Transcript:

Brad Newbold 0:00
Hello everybody, and welcome to We Measure the World, a podcast produced by scientists, for scientists…

KATE SMITS 0:07
Okay, we got this project. We need to measure the gas concentration the subsurface at 50 locations. What do we have that can do it? Oh, by the way, we don’t have anything. Okay, so let’s try to figure out how we can match what’s commercially available with some different techniques to engineer a casing and then test that in our lab, of course, before we then go deploy it into the field and try to address all of the field issues and conditions.

BRAD NEWBOLD 0:37
That’s just a small taste of what we have in store for you today. We Measure the World explores interesting environmental research trends, how scientists are solving research issues and what tools are helping them better understand measurements across the entire soil, plant, atmosphere, continuum. Today’s guest is Dr. Kate Smits. Kate is a professor at Southern Methodist University’s Lyles School of Engineering, serving as chair of the Department of Civil and Environmental Engineering and the Solomon professor for global development. Prior to SMU, she was a professor at the University of Texas at Arlington, and an associate professor at the Colorado School of Mines and the US Air Force Academy. She earned a bachelor’s degree in environmental engineering from the US Air Force Academy, masters in Civil Engineering from the University at Texas at Austin, and Doctorate in Environmental Science and Engineering from the Colorado School of Mines. She served as a civil and environmental engineering project manager and officer in the US Air Force, and her research interests are focused on energy and the environment with applications to natural gas leakage, the cleanup of contaminated soils and waterways and the storage of renewable energy, and today, she’s here to talk to us about her most recent research on natural gas leakage from pipelines. So Kate, thank you so much for being here.

KATE SMITS 1:52
Thanks, Brad, yeah, great to be here, and thanks for the invitation.

BRAD NEWBOLD 1:54
With all of our guests, we would love to get to know you better. And would you be able to tell us a little bit about your background, how you got into sciences in general, and what brought you to, you know, Civil and Environmental Engineering.

KATE SMITS 2:06
Yeah, I’ve, I’ve always, always really loved science and engineering since I was young. The thing that that attracted me to environmental engineering is my passion for this intersection of engineering solutions to environmental problems, and most environmental problems also involve the complexity of humanity, and I love working at that intersection between environmental issues that involve both science and engineering and this whole human aspect to it as well. And so that’s always really, really motivated me. And I’ve always wanted to to work in that area in my career.

BRAD NEWBOLD 2:47
Was there a specific, I don’t know, a specific trigger during your education where you said, Yes, this is the path. I was thinking about some other things, but I want to go down this road now.

KATE SMITS 2:55
Yeah. So when I was, when I was an undergrad student, I was at the US Air Force Academy, and I actually wanted to major in aerospace engineering, is where I really, really thought I was passionate about but I met a professor when I was there. Guy’s name is Rod Jenkins. He’s retired now, and I found his work so interesting and motivating, because with environmental engineering, we study lots of issues. So not only the traditional aspects of environmental engineering, a lot of folks see us as either landfills or sanitation engineering, and that, of course, if we go back 50 years, was the foundation of it. But his work was really pulling in energy issues and sustainability issues, and I found that really fascinating and motivating to major in that field. But in terms of of research, I didn’t get interested in research until I was back teaching at the Air Force Academy, so I had a master’s degree. I was still on active duty in the Air Force, and went back to the academy to teach. And one of my advisors that was there, John Christ, who’s also an environmental engineer, he started introducing me to a couple of different papers that he had been working on in the biological field that was on environmental remediation using a specific organism that was Dehalococcoides. And I started reading these papers, and started noticing the holes in the research, as I like to call it. The holes are the gaps in the knowledge. And it was really the first time that I ever acknowledged that that I was going, Oh, I can see where there needs to be additional research or an improvement, and that was the first time working with him, that I was able to experience that and go, Oh, I think that’s really fascinating. I’m curious about these gaps, and I have ideas on how to. Fill those gaps and how to address some of the questions that arise, because before that, I never understood how to do research or how to come up with a question that was even novel. I always thought that’s for really smart people, not necessarily for for me. And, you know, didn’t, didn’t have that level of confidence yet, but that’s one of the things that really drove me into wanting to to stay in academia and be a professor and work with students and help them to find that pathway with with research. So I find that very motivational to be a faculty member and my favorite part is, is getting to work with students. We mess up the whole faculty positions with all the admin crap that we end up doing, but, uh, but in general, you know, the the teaching, and especially the teaching of graduate students through that mentoring with with research, I find absolutely, uh, wonderful.

BRAD NEWBOLD 2:59
You mentioned, you talked about some of the beginnings of environmental engineering. Could you back up and kind of give us a quick overview of that discipline and its overlap with and distinction from, you know, civil engineering and environmental science?

KATE SMITS 6:15
Yeah, absolutely. And this is Kate’s version of it, so I’m sure there’s a there’s a more technical version of it, but environmental engineering really stemmed out of civil engineering, where we had sanitation engineering, so treating water and wastewater, and then landfill trash management, and that held with the major for a long time. And the thing that then made it, I think, break off from just being part of civil engineering, is what you’re getting at Brad, is this intersection with environmental science? Because with environmental engineering, it’s really this bringing together of an understanding of chemistry and biology and physics as well as the whole engineering process and mindset, and how to integrate that around issues that have to do with the environment and making engineering processes better and more sustainable and more environmentally focused initiatives. Today, I think environmental engineering is really moving more forward with the integration of sustainability and big focus on energy and energy issues that we have, and that includes traditional energy issues as well as renewables. And so it’s an it’s a neat place to be and see how the degree and then the different career options have branched into a lot of different areas over the years. But yeah, but I think it’s it’s a great degree for students who are interested in this intersection of trying to solve engineering problems, but doing that with an environmental focus and an environmental motivation and mindset.

BRAD NEWBOLD 8:05
Right, right. I was also checking on your LinkedIn bio, and you mentioned there that you’re looking into the development of socio technical systems and creating models to better understand those I was that caught my attention. I can you tell us a little bit about what you mean by social or socio technical systems?

KATE SMITS 8:30
Yeah, we, I mean, we could, we could go on a down a rabbit hole on this one for a long time, but to give you the skinny on it, a lot of times as engineers, we look at any sort of problem as it has an engineering solution to it and that can work, and a lot of folks that go into engineering are motivated by those engineering solutions. However, as engineers, everything that we engineer has a human behind it and has a huge social component to it. And so what my work really looks at is how we can integrate both of those, not just look at them individually. Because I think a lot of the work in the past with engineering and with social issues has been parallel, as opposed to integrated efforts, but really looking at how we can address an issue from both the social components and looking at all of the human aspects behind it, and integrating that with an engineering solution, I think, is critical for us going forward. And there’s so many examples out there of engineering solutions that have failed, and the number one reason why they fail is because they don’t consider integrated stance, or integrated component, that social component. And you know, maybe we, oh, but we went and we talked to a couple of stakeholders, or we. Did a survey. You know, as as engineers, we like to say, oh, that checked the box in terms of considering the social component. But what we know is that it doesn’t. And we need to go a lot deeper into the understanding of why people do things, why their why their system is the way it is. Maybe the folks that we’re trying to design something for already have the solution. But, oh, by the way, we failed to ask what that solution, solution set is, because we thought we knew better, or we had this fancy education. And, you know, how could they know the solution? We’re just going to take our engineering hammer and put put it behind it. So a lot of my work integrates those components into the the overall solution set.

Brad Newbold 10:47
So it really is a kind of a interdisciplinary, or at least it could be, or should be interdisciplinary between, yeah, engineering, environmental science, you know, even getting to sociology, organizational behavior, all that kind of fun stuff.

KATE SMITS 10:47
Absolutely, I work with anthropologists, and just like you said, engineers and scientists and you know, to truly integrate those on equal playing fields within the solution set, as opposed to seeing certain things as as an afterthought.

Brad Newbold 11:15
You’ve done a lot of work in and we mentioned this in your bio your research interests are varied when it comes to environmental engineering, and one of your more recent projects deals with natural gas leakage from pipelines. And I think this is interesting, just because here on the podcast, we’ve talked a lot about soil scientists, or we’ve talked with soil scientists, and we’ve talked a lot about, you know, water movement through through soil or nutrient transport, but this is the first time I think that we get to touch on and discuss gas movement within the soil. So I’m super excited to talk about this project. And I just want to know, just as a background, how did getting into natural gas, how did this come about? What is the background of it? What are the objectives? Can you just kind of give us a little bit of insight into how all this got started.

KATE SMITS 12:03
Yeah, absolutely. So my PhD work was on multi phase flow and transport through porous media, and it was sponsored by the Department of the Army, by urtic, the Engineering Research and Development Center, and we’re looking at land mine detection and how, if we can better understand the environmental conditions in which landmines are placed, we can work that understanding into the algorithms that the army is using to detect the mines. So to give you a simplified example to detect land mines operators can use ground penetrating radar, they can use thermal imagery, they can use some sort of gas sensing. And what normally happens is they’ll use multiple technologies in unison, and then, for a lack of a better word, triangulate the data, right? So if you have some understanding of a moisture difference, if you have some understanding of a temperature difference, and maybe you have some sort of gas sensor, when you look at all of this information together, you can then better understand, do I have a buried object that I want to respond to, or do I have something that’s maybe a buried rock or a buried soda can. And so what we were working with, it, with the army, is if we can take the understanding of the environmental conditions work that information into their algorithms that they’re using to detect the mines, they’ll have less false positives, spend less time, manpower, money, digging up stuff that is is not actually there. And so through that experience with my PhD, I had the opportunity to look at that both through experimentation and then through mathematical modeling. And so with the experimentation, we were measuring moisture content, like you mentioned, Brad, we were mentoring the measuring temperature, thermal properties of the of the soils, and then really getting into differences in surface properties and how that was impacted by changes in weather conditions, and trying to integrate all This information and what that really led me to question, or try to understand better, is the gas itself. So if we have these buried objects that are that are made up of explosives, over time, the gas is going to start to come out of these buried objects, and it’s going to move through the subsurface, through a very tortuous pathway because of the soil, because of the differences in soil type, because of the moisture that’s involved, that’s creating these torturous pathways. And those gas molecules are eventually going to get to the surface, and then they’re going to exchange with the atmosphere. And maybe there’s. An opportunity to be able to use gas sensing more more intentionally, to detect the mines, both in the atmosphere, on the surface or even below the ground. So if we had some sort of device that we could do that, then we could better understand the detection of the land mines, and so that then got me questioning quite a bit of, where is the gas going, and how is the subsurface impacting that gas transport? How is the differences in the surface type, and whether that be a grass condition or a sand condition, pavement, etc. How is that impacting the exchange processes between the soil and the atmosphere, and then after those gas molecules get into the air, how are the changes in the weather conditions really impacting where that molecule goes? And of course, when we’re talking about measurement, if we’re trying to measure something below the ground, it’s going to be a different approach and at different concentrations than if we’re trying to measure it on the surface, or if we’re trying to measure it in the atmosphere. So all of that understanding of the flow in transport from a gas perspective, then got me linked up that with the questions of natural gas leakage from from pipelines. So the work there actually started through a couple of projects that were sponsored by the Department of Energy. So I’m going back over a decade now, when I was a assistant professor and then an associate professor, and so I paired with a researcher at Colorado State University, Dan Zimmerle, on a Department of Energy Project, and did a small portion of a huge effort. So we’re talking, you know, 100k portion of a multi million dollar project to try to understand Leak Detection linked with natural gas leakage from below ground environment. And to make a long story short, we did a great job. My students and I did a great job on this effort that it really then started growing legs, as I like to say. And that research project then led to another research project sponsored by the Department of Energy’s RPE, which then led to research that I do now through the Department of Transportation’s Pipeline and Hazardous Materials Association, as well as some Colorado groups and industry groups on natural gas leak detection. And so my interests now are multi functional, multi phased right? So it’s on the the behavior of the gas in in the subsurface, how that’s impacted by both operating conditions as well as the soil and transportation conditions, and then how we can use that understanding of that transport, both below ground and above ground, and integrate that into our leak detection technologies that we’re using to mitigate gas leakage and and therefore its occurrence and and its consequences. My interest specific to pipelines is because of the vast network of pipelines we have in in the United States, there’s over 2 million miles of natural gas pipelines throughout the United States, and so this includes all the way from the source, so our gathering lines all the way to the customer, and these distribution lines and the transportation lines in between. And there is a great need to be able to understand the leaks from these pipelines and how to find them and fix them. So ultimately, my goal is to be out of a job once we figure out how to find these leaks effectively and fix them and do that efficiently, so that that I can move on to other topics.

Brad Newbold 19:05
With the pipelines that you’re working with. You talked about, you know, the distribution the gathering distribution lines, and this is all compressed natural gas. Is that? Is that correct? I mean, guess we’re not dealing with like liquefied gas that would be for large transport or things like that, right? All right. So we’re doing those compressed gas, natural gas, again, for those in our audience who may not know that we’re dealing with methane, colorless, odorless, a huge, you know, greenhouse gas when it comes to, you know, efficiently trapping heat, right? But so, yeah, so very, very important to be able to, yeah, transport this safely. And as we’ve seen, unfortunately, it’s highly flammable, so there’s, there’s definitely lots of potential issues when it comes to how best to manage natural gas and its flow and transport and all of that. I’m super interested in, in your project setup, and because you guys got to build stuff and testing things out that, I guess from the stuff that we’ve seen. Previously with other environmental scientists and soil scientists and others. A lot of times they don’t get to build stuff to test things out. And so can you tell us a little bit about your about that setup that you’ve you had going on?

KATE SMITS 20:10
Yeah, absolutely. So the best part of my job, besides working with students, is getting to be creative in the lab and in the field with experiments, what we typically do is try to measure things in new ways that haven’t really been done before. So we oftentimes have to take commercially available systems and then modify them, sometimes a little bit, sometimes a lot, to meet our purposes, and that’s because of two reasons. Number one, because we’re poor academics and don’t have the funding to go buy fancy dancy equipment for everything, and so we want to to be able to kind of build it ourselves, is what ends up happening. And number two, because maybe there’s not something that’s commercially available, so there’s part of it that is, but we need to modify it in some way. So I’ll give a couple of examples of that. So most recently, with my work with natural gas and pipeline leakage, I’ve built test site in collaboration with Colorado State University, and specifically with Dan Zimmerle, Zimmerle’s research group at the Methane Emission Technology Evaluation Center. So it’s called METEC. And as part of METEC, we have a pipeline test bed. And so the pipeline test bed consists of about 50 below ground controlled leak locations that will simulate different size and type of leaks from the subsurface. And so what this allows us to do, which is what we cannot do in in the field, in a normal field environment, is to know the ground source, as I call it, so we know the actual size and type and composition and location of the leak. And if we know that information, we can then ask and address a whole variety of questions around it. And so that’s what we’ve been doing with this test site. So the test site set up, if you can imagine, about an eight acre site that has, like I mentioned, these 50 below ground leak sites that we can turn on and turn off. And we can do that from really small leaks to really big leaks. So from for leak people out there, it can go anywhere from about one standard liter per minute all the way up to about 200 standard liters per minute. So that’s about 2 to 400 standard, standard cubic feet per hour. So that’s a tiny leak that you would see in a distribution system all the way to a really big dozer of a leak that would make the front page of the morning news. And then, so what we do is then instrument the subsurface, the surface, in the atmosphere with a wide variety of sensors, so that we can continuously monitor the soil moisture. So in terms of the soil properties, we’re interested in the soil moisture and pressure and temperature, and then from a weather perspective, we’re interested in measuring all of our weather variables. So we use, for example, the Atmos 41 that y’all have, I think it measures like 12 weather variables. So we have those set up all over the site. Then we measure our subsurface natural gas concentration. So we’re actually measuring methane and ethane below the ground. And so we do that at anywhere from two locations up to about 50 locations at a time below the ground. And then we do that on the surface. And then we also have atmospheric sensors that are measuring the methane concentration and the Ethane concentration. And so when we’re measuring the the subsurface gas concentration, if you can imagine a gas leak and putting sensors in the ground, the the concentrations are going to be much, much higher than the concentrations once that gas gets into the atmosphere. So the sensors we’re using for atmospheric measurements are trace gas sensors. So this is at like the part per billion range, but when we’re trying to measure below ground gas concentrations, or surface gas concentrations, we can measure in the parts per million range. And so we’re able to use a sensor that is less accurate, has less sensitivity, is oh, by the way, a lot cheaper, but we can then do so at a higher space and time, higher spatial and temporal resolution than we can in the atmosphere. If we’re using a trace sensor in the atmosphere, that sensor is. Is going to work amazingly for trace gas concentrations, but if we take that same sensor and stick it below ground, it’s going to come unglued because the concentrations are too high. So it’s very important to match the sensor with what we’re trying what we’re trying to measure. So the sensors that we use for measuring methane below ground, it’s a INIR sensor. So it’s an IR absorption sensor that’s commercially available, and I think it’s made by SGX or something. Anyway, that sensor is normally used in some sort of it’s not a fire alarm, but, but some sort of emergency alarm system. And what we we did with the sensor is we created a new casing for it so that it would not be affected by the subsurface conditions, because in the subsurface, we have really high humidity. Even if the moisture is low, the humidity is still really high. And then, oh, by the way, we often have high moisture, and so we needed to be able to have a sensor that could operate in that environment, but do so within the range of concentrations we were trying to, trying to measure. And so, you know, to be able to do that was a lot of fun, because it was, I always call it a pre project, to a project. So, okay, we got this project. We need to measure the gas concentration the subsurface at 50 locations. What do we have that can do it? Oh, by the way, we don’t have anything. Okay, so let’s try to figure out how we can match what’s commercially available with some different techniques to engineer a casing and then test that in our lab, of course, before we then go deploy it into the field and try to address all of the field issues and conditions. And so we’re real successful about being able to do that with our subsurface sensors. Did the same thing with a surface sensor, but with a different type of sensor. We’re using catalytic oxidation sensor for our surface and our below ground, near surface measurements, and then trace gas analyzers for our atmospheric measurements. So I think what makes our experimental setups really unique is that we’re able to measure the entire continuum for gasses, so both in the surface, on the surface, and in the atmosphere, and then link that with all of this weather and soil data, so that we have this complete picture of what’s going on in the environment. So it creates these massive data sets that are also very powerful, because it takes away a lot of the ambiguity in, oh, well, we’re going to blame it on, you know, on one process, one physics process versus another, we can actually measure it and then understand the whole picture.

BRAD NEWBOLD 28:00
With a lot of these, these measurements, are you? Are you testing these out in the lab as well as the fields? Are you comparing lab results versus field results with with these measurements?

KATE SMITS 28:09
Yeah, yeah. We do a lot of calibration and validation in the lab. So in my lab, I have soil tanks that are various sizes. Some are, you know, the size of a fish aquarium that you’d have in your house, all the way up to some larger ones that are maybe about the size of a car, and we instrument them with these same sensors and run pilot scale tests in the laboratory. Other times, we run smaller stuff where it would just be. We use the term a Tempe cell scale size, so just the size of a large coffee mug that we instrument with one sensor and then run gas through it, change the soil moisture. We have a controlled temperature room in my lab where we can make it really cold or really hot and change that condition, and then test out how our sensors are operating. What I’ve really learned over the years, and I’m sure Brad, working METER you can, you can resonate with this, is that it’s really easy to get average data, really easy that you can just okay. I can read a user manual, I can plug in a sensor, and I can get data what’s really the whole as I tell my students, the devils in the details, what’s really difficult is to get scientifically repeatable and verifiable data that you really trust, and that involves a lot of steps to go through so that we can weed out, you know, where the problem is in the data set, or in the operation or in the person that is operating the sensor, in order to get data that we trust. And so when we go to the field and we’re trying to measure the whole soil atmospheric continuum continuously at high space and time resolutions, we need to be able to do that and have all sensors operating in unison together. So we do a lot of practice, like we’re going to play in the lab, to figure out how this is all working before we go and do that in the field. And you know, even after, you know, trying to do this multiple years, we still, every time we have a field experiment, we have hiccups. But yeah, there is Yeah, but the goal is to have that backup, right, and duplicate, if not, the triple it, so we can ensure we at least get the data that we need. Because that’s always the question, okay, what’s kind of the most amazing data set that we could get, and then what’s the bare minimum that we need? So if we’re not at least going to get that bare minimum then, yeah, then it’s not worth running the experiment.

BRAD NEWBOLD 31:03
Right, tangential question, but I think it’s related. Do you what is your prefer preference, lab or field work?

KATE SMITS 31:12
Yeah, so I started in the lab and was trained by lab scientists, and I think that that gave me a level of detail that I bring to the field that perhaps some field scientists don’t necessarily have because they started in the field. So I’m very thankful that I was able to start at start at the lab. My preference is looking at field scale issues. And it seems as I progress in my career, I keep getting bigger and bigger, going from just maybe a plot scale to an area, to a basin to a region. And I think depending on on the question that we have, we need to scale the experiment to the question, it’s just my questions have evolved and changed to looking at, okay, how do we understand how to quantify emissions from a single leak, versus how do we understand what our emissions are at a basin or at a regional scale so we can work that into an EPA inventory of greenhouse gas emissions. Those are two totally different questions that involve two totally different experiments. Both have absolute validity and both need to be addressed. It’s just how we would address them would be would be different, but at this point in my career, I enjoy being in the being in the field, but it clearly has different challenges associated with it, especially working in oil and gas fields. And you know, for example, down here in Texas, going out to the Permian Basin in West Texas in July is not for the faint of heart. I always tell my students, it’s, it’s more than just sunscreen and bug spray. You know you need, you need to be in shape to be out there. And withstand that heat for working in the field for for a few days.

BRAD NEWBOLD 33:16
Yeah, so, yeah, yeah, no. I always liked having that balance as well. Like, yeah, you’re in the lab, stuck in the lab for a while, and you’re like, man, I need to get out. And then you get to go out and do field work, and you’re like, out there for a while, like, okay, I’m done. I can go back inside. Let’s go find some air conditioning. So it’s good to, it’s good to have that, that balance.

KATE SMITS 33:33
Absolutely, yeah, I think, you know, I talked to a lot of students, and they’re so well, motivated and minded of they are interested in environmental work because they want to be in the field. And I would just encourage students, even if you’re working in the lab and you just have this heart and desire to be in the field, know that everything that you’re learning at that smaller scale, at, you know, at the REV scale, or at the pilot scale in the lab will do you wonders when you finally do get to the field, and, you know, and vice versa. So I think that there’s benefits to both. And I think the folks, you know, and this is, again, I could talk about this forever, but folks at various scales, we don’t communicate with each other enough, so we have all these interesting findings at the poor scale that very often don’t get translated to that representative elementary volume scale, that don’t get then properly translated to that field scale, because I think we undervalue the bridges and the intersections between them, you know, and that’s due to how many issues, but in part to how we’re funded for our research, right? And, you know, and that doesn’t then value that that linkage part.

Brad Newbold 34:52
So with all of the setup at your test site, and you said that you’ve tested things out these various leaks in different situations. Situations, different environmental factors in play. What were some of the results then, what are the findings that you came across? What did you learn?

KATE SMITS 35:07
Yeah, absolutely. So most recently, we were looking at the impact of different surface conditions on the gas transport below ground, and what we were really able to show with that work was the relative difference in the distance that the gas was moving and the time that it was moving when we had different surface treatments. So to give you an example, if we just had a leak that was in a grassy field, and then had take that same leak and put it under pavement, and as a result, that the impact of just that one change in the surface condition. So if you can imagine a leak being under a driveway, for example, compared to the leak being under, you know, in someone’s front yard, just in their in their grass, the impact is an eight times further and about a four times faster gas movement in that paved environment compared to the unpaved environment. And so by having this, this ability to run these tests very systematically, we’re able to put values behind ideas that maybe fundamentally we already knew that, okay, you take a pavement, you put a cap on the ground, of course it’s going to make the gas move faster underneath the ground, because it can’t get out. Everybody knows that. It’s the duh kind of kind of factor. But the point being is what we didn’t know before was by how much and what the timing was the timing associated with that. And so those are two very interesting findings to first responders and two operators who are trying to prioritize fixing a leak. And so from a first response perspective, the reason that that finding has a lot of impact is because if a first responder, so I’m talking about a fire, fire group, or hazmat group, comes to a site. They don’t know what’s going on underground. They they’re just, they have some sort of optical imagery sensor, or some above ground sensor that they’re just measuring concentrations in in the air or perhaps on the surface, but they have no indication of the the the spread of the gas below ground, and so this gives some indication of that spread from a repair perspective. That helps us to that helps operators to potentially prioritize repair. So if we have a leak that is is in and I’m just keeping it simple with pavement versus we looked at many, many conditions versus grass, but it helps with the prioritization of repair based on the spread and the timing of that leak. What we also looked at was transient conditions. So in the case, maybe we have a snow pack that occurs. So maybe there’s a known leak, and that leak that then there’s a snow condition that’s then impacting the escape of the gas from the subsurface. That snow condition then turns into a melting snow condition, which would be similar to an infiltration front of water that’s going through the subsurface, and perhaps compressing the area that’s available for the gas transport that’s then pushing the gas out and pushing the gas downwards. And what we were able to do with this work is to actually quantify that with how far and how fast the gas would travel when we have these changes in our environmental conditions, and so the way we translate that to practice is a couple of ways. So yes, we go write our fancy journal article papers that maybe someone does or doesn’t read, depending on who you are, but in terms of operators, they don’t read our fancy journal article papers, no matter what the impact factor is, because they probably don’t even have access to them. And we write them in such a way that you know only if you have a PhD in the area you can really even read them right. And so what we do it to translate that science understanding into impact and into operator. First Responder practice is creating things like reference manuals by creating PowerPoint presentations that we then publicly have available that first responders can work into their hazmat training. For example, we translate that through at CSU METEC, we call research alerts. So this is just again, a publicly available, hey, we ran these experiments. We found this information, and I’m going to try to explain it to you in a simplified way, so that we can have that connection to either industry or operator practice or also, I failed to. Mentioned folks that are doing the the leak detection, so the solution providers and how they can work that knowledge into their practices as well. And this is just giving one, one example of of some of our some of our findings, but I really want to highlight how what we’re trying to do is not just have this science finding. But how can we then take that and work that into practice, by partnering with industry and partnering with our our first responders, to make it meaningful to them, and again, talking about something that’s that’s under valued in the research world. It’s that translation of the of the impact to different communities, because that’s a hard thing to do, because we have to, you know, try to explain something, and then whoever we’re explaining it to has to go, well, that either makes sense or it doesn’t make sense. And how can we, you know, how can we have that conversation and make it something that’s usable versus something that, oh, well, that’s just a science finding, and I’m not sure how to implement it. So it involves knowing thy, you know, knowing thy user, knowing the practice, which takes, uh, takes a lot of effort.

Brad Newbold 41:13
Yeah, yeah. I was gonna say, do you, do you have any lessons that you might be able to share with with folks? A lot of our audience are scientists and and there’s always issues in being able to communicate to various stakeholders. Like you said. You can communicate within the academy to you can have your your your papers and articles that can be very dense. But on the other hand, there’s often times when scientists need to and researchers need to communicate with the lay public. And so, yeah, do you have any any thoughts or lessons on on things that you have either, I guess, either found successful or found success in or, or otherwise? Yeah,

KATE SMITS 41:48
I the one that comes to mind is one of my students, recent master’s student, and when he started, the first thing that I put him on was a review of what I call gray literature. And gray literature is not the the published, peer reviewed journals, but this is is things like YouTube videos and websites and chat rooms and such. And it was really a review of the gray literature on leak detection and quantification methods for pipeline pipeline, scenarios specific to pipeline scenarios. And I said, there’s papers out there, I want you to put those aside for a while and really just focus on the gray literature and the the understanding. And he did this for about a month. And then, after looking at that, I have my students give short presentations, short summary presentations, on the bottom line of what they’re what they’re finding. And you know, it’s really interesting that he was already identifying, just after a month, some major holes. I said, Well, what do you think you need to do to fill those holes? And so I need to talk to operators. I said, Okay, I’m going to open up my rolodex for you, you better not mess this up. And here’s a handful of operators that I want you to go interview and talk to about their experiences, but first go figure out how to frame the questions properly and how to do that interview process right? So he spent a good month putting together these questions, reviewing them with myself and a couple other colleagues, to the point that he was then available to be a good, interactive interviewer, right, which is an art form, as you, I’m sure, know from your job, exactly, and you know, and through this process, he was really able to, number one, build a network of industry folks, of first responders, of solution providers that he has then used for his entire master’s degree. This would be the same way for a PhD student, right. But then also just have that knowledge of what is, what am I really trying to solve? It’s one thing to say, oh, you know, methane emissions, and I want to decrease greenhouse gasses. So yes, that’s important, but what is the actual thing that you’re trying to solve, and who’s the person on the other end of it? And I think having us identify those things at the really early stage of the research is absolutely critical, and it takes getting off of just the typical pathway of I’m going to spend all my time, you know, running this mathematical model or designing an experiment, both of which are extremely important. But it’s taking a step back and saying, Let me truly understand the problem before I try to find a solution set to it. And so I think that problem identification with the people who are experiencing the problem is key. So any way to really get into the actual practice of where. The problem is, is and embedding ourselves in that for a period of time is critical. And the student I was talking about, his name is Richie. He was he was great. He got to the point where he was developing his own relationships with these industry operators, and was then going on leak detection survey operations, because he goes, well, I need to see what they’re actually doing in the field, and taking three or four days to go do that, and, you know, and walk around or drive around with folks, or fly UAVs, and understand their opportunities as well as their limitations with their practice. So I think that that is ultimately the key, is finding the way into into understanding the understanding the the true problem, through integrating ourselves into it, going all in.

BRAD NEWBOLD 42:11
You’d mentioned modeling, and I know that modeling is part of this project as well. And as you create, I guess, predictive models from from your findings, what, what are, what would be some of those key parameters that would be the main, I guess, the main drivers for for gas flow within the soil?

KATE SMITS 46:08
Yeah, yeah, the models, we use different types of models. And again, just like with an experiment, it’s matching the model to the question. So one model does not work for all sizes and shape of of research. But when we’re looking at gas movement through the soil, it’s, it’s caused by four, four main different things. So it’s caused by the gas moves due to a concentration gradient. So this is your diffusion through the through the soil. It moves due to a gradient in temperature. So be your convection density differences. So these buoyancy effects and then pressure differences that we often call advection through the soil. And so when we have a leak from a pipeline really close to the leak itself, the main driver of the gas movement is due to the pressure differences, so that advective transport. But then as we move away from the leak, the concentration gradient takes over. So we have more of a concentration this diffusion effect as we move away from the actual, actual leak location. And then, of course, throughout we have these gradients in temperature, and that is more influenced when we’re close to the surface, and due to the diurnal changes in the in temperature and then density. Well, methane is a light gas, and so of course, buoyancy will will come into play there depending on the amount of methane versus other components that we have in the natural gas mixture. And so with our work, one thing that we have focused a lot on is that diffusion effect. Another finding that we had that was really interesting, that we were able to show, first through our experimentation, but then really confirm with our validated numerical models that were validated based on all of this experimentation, is the impact of the diffusion on the gas transport, because that’s a that’s a major one, when we’re talking about especially these low level leaks that persist for long periods of time. And so you get this diffusion transport, this diffusivity that occurs over time. And even if that leak is turned off, you are fixed. If you think about the outer edge of a gas plume, the constant, because you still have a concentration gradient on that outer edge, you you still are going to get diffusion, so you’re still going to get transport away from the actual leak location. And that was another interesting point that industry hadn’t necessarily considered in in all of their practices, that okay, you know, normally it’s a we fix the leak, and the leak should eventually, the gas should clear up in the subsurface, and it does over time, depending on the conditions. But that outer boundary of the leak, what we were really able to show, can continue to creep out about three to 4% for just your average leak situation that’s underneath some sort of surface barrier. And so you know that three or 4% difference in distance may or may not be important depending on the leak scenario that’s occurring.

Brad Newbold 49:34
So I know we’ve got a lot of soil scientists around here, and they would get upset with me if I didn’t ask about how the soil and soil characteristics affected that flow of gas, whether it’s, you know, permeability of the soil, or soil moisture or other other characteristics?

KATE SMITS 49:50
Yeah, permeability is a is, is a big one with our gas transport. So when we have a highly permeable soil. Soil, the gas is going to move quicker through it than a low permeability soil. The thing that’s interesting to me, and this may sound stupid, but your soil scientists are going to be laughing, is when I talk to the lay public, they get porosity and permeability mixed up a lot. You can have a soil that has a high porosity but a low permeability. Is a concept that just I it just I never realized, because of my background in training as well, that that would be something that folks wouldn’t quite understand. So you take clay, for example. Clay has a really high porosity to it, but it has a really low permeability. So what happens is the gas gets trapped in the clay, and a lot of it because there’s a lot of pore space that’s available for that gas to go and so this is an issue in in the field I take I’ll just give you an example down here in Texas, where we have a lot of clay soils, and there was an incident, I think it was back in 2019 in Georgetown, Texas, where they had to shut down a huge area of Georgetown, Texas. I don’t know what the total area is off the top of my head, but was for a long period of time, months, and it was, it was both housing and industry areas, so commercial, commercial areas with a gas station and a dry cleaner and restaurants, etc, because of natural gas that had gotten into the clay and They couldn’t get it out. And and that’s because of that permeability issue. So yeah, it got in there, and a whole bunch of it got in there, but they couldn’t get the concentrations below the proper safety levels. Just like you were saying Brad, that natural gas is highly explosive. Methane is lower explosive limits 5% and then the upper explosive limit, I think, is 11% so you have this range where you know, yet we really have a have a problem. And so of course, the those values for operators are even lower that they’re concerned with concentrations, and they couldn’t get the gas removed from the subsurface due to this high porosity, but low permeability soil. So this is something that we we consider in our models. This is something that we consider in our experimentation is looking at different soil types, looking at different soil layering, because in a lot of cases, we may have a sand soil, for example, that’s then overlain by a clay soil that maybe you then have some sort of top soil situation. And so looking at how we can incorporate different soil, soil layers, soil textures, and then, of course, different soil moistures into our into our understanding when we do our experiments, one thing we then go try to back out from a field perspective, how does, how do operators look at soil and soil types? And just, I’ve never done an actual survey on it, but just asking people of you know, just go ask your kids, right? Of what? What are the different types of soil that exists? And you know, they’ll say, well, there’s a clay, there’s a sand, and there’s something else, maybe. And in general, even if you ask very educated people, that’s kind of how they view soil, right? As as soil scientists, we love to look at the whole spectrum of soils and all the little idiosyncrasies in each one that then impact the physical and thermal properties of the soil and hydraulic properties, but the rest of the world views soil, I think, in these larger categories, and how we can integrate that understanding with what we’re seeing with our experimentation and numerical modeling is again, always, always a challenge.

BRAD NEWBOLD 54:08
So from here on out, what are the applications elsewhere? What can you take and, you know, share with stakeholders or others when it comes to helping improve, I guess, you know, mitigation, prevention, even getting into regulation, or, you know, policy frameworks, how? What are the next steps there? And I guess, what are the implications of what you’re finding here?

KATE SMITS 54:28
Yeah, that’s, that’s a great question. So what we’re really showing is that the environmental conditions have a big effect on where the gas is going, both below ground, and after that, gas escapes into the atmosphere, and this information then impacts number one, the first responder response, but then number two, the leak detection, and specifically your chance, or your probability of detecting. The leak, and what we’ve been looking at, most recently, through a project that’s sponsored by the Department of Transportation’s PHMSA, is how weather conditions and subsurface conditions affect the detection probability, and looking at that for all of the different mobile survey applications so to detect a leak, operators use one of a wide variety of leak detection methods. So the most traditional one is doing a walking survey, where you’re taking a sensor and walking along a pipeline extent. Another one is driving along that same pipeline extent using a mobile operation, so a vehicle with sensors mounted on the vehicle. There’s also UAVs, or fixed wing to aircraft, and then, more recently, using satellites to try to detect leakage. And so what we’ve really been showing is, first and foremost, pipeline leaks are different than above ground leaks. So if you have a below ground leak, and this can be a pipeline, or it could be a well, or anything it could be, we could talk about carbon sequestration sites. We could talk about a hydrogen pipeline or a carbon dioxide pipeline, because of the subsurface environment that’s going to impact the development of the gas plume, the surface presentation of that plume, and therefore the exchange with the atmosphere. And so none of that, to my understanding, is currently being incorporated into our Leak Detection protocols, where the leak detection community has developed based on above ground leak scenarios. So we’re talking about leakage from infrastructure on, well, pads or these. I don’t even know what the above ground stuff is called, but the same solution set can’t be translated to below ground leak scenarios. And we’ve, we’ve really been showing that and the impact of the diverse environmental conditions on the detection probability. And so just to give you a very simple example, we know if it, if it’s raining, you’re not, you’re going to have a less chance, less of a chance, of detecting a below ground leak than when it’s not raining. The question is, by how much? And we can also say that about the, you know, about the wind conditions, about the atmospheric stability, then we can, we can link in the operator practice. So what if we’re walking or driving or flying a UAV over a pipeline, extent versus being, I don’t know, five feet off of the pipeline extent. How’s that impacting our detection probability? Or if we have our sensor that is mounted at a certain location on our mobility unit, on our vehicle, or if we’re changing the speed of our Leak Detection operation, and how can we pull all of these different variations in both our practice as well as the environmental condition into an understanding of how to better detect leaks? And so we’ve really been trying to pull that together from a policy perspective. Most recently, there’s been some regulations that have draft regulations that have come out through the Department of Transportation, PHMSA and then through the Environmental Protection Agency on leak detection. And our work is is really foundational, from a science perspective, to those regulations when we’re looking at trying to define what sensor minimum detection limits are needed, and how we can properly define that we may need a different minimum detection limit from an above ground leak than a below ground leak, but we don’t know that unless we do the science behind it. You know, more recently, there’s been a focus with the EPA on measuring emissions from natural gas infrastructure, and so in the past, that’s been done through a process called emission factors. And we, you know, we need to get more science and, you know, and testing into the development of those emission factors that then can serve as a foundation to part of the regulation that that happens piecemeal, as as we all know, in our system, and you know, and I think the more that we as scientists can think about how our own work translates to to policy, or how we can do work that could potentially inform policy through the that science foundation and understanding, I think, is really important.

Brad Newbold 59:57
So that leads into, then my final question of. About the future of this research. What do you see going forward next 510, years or so? Are there any emerging technologies that you’d love to get your hands on? I mean, you talked about UAVs and satellites. What do you think is is, yeah, is in store for for this kind of research?

KATE SMITS 1:00:15
Yeah. I think really looking at the understanding between these, we call them bottom up versus top down inventories of greenhouse gas emissions is an interesting space. When I talk to solution providers, there is a lot of disconnect between understanding of what we’re measuring, what we think we’re measuring, and what we’re actually measuring, and a lot of that is because of a lack of validated testing, so controlled testing, where as as I mentioned before, we know the ground truth, and we can run either the same test over again or or look at the impact of changing just one variable on our outcome. And I really think that we need to do that more. I think we need to do that at a larger scale. The issue with that is that the solution set is not always the same for all leak scenarios. The other thing that I think we need to be looking at from a sensor perspective, is how to measure leakage, both the existence of a leak and then the amount of the leakage. So you know, the concentration and the volume, especially in light of carbon sequestration. And you know, we talk a lot about using the subsurface to store stuff, but we don’t think a lot about, well, how do we know that that’s actually working? And it’s, it’s, to me, it’s a bit of the cart before the horse. And we really need to think about what it is that we’re doing and how we’re ensuring both the safety and the environmental concerns that are associated with that. So I think that there’s a lot of interesting questions in that space as well.

BRAD NEWBOLD 1:02:07
Any final thoughts, anything else you’d like to share before we wrap things up?

KATE SMITS 1:02:11
No, I think your questions were fantastic, and appreciate the opportunity to share some of my research. So always loved talking about about research opportunities, and especially with you all so using a lot of your moisture sensors and atmospheric sensors over the years. So appreciate that.

Brad Newbold 1:02:33
Oh, good. Well, thank you. We appreciate you coming on, Kate, thank you again. Our time’s up. Yeah, it’s been a really interesting conversation. Again, like I said, this has been the first time that we’ve really been able to talk been able to talk about gas exchange and transport within within the soil. So it’s been really enlightening. It’s been fun.

KATE SMITS 1:02:48
Thanks, Brad. Appreciate it.

Brad Newbold 1:02:50
And if you in the audience have any questions about this topic or want to hear more, feel free to contact us at metergroup.com, or reach out to us on Twitter @meter_env, and you can also view the full transcript from today in the podcast description. That’s all for now, stay safe and we’ll catch you next time on We Measure the World.