How Much Methane Escapes from Leaking Natural Gas Distribution Pipes?

I'm Eric Crosson, the CTO of Picarro. I spend a lot of my time out in the field, talking to our customers, learning what they are thinking about so we can make sure that our technology roadmap matches their needs. Lately I've been driving around in circles in Boston and the Bay Area looking for methane leaks. Methane is a potent greenhouse gas that has roughly 25 times the warming effect on Earth per molecule than does carbon dioxide.

Methane is also another word for natural gas. And methane leaks are quite common in the century-old natural gas distribution networks that crisscross this country. Our engineers have built an integrated system designed to locate and measure plumes of methane while driving at normal driving speeds on city streets or even on a freeway. What sparked our interest on this topic was the San Bruno tragedy in California and a subsequent wave of coverage discussing how the country's natural gas distribution systems were obsolete and made from pipes that are prone to leaks.

In a few days of driving around Boston (with Boston University scientist and Picarro user Nathan Phillips), we found numerous leaks, some with concentration levels 15-times higher than the background level for methane in the global atmosphere. The image shows some of those leaks. It is possible that these types of leaks have grown so common and pervasive that they may actually be a significant source of global atmospheric methane. For his part, Nathan is interested in the methane leaks not only for GHG impacts but as part of research into whether the leaks are killing trees in urban areas by changing soil chemistry in the area adjacent to the leaks. The neat thing is, we can do these measurements with an analyzer the size of a large PC placed in the trunk of a Toyota Prius or another small car and pull in near real-time data that can then be layered onto Google Maps to show a stunning visual representation of the plumes that surround us. 

On Wednesday of this week, I'm presenting a talk at the NOAA Earth System Research Laboratory Global Monitoring Conference.  As part of this talk I'll discuss some of my early findings. This is an important part of our ongoing work at Picarro trying to understand the impact of urban emissions on total atmospheric greenhouse gas levels. We've also been talking to cities about helping them actually measure greenhouse gas levels over their areas, as opposed to estimating with software tools. So here's an abstract from my NOAA talk. Look for more interesting research in this area with mobile platforms measuring methane leaks from Picarro in the near future. 

"The identification and quantification of greenhouse gas emissions from urban centers are becoming of more interest. Recent measurements indicate that urban emissions are a significant source of Methane (CH₄) and in fact may be substantially higher than current inventory estimates. As such urban emissions could contribute 7-15% to the global anthropogenic budget of methane.  Although it is known that the per capita carbon footprint of compact cities such as New York City, Boston, and San Francisco are smaller than sprawling cities such as Houston, the strengths of individual sources within these cities are not well known.  Such information is of use to government policy makers because it can be used to incentivize changes in transportation and land use patterns.

In an attempt to identify major methane sources in Boston and Indianapolis, systematic measurements of CH4 dconcentrations were made at street level using a vehicle mounted cavity ringdown analyzer.  A number of discrete sources were detected at concentration levels in excess of 15 times background levels.  Background levels of methane were also measured to be 10% higher than the world wide average of 1.860 ppm.  Measurements of CH4 concentration levels along with detailed location information will be presented.  In addition, chamber flux measurements of discrete sources will also be presented."