California’s methane super-emitters

Duren, Riley; Thorpe, A. K.; Foster, K. T.; Rafiq, Talha; Hopkins, F. M.; Yadav, Vineet; Bue, Brian D.; Conley, Stephen; Colombi, Nadia K.; Frankenberg, Christian; McCubbin, Ian B.; Eastwood, Michael L.; Falk, Matthias; Herner, Jorn; Croes, Bart; Green, Robert O.; Miller, Charles E.

doi:10.1038/s41586-019-1720-3

Cited by 268 publications

(337 citation statements)

References 34 publications

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“…In particular, cattle feedlots and barns can be superemitters, as reported here using University of New South Wales/Royal Holloway, University of London measurements around Beef City, a 26,500 cattle feedlot in Australia (Figure 19). Similarly, Duren et al (2019) found that dairies alone accounted for 26% of California's methane point-source emissions. Given the size of the total emissions, even small percentage reductions will have large impacts.…”

Section: Reducing Agricultural Methane Productionmentioning

confidence: 97%

“…The emission rate depends on engine construction, plant design, and operation. Emissions can come from water handling facilities, gas engine exhausts, gas flaring, leaks from pipes, biogas upgrading units, tanks, etc., or from deliberate venting (Angelidaki et al, 2018;Duren et al, 2019;Fredenslund et al, 2018;Liebetrau et al, 2018;Samuelsson et al, 2018;Scheutz & Fredenslund, 2019). Some emissions can be single large leaks or long-lasting bursts from pressure relief valves (Reinelt & Liebetrau, 2019).…”

Section: Methane Emissions From Biodigesters and Biogas Generatorsmentioning

confidence: 99%

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Methane Mitigation: Methods to Reduce Emissions, on the Path to the Paris Agreement

Nisbet

Fisher

Lowry

et al. 2020

Reviews of Geophysics

214

131

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The atmospheric methane burden is increasing rapidly, contrary to pathways compatible with the goals of the 2015 United Nations Framework Convention on Climate Change Paris Agreement. Urgent action is required to bring methane back to a pathway more in line with the Paris goals. Emission reduction from “tractable” (easier to mitigate) anthropogenic sources such as the fossil fuel industries and landfills is being much facilitated by technical advances in the past decade, which have radically improved our ability to locate, identify, quantify, and reduce emissions. Measures to reduce emissions from “intractable” (harder to mitigate) anthropogenic sources such as agriculture and biomass burning have received less attention and are also becoming more feasible, including removal from elevated‐methane ambient air near to sources. The wider effort to use microbiological and dietary intervention to reduce emissions from cattle (and humans) is not addressed in detail in this essentially geophysical review. Though they cannot replace the need to reach “net‐zero” emissions of CO2, significant reductions in the methane burden will ease the timescales needed to reach required CO2 reduction targets for any particular future temperature limit. There is no single magic bullet, but implementation of a wide array of mitigation and emission reduction strategies could substantially cut the global methane burden, at a cost that is relatively low compared to the parallel and necessary measures to reduce CO2, and thereby reduce the atmospheric methane burden back toward pathways consistent with the goals of the Paris Agreement.

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Section: Reducing Agricultural Methane Productionmentioning

confidence: 97%

Section: Methane Emissions From Biodigesters and Biogas Generatorsmentioning

confidence: 99%

Methane Mitigation: Methods to Reduce Emissions, on the Path to the Paris Agreement

Nisbet

Fisher

Lowry

et al. 2020

Reviews of Geophysics

214

131

View full text Add to dashboard Cite

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“…The AVIRIS-C and AVIRIS-NG methane retrieval is based on absorption spectroscopy between 2100 and 2500 nm and uses a linearized matched filter to calculate a mixing ratio length in units of ppm-m representing the thickness and concentration within a volume of equivalent absorption (Thompson et al 2015). This and related techniques have been demonstrated in a number of previous airborne campaigns (Thompson et al 2015, Thompson et al 2016, Thorpe et al 2017, Krautwurst et al 2017, Duren et al 2019. Thorpe et al (2016) demonstrated that plumes for controlled releases as low as 10 kgCH 4 h −1 were consistently observed by AVIRIS-NG across multiple flight altitudes and wind conditions and a minimum detection limit of 2 kgCH 4 h −1 .…”

Section: Airborne Imaging Spectroscopymentioning

confidence: 56%

“…Thorpe et al (2016) demonstrated that plumes for controlled releases as low as 10 kgCH 4 h −1 were consistently observed by AVIRIS-NG across multiple flight altitudes and wind conditions and a minimum detection limit of 2 kgCH 4 h −1 . Frankenberg et al (2016) quantified emission rates ranging from 2 to 5000 kgCH 4 h −1 for the Four Corners region primarily from natural gas production and Duren et al (2019) reported methane emissions between 9 and 2600 kgCH 4 h −1 for methane plumes observed from the landfill, agriculture, and waste management sectors of California.…”

Section: Airborne Imaging Spectroscopymentioning

confidence: 99%

“…On October 6, 2017 coincident AVIRIS-NG and Scientific Aviation flights resulted in significantly different emission estimates. The Scientific Aviation aircraft measures wind speed according to Conley et al (2014), using true airspeed and GPSderived ground speeds to derive an average wind speed of 2.3 m s −1 for the period of measurement between 19:24 and 19:41 UTC (corresponding to the duration of 4 AVIRIS-NG scenes), significantly higher than wind speeds of 0.7 m s −1 derived from HRRR (Benjamin et al 2016) that were used in the AVIRIS-NG mass balance analysis (Duren et al 2019). Local meteorological station wind data (CIMIS Holt #248 station) indicated a higher wind speed (1.7 m s −1 ) compared to HRRR, and the resulting emission estimate (see figure 8, orange) showed improved agreement with results from Scientific Aviation on October 6, 2017.…”

Section: Emission Estimates Indicate High Variability Betweenmentioning

confidence: 99%

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Methane emissions from underground gas storage in California

Thorpe

Duren

Conley

et al. 2020

Environ. Res. Lett.

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Accurate and timely detection, quantification, and attribution of methane emissions from Underground Gas Storage (UGS) facilities is essential for improving confidence in greenhouse gas inventories, enabling emission mitigation by facility operators, and supporting efforts to assess facility integrity and safety. We conducted multiple airborne surveys of the 12 active UGS facilities in California between January 2016 and November 2017 using advanced remote sensing and in situ observations of near-surface atmospheric methane (CH 4 ). These measurements where combined with wind data to derive spatially and temporally resolved methane emission estimates for California UGS facilities and key components with spatial resolutions as small as 1-3 m and revisit intervals ranging from minutes to months. The study spanned normal operations, malfunctions, and maintenance activity from multiple facilities including the active phase of the Aliso Canyon blowout incident in 2016 and subsequent return to injection operations in summer 2017. We estimate that the net annual methane emissions from the UGS sector in California averaged between 11.0±3.8 GgCH 4 yr −1 (remote sensing) and 12.3±3.8 GgCH 4 yr −1 (in situ). Net annual methane emissions for the 7 facilities that reported emissions in 2016 were estimated between 9.0±3.2 GgCH 4 yr −1 (remote sensing) and 9.5±3.2 GgCH 4 yr −1 (in situ), in both cases around 5 times higher than reported. The majority of methane emissions from UGS facilities in this study are likely dominated by anomalous activity: higher than expected compressor loss and leaking bypass isolation valves. Significant variability was observed at different time-scales: daily compressor duty-cycles and infrequent but large emissions from compressor station blow-downs. This observed variability made comparison of remote sensing and in situ observations challenging given measurements were derived largely at different times, however, improved agreement occurred when comparing simultaneous measurements. Temporal variability in emissions remains one of the most challenging aspects of UGS emissions quantification, underscoring the need for more systematic and persistent methane monitoring.

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Thermodynamic Analysis of Dry Reforming of Methane for Valorization of Landfill Gas and Natural Gas

Jensen

Duyar

2021

Energy Tech

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Dry reforming of methane (DRM) is a promising technology to convert carbon dioxide (CO2) and methane (CH4), two major greenhouse gases into syngas (a mixture of carbon monoxide (CO) and hydrogen (H2)). A thermodynamic equilibrium analysis for DRM with a focus on carbon formation is carried out in Aspen Plus using the Gibbs free energy minimization method. The effects of feed CO2/CH4 ratio (0.5–3), reaction temperature (773–1373 K), and system pressure (0.1–10 atm) on the equilibrium conversion, product distribution, and solid carbon formation are investigated. From the analysis, it was found that the optimal operating conditions of 1 atm, 1123 K, and a feed ratio (CO2:CH4) of 1:1, minimized carbon formation, produced syngas at a H2/CO ratio of 1 (sufficient for downstream Fischer–Tropsch synthesis), while minimizing energy requirements. It is found that adding small amounts of oxygen or water significantly reduced carbon formation, minimized loss in syngas production, and reduced energy requirements. Three application scenarios were simulated to reflect the valorization of vented and flared natural gas and landfill gas (LFG). It was found that using captured CO2 with natural gas and LFG produced favorable results and therefore may be an opportunity for commercial DRM.

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California’s methane super-emitters

Cited by 268 publications

References 34 publications

Methane Mitigation: Methods to Reduce Emissions, on the Path to the Paris Agreement

Methane Mitigation: Methods to Reduce Emissions, on the Path to the Paris Agreement

Methane emissions from underground gas storage in California

Thermodynamic Analysis of Dry Reforming of Methane for Valorization of Landfill Gas and Natural Gas

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