Quantifying methane emissions from natural gas production in north-eastern Pennsylvania
Natural gas infrastructure releases methane (CH<sub>4</sub>), a potent greenhouse gas, into the atmosphere. The estimated emission rate associated with the production and transportation of natural gas is uncertain, hindering our understanding of its greenhouse footprint. This study pr...
| Main Authors: | , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-11-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/17/13941/2017/acp-17-13941-2017.pdf |
| _version_ | 1818586225805623296 |
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| author | Z. R. Barkley T. Lauvaux K. J. Davis A. Deng N. L. Miles S. J. Richardson Y. Cao C. Sweeney A. Karion M. Smith E. A. Kort S. Schwietzke T. Murphy G. Cervone D. Martins J. D. Maasakkers |
| author_facet | Z. R. Barkley T. Lauvaux K. J. Davis A. Deng N. L. Miles S. J. Richardson Y. Cao C. Sweeney A. Karion M. Smith E. A. Kort S. Schwietzke T. Murphy G. Cervone D. Martins J. D. Maasakkers |
| author_sort | Z. R. Barkley |
| collection | DOAJ |
| description | Natural gas infrastructure releases methane (CH<sub>4</sub>), a potent greenhouse
gas, into the atmosphere. The estimated emission rate associated with the
production and transportation of natural gas is uncertain, hindering our
understanding of its greenhouse footprint. This study presents a new
application of inverse methodology for estimating regional emission rates
from natural gas production and gathering facilities in north-eastern
Pennsylvania. An inventory of CH<sub>4</sub> emissions was compiled for major
sources in Pennsylvania. This inventory served as input emission data for the
Weather Research and Forecasting model with chemistry enabled (WRF-Chem), and
atmospheric CH<sub>4</sub> mole fraction fields were generated at 3 km resolution.
Simulated atmospheric CH<sub>4</sub> enhancements from WRF-Chem were compared to
observations obtained from a 3-week flight campaign in May 2015. Modelled
enhancements from sources not associated with upstream natural gas processes
were assumed constant and known and therefore removed from the optimization
procedure, creating a set of observed enhancements from natural gas only.
Simulated emission rates from unconventional production were then adjusted to
minimize the mismatch between aircraft observations and model-simulated mole
fractions for 10 flights. To evaluate the method, an aircraft mass balance
calculation was performed for four flights where conditions permitted its
use. Using the model optimization approach, the weighted mean emission rate
from unconventional natural gas production and gathering facilities in
north-eastern Pennsylvania approach is found to be 0.36 % of total gas
production, with a 2<i>σ</i> confidence interval between 0.27 and 0.45 % of
production. Similarly, the mean emission estimates using the aircraft mass
balance approach are calculated to be 0.40 % of regional natural gas
production, with a 2<i>σ</i> confidence interval between 0.08 and 0.72 % of
production. These emission rates as a percent of production are lower than
rates found in any other basin using a top-down methodology, and may be
indicative of some characteristics of the basin that make sources from the
north-eastern Marcellus region unique. |
| first_indexed | 2024-12-16T08:49:35Z |
| format | Article |
| id | doaj.art-14467350b5944a27a2420ee7c77505b1 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-16T08:49:35Z |
| publishDate | 2017-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-14467350b5944a27a2420ee7c77505b12022-12-21T22:37:29ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242017-11-0117139411396610.5194/acp-17-13941-2017Quantifying methane emissions from natural gas production in north-eastern PennsylvaniaZ. R. Barkley0T. Lauvaux1K. J. Davis2A. Deng3N. L. Miles4S. J. Richardson5Y. Cao6C. Sweeney7A. Karion8M. Smith9E. A. Kort10S. Schwietzke11T. Murphy12G. Cervone13D. Martins14J. D. Maasakkers15Department of Meteorology, The Pennsylvania State University, University Park, PA 16802, USADepartment of Meteorology, The Pennsylvania State University, University Park, PA 16802, USADepartment of Meteorology, The Pennsylvania State University, University Park, PA 16802, USADepartment of Meteorology, The Pennsylvania State University, University Park, PA 16802, USADepartment of Meteorology, The Pennsylvania State University, University Park, PA 16802, USADepartment of Meteorology, The Pennsylvania State University, University Park, PA 16802, USADepartment of Geography, The Pennsylvania State University, University Park, PA 16802, USANOAA/Earth Systems Research Laboratory, University of Colorado, Boulder, CO, 80305, USANational Institute of Standards and Technology, Gaithersburg, MD 20899, USADepartment of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, 48109, USACooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USACooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USAMarcellus Center for Outreach and Research, The Pennsylvania State University, University Park, PA 16802, USADepartment of Geography, The Pennsylvania State University, University Park, PA 16802, USAFLIR Systems, West Lafayette, IN 47906, USASchool of Engineering and Applied Sciences, Harvard University, Pierce Hall, 29 Oxford Street, Cambridge, Massachusetts 02138, USANatural gas infrastructure releases methane (CH<sub>4</sub>), a potent greenhouse gas, into the atmosphere. The estimated emission rate associated with the production and transportation of natural gas is uncertain, hindering our understanding of its greenhouse footprint. This study presents a new application of inverse methodology for estimating regional emission rates from natural gas production and gathering facilities in north-eastern Pennsylvania. An inventory of CH<sub>4</sub> emissions was compiled for major sources in Pennsylvania. This inventory served as input emission data for the Weather Research and Forecasting model with chemistry enabled (WRF-Chem), and atmospheric CH<sub>4</sub> mole fraction fields were generated at 3 km resolution. Simulated atmospheric CH<sub>4</sub> enhancements from WRF-Chem were compared to observations obtained from a 3-week flight campaign in May 2015. Modelled enhancements from sources not associated with upstream natural gas processes were assumed constant and known and therefore removed from the optimization procedure, creating a set of observed enhancements from natural gas only. Simulated emission rates from unconventional production were then adjusted to minimize the mismatch between aircraft observations and model-simulated mole fractions for 10 flights. To evaluate the method, an aircraft mass balance calculation was performed for four flights where conditions permitted its use. Using the model optimization approach, the weighted mean emission rate from unconventional natural gas production and gathering facilities in north-eastern Pennsylvania approach is found to be 0.36 % of total gas production, with a 2<i>σ</i> confidence interval between 0.27 and 0.45 % of production. Similarly, the mean emission estimates using the aircraft mass balance approach are calculated to be 0.40 % of regional natural gas production, with a 2<i>σ</i> confidence interval between 0.08 and 0.72 % of production. These emission rates as a percent of production are lower than rates found in any other basin using a top-down methodology, and may be indicative of some characteristics of the basin that make sources from the north-eastern Marcellus region unique.https://www.atmos-chem-phys.net/17/13941/2017/acp-17-13941-2017.pdf |
| spellingShingle | Z. R. Barkley T. Lauvaux K. J. Davis A. Deng N. L. Miles S. J. Richardson Y. Cao C. Sweeney A. Karion M. Smith E. A. Kort S. Schwietzke T. Murphy G. Cervone D. Martins J. D. Maasakkers Quantifying methane emissions from natural gas production in north-eastern Pennsylvania Atmospheric Chemistry and Physics |
| title | Quantifying methane emissions from natural gas production in north-eastern Pennsylvania |
| title_full | Quantifying methane emissions from natural gas production in north-eastern Pennsylvania |
| title_fullStr | Quantifying methane emissions from natural gas production in north-eastern Pennsylvania |
| title_full_unstemmed | Quantifying methane emissions from natural gas production in north-eastern Pennsylvania |
| title_short | Quantifying methane emissions from natural gas production in north-eastern Pennsylvania |
| title_sort | quantifying methane emissions from natural gas production in north eastern pennsylvania |
| url | https://www.atmos-chem-phys.net/17/13941/2017/acp-17-13941-2017.pdf |
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