Scientists: Replacing old gas pipes reduces leaks

Nick Penzenstadler | USA TODAY

Millions of dollars invested in the last decade to replace crumbling natural gas mains in cities like Cincinnati and Durham, N.C. are having a dramatic impact on leaks, a new study released today shows.

Researchers also cruised the streets of Manhattan with a methane-detecting instrument to map the dramatic frequency of leaks from Civil War-era pipes that still plague the gas infrastructure.

The differences in the leaks detected across those cities are dramatic. In New York, where it could take more than 50 years to upgrade old iron and bare-steel pipes, researchers found more than 1,000 gas leaks still plaguing the city.

By comparison, the scientists found 132 and 351 gas leaks respectively in Durham and Cincinnati, where utilities are executing aggressive replacement plans, according to the findings published today in the peer-reviewed journal Environmental Science and Technology.

“There hasn’t before been a solid example of the efficacy of pipeline replacement programs,” said Rob Jackson, an author of the paper and environmental scientist at Stanford University.

In addition to the monetary costs of leaky pipes, which is estimated to be about $2 billion annually, the greenhouse gas contributes to smog and global warming, Jackson said.

And the leaks can lead to devastating, sometimes deadly, explosions. Gas leak incidents have trended downward across the United States as mains are upgraded, but last year 65 gas pipeline leaks resulted in 18 fatalities, 93 injuries and $73 million in property damage, the researchers said. Among last year's toll was a gas explosion that leveled part of a New York City block in East Harlem, killing eight people and injuring 48 more.

The scientists began their work in 2011 mapping leaks in Boston and then Washington, D.C. where they found similar leaks-per-mile to what they found in New York.

“Those cities are making progress, but very slowly,” Jackson said. “I’d like to see it move much faster. But like roads and bridges we’re under investing in our nation’s infrastructure.”

The pipes in all three cities are among the oldest and most leak-prone in the U.S., according to a USA TODAY Media Network analysis of federal pipeline safety data conducted last year. That review of federal data found tens of thousands of miles of cast-iron and bare-steel gas mains lurking beneath American cities and towns — despite these pipes being a longtime target of National Transportation Safety Board accident investigators, government regulators and safety advocates who said the pipes need replaced soon.

Jackson said public utility commissions are under pressure to keep rates low, but he proposes offsetting replacement costs with savings from fewer leaks. In cities with significant progress on aging pipes, leaks were reduced by 90 percent or more. It can cost $1 million per mile, or more, to replace aging pipe, costs typically passed to customers.

That was the case in Cincinnati with $900 million in investment since 2001 to replace hundreds of miles of older pipes, said Sally Thelen, a spokeswoman for Duke Energy, the area’s primary natural gas provider.

“We had some pipe that had been in the ground since 1873,” Thelen said. “We’re on par to finish replacing all of our mains by the end of this year.”

Next, Thelen said the company is aiming to tackle service lines, the smaller pipes that connect gas distribution lines to homes and businesses. That process that could take several more years.

Other cities are decades from full replacement of old pipes. At its current pace, Baltimore is projected to finish its replacement program by the year 2155, the researchers said.