Mobile methane detection

Boulder scientist building a better way to monitor air emissions on the go

Christi Turner | Boulder Weekly

Bruce Vaughn is behind the wheel of his pickup, and I’m cradling an iPad in the passenger seat. The screen shows a GPS map of our location and a colored line behind where we’ve traveled.

I’m supposed to be navigating, but I’m absorbed by the iPad. An arrow swivels on its axis and leaves a tail of colored pixels, showing the wind’s speed and direction. Along the bottom of the screen, a colored line graph dips and climbs and changes color as we travel. Colored dots along the left-hand side explain the changing colors of the line.

“The nice thing about this is, let’s say I’m by myself, I can’t really drive and look at that at the same time,” Vaughn remarks. “All this data is being pumped up to the cloud, so it can all be stored and I can look at it later.”

Behind me hangs a large computer monitor, suspended and latched to the backseat to protect it from bumpy roads. A MiFi mobile wireless device sits in the center console. Above our heads, a three-and-a-half-foot mast stamped with the word “PICARRO” is bolted to the roof of the cab, whistling in the wind as we drive. In the bed of the truck, Vaughn has bolted and belted a battery, inverter and two large gray boxes to a wooden platform. Thin plastic tubes connected to the mast wind their way down to the truck bed, feeding into the back of the gray boxes.

This array of equipment and an independent power source have converted his sturdy pickup truck into a mobile methane emissions detection unit. As a scientist behind the scene of the AirWaterGas project, he’s responsible for exploring the equipment’s potential to bring clear data to the hazy debate over methane emissions resulting from fracking.

The instruments hidden inside the gray boxes are what make Vaughn’s mobile laboratory so interesting: one box measures methane concentration and the other reads its isotopic signature — a sort of “fingerprint” that indicates the type or source of methane.

Vaughn’s other job is director of the Stable Isotopes Laboratory at the Institute for Arctic and Alpine Research, housed at the University of Colorado Boulder. He’s a certified isotopic expert.

“Why don’t we go out to a landfill where I know I can get a signal?” Vaughn asks. “From there, we can head out to Weld County.”

We drive to Marshall Landfill in southeast Boulder, capped since 1992. Methane from landfills is biogenic — a result of bacterial decomposition of organic matter in the waste. This is different from thermogenic, or petrothermic, sources of methane — methane that originates deep underground, like in shale beds that store vast amounts of natural gas.

Each type of methane has a distinct isotopic “signature.” As we drive alongside the capped landfill, the Picarro is constantly sampling the air through the plastic tube intakes along the mast and measuring the atmospheric concentration of methane. Any concentration higher than four parts per million — about twice the normal levels of methane in the air — will trigger an isotopic analysis, and the air will be pumped into the appropriate gray box, humming along in the truck bed. The sonic anemometer at the top of the mast — a high-tech wind gauge — can tell where the methane originated, even as the truck moves past the source, ideally at speeds no higher than 30 miles per hour. And all of this complex computing is displayed in real time, in the form of a map and a graph on the monitor hanging behind me and on the iPad in my lap. I watch the display as we talk in the truck.

“We got a little spike! Just 2.18, I think,” I inform Vaughn, adding that even as a non-scientist, the iPad interface seems very intuitive.

“They won’t be big leaks out here,” Vaughn says.

The biggest spike on the graph from the landfill is no higher than 4 ppm; apparently its methane capture process is doing a pretty good job. We expect a different scenario when we reach Weld County, the largest oil and gas producer in the state with more than 17,000 active wells, and a hotspot for the debate over methane emissions from oil and gas exploration.

The recent advent of horizontal drilling in hydraulic fracturing has revolutionized the “fracking” process, making it possible to extract vast quantities of formerly inaccessible natural gas in shale-beds — but it may also be unlocking unknown quantities of methane, contaminating the air and water supply. The Colorado legislature is debating proposed amendments to emissions regulations, aimed at controlling methane as well as other hydrocarbons and volatile organic compounds (VOCs).

Meanwhile, Vaughn’s research with the Picarro mobile methane unit may ultimately help enforce the new legislation and inform the heated public debate.

Will Allison, director of the state Air Quality Control Division, calls the proposed revisions to emissions regulations both firm and fair.

“I think that’s reflected by the fact that we’ve already got support from some of the biggest environmental and industry groups in the state,” Allison says, referring to the Environmental Defense Fund, and major oil and gas players Noble, Anadarko and Encana.

In broad terms, the proposed revisions will do two things: expand the state’s control over storage tanks in the oil and gas industry, and create a statewide leak detection and repair program to reduce hydrocarbon emissions — both VOCs (that contribute to ozone, among other hazards), as well as methane, the second-most potent greenhouse gas behind carbon dioxide. The proposed revisions will be open to public comment on Feb. 19 at a session held at the Aurora Municipal Center, big enough to house the expected large crowd of participants.

While the Picarro is crunching complex data into a precise analysis of methane in the air, Vaughn contemplates how difficult it can be for even a well informed layperson to judge the presence and level of risk surrounding methane emissions in the oil and gas debate.

“I think a significant portion of the power of this technology is that seeing is believing,” Vaughn says. “Providing factual information to the discussion is really important to the issue, and that’s where AirWaterGas comes in. We don’t have an agenda. We just want to provide solid data to support informed discussion.”

Besides, it would be disingenuous to simply point a finger at frackers, or at the oil and gas industry in general. In one way or another, we all still rely on fossil fuels whether we like it or not.

“We just got another spike,” I tell Vaughn — only 2.034 this time.

Eventually, driving by a well head in Erie, the line graph jumps to just above 15 ppm — about eight times “normal” background levels — but that’s the highest number we record on our two hour drive. And taken in the context of our rather small and only somewhat random sample, it’s no cause for alarm.

The Picarro is one of several of technologies that can detect the location, size and nature of a methane leak — like infrared devices, mentioned in the proposed revisions to Colorado’s air quality regulations for methane and VOCs — and could be used to enforce new regulations when they eventually come online. But it is arguably the most sophisticated technology available, three orders of magnitude more sensitive than the competition, according to Picarro Chief Technical Officer Eric Crosson. That’s not to mention its ability to constantly sample the air as it moves, while feeding its analysis into a sleek user interface. I can’t help imagining a fleet of mobile methane measuring machines roving the state, holding violators accountable and answering valid public concerns with clear scientific data.

AirWaterGas is funded by the National Science Foundation Sustainability Research Network and led by the University of Colorado Boulder.