Host Daniel Raimi talks with Arvind Ravikumar, assistant professor of Energy Engineering at Harrisburg University of Science and Technology. They discuss methane’s impact on climate change, new technologies used to measure methane emissions, and what governments are doing to encourage the deployment of these new technologies. Plus, Arvind will give an update on how climate change is affecting the annual Iditarod race in Alaska.
Listen to the Podcast
Top of the Stack
References and recommendations made during the podcast:
- “Three Considerations for Modeling Natural Gas System Methane Emissions in Life Cycle Assessment” by Emily A. Grubert and Adam R. Brandt
- “The Mush in the Iditarod May Soon Be Melted Snow” by John Branch, New York Times
- “Burp by Burp, Fighting Emissions from Cows” by Maya Wei-Haas, National Geographic
The Full Transcript
Daniel Raimi: Hello and welcome to Resources Radio, a weekly podcast from Resources for the Future. I'm your host, Daniel Raimi. This week, we talk with Arvind Ravikumar, assistant professor of energy engineering at Harrisburg University of Science and Technology in Pennsylvania. I'll talk with Arvind about methane emissions from oil and natural gas systems, their effect on climate change, new technologies which can detect and reduce those emissions, and what governments are doing to encourage the deployment of those new technologies. Plus, Arvind will give us an update on how climate change is affecting the annual Iditarod race in Alaska. Stay with us.
Arvind Ravikumar from Harrisburg University, thank you so much for joining us today on Resources Radio.
Arvind Ravikumar: Thanks for having me.
Daniel Raimi: So, Arvind, we're going to talk about methane emissions—the environmental implications. We're going to talk about technologies related to methane, and more—but before we do that, we always like to learn how our guests got interested in energy and environmental topics in the first place. What was your path to the world of energy and the environment, and how did you find yourself working on methane emissions?
Arvind Ravikumar: Sure. It's kind of almost by accident that I came into this field—and I'd even say it's one of the riskier decisions I've made in my career. When I was in grad school at Princeton, I was working on developing lasers and sensors that measured gases in the environment and human health applications for, say, disease markers. By a series of coincidental meetings, I got involved in a student group called the Princeton Energy and Climate Scholars, which is mostly a group of 20 students interested in the broad energy and environmental space from different departments. This was Princeton's way of getting students together from various schools, so they can work on interdisciplinary questions.
I listened to people. I got very interested in energy and environmental policy. And, against all practical advice and when I was desperately trying to finish my dissertation in my fifth year, I decided to take two graduate classes at the Woodrow Wilson School for Public Policy (which was not the most fun year). It just became too much work, but that's where I got introduced to a lot of energy and climate policy and energy systems. I decided my fifth year, now's the right time to switch fields and get more involved in this. It was a gamble. Through connections from my professors, I got in touch with Adam Brandt at Stanford and that's when I moved into methane.
Luckily for me, right when I started on methane (this is late 2015, early 2016), was also when the Obama administration was interested in developing methane policy and the US–Canada–Mexico methane regulation agreement was signed. So it became a lot of coincidental events that got me into this field. The interesting thing is, once I started working on this and talking to policymakers and businesses, it soon became very clear that my background in engineering and developing these sensors would be very useful from a technology perspective—looking at methane mitigation and how new technologies can become more cost-effective in managing the climate problem.
Daniel Raimi: Yeah, that makes sense and that's so fascinating. I think probably the majority of people who we have on the show, when we ask them that question of how they got into energy and the environment, it's almost always somehow by accident. But yours certainly wasn't by accident—it was a very conscious decision at a really interesting point in your career. That's fascinating.
Arvind Ravikumar: Right.
Daniel Raimi: We will be talking about this issue of methane emissions. You're an expert on it. I've worked on the topic to some extent as well, but many of our listeners probably don't know a ton about methane. Let's lay some groundwork. Can you tell us a little about what methane's role is when it comes to climate change and how it might compare to the gas that we hear more about which is carbon dioxide? And can you give us some examples of what the major sources of methane emissions are, anthropogenic sources, in the United States or perhaps around the world?
Arvind Ravikumar: Methane, like carbon dioxide, is a greenhouse gas. And for the same amount of both gases, the key issue is that methane absorbs a lot more infrared radiation—and this is what people mean when they often say that methane has a higher global warming potential. But there are key differences on climate impacts between methane and carbon dioxide. For example, one difference is that methane stays in the atmosphere for only about 12 years, on average, as opposed to carbon dioxide—which stays for hundreds of years. Much of the warming impacts of methane are often in the initial few years of emissions, which is why it becomes very critical to reduce it—now—as much as possible.
The other interesting aspect that often gets left out in discussions around methane is that, because it has a short lifetime in the atmosphere, it has very important and interesting implications for climate change and warming. For example, if annual methane emissions are constant, the warming associated with methane is also constant—because methane sort of reaches a steady state in the atmosphere, which means its concentration does not grow. It warms steadily for 12 years. The interesting thing that happens is when you start reducing methane emissions, it actually reduces warming associated with methane. So, in effect, you can consider reducing methane as acting as a cooling effect in terms of climate change.
This is really important—because when you start reducing methane and you reduce the warming effect from methane, it gives you more breathing room, so to speak, as far as carbon dioxide [CO2] emissions go. Therefore, when you talk of carbon budgets, you know, how much we can emit to keep global warming to, say, less than two degrees Celsius, reducing methane gives you that much more room for carbon dioxide. You can develop all of your technologies—carbon capture or negative emissions technologies for CO2—in a longer timeframe than you would if you didn't stop methane emissions. I think this is a key difference between methane, of reducing methane emissions, and carbon dioxide.
Daniel Raimi: Right. It's a little bit more of a flow than a stock-type of pollutant, which is how we think of carbon dioxide, usually.
Arvind Ravikumar: Exactly. The interesting thing is, there are a lot of different sources of methane that go into the atmosphere. For example, in the US, about 11 percent of our greenhouse gas emissions come from methane—and the sources are fairly diverse. The oil and gas industry, which is one of the largest sources of anthropogenic methane, is about 33 percent. And this is spread all the way from production—the oil and gas fields—all the way to the distribution pipelines under our homes. Agriculture is another big source for methane. So, you have fermentation, you have manure management, you have cows and rice fields that also leave a lot of methane that, in total corresponds to about 37 percent. The next big source is from landfills and waste management in cities and states across the world, and that's about 20 percent. There's also methane from coal mining operations—so it's what we call “coalbed” methane—and that's the rest of methane, which is about 10 percent.
There are a lot of diverse sources of methane—and if you really look at solutions for managing or mitigating these emissions, some sectors are easier than other sectors. The key question is: How do we reduce methane from all of these different sectors?
Daniel Raimi: Right. Yeah, and I think one of the reasons why there's been so much interest in the oil and gas sector is because many people have argued that oil and gas systems are a relatively low-cost opportunity for reducing methane emissions. A large part of that is because natural gas is, for the most part, methane. Companies are often in the business of producing and selling the stuff, so it's logical that they would be able to capture it in a relatively inexpensive way.
When natural gas does come out of a well and go through pipelines, processing facilities, it could leak anywhere along that value chain and have the climate change effect that we've been talking about. In the last 10 years or so, there's actually been a lot of debate about this topic because of the shale boom, all the growth in US oil and natural gas production—there've been a bunch of studies that have come out trying to assess how much methane is actually being emitted across the value chain. Can you get us up to speed on our current state of knowledge of methane emissions from the oil and gas system in the US?
There are several parts of this that I'm interested in (and we might not be able to get to all of them)—three of them that I would throw out there are, if you think about the percentage of natural gas that's produced in the US, how much of that is emitted as methane? People often use those percentage terms. Second, what are the major sources within the oil and gas system? Is all that methane coming from wells? Is it coming from distribution networks underneath my house and your house? Then there are still uncertainties here on this topic—so what do we know and what do we still really need to know when it comes to methane? I've been talking too long and I've just asked you three big questions, so take any pieces of those that you'd like.
Arvind Ravikumar: Sure. I'm going to start the uncertainty part because it's really key to understanding why measuring methane emissions is far more difficult than measuring, say, carbon dioxide emissions. The problem with methane, let's just take the oil and gas sector as an example)—the problem is that methane is emitted from a lot of different sources. Unlike carbon dioxide—there, in the power plant, you put a sensor on the stack from carbon dioxide facilities. It measures total volume in a given year. The problem with methane is that a production facility or a pipeline or distribution system—there are so many different components that can actually leak methane.
In a processing facility, you can have hundreds of equipment. Each equipment can have tens of different components that can potentially leak. Now, you look at this and you multiply by the number—the hundreds and thousands of wells in the country, the millions of miles of transmission and distribution pipelines—you're looking at a very large, very dispersed set of equipment that can potentially leak. And measuring them individually is a humongous task. What people normally do is they measure a small part of it. And then, using that data and sophisticated statistical analysis, they extrapolate that to all of the United States. Because of this, there's a lot of uncertainty.
Daniel Raimi: Right.
Arvind Ravikumar: That's where the big uncertainty errors and numbers come from.
Daniel Raimi: Yeah. I think oftentimes people associate methane with the rotten egg smell that they might smell in their kitchen if the natural gas has been left on. But—many of our audience listeners probably know this—that smell is actually something called mercaptan, which is added to natural gas before it is delivered to end-use customers. It's not like you can see or smell natural gas out in the field where it's being produced or transported across most of these pipelines, and just adds another layer of complexity to detecting it.
Arvind Ravikumar: Exactly. Because it's not visible, you need different kinds of sensors to actually see it. What makes it even more difficult is that it's not something where we have predictive power. We can't say when a leak is going to happen—it just happens because things get old. There's wear and tear, someone makes a mistake, so all of these random events makes it even more difficult to figure out when and how much methane is emitted across different facilities.
Daniel Raimi: Right. Can you give us a sense of that percentage figure we were talking about earlier? This is a number that's been much debated but, based on what we know currently, do you have a sense or maybe a range of what we think methane emissions might be on a national scale?
Arvind Ravikumar: Sure. There have been a lot of studies in the last five years that measure methane emissions in different parts of the country. There was a recent paper in Science by Ramon Alvarez from EDF [Environmental Defense Fund] that sort of took all these recent studies and tried to get at a best estimate of what the methane emissions are. They have figured out that the number is about 2.3 percent. What they're saying is, out of gross natural gas production in the US, 2.3 percent of it gets emitted into the atmosphere. This number is interesting for a number of reasons. First of all, it's a good number in that a lot of recent studies have coalesced around the 2 percent to 3 percent value and, thankfully, on the lower end of some of the more out-there predictions on methane emissions. But this 2.3 percentage number masks a lot of nuance.
One thing is, it's very location dependent. There have been a lot of studies where we find that emissions, say, in a gas-rich place, for example, the Marcellus in Pennsylvania tend to have lower emissions than, say, an oil-rich place for example, Bakken in North Dakota. There's a huge variation underlying the 2.3 percent number.
Now, if you look at the life cycle or the stages of natural gas production and use, what we find is that most of the methane emissions are concentrated in the production and gathering systems. The gathering systems are basically those pipes that gather gas from different production wells and bring them together for the next stage, which is processing them and cleaning them up. From a numbers perspective, if you look at it, about 80 percent of this 2.3 percent number comes from the production and gathering stage. The processing, transmission, and storage actually corresponds to about 20 percent. So a lot of efforts in reducing methane should ideally be directed toward the front half of the portion—the production and gathering system.
Daniel Raimi: Right, great. There have been a variety of efforts in this area both on the technology side and on the policy side, to try to figure out smart ways to reduce these emissions. I know one thing that you've done a whole lot of work on is looking at some of these new technologies and trying to get a sense of what might be most cost-effective in allowing us to identify and eventually reduce emissions from the places they occur. As you said, that's primarily what we'd call “upstream”—so near production and gathering facilities.
Can you tell us a little bit about how methane emissions have been detected in the past? And what some of these new technologies are that are emerging—and how or why they're better than the older technologies?
Arvind Ravikumar: Sure. When it comes to managing methane emissions, there are essentially two policy tools that most jurisdictions use to reduce them. Companies and even the governments split methane emissions into two different aspects. One [is] leaks—which happen because of errors and which cannot, or so far cannot be predicted early on. The other category [is] vents. Venting emissions are emissions that are expected, that are part of a process of different processes that happen at a facility.
Daniel Raimi: Right. Those are usually for safety reasons and things like that—right?
Arvind Ravikumar: Right. Those are usually for safety reasons and how certain operations work. Those are normally regulated by putting an annual cap on venting emissions. So if you have a facility, this is how much gas you produce—every facility will have a cap on how much they can vent.
The other part—which is the leaks and where new technologies come in—is typically regulated through a process called “leak detection and repair.” What this basically means, is operators are required to go out on their facilities and look for leaks periodically. In some jurisdictions, it's once a year. In some of the places it can be 12 times a year. The way it's done is often using something called infrared cameras. These are basically like handheld camcorders and they operate very much like any other camera would, but they operate in an infrared region because that's where you can make methane visible.
Typically, two people walk around the facility with a camera in their hand looking at every single piece of equipment that's there and seeing if any of them are leaking. It works. It has good sensitivity and operators can usually find most of the leaks in the facilities. The problem is it's very slow.
Daniel Raimi: Right.
Arvind Ravikumar: I mean, a facility, for example—two people can finish five to six facilities or well sites in a given day. So if you're looking at hundreds and hundreds of facilities, that's a long time. And if the regulation is that you have to do it 12 times a year (or once a month), that becomes a lot of physical manual labor and that exponentially increases the costs of doing these surveys. The key goal for leak detection and repair programs going into the future is how to reduce the cost of doing these surveys and how best to automate it as much as possible, so there's not as much manual labor involved.
Daniel Raimi: Yeah, that makes sense. Can you tell us a little bit about what some of these new technologies are? Some of these new systems, and how they differ from two people walking around an oil and gas field with a camera?
Arvind Ravikumar: Right. This is sort of the most exciting part of the whole methane problem—in that, because of regulations spurred by both states as well as the federal government, as well as Canada, there's been a lot of activity from entrepreneurs and startups to develop new and faster and more cost-effective methane detection systems. You're seeing this whole host of different companies that are developing new technologies. On the one hand, you have all these low-cost sensors that are stationary, that are continuous monitoring—so you just put them on the field and they continuously monitor emissions. And through WiFi systems, they basically send you real-time data into the control room. This does not require any manual intervention and, more interestingly, it is continuous—so it's not about doing it once a year or two times a year. It's about every minute of the sensor that's there. It tells the information on your site, which is great. But there are also other new fascinating technologies.
You have sensors that are deployed on trucks, that are deployed on drones, and deployed on airplanes. Now you have a sensor on an airplane that can fly really fast, about a 150 knots or kilometers an hour, they can fly over a large region very quickly and tag emissions. This is really cool because now you can cover a much larger area in a much shorter time, so the cost of this technology is spread over how many other facilities are under its range.
Daniel Raimi: Right.
Arvind Ravikumar: The key is... so there's a trade-off between speed and sensitivities sometimes. For example, an airplane cannot detect the smallest leaks that a ground crew can detect. The question becomes—where’s that trade-off? Where's that balance? How do you strike the balance between sensitivity and the speed at which you need these things done?
Daniel Raimi: Right. Yeah, that makes sense. The airplane, or the drone, can go over and give you a sense of, very coarsely, where are the big problem areas, and then you can dispatch a crew to that area. Whereas the more manual, field-level, two-people-walking-around-with-a-camera approach is much more sensitive—but, of course, takes a lot more time and perhaps a lot more money.
How much are these technologies actually being deployed today in the field in the US? And do you have a sense of the mix of technologies that are out there? Is the flyover approach happening a lot today, or is it something that's still kind of at a pilot phase?
Arvind Ravikumar: That's a very interesting question, and it's a big of a chicken-and-egg problem here. The way it works is this: every new technology for leak detection surveys needs to be approved by the regulator, saying that the emissions reductions that you get from this new technology are at least as good as the ones that you get from the old technology. What the regulators are saying is—we can't just approve a new technology without looking at the data, without looking at how they perform. What the operators are saying—we can't pilot these new technologies without knowing that they will be approved in the future, because otherwise we are just wasting a bunch of money.
Daniel Raimi: Yeah.
Arvind Ravikumar: There's this chicken-and-egg situation here, and what scientists are trying to do is sort of bridge this gap. We just finished something called the Mobile Monitoring Challenge, where we invited about 10 technologies to test and evaluate their performance. We see this happening more and more in the future—where operators, scientists, as well as policymakers collaborate on trying to get some of the newer technologies out into the field and develop this, sort of, what we call the “equivalence problem” [...] proving that the new technologies are at least as good as the old ones in introducing emissions.
Right now, there are many companies that are starting some pilot phases. We are actively working with regulators, as well as operators, to help get these technologies out there in the field and test their performance. I think there's a lot of movement, there's a lot of interest from the regulatory side, where policymakers are interested in getting these new technologies approved, so everyone is coming together to see what we can do to solve this challenge and evaluate these technologies for a full deployment.
Daniel Raimi: Great. When it comes to this issue of regulation and the chicken-and-egg problem that you describe—there are a number of state governments in the US and also provincial governments in Canada that are, just in the last few years, they've been rolling out new methane emissions regulations on the oil and gas sector. Are there examples of policies or regulatory approaches that are out there from a particular state or a particular province that are helpful in allowing some of these new technologies to be deployed? Or are they all still kind of wrestling with this chicken-and-egg problem?
Arvind Ravikumar: That's a very good question. I think, to some extent, a lot of governments are trying to figure out how best to move forward with these new technologies. I would say the most advanced, in terms of policymaking, would be the state of Colorado and the province of Alberta. They've been up front and center on this issue and they're actively working with scientists and operators to develop these equivalent approaches so that new technologies can be introduced in the methane mitigation space.
One example, the state of Colorado—we are working with them collaboratively and we just started something called the AFOLD Initiative (AFOLD stands for accelerating the future of leak detection), which is basically developing a framework to systematically evaluate new technologies and move them through the regulatory process where they have a chance to be approved by the state of Colorado for leak detection operations. This is a joint effort between industry, academia, and the government. A lot of state government regulators are looking at this and interested in this and part of this initiative. I think in the next few months and years, you'll see something come out of this work in terms of selecting a few technologies to see whether they’ll be able to be deployed in the facilities.
Simultaneously, [in] Canada, because they have federal methane emissions regulations—each province is trying to develop their own framework to comply with federal regulations and also make it more cost-effective for their own province. One example is Alberta: they are very, very interested [in] all these new technologies. We are working with them as well, to help them assess some of the new technologies and have them as part of their regulatory framework.
Daniel Raimi: Great. That makes sense. It's so interesting to hear about all these things developing. One note, just to add onto your comments—some of our listeners might be wondering, why are we talking about states in the US? Why aren't we talking about the federal government? The answer to that is, the federal government, under the previous administration, did develop some regulations for methane emissions from the oil and gas sector, but those regulations are currently on hold and potentially on their way to removal under the current Trump administration. Right now, the action is really at the state level when it comes to methane emissions in the United States. In Canada, of course, it's a different story.
Arvind Ravikumar: Right.
Daniel Raimi: Great. This has been fascinating, Arvind, thank you so much for sharing all of this information about methane. We're going to move onto our final segment—which we do for all of our guests. We like to ask you what you've been reading or what you've been watching or listening to that you find really fascinating and that you'd recommend to our listeners. My co-host Kristin Hayes and I have decided that we want to get in on the action as well. I'm going to make a recommendation very quickly and then turn it over to you to hear what you're most interested in lately.
The “Top of the Stack” item for me today is not really anything to read or see. It's just a factoid related to methane—which is, oftentimes, when people talk about cows and methane, people giggle a lot because they say that cows fart methane. I learned fairly recently that that's not exactly true. Cows actually mostly burp methane. Cows have four stomachs and most of the fermentation happens in the first two stomachs of the cow—so most of that methane comes out of the front end of the cow rather than the back end of the cow. That's my little factoid on methane for the day. Now, Arvind, let me turn it over to you and ask you what you've been reading and watching these days.
Arvind Ravikumar: Definitely—and I think I'm going to make two recommendations. One of them is way out there, and I don't think any of your listeners would have heard this before. I'm a huge fan of mushing and I follow the Iditarod very carefully every year. One of the great things, or one of the most interesting things I've been seeing, especially over the past year, is how much climate change has affected Alaskan communities in the Arctic. For those listeners who do not know, the Iditarod is called the “last great race on Earth.” It's a 1,000-mile race with mushing and typically about 50 to 80 contestants take part every year. It goes from Anchorage, Alaska, to Nome, which is on the Bering Sea coast, on the western coast of Alaska.
Typically, the race happens in March and large portions of the trail go on sea ice, but what happened this year was the sea ice off the coast of Nome in the Bering Sea has been completely absent—so they have been forced to move the trail for the race on land because there's no sea ice there. This is something that's never happened in the history of this race. Over the past few years, we've been seeing many of these mushing races up in the Arctic being canceled because of poor trail and snow conditions because there's been no snow. I think the rate of change they see in these Alaskan communities is very stark compared to what we are seeing in the lower 48. This is something that often gets lost in the news, that climate change is affecting these communities so much these days.
Daniel Raimi: Yeah, that's so fascinating. And when people talk about climate change, we often talk about global average mean temperatures but, as you point out, different parts of the world warm at different paces. And in the Arctic, I believe it is expected to warm much faster than average temperatures.
You had a second recommendation as well?
Arvind Ravikumar: Yes. I just recently came across a paper from one of my former colleagues on methane. They were looking at how methane leakage affects emissions across a whole host of products that use natural gas as feedstock. What they find is that in addition to oil and gas emissions, methane leakage has a huge impact on, say, plastic and fertilizer production. Current estimates of emissions from those sectors do not actually account for leakage and I think, going forward, that is something we have to look into and it's going to be a big part of the conversation when talking about the climate benefits of using natural gas and how methane leakage actually impacts those benefits.
Daniel Raimi: Yeah, great. For listeners who want even more methane after listening to us talk about it for 30 minutes, Arvind, who are the authors of that paper so people can find it?
Arvind Ravikumar: It's Emily Grubert—she's now an assistant professor Georgia Tech.
Daniel Raimi: Great. We'll put a link to that paper up on our show page. Arvind Ravikumar, thank you so much for joining us and sharing your insights on methane and mushing and everything in between.
Arvind Ravikumar: Thank you very much for having me.
Daniel Raimi: Thank you so much for joining us on Resources Radio. We'd love to hear what you think, so please rate us on iTunes or leave us a review—it helps us spread the word. Also, feel free to send us your suggestions for future episodes. Resources Radio is a podcast from Resources for the Future. RFF is an independent, nonprofit research institution in Washington, DC. Our mission is to improve environmental, energy, and natural resource decisions through impartial economic research and policy engagement. Learn more about us at rff.org.
The views expressed on this podcast are solely those of the participants. They do not necessarily represent the views of Resources for the Future, which does not take institutional positions on public policies. Resources Radio is produced by Kate Petersen with music by Daniel Raimi. Join us next week for another episode.