ENVIRONMENT

Google car helps PSE&G target leaky gas pipes

To prioritize which aging gas mains to replace, the utility used a Google Street View car equipped with methane sensors.

James M. O'Neill
Staff Writer, @JamesMONeill1

To better prioritize which of its aging gas mains across North Jersey to replace first, PSE&G drove a Google Street View car equipped with methane sensors around certain neighborhoods for six months, the company announced Tuesday.

The state’s largest utility was able to learn not only where leaks were, but how serious they were by running the collected readings through algorithms that could determine the volume of methane escaping. As a result, the utility could replace fewer pipeline miles by targeting the spots with the greatest volume of methane being released.

Google Street View car equipped with methane sensors that helped PSE&G find leaks and prioritize which aging gas mains to replace first

The effort is part of a larger, $905 million Public Service Electric & Gas project to replace more than 500 miles of aging gas lines in the region by 2018. The company has already repaired or replaced about 170 miles worth of lines, said Wade Miller, PSE&G’s director of gas transmission and distribution engineering.

See where the Google car was used and where leaks were detected

PSE&G collaborated on the leak detection effort with the Environmental Defense Fund, Google and Colorado State University. The utility learned about work EDF and Google had done mapping gas leaks in Boston and Indianapolis, and asked to work together to do the same in North Jersey.

The EDF collaborators have since mapped gas leaks in Dallas, Syracuse, Los Angeles, Chicago, Pittsburgh and elsewhere. This was the first project in which the EDF group worked directly with a utility to map out leaks.

The PSE&G gas main replacement project is designed to improve safety, waste less gas and reduce emissions of methane -- the main component of natural gas -- that contribute to climate change.

“Reducing methane emissions is one of the quickest ways we have to protect the climate,” said EDF President Fred Krupp. “It takes courage to invite an environmental group to come sniffing around for leaks in their system. By tackling these leaks faster, PSE&G will achieve a lot more environmental benefit for their infrastructure dollars.”

The typical cost of replacing a mile of gas line in the PSE&G system is about $1.5 million to $2 million, according to the company.

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The company used the Google Street View car to gather millions of readings over hundreds of miles of roadway in Bergen, Passaic, Hudson and Essex counties. The car was used in Fort Lee, Edgewater, Paramus, Ridgewood, Wayne, Fairview, Northvale, Paterson, Clifton and Passaic, as well as other towns.

There are four Google Street View cars specially equipped with the technology developed by EDF, Google and Colorado State University. The technology not only allows volume to be measured with great precision, but also maps the leaks. EDF, Google and CSU spent five years putting the technology, the data processing and the analytical expertise together in one package.

In the future, systems like these could be fitted to other vehicles, whether they belong to PSE&G or Google or somebody else, according to EDF.

PSE&G does its own leak detection work routinely, and has developed a hazard index to prioritize which of its mains need more immediate repair or replacement. The index is determined by looking at a pipe’s age and material, how long ago prior repairs were made, and how close the main is to buildings in populated areas.

It had already used that system to prioritize which gas mains it needed to replace first, but then, in cases where two mains had a similar hazard value, it used the extra information from the EDF algorithms to move certain pipes with higher-volume leaks further up the replacement list.

PSE&G has an aging network of gas lines, some more than 100 years old, Miller said. And since cast iron was the material of choice for such pipes back in the early 1900s, PSE&G has the most cast iron pipes of any company in any state, he said.

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That’s a problem for the utility, since cast iron is brittle and prone to cracking, which makes it more susceptible to leaks. The system’s joints also often involved lead and cement, which can come apart as the pipes settle and the ground moves from frost.

“Under our $905 million program, we are accelerating the modernization of our gas system, replacing 170 miles of pipe each year versus an average of 54 miles in the past,” PSE&G president Ralph LaRossa said in a statement.

“Reducing methane is a serious challenge for utilities, but also a big opportunity,” LaRossa said. “Using the data from EDF, we were able to keep safety paramount, while achieving more environmental value, at less cost and more quickly than before, which benefits both our customers and the climate.”