In an effort to help officials measure emissions — and their impacts — researchers at Sandia National Laboratories have built a mobile research facility to measure greenhouse gases. Hope Michelsen, a Sandia chemist and lead project researcher, spoke with me last week about the project, a collaboration with Lawrence Livermore National Laboratory and Los Alamos National Laboratory. Below are excerpts from our interview.
Let’s start from the beginning. Why did you decide to build this mobile research facility? What problem were you trying to solve?
We wanted to understand where greenhouse gases are coming from and what their sources are. In California, there’s a new law in which the state is required to regulate greenhouse gases. There are so many different sources of CO2. In order to mitigate emissions, you have to know what your big sources are. People usually calculate their emissions. You know how much coal you’re burning or how much oil you’re buying. You can predict how much CO2 you’re emitting. But when people estimate, there’s a discrepancy between what you think you’re emitting and what you’re actually emitting.
If you’re the mayor of a city and you want to [create] a policy to limit CO2, you want to know if that actually works. The goal of the project was to figure out if it works. We measure other species of CO2 and each process has a different set of emissions. If you measure CO2 along with other species, you can tell where it comes from.
What does the facility look like? How does it work?
We have two 30-foot trucks. They’re U-Haul type trucks. Inside the trucks are shelves where we have individual instruments. There are shelves on both sides where instruments are mounted. They’re all plugged into cables that go to one central computer. Each instrument measures one or a few species. They’re all running simultaneously. They’re fast instruments. We have one instrument where we suck in air masses and store them in a cylinder. We ship those off for analysis. Everything else is continuous measurements. We deployed it last fall in Oklahoma for six weeks.
You make a distinction between biogenic (coming from plant sources) and anthropogenic (coming from man-made sources) gases. Why is that important?
CO2 has a large biogenic component. There’s a lot of CO2 being sucked into the biosphere. During photosynthesis, plants will take up CO2. That’s during the day, when the sun is out. At night, they emit CO2. A large amount of CO2 is coming in and out of the plant. That variability is larger than the anthropogenic component of CO2.
If you’re worried about climate change, you have to understand how much we’re emitting relative to the biogenic. We want to know if a big puff of CO2 is coming from a plant source or a refinery. That’s why we’re trying to measure other [gases] because they’re associated with anthropogenic emissions.
We didn’t already have tools to make these types of measurements?
People have been trying to figure out what the carbon cycle is — how plants are emitting CO2 and taking it up, how it’s going into the atmosphere and the oceans. There’s a network of sensors run by different agencies. The National Oceanic and Atmospheric Administration is probably the most well known. They measure CO2 and some of the other carbon species. They’ve been doing this for decades. Because they’re trying to answer a different question, they’ve been trying to place [sensors] far away from anthropogenic sources. Their sensors are in remote locations.
What we can do is come in with a mobile lab, sit next to an anthropogenic source and measure all the species. We target something that they try very hard not to look at. That’s the role we play. We’re taking the baseline of the carbon cycle work and adding this targeted approach to understanding the anthropogenic sources.
Is the device commercially available?
We have two trucks. What we see in the future is having multiple trucks. If someone needs us, we could go and make emissions measurements.
We’re still in the phase of figuring out how to do this. The complications are not just how you make the measurements, but where. How do you do modeling to figure out where the wind has come from? We’re going to have to work out a lot of that. Sandia does a lot of technology development that someone then takes over and uses. We don’t do monitoring ourselves.
Photo, top: Mobile research facility / By Hope Michelsen
Photo, bottom: Hope Michelsen