Retracted: Methane emissions from the Marcellus Shale in southwestern Pennsylvania and northern West Virginia based on airborne measurements

Abstract

Natural gas production in the U.S. has increased rapidly over the past decade, along with concerns about methane (CH 4 ) leakage (total fugitive emissions), and climate impacts. Quantification of CH 4 emissions from oil and natural gas (O&NG) operations is important for establishing scientifically sound, cost‐effective policies for mitigating greenhouse gases. We use aircraft measurements and a mass balance approach for three flight experiments in August and September 2015 to estimate CH 4 emissions from O&NG operations in the southwestern Marcellus Shale region. We estimate the mean ± 1 σ CH 4 emission rate as 36.7 ± 1.9 kg CH 4 s −1 (or 1.16 ± 0.06 Tg CH 4 yr −1 ) with 59% coming from O&NG operations. We estimate the mean ± 1 σ CH 4 leak rate from O&NG operations as 3.9 ± 0.4% with a lower limit of 1.5% and an upper limit of 6.3%. This leak rate is broadly consistent with the results from several recent top‐down studies but higher than the results from a few other observational studies as well as in the U.S. Environmental Protection Agency CH 4 emission inventory. However, a substantial source of CH 4 was found to contain little ethane (C 2 H 6 ), possibly due to coalbed CH 4 emitted either directly from coalmines or from wells drilled through coalbed layers. Although recent regulations requiring capture of gas from the completion venting step of the hydraulic fracturing appear to have reduced losses, our study suggests that for a 20 year time scale, energy derived from the combustion of natural gas extracted from this region will require further controls before it can exert a net climate benefit compared to coal.

Methane Emissions from the Marcellus Shale in Southwestern Pennsylvania and Northern West Virginia Based on Airborne Measurements

“…This instrument error affected some, but not all of our wind measurements. Data reported here supersede those reported in a retracted paper (Ren, Hall, et al, ); see section S1 of the supporting information (SI) (Conley et al, ; Healey et al, ; Mueller & Wagner, ).…”

Top‐Down Estimates of NOx and CO Emissions From Washington, D.C.‐Baltimore During the WINTER Campaign

“…To improve our understanding of wintertime emissions of reactive air pollutants, mass balance flights were conducted during WINTER using the Purdue University Airborne Laboratory for Atmospheric Research (ALAR) and the University of Maryland (UMD) experimental Cessna aircraft to quantify emission rates of NO x and CO from D.C.-Balt. Airborne mass balance experiments have been used to quantify emissions from power plants (Ryerson et al, 1998;Trainer et al, 1995), oil and gas fields (Karion et al, 2013Lavoie et al, 2015Lavoie et al, , 2017Peischl et al, 2015Peischl et al, , 2016Pétron et al, 2014;Ren et al, 2017), and cities (Cambaliza et al, 2014Gioli et al, 2014;Heimburger et al, 2017;Kalthoff et al, 2002;Mays et al, 2009;O'Shea et al, 2014;Salmon et al, 2017). Measurements of NO y aboard the NCAR C-130 during WINTER are also used to provide information about NO y partitioning downwind of D.C.-Balt.…”

“…The measured 5-second precision for UMD CO 2 and CO measurements were ± 20 ppbv and ± 8 ppbv, respectively. Other instrumentation installed in the UMD Cessna has been discussed by He et al (2014) and Ren et al (2017). 2.2.3.…”

Retraction: Methane Emissions From the Marcellus Shale in Southwestern Pennsylvania and Northern West Virginia Based on Airborne Measurements

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The article, Ren, X., et al (2017), "Methane emissions from the Marcellus Shale in southwestern Pennsylvania and northern West Virginia based on airborne measurements," has been retracted by the authors because of an error in wind measurements used to calculate methane emissions in the southwestern Marcellus Shale region. The error was discovered by the authors in October 2017 upon their installation of an improved, differential GPS, wind measurement system onto the aircraft used in this study.

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