Emissions from oil and gas operations in the United States

1. Michael T. Kleinman

The U.S. Energy Information Administration (EIA) has projected that increased production of natural gas, primarily from hydraulic fracturing (or “fracking”) of shale formations, will be a dominant source of domestic natural gas supply over the next several decades, dramatically changing the energy landscape in the United States (Allen, 2014). Over the long term, EIA has indicated that increased domestic production of natural gas, natural gas plant liquids, and oil will persist for decades, and that the United States may become a net energy exporter over the next two decades (EIA, 2015).

Large amounts of natural gas and oil are now domestically available because of dramatic advancements in technology.

Tapping these resources has created significant economic benefits and greatly improved our energy security, leading to the United States becoming one of the largest producers, if not the largest producer, of oil and natural gas in the world. Natural gas burns substantially more cleanly than other fossil fuels, and our increased use of natural gas in power generation can help reduce U.S. carbon dioxide emissions. However, these benefits may not come without consequences. Methane, the primary component of natural gas, is a potent greenhouse gas that can be released into the atmosphere during natural gas production, processing, and transportation.

Environmental impacts associated with increased natural gas production and fracking have been controversial, and several reports have raised questions about the overall effect of natural gas usage on total U.S. greenhouse gas emissions and whether or not the impact of emissions associated with oil and gas production is effectively offset by reduced emissions from replacing less cleanly burning fuels with natural gas in domestic automotive, industrial, and power generation applications (Pacsi et al., 2013). Widely varying assumptions concerning the potential emissions of methane during extraction and production processes make it highly uncertain much methane is released into the atmosphere during these processes, largely because the availability of measured data is limited and because drilling processes continue to evolve. The less methane leaked into the atmosphere, the more the climate benefits of using natural gas as compared to other fossil fuels are preserved. However, in one study, when observed concentrations were compared to concentrations predicted using a dispersion model (AERMOD) and a spatially resolved inventory of volatile organic compound (VOC) emissions from natural gas production (Barnett Shale Special Emissions Inventory) prepared by the Texas Commission on Environmental Quality, and other emissions information, the predicted concentrations of VOC due to natural gas production were as much as 40% lower than background corrected measurements (Zavala-Araiza et al., 2014).

The 2016 Critical Review, “Emissions From Oil and Gas Operations in the United States and Their Air Quality Implications,” by Dr. David T. Allen (2016), directly addresses the current and potential air quality impacts: specifically, changes in greenhouse gas, criteria air pollutant, and air toxics emissions from oil and gas production activities that are a result of these changes in energy supplies and use. Dr. Allen holds the Melvin H. Gertz Regents Chair in the Department of Chemical Engineering and is the director of the Center for Energy and Environmental Resources at the University of Texas in Austin, TX. He is the author of six books and more than 200 papers in areas ranging from coal liquefaction and heavy oil chemistry to the chemistry of urban atmospheres. For the past decade, his work has focused primarily on urban air quality and the development of materials for environmental and engineering education. Dr. Allen was a lead investigator for the first and second Texas Air Quality Studies, which involved hundreds of researchers drawn from around the world, and which have had a substantial impact on the direction of air quality policies in Texas. He is, therefore, uniquely placed and qualified to summarize and analyze the current and future trends in oil and gas production and provide insights on the data gaps and methodological issues that can confound modeling predictions. This review also brings into perspective the small groups of devices or sites, referred to as super-emitters, that can contribute a disproportionally large fraction of total emissions. Accounting for super-emitters can greatly improve our ability to accurately model and estimate emissions. A key challenge, moving forward, will include identifying super-emitters and reducing their emission impacts. Much of Dr. Allen’s review focuses on emissions from energy supply infrastructures; however, regional air quality implications of some coupled energy production and use scenarios are also examined to evaluate the extent to which impacts are likely to vary among regions.

Air & Waste Management Association (A&WMA) members and their guests are invited to read, attend, and comment on the 2016 Critical Review at the A&WMA’s 109th Annual Conference & Exhibition to be held in the Empire Ballroom of the the Hyatt Regency hotel in New Orleans, LA. Following the presentation, a panel of invited experts will critique the presentation and the author’s conclusions, and will offer their views on the topic. The presentation of the review and the discussants commentary is planned for Tuesday morning, June 21, 9:00–11:45 a.m. Invited discussants will include:

• Gary R. Mueller, Principal Consultant Air Quality, Shell Projects and Technology;

• Ramón Alvarez, Lead Senior Scientist, U.S. Climate and Energy Program, Environmental Defense Fund;

• Anthony J. Marchese, Associate Dean and Professor of Engineering, Colorado State University; and

• Eric Stevenson, Director of Meteorology, Measurement, and Rules, Bay Area Air Quality Management District.

The discussants will provide additional perspectives on the impacts of modern oil and gas production and the potential risks and benefits of our changing energy landscape. The discussants are drawn from various stakeholders in this arena, which will have an impact on our health, productivity, and prosperity for generations to come. The discussants, and you, may agree with, or challenge, the author’s conclusions drawn from his evaluation of the available literature and the state of the science. You are encouraged to participate in this important discussion. Comments will be solicited from the floor after the presentation, and written submissions to the Critical Review Committee Chair are encouraged. The Committee Chair will synthesize these comments for publication in the November issue of the Journal of the Air & Waste Management Association (JA&WMA). Comments should be submitted in writing to Dr. Michael T. Kleinman, Critical Review Committee Chair, at [email protected] by no later than July 31, 2016.

Members are also encouraged to suggest topics for future reviews and to seek membership on the Critical Review Committee to participate actively in this important element of A&WMA’s science reporting mission. If you are interested in joining the committee, please send an e-mail to [email protected] and consider attending the Annual Meeting of the Critical Review Committee on Tuesday, June 21, 2016, at 3:00–4:00 p.m. in room Imperial 5C, Level 4, Hyatt Regency New Orleans.

2016 Critical Review Committee

• Michael T. Kleinman, Chair

• Sam L. Altshuler, Vice Chair

• Gwen Eklund, Immediate Past Chair (2013–2014)

• George Hidy, Past Chair (2009–2012)

• Judith Chow, Past Chair (2001–2008)

• John Watson, Past Chair (1994–2000)

• John D. Bachmann

• Patricia A. Brush, Technical Council Liaison

• Prakash Doraiswamy

• Naresh Kumar

• Eric Stevenson

• Abhilash Vijayan