Articles | Volume 8, issue 5
Research article
07 May 2015
Research article |  | 07 May 2015

Measurements of methane emissions from natural gas gathering facilities and processing plants: measurement methods

J. R. Roscioli, T. I. Yacovitch, C. Floerchinger, A. L. Mitchell, D. S. Tkacik, R. Subramanian, D. M. Martinez, T. L. Vaughn, L. Williams, D. Zimmerle, A. L. Robinson, S. C. Herndon, and A. J. Marchese

Abstract. Increased natural gas production in recent years has spurred intense interest in methane (CH4) emissions associated with its production, gathering, processing, transmission, and distribution. Gathering and processing facilities (G&P facilities) are unique in that the wide range of gas sources (shale, coal-bed, tight gas, conventional, etc.) results in a wide range of gas compositions, which in turn requires an array of technologies to prepare the gas for pipeline transmission and distribution. We present an overview and detailed description of the measurement method and analysis approach used during a 20-week field campaign studying CH4 emissions from the natural gas G&P facilities between October 2013 and April 2014. Dual-tracer flux measurements and on-site observations were used to address the magnitude and origins of CH4 emissions from these facilities. The use of a second tracer as an internal standard revealed plume-specific uncertainties in the measured emission rates of 20–47%, depending upon plume classification. Combining downwind methane, ethane (C2H6), carbon monoxide (CO), carbon dioxide (CO2), and tracer gas measurements with on-site tracer gas release allows for quantification of facility emissions and in some cases a more detailed picture of source locations.

Short summary
This report presents an overview and detailed description of the measurement methods, analysis approach, and example data from a 10-week EDF-sponsored field campaign measuring methane emissions from natural gas gathering and processing facilities across the US. The dual-tracer ratio method was employed to quantify methane release rates and identify emission sources at a wide variety of facilities, using downwind measurements of CH4, C2H6, CO2, and CO with N2O and C2H2 as tracers.