Inefficient and unlit natural gas flares both emit large quantities of methane
Fueling global warming
Flaring, the process of burning natural gas escaping from oil and gas wells, is primarily intended to combust the powerful greenhouse gas methane to minimize its emission. But is flaring as effective as is claimed? Plant et al. used airborne sampling to measure flare efficiency in three major gas production regions in the United States and found that methane emissions are five times higher than currently thought (see the Perspective by Duren and Gordon). Therefore, flaring is often not as efficient as presumed—or methane plumes simply are not combusted at all. —HJS
Abstract
Flaring is widely used by the fossil fuel industry to dispose of natural gas. Industry and governments generally assume that flares remain lit and destroy methane, the predominant component of natural gas, with 98% efficiency. Neither assumption, however, is based on real-world observations. We calculate flare efficiency using airborne sampling across three basins responsible for >80% of US flaring and combine these observations with unlit flare prevalence surveys. We find that both unlit flares and inefficient combustion contribute comparably to ineffective methane destruction, with flares effectively destroying only 91.1% (90.2, 91.8; 95% confidence interval) of methane. This represents a fivefold increase in methane emissions above present assumptions and constitutes 4 to 10% of total US oil and gas methane emissions, highlighting a previously underappreciated methane source and mitigation opportunity.
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Science
Volume 377 | Issue 6614
30 September 2022
30 September 2022
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Copyright © 2022 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
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Received: 23 March 2022
Accepted: 19 August 2022
Published in print: 30 September 2022
Acknowledgments
We acknowledge T. Sullivan and P. Wliczak for piloting the airborne measurements campaigns presented here. We thank fellow F3UEL team members Ã. Adames-Corraliza for assistance with flight planning, and C. Hausman, M. Allan, and A. Stoltenberg for useful discussions throughout. We are grateful to B. Hmiel, D. Lyon, and J. Warren of the Environmental Defense Fund for their insightful discussions about their work in the Permian.
Funding: This work was supported by the Alfred P. Sloan Foundation (G-2019-12451).
Author contributions: Conceptualization: E.A.K. and G.P. Investigation: G.P., E.A.K., A.R.B., Y.C., G.F., A.M.G.N., S.S., and M.S. Writing – original draft: G.P. and E.A.K. Writing – review & editing: G.P., E.A.K., A.R.B., Y.C., A.M.G.N., M.S., and D.Z.-A.
Competing interests: The authors declare that they have no competing interests.
Data and materials availability: The airborne data presented in this work are available publicly in the University of Michigan Deep Blue Data Repository [2020 campaign (45) and 2021 campaign (46)]. Daily VIIRS data are available at https://eogdata.mines.edu/products/vnf/, and annual data are available at https://eogdata.mines.edu/download_global_flare.html.
License information: Copyright © 2022 the authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original US government works. https://www.science.org/about/science-licenses-journal-article-reuse
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Alfred P. Sloan Foundation: G-2019-12451
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- Tackling unlit and inefficient gas flaring, Science, 377, 6614, (1486-1487), (2022)./doi/10.1126/science.ade2315
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