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Monday, December 03, 2012
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Emerging Issues in Shale Gas Development: Protecting Air Quality

By Guest Author, Gabe Scheffler, Yale Law School '14

This post was co-written with YCELP Fellow Bruce Ho.

On Wednesday, December 5, from 3-4pm EST, Florida State University Law Professor Hannah Wiseman will present a webinar on “Understanding and Improving Regulation of Shale Gas Development” as part of the Yale Center for Environmental Law and Policy’s ongoing Policy Workshop Webinar Series on “Emerging Issues in Shale Gas Development.”

Please click here to register to participate in this free online event.

As a lead-in to Professor Wiseman’s webinar, this blog focuses on one key area of environmental regulation—the regulation of air pollution from shale gas development—at both the state and federal levels. As Yale Professor of Hydrology Jim Saiers discussed in the Center’s first shale gas webinar earlier this fall, air pollution is one of many potential environmental concerns associated with shale gas development.  Shale gas drilling can impact air quality and human health in several ways, including through the release of methane (the principle component of natural gas), which contributes to climate change; nitrogen oxides (NOx) and volatile organic compounds (VOCs), which can lead to both ground-level ozone and particulate matter (PM), which are in turn linked to heart attacks and respiratory morbidity; carbon monoxide; and hazardous air pollutants, such as benzene. This blog looks at the sources of these air pollutants and regulatory steps that states and the U.S. EPA have taken to limit this type of pollution.

Shale Gas Development and Air Pollution

In February, the National Oceanographic and Atmospheric Administration (NOAA) reported research suggesting that air pollution from natural gas operations in Colorado is much higher than previously understood. While this research is from one area only, and applies to natural gas operations in general rather than shale gas specifically, it raises concerns about the potential air pollution that could occur locally and globally as a result of the shale gas boom.

Air pollution can occur at many stages in the shale gas supply chain, from gas production to transportation, distribution, and use. At the production stage, shale gas wells can “leak” methane and VOCs into the atmosphere during the period between well drilling and hydraulic fracturing and the point at which newly drilled wells are connected to gas collection, processing, and compression equipment and pipelines. While “green completion” technology can be used to capture all or most of this methane and other gases, and thus avoid air pollution, this technology is not always used. In the absence of green completions, gas capture may be delayed until after the initial “flowback” and “produced” water flows out of the well.[1]

In some cases, methane and other gases leaking from newly-fracked wells are burned or “flared.” Flaring converts the gas into less harmful substances, such as carbon dioxide (CO2). In other instances, methane and other well gases are simply “vented,” unchanged, into the atmosphere. Because methane is a much more potent greenhouse gas than CO2, flaring is better for the climate than venting. That being said, flaring is by no means a perfect solution since it still generates climate-polluting CO2, NOx, and other air pollutants.

Methane can also be released at other points in the natural gas supply chain, including from leaks in the pipelines used to transport the gas to market and from local gas distribution lines, as the New York Times recently reported. Dr. Ramon Alvarez from the Environmental Defense Fund discussed these methane leakage issues last month in the second installment of our webinar series. You can read a summary of Dr. Alvarez’s presentation and also view an archived recording of his webinar here.

Beyond methane leakage, other sources of air pollution associated with shale gas development include emissions from the machinery used to drill wells and transport gas and, where gas is used for energy, from the eventual combustion of this gas itself. For example, shale gas drilling involves a significant number of trucks (generally diesel) and other equipment. The internal combustion engines in these trucks, well-drilling machinery, and gas compressors produce air pollution in the form of CO2, NOx, and PM. When natural gas is combusted to generate heat or electricity, it also releases CO2. And while the CO2 emissions from natural gas are lower on a per-unit energy basis than other fossil fuels—e.g., coal and petroleum—the CO2 released during gas combustion still contributes to global warming at non-negligible levels.

Regulating Shale Gas Impacts on Air Quality

While some amount of air pollution from shale gas development is likely inevitable, the types and scales of these environmental impacts can be reduced through regulatory safeguards.

In their paper, “Regulation of Shale Gas Development, Including Hydraulic Fracturing,” Professor Wiseman and her co-author Francis Gradijan discuss current federal and state air quality regulations that aim to reduce this pollution. On the federal side, the EPA has established National Ambient Air Quality Standards (NAAQS) under the Clean Air Act for “criteria pollutants” (pollutants that are common throughout the U.S.) and technology-based standards for “hazardous air pollutants” (pollutants that are toxic or hazardous to humans).

Shale gas development produces both criteria and hazardous air pollutants.  Yet Professor Wiseman notes that because the Clean Air Act focuses primarily on “major” sources, many EPA regulations do not apply to shale gas wells, which, while potentially cumulatively significant, generally do not individually emit sufficient quantities of pollutants to qualify as major sources. Professor Wiseman notes that the EPA may soon redefine its methodology for calculating major sources in a way that could bring more shale gas (and other natural gas) sites within the scope of its regulations although this step has not yet occurred.

There are, however, some situations in which EPA regulations do limit air pollution from shale gas wells. For example, Professor Wiseman explains that even “minor” gas operations may be subject to federal regulations if these operations are located in “nonattainment” areas, which are locations that currently exceed the federal NAAQS and are thus subject to more stringent requirements. Additionally, new gas compressor stations and existing stations that increase their hourly pollutant emissions are subject to technology requirements under EPA’s New Source Performance Standards (NSPS). EPA recently promulgated new NSPS for VOCs emitted from fractured and re-fractured wells, which will eventually require drillers to use green completions.

Nevertheless, the limitations of federal regulations mean that state law may often provide the only applicable air quality controls for many shale gas wells. Professor Wiseman writes that New York and Colorado currently have the strongest regulatory regimes in this respect, but that many states lack regulations to control or even monitor air pollution from shale gas wells.

As can be seen in the following table, air quality regulations for shale gas development in the five states – Texas, Louisiana, Oklahoma, Arkansas, and Pennsylvania – with the highest levels of shale gas production in 2010 (the most recent year for which data from the U.S. Energy Information Administration is available), vary widely. These regulations generally apply to both shale gas wells and conventionally-drilled natural gas wells.

(click to download)

The table, which draws from Professor Wiseman’s paper and research conducted by Resources for the Future (in which Professor Wiseman is also involved), shows that four of these five states regulate gas venting to at least some extent, such as by requiring flaring if emissions reach certain levels. However, Texas includes numerous exceptions to these requirements and Pennsylvania’s regulation prohibits venting only in cases “when the venting produces a hazard to the public health and safety” (e.g., due to a risk of explosion).

Most of these states also regulate emissions from other areas of the shale gas development process, though these regulations may be circumscribed in scope or, as in Pennsylvania, subject to significant exceptions.

Given that shale gas development is a relatively recent phenomenon, its air quality impacts—and the effects of specific regulations—are still uncertain. Thus, one key area of regulation is the extent to which states require monitoring and reporting, which can help policymakers better understand air quality impacts and regulatory outcomes. Monitoring and reporting are also critically important for compliance enforcement. Louisiana currently requires monitoring and recordkeeping for flaring and venting of natural gas and glycol dehydrators. Other states, such as Arkansas and Pennsylvania have conducted surveys of air pollutant emissions from shale gas development, which could help improve future efforts. Texas has implemented an air quality monitoring program in the Barnett Shale Area.

Understanding and Improving Regulation of Shale Gas Development

Whether these current regulations will ensure that air quality remains at an acceptable level is a key question for policymakers moving forward and for states that have yet to develop their own approaches to shale gas regulation. On Wednesday, December 5, we will address these issues explicitly as we discuss current local, state, and federal approaches to regulating shale gas’ air impacts; regulation of other shale gas impacts, including on water quality; and the implications of these current approaches for future regulatory regimes through Professor Wiseman’s webinar on “Understanding and Improving Regulation of Shale Gas Development.”

 


[1]Fracking entails high pressure underground injection of large volumes of water mixed with chemicals, sand, and other substances, a portion of which returns to the surface as “flowback.” “Produced water” is naturally-occurring subsurface water, which also flows out of wells and may contain dissolved solids, metals, organic and inorganic compounds, and naturally-occurring radioactive material.

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