Preprints
https://doi.org/10.5194/amt-2023-27
https://doi.org/10.5194/amt-2023-27
13 Mar 2023
 | 13 Mar 2023
Status: this preprint is currently under review for the journal AMT.

Controlled release testing of the static chamber methodology for direct measurements of methane emissions

James Philip Williams, Khalil el Hachem, and Mary Kang

Abstract. Direct measurements of methane emissions at the component level provide the level of detail necessary for developing actionable mitigation strategies. As such, there is a need to understand the magnitude of component level methane emission sources and test methane quantification methods that can capture methane emissions from component level sources. The static chamber method is a direct measurement technique that is being applied to measure large and complex methane sources such as oil and gas infrastructure. In this work we compile component level methane emission factors from the IPCC emission factor database to understand the magnitude of component level methane flowrates, review the tested flowrates and measurement techniques from 38 controlled release experiments, and perform 64 controlled release testing of static chambers methodology with mass flowrates of 1.02, 10.2, 102, and 512 grams of methane per hour (g/hour). We vary the leak properties, chamber shape, chamber size, and usage of fans to evaluate how these factors affect the accuracy of the static chamber method. We find that 99 % of component level methane emission rates from the IPCC emission factor database are below 100 g/hour, and that 76 % of previously-available controlled release experiments did not test for methane mass flowrates below 100 g/hour. We find that the static chamber method quantified methane flowrates with an overall accuracy of ±14 %, and that optimal chamber configurations (i.e., chamber shape, volume, usage of fans) can improve accuracy to below ±5 %. We find that smaller chambers (<20 L) performed better than larger volume chambers (>20 L), regardless of the shape of chamber or usage of fans. However, we found that the usage of fans can substantially increase the accuracy of larger chambers, especially at higher mass flowrates of methane (>100 g/hour). Overall, our findings can be used to engineer static chamber systems for future direct measurement campaigns targeting a wide range of sources, including landfills, manholes, and oil and natural gas infrastructure.

James Philip Williams et al.

Status: open (until 17 Apr 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2023-27', Jesper Christiansen, 13 Mar 2023 reply

James Philip Williams et al.

James Philip Williams et al.

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Short summary
Methane is powerful greenhouse gas, and to reduce methane emissions it is important that the methods used to measure methane are tested and validated. The static chamber method is an enclosure-based technique that directly measures methane emissions, however there are a lack of studies that have tested it for the new variety of methane sources it is being used for. We find that the static chamber method can accurately measure methane emissions under a wide range of methane emission rates.