Study Confirms Sound Policies, Responsible Management Help Local Utilities Reduce Methane Emissions from Natural Gas Leaks

But uneven results show more work still needed to reduce emissions

March 31, 2015


Anna Geismar, (512) 691-3468,

(NEW YORK – March 31, 2015) A study released today by Washington State University finds that extensive infrastructure upgrades, better leak detection and repair, and important regulatory changes at both the state and federal levels have resulted in reduced methane emissions from local natural gas systems — 36 to 70 percent lower than estimates from the early 1990s, the last time direct measurements were made.

While the figures show an overall decrease in methane emissions over two decades, they also reflect continuing issues for gas utilities and regulators. The study shows substantial variation in leak rates by region and type of pipe, indicating particular need for action in some places. Methane is the main component in natural gas. EDF believes the challenge can be seen as an opportunity to reduce emissions of a powerful climate pollutant.

“The study confirms that when regulators and utilities both set themselves to fixing a problem, they can get good results,” said Jonathan Peress, EDF Air Policy Director for Natural Gas. “But utilities are losing as much as $195 million worth of natural gas each year. Because methane is a particularly potent greenhouse gas, 84 times more potent than CO2 over 20 years, the annual methane emissions are comparable in effect on the climate over a 20-year period to the CO2 from as many as 19 coal-fired power plants”

Methane is a particularly powerful climate warmer – 84 times more potent than carbon dioxide over a 20-year timeframe. EDF believes the study underscores three takeaways:

  • Utility efforts and public policies to find and fix leaks – and to replace leak-prone pipe – are working. These efforts should be accelerated and expanded;
  • Leak surveys and reporting by utilities should include the direct measurement of the amount of methane escaping;
  • A small number of leaks cause a large share of emissions with big differences among utilities and regions. Both facts suggest case-by-case data is more telling than national averages.

New Standards & Better Practices

Utilities have invested heavily in replacing leak-prone hardware and infrastructure as both state and federal regulators have sharpened their focus on improving local distribution systems.

For example, the federal Pipeline and Hazardous Materials Safety Administration (PHMSA) introduced extensive new planning and monitoring rules for utilities in 2003, and the Environmental Protection Agency issued greenhouse gas measurement and reporting requirements for gas utilities in 2011. About 40 states have replacement programs for leak-prone utility pipes, and 15 require leak classification and repair timelines. Additionally, 2011 EPA regulations require gas utilities to measure and report methane leaks from metering and regulating equipment.

As a result of these and other policies, companies have replaced close to 40 percent of the leakiest pipes that were in service in 1990, according to PHMSA. But that leaves 60 percent of these old cast iron and unprotected pipes still in the ground. At today’s rate, it will take at least another 50 years to replace them.

“Cast iron and unprotected steel represent less than 10 percent of the nation’s utility distribution system pipeline miles, but they are responsible for almost half of the total emissions from those systems,” Peress said. “More than a third of the emissions estimated in the study were in the Northeast, and 70 percent of the Northeast emissions were from old iron and steel pipes. Despite improvement over the past 20 years, many utilities are leaking far more harmful methane than is acceptable ”

“The leak with the highest emissions found in this study was a Grade 3 leak. Grade 3 leaks are defined as low safety risks and therefore are allowed to leak indefinitely. Better practices to find and quantify leaks can help ensure that big leaks like these are found and fixed quickly, saving money for the utility and its customers as well as reducing potent methane emissions.”

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