A chance encounter during a walk a few years ago inspired tree scientist Nathan Phillips to help come up with a better way to detect gas leaks in aging underground pipes. The connection between trees and pipes isn't as far-fetched as you might think.
Phillips, a Boston University professor, came upon a gas line surveyor in his Newton neighborhood and realized the technology he uses to track the effects of greenhouse gases on urban environments and trees could also find potentially hazardous leaks beneath city streets.
"I kind of played the role of matchmaker a little bit," Phillips said, recalling how he got in touch with Picarro Inc., the California maker of scientific equipment he uses in his tree work, and said, "Hey, this is the perfect situation for your instrumentation."
Picarro's design team went to work. It created a suitcase-sized analyzer that Phillips and Bob Ackley — a gas leak specialist with the Southborough firm Gas Safety USA — used as they drove along Boston's streets searching for leaks. The two men ultimately identified more than 3,300. The results of their work, published late last year, have since gained Picarro the attention of industry representatives and regulators who consider the super-sensitive detector a potentially critical tool in helping to plug leaks that pose safety threats and cost consumers millions of dollars in lost fuel.
Picarro chief executive Michael Woelk says the device, which uses a laser and three mirrors to measure gas concentrations in the air, is about 1,000 times more sensitive than standard detection equipment.
The device fits in the trunk of a car, where a tube feeds it continuous readings of methane levels — the main ingredient in natural gas — from the air in front of the vehicle. The information is then wirelessly combined with data from onboard GPS and wind measurement systems to map the location and severity of leaks in real time.
"Our technology can be 100 yards away [from a leak] and still be able to find it," Woelk said. The hand-held devices and truck-mounted sensors utilities use typically need to be much closer to make an accurate reading, he said.
A recently released congressional study commissioned by Senator Edward J. Markey, a Malden Democrat, estimated natural gas customers in Massachusetts paid up to $1.5 billion over the last decade for fuel lost to gas leaks. Markey's staff recently met with Picarro officials to discuss the company's technology.
"I believe there are three pillars to help fix our aging natural gas infrastructure: identify the leaks, create the right incentives for utilities to replace old pipes, and protect consumers," Markey said. "New technologies can help to identify the leaks, but we also need new policies that ensure we actually carry out the job of updating our natural gas system for the 21st century."
Utilities defend the equipment they currently use to find leaks, but said they are constantly on the lookout for improvements.
The American Gas Association said its members spend about $7 billion annually to monitor, maintain, and upgrade gas pipelines.
Emissions have dropped 16 percent since 1990 even as nearly 300,000 miles of distribution lines were added, it said.
"Safety is paramount for all natural gas utilities, therefore, as an industry, we regularly identify and research promising new technologies as they come to the market," said NStar spokeswoman Caroline Pretyman. "While we can't publicly endorse one over another, we'll certainly continue taking a close look at all of the options available to use as gas leak detection technology evolves."
National Grid spokesman David Graves said the company, which is the main gas distributor in Boston, acknowledged there are potentially hazardous leaks in the Boston area, but said the utility has an "aggressive program" to address the problem.
In the last two years, National Grid replaced 300 miles of old piping with more flexible plastic, and it expects to replace about 150 more miles this year.
The utility constantly surveys its territory for gas leaks, Graves said, using vans outfitted with sensors that take air readings.
"There are [also] hand-held devices that we use to check out manholes, sewers — any place where gas would normally collect," he said, in addition to ground probes.
Even knowing how precise Picarro's instrumentation is — given that he helped design it — company chief technical officer Eric Crosson said he was still amazed the first time he went out with Phillips to test the technology.
"We drive no more than a block and suddenly, there's a huge amount of methane," Crosson recalled. "Then we drove a little farther and there was another one, and then we drove a little farther and there was another one."
That accuracy is what caught the attention of executives at San Francisco-based Pacific Gas and Electric Co., which now has six Picarro gas detection systems. Nick Stavropoulos, executive vice president of gas operations at PG&E, said it uses the detectors along with other "excellent technology" to seek out leaks.
"What we've found is the sensitivity of the Picarro equipment can help us locate hard-to-find leaks," Stavropoulos said.
Despite the technology's potential, Picarro may find it difficult to compete against technologies that have become entrenched in many utility companies' operations. Woelk also sees another challenge — the company delivers too much bad news.
"We've had a little bit of a struggle getting any of the Northeast utility companies to talk to us and the simple reason is because we find more leaks than they've ever seen before," he said, estimating that on average one in five of the leaks his company finds is big enough to be a hazard. "This is not just a Boston problem. . . . You've got 2.5 million miles of pipe [in the US] and much of it is full of holes."