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Fueling Global Warming, Not Homes

CAS researcher maps gas leaks on city streets


Nathan Phillips is a meter-reader for the 21st century.

The College of Arts & Sciences associate professor of geography and environment recently piled into a Nissan Murano with collaborators Bob Ackley and Eric Crosson and rambled through the streets of greater Boston to hunt for natural gas leaks. With the help of a strange-looking vacuum device attached to the car just below the rear bumper, the three have found geysers of gas gushing invisibly from underground pipes corroded by age. The leaks, Phillips says, contribute to global warming, could create explosions in some extreme cases, have killed or damaged up to 10,000 trees in Massachusetts (a disputed matter under litigation), and shaft rate-paying gas customers who must pick up the tab for wasted gas.

The vacuum sniffs up molecules into a suitcase-sized machine in the hatch called a cavity ringdown analyzer, where a laser beam ricochets off mirrors and through the collected particles. The more natural gas collected, the more the laser diminishes. When the machine detects a leak, numerical values on a display screen indicate how much gas is spurting; if there are multiple leaks, the display “looks like a stock market index during a busy day,” says Phillips. The machine instantly spits out the leaks’ locations and shows them on Google Earth maps as shafts of green, punching skyward like a light show.

Google Earth image shows gas leaks in the area of Boston University Charles River campus

The Google Earth image above shows shafts of bright green indicating natural gas leaking around BU’s Charles River Campus. If there are multiple leaks, the display “looks like a stock market index during a busy day,” says Nathan Phillips. Photo courtesy of Nathan Phillips and Picarro, Inc.

There are a lot of leaks. One utility, National Grid, counts 14,000 in its system, which serves half of the Bay State, while Ackley, president of Gas Safety USA, a Massachusetts leak-detection company, puts the figure for all leaks at up to 30,000. Utilities reported 13.5 million cubic feet of gas lost from leaks throughout Massachusetts in 2009, an amount that is surely an undercount, according to the federal government, which collects the data.

In May, Phillips and company found a leak in Newton, Mass., that was spewing 400 cubic feet of gas per day. “The average household uses about 200 cubic feet per day,” says Crosson, whose California company, Picarro, makes the analyzer. “So that leak was equivalent to two households opening up their gas stoves and heater without igniting them.”

The perils and price of leaking gas are the subject of a paper that Phillips, Crosson, and Ackley presented at a conference last spring sponsored by the National Oceanic and Atmospheric Administration. Their research suggests that 7 percent to 15 percent of manmade methane (the main component of natural gas) in the atmosphere comes from these urban emissions. And that’s a problem: methane is a greenhouse gas that according to the United Nations is 21 times more potent than carbon dioxide at trapping heat in the atmosphere.

Then there’s the money. The eight billion cubic feet of gas vented in Massachusetts in 2005 (that’s leaks plus gas unaccounted for because of other factors) was worth $41 million, and that annual leak of gas and dollars continues. Gas customers pay a monthly maintenance charge already, in addition to being charged for the gas that leaks away, says Ackley, who for years worked to detect leaks for National Grid and other utilities. He estimates that leaks could add $40 a year to the average Bay State residential gas bill.

Leaking gas also kills or damages millions of dollars worth of urban trees—between $15 million and $25 million just in the commonwealth alone, says Ackley, who with Jan Schlichtmann (the lawyer hero of the book and film A Civil Action) runs the Massachusetts Public Shade Tree Trust, which seeks damages from utilities for affected municipalities.

Nathan Phillips and Eric Crosson detecting natural gas leaks in Boston

Nathan Phillips (left) and Eric Crosson check a display screen indicating the extent of a natural gas leak. Photo by Kalman Zabarsky

Brookline is suing National Grid, which serves 1.2 million customers there and throughout Massachusetts, for damages to town trees allegedly caused by gas. Company spokesman David Graves says he can’t comment on pending litigation, but he does say that there is no scientific evidence supporting claims that underground gas leaks cause widespread damage to trees. “We work with communities on individual cases where they believe gas may have damaged a tree,” he says. “If we can prove gas is responsible, we replace the tree at our cost.”

Graves says his company takes the leaks issue very seriously and responds to every reported odor of gas. “We are in complete compliance with state and federal standards in leak management,” 
he says.

Phillips says utilities triage their repairs to remedy catastrophic leaks, such as the one that occurred near San Francisco last year, when a gas transmitting line exploded, killing four and torching dozens of homes. He found one leak in West Newton with methane levels that would rate as potentially explosive.

By contrast, Phillips says, slower street-level leaks are bottom-tier concerns for repair, even though pedestrians occasionally can smell the gas.

Ackley tracked gas leaks for years before teaming with Phillips, whom he met by chance. Walking with his toddler son in their Newton neighborhood, Phillips spied Ackley in a yard wielding a strange handheld device. Curious, he asked Ackley what he was doing.

Picarro’s machine has revolutionized the labor of leak detection since Phillips and Ackley began using it last winter. “I can find the leaks with the old-school equipment we’ve been using in the gas industry for years,” says Ackley, “but this equipment is much more sensitive, and it has the ability to map out on GPS, right on a computer screen,” a leak’s location, “and also quantify the gas a little bit better.” The machine can sense leaks at any car speed, Crosson adds. “I’ve done it doing 65 miles an hour.”

So far, Crosson, Phillips, and Ackley have surveyed only a small percentage of Boston streets, and they plan to publish more comprehensive leak data from the city.

Rich Barlow, Senior Writer, BU Today, Bostonia, Boston University
Rich Barlow

Rich Barlow can be reached at barlowr@bu.edu.

15 Comments on Fueling Global Warming, Not Homes

  • Cynthia on 09.29.2011 at 9:32 am

    How can we see if our area is affected? Is there a link to their map on Google Earth?

  • kat on 09.29.2011 at 9:35 am

    Great work by the professors and by Rich Barlow for covering this. Please continue to draw more attention to this issue in the hope that the gas companies are forced to do something about it.

  • Howard I. Cohen on 09.30.2011 at 12:42 pm

    Excellent work by Prof. Phillips and his team. Hopefully a variety of pressures could, and should be brought to bear on the gas utility company or companies whose gas is leaking. The most direct pressure would be to identify and quantify as much leaking as possible and not allow the utility company to spread the cost of that gas over its customer base, but pay for it out of profits. Then see how quickly they rush to remedy their leaks.

  • Kyle on 10.06.2011 at 11:42 am

    An enlightening study. Perhaps the Gas utilities could be forced to repair the tens of thousands of leaks all accross the state instead of spending money on negative ad campaigns. I think the $700k they are currently spending on bashing the oilheat industry could be better spent on making sure the commonwealth and its residents are safe.

  • Rupert Manlove on 10.07.2011 at 4:18 pm

    This is good to know; all this time I just thought I had neighbors that smelled like farts.

  • Matt on 10.18.2011 at 10:25 pm

    For the 5 and a half years that I lived near the Shawmut station in Dorchester, there has been a persistent leak on Center Street, right next to the T. Everyone Ive ever asked who has walked through that zone has been able to clearly detect the sulfur based gas additives (that added rotten egg smell that makes detecting leaks ‘easier’) and there has never been any attention given to calls or complaints.

    The street has been dug up for other purposes, but the area consistently smells of leaking gas (and its pretty strong walking through it.) I seriously worry about the health of the residents… its a residential street with Dorchester’s usual spread of victorians.

  • Sue on 10.20.2011 at 12:33 pm

    Maybe National Grid is doing something about it. They’re replacing gas pipes on my street in Brighton, and quite a few other streets in Brighton as well. You never sknow where you’re going to have a detour. They won’t be finished until mid-November. Please let the snow hold off until they’re finished. :-)

  • MJP on 11.22.2011 at 9:53 am

    Excellent work being done here. This type of proactive science is exactly the type of science that can identify where Federal dollars in tax breaks should be allowed to each business, should our government approve plans such as Candidate Romney’s proposal. In other words; allowing tax relief for corporations in exchange for infrastructure repair/improvement,based on the actual cost, up to the maximum expense of necessary improvement repair. If business want tax credits then, they should have a sound infrastructure that is in-line with environmental policies and no tax break should be allowed to increase profit until it is proven that the business is well maintained and, as reasonably green as possible. It is time for acceptable losses at the consumer/taxpayer’s and environments expense be eliminated. This behavior alone would create job’s and can span many other sectors.
    Good Job on this work! I would like to see this science examining the electrical grid’s and assessing the equipment that is inefficient and or should be improved as that area of public utility is in need of creditable trusted scientific evaluation.

  • MJP on 11.22.2011 at 10:03 am

    I should have also mentioned that BU Engineering and this department should look into economical and long-term effective engineering methods/design that should also be imposed on these businesses with tax relief allowed for infrastructure repairs. This engineering solution setting the minimum standard of an acceptable repair solution and, a standard government officials should could use to impose improved guidelines for long-term effective improvement.

  • BJ on 11.22.2011 at 4:11 pm

    The Chemistry show that biological operating systems are impacted by synthetic methane and other compounds in the admixture of natural gas; combined with toxic products in the environment. Humans and animals exposed to these toxins are at risk of biological dysfunction, the problem posed is that theses compounds are constractants and or dehydrators which block or prevent bio generation i.e. cell growth..

    We must bring Human Security to the agenda

  • Jim on 02.02.2012 at 3:53 pm

    Ackley is a trailblazer who is snowballing towards the credit he deserves.

  • Shruti on 03.20.2012 at 11:42 am

    Nice use of technology to solve environmental and infrastructure related issues. Like the video. is there a system where the residers could also proactively report about the leaks so that the team can come around with the analyzer and take a look?

  • Subash Bose on 04.13.2013 at 2:44 am

    Comment about Specific fuel consumption and refuelling of CNG and for gasoline.?

  • s Q o on 06.11.2013 at 5:22 pm


    • David Keefe on 06.12.2013 at 10:27 am

      How so? And worst offender of exactly what? Gas leaks? I’m asking out of pure interest, too. Not trying be argumentative.

      BU puts a lot of emphasis on its sustainability programs and energy efficiency of its buildings, etc. I’m sure the researchers featured in this story would be interested in hearing why you feel the way you do…

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