Far More Methane Leaking at Oil, Gas Sites in Pennsylvania than Reported

An EDF comparison of company-reported data and research measurements finds as much as 5 times more methane, a climate-warming greenhouse gas, is leaking.

A natural gas well in a yard in Pennsylvania. Credit: Anna Belle Peevey

The Environmental Defense Fund estimates that nearly $68 million worth of energy resources are wasted through methane leaks in Pennsylvania's Marcellus Shale. Credit: Anna Belle Peevey

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Leaks of methane, a powerful greenhouse gas, from oil and gas sites in Pennsylvania could be five times greater than industry reports to state regulators, according to a new analysis by the Environmental Defense Fund.

Drawing from peer-reviewed research based on measurements collected downwind of oil and gas sites, along with government data, the EDF analysis estimates that the state's oil and gas wells and infrastructure leak more than 520,000 tons of methane annually, largely due to faulty equipment.

"This wasted gas causes the same near-term climate pollution as 11 coal-fired power plants and results in nearly $68 million worth of wasted energy resources," the group said in its report, released Thursday.

The underreporting of methane leaks in Pennsylvania is part of a nationwide pattern that peer-reviewed studies have uncovered in recent years as scientists compare federal and state statistics to data they gather on the ground and in aircraft flyovers.

Comparison of Pennsylvania Methane Emissions

The disparity between what researchers find and what industry reports raises important questions about the actual level of greenhouse gas emissions in the United States and the viability of natural gas as an alternative to coal, if limits aren't placed on methane leaks from gas and oil infrastructure.

Methane, the primary constituent of natural gas, is a greenhouse gas about 30 times more potent than carbon dioxide over a century. The Trump administration has been working to roll back several policies and initiatives that were designed to rein in methane emissions, most recently to end requirements to limit leaks at oil and gas sites on federal land.

As Much as 5 Times More Methane

In the new report, EDF analyzed methane leaks from Pennsylvania's conventional oil and gas wells, mostly drilled before 2008, and from unconventional wells, those unlocked since then using hydraulic fracturing. There are far more conventional wells than unconventional ones in the state, and because they are older they leak at a much higher rate. Twenty-three percent of methane at a conventional well leaked into the atmosphere compared to 0.3 percent at a fracked well, EDF estimated.

But the newer fracked wells produce considerably more natural gas than the older wells. As a result, even a small leakage rate of 0.3 percent led to a vast amount of methane entering the atmosphere, the analysis estimated. EDF calculated that fracked wells spewed about 253,500 tons of methane in 2015, and conventional wells, 268,900 tons.

The Pennsylvania Department of Environmental Protection tracks methane only from unconventional oil and gas sites. In 2015, its data showed 112,100 tons of methane leaked.

Maps: Pennsylvania Methane Emissions Are Higher Than Reported

Industry's underestimation of methane leaks comes from outdated methodology, said David Lyon, the lead scientist for the EDF report.  Much of the methodology can be traced back to standards for estimates established years ago by the Environmental Protection Agency, he said.

Pennsylvania Considers New Methane Rules

EDF chose to look at Pennsylvania's methane leaks because the state is expected to issue rules in March to reduce methane leaks from new oil and gas sites. The state Department of Environmental Protection is reviewing the EDF findings, said spokesman Neil Shader.

"DEP is nearing finalization of new permits that will establish thresholds for methane for new unconventional well sites and compressor stations," he said. He did not indicate if or when Pennsylvania would move to cut emissions from existing sites.

Energy In Depth, an industry advocacy group, did not respond to an email about the EDF study. 

Colorado and California have adopted rules to cut methane leaks from oil and gas sites, Lyon said, which gives him hope for Pennsylvania, Texas and other oil and gas states.

"I would take an optimistic message from this: There are many solutions, and emissions can be reduced if we implement comprehensive practices," Lyon said. "The main one is frequently doing leak detection and repair. Another is looking for malfunctions and site design issues, so that you're not only working on ongoing problems but predicting future issues as well."

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