things like pressure and temperature and will those minerals reprecipitate elsewhere and things like that. So yeah, there’s a bit of chemistry involved.
Ross Chambless
Yeah, well I’m sure those are the things that you’re looking at with this kind of research, you know, I guess the potential of it to move around. Does it shift underground at times? Could it be triggering earthquakes? Could it be impacting groundwater? Is there potential for it to leak? Those kind of things?
Liz Mahon
Yeah, so, risk mitigation is a big aspect of this. We can do sort of forward modeling using computer software where you input all of your data, information about the rocks, about the geology. And then you can predict the behavior of the plume in the subsurface. So, we can kind of incorporate that aspect into our research, so we know if there’s going to be any big issues. For instance, we know that the plume may migrate toward groundwater. Or if there’s a fault, we won’t put the CO2 where there’s a fault because it will leak. That sort of thing. So yeah.
Ross Chambless
Well, and with your kind of research what sort of tools are you using, I mean do you use a lot of computer modeling or are you actually out in the field doing sort of test injections and seeing what happens? What are the main tools that you that you use?
Liz Mahon
Sure. One of the really nice things about the Glen Canyon Group is that it is both in outcrops, so we can go and walk around it, but it’s also in the subsurface. So, it’s really useful where we can go and actually look at the rocks. We can take samples; we can make observations and record data. And then we can apply that information into where it occurs in the subsurface, where we might potentially inject CO2. In addition, there’s also a lot of subsurface data. So, with industry interest in the geology in Utah, there’s well logs, and there’s a little bit of seismic data, and there’s core, which is where they’ve drilled the rocks in a well. So, we can kind of take a combination of our outcrop data, our subsurface core wireline data, and put that together and build a really robust geologic model. So, it kind of reduces the uncertainties and we can put together multiple types of data.
Ross Chambless
Interesting. I’m curious, just looking at the field generally of carbon capture of CO2 and sequestration, because I know this area of research has existed for some time, at least as far as I know, several decades. But what’s your sense of how it’s matured or advanced as far as general understanding of its potential uses? People are continually studying it and learning more, right?
Liz Mahon
Yeah, that’s right. And it is quite a complex sort of science or process. It has many, many variables. So, you could do a study on a particular place in the world and that works great and it’s awesome. But you move to a different geologic locality and it’s different, you know, the rocks are different, the pressures are different, the groundwater is different. So, it is quite a complex thing to research. So, I think it is a proven kind of process. You know, industry have been using it for a while for EOR, but there is still quite a bit more to do because of all those variables that we’re kind of trying to put together. So, I think as a kind of a whole, it’s actually coming along quite well. Like I think we’re learning a lot every time we do a test project, another organization has a go, we learn. So having more interest on it, we’re learning more and getting better and better.
Ross Chambless
And so, you were doing a lot of research in Australia and now coming here. What is your sense of maybe similarities or differences in the geology of sort of Australia versus here in Utah?
Liz Mahon
Well, Utah is known for its beautiful rocks. Yeah, where I was based in Melbourne, the rocks I was looking at were buried under the seafloor. So, my primary data was seismic data, 3D seismic images, the subsurface. So, in that instance, I couldn’t really go look at the rocks. And I was also looking at coastal plains and coals and things. Here I’m looking at desert systems, Aeolian systems, beautiful sandstones that are in outcrop, which are really lovely. I’m really excited to do a bit of fieldwork when it stops snowing.
Ross Chambless
Something I wanted to mention too, that I also find fascinating, and you mentioned something about this, about your interest in ancient landscapes and understanding the early living organisms, what life was like on this planet many millions of years ago. What we’re talking about, the geologic layers that we’re talking about as far as where this CO2 would be injected into, and really maybe it’s a little ironic, is that those are the same time periods – if you think about the geologic layers in that way – I’m guessing like the Jurassic or Triassic periods when we had various many different kinds of creatures that don’t exist on this planet, where this carbon originated from that was plant matter. And we have harvested it for energy and emitted it. And now we’re trying to put it back into that time period. Is that an oversimplification? What do you think?
Liz Mahon
Yeah, I agree with that. We have Mesozoic coals and rocks and things. There is an irony there. I also think it’s quite a nice synergy that the Mesozoic was a greenhouse period, so CO2 levels were higher during the Mesozoic. And now we’re looking at putting CO2 back into those rocks. So the Glen Canyon Group is an example of a massive desert system that formed during a greenhouse period when CO2 levels are really high. So, the earth was really hot. So, it’s a nice kind of analogy of Earth history from past to future, but then also using that rocks because they make excellent reservoirs.
Ross Chambless
That’s fascinating. It is a fascinating cycle that we’re participating in, if you think about it that way, in engaging with the history of our planet.
Liz Mahon
Yeah, that’s right. I think the geologic history of Earth is just fascinating. I think it’s really interesting. A lot of people are really kind of interested. I wish we did a little bit better with our science communication and education of geology when kids are younger, but it’s such a fascinating thing. And the concept of time is quite interesting, too. You know, we tend to think on a much different timescale as geologists, you know, in millions of years rather than hundreds.
Ross Chambless
Yeah, absolutely. Well, I agree we could do better as far as our education with children and especially talking about geology. I remember one thing that really fascinated me was there is a museum down in Price, Utah, where they have collected a lot of dinosaur footprints that were actually collected, gathered by coal miners there, because when they were working in the coal seams, they were routinely find these dinosaur footprints that were actually falling out of the ceiling. And they were quite hazardous. Sometimes they have to bolster them so they wouldn’t fall. But just that sense of, you know, they were working in a very different period and there was evidence of it all around. Even above them.
So, I just find that really interesting as far as when you start digging into the ground and what you see. And then obviously now it’s the focus of very important research, such as what you’re doing.
Liz Mahon
Yeah, the preservation of Earth’s history is really fascinating. The way that we can preserve beaches or swamps or a footprint. It’s a moment in time. It’s like a little snapshot for that little moment by a life form that doesn’t exist anymore.
Ross Chambless
Well, just a few more questions. As far as long term, in the next few years, where do you hope that your research will take you? Do you have any short-term goals or long-term goals that you’d like to see happen with this?
Liz Mahon
So, I’m hoping to kind of do my small part in contributing to kind of solving these global warming issues. I think it’s a pretty important aspect that’s affecting our world right now. So personally, I’m happy to sort of help where I can with that aspect. And so hopefully over the next two years, I develop and produce some nice research that helps with that. And then after that, who knows?
Ross Chambless
Well, yeah, we’ll have to invite you back next year and see where we’ve gone. And since you’ve landed here in Utah and you’ve had a little time to explore, I’m just wondering what you enjoy doing in your free time when you’re not hard at work doing research?
Liz Mahon
My free time? Good question. So, I guess it’s currently winter. It’s a bit snowy. But I usually like to get out and do some bushwalking, camping, and I’m hoping to go and try a little skiing. I haven’t quite got the I haven’t got a car. I’ve got to work out how to drive on the other side of the road.
So, once I do that, yes, generally getting outside when the weather’s kind of yucky, it’s nice to stay in. I like to do a bit of art, a bit of drawing and things. So, yeah.
Ross Chambless
Wonderful. Well, Liz Mahon, thank you so much for talking with us.
Liz Mahon
Thanks for having me.