Most concerns about environmental impacts and other risks from leaking natural gas have focused on the fast-expanding production end of America?s vast system of wells, compressors and pipelines. But the urban maze of (often ancient) pipes that carries gas to furnaces and stoves has long been known to be leaking, as well.
Earlier this year, to take a snapshot of this problem, scientists from Boston University and Duke University took equipment that detects methane ? the main constituent of natural gas ? on a 785-mile van ride through Boston?s streets. The result, published today in the journal Environmental Pollution, is a map showing more than 3,300 spikes in gas concentrations representing leaks of various sizes. [I'll add a direct link soon.]
My friend Beth Daley of the Boston Globe has a thorough piece on the findings that is well worth reading. Most of the leaks are minor, but some could pose an explosion risk and they add up to a lot of lost money and an unnecessary source of greenhouse gas emissions. [10:55 a.m. | Updated Joanna Foster has more details on the Green Blog.]
I posed some questions to the lead researcher, Nathan Phillips of Boston University, and you can see his responses below.
To go deeper, I recommend a thorough 2009 report in Pipeline and Gas Journal on gas leaks from our antiquated distribution system. Here?s one telling nugget from the article:
Fugitive methane emissions from distribution mains account for 32 percent of methane emissions from the U.S. natural gas distribution sector. Cast iron pipelines contribute the most to these emissions, despite representing only 3 percent of the miles of the U.S. distribution mains.
This situation is deeply reminiscent of similar issues with leaky old water mains ? some are a century old ? in aging cities.
It takes money to fix such problems. Tokyo has become a global leader in stanching water leaks, for example. A core component of that fix has been costly stainless steel pipes. Updating invisible infrastructure also takes a culture shift.
Studies like the one in Boston ? revealing the invisible waste ? can go a long way toward building the motivation for change. (This is also one reason I like the use of infrared imagery to spot possible gas leaks from drilling sites and pipelines.) Here?s a closeup image of some Boston?s distribution-system leakage:
Here?s are responses from Nathan Phillips to a couple of questions (with some e-mail shorthand fleshed out). Pose your own and I?ll send them to the authors.
Q.
Did you get any estimates of volume escaping per unit of time?
A.
It?s too soon. But we know from just dozens of chamber measurements that some of the leaks can exceed daily U.S. household usage (200 cubic feet a day). I think the distribution is skewed with a long tail ? many small leaks, and a few really big ones.
Q.
The relationship to ancient cast iron mains speaks volumes about our infrastructure issues in this country.
A.
There is a term that geographers and urban planners are using now called infrastructure ecology, to describe the interdependency of our infastructures, relating to resilience, vulnerabilities. It provides a good framework for thinking about how we approach spatially co-located infrastructures. We should be replacing underground infrastructure when we are already repaving streets, rather than addressing one infrastructure in isolation of the others. It would save a lot of money.
Here?s a view from the ?cockpit? during their Boston leak-detection tour:
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