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

Abstract

Abstract. Direct measurements of methane emissions at the component level provide the level of detail necessary for the development of actionable mitigation strategies. As such, there is a need to understand the magnitude of component-level methane emission sources and to test methane quantification methods that can capture methane emissions at the component level used in national inventories. The static chamber method is a direct measurement technique that has been applied to measure large and complex methane sources, such as oil and gas infrastructure. In this work, we compile methane emission factors from the Intergovernmental Panel on Climate Change (IPCC) Emission Factor Database in order to understand the magnitude of component-level methane flow rates, review the tested flow rates and measurement techniques from 40 controlled-release experiments, and perform 64 controlled-release tests of the static chamber methodology with mass flow rates of 1.02, 10.2, 102, and 512 g h−1 of methane. We vary the leak properties, chamber shapes, chamber sizes, and use of fans to evaluate how these factors affect the accuracy of the static chamber method. We find that 99 % of the component-level methane emission rates from the IPCC Emission Factor Database are below 100 g h−1 and that 77 % of the previously available controlled-release experiments did not test for methane mass flow rates below 100 g h−1. We also find that the static chamber method quantified methane flow rates with an overall accuracy of +14/-14 % and that optimal chamber configurations (i.e., chamber shape, volume, and use of fans) can improve accuracy to below ±5 %. We note that smaller chambers (≤20 L) performed better than larger-volume chambers (≥20 L), regardless of the chamber shape or use of fans. However, we found that the use of fans can substantially increase the accuracy of larger chambers, especially at higher methane mass flow rates (≥100 g h−1). Overall, our findings can be used to engineer static chamber systems for future direct measurement campaigns targeting a wide range of sources, including landfills, sewerage utility holes, and oil and natural gas infrastructure.

Assessing Ammonia and Greenhouse Gas Emissions from Livestock Manure Storage: Comparison of Measurements with Dynamic and Static Chambers

“…To reduce measurement uncertainties, the static chamber design used in this study could also be improved. In general, the smallest chambers produce the lowest errors, and for larger chambers (above 20 L), such as the one used in this study, the use of fans appears critical to reducing measurement error, making it comparable to smaller chambers when fans are used [46]. ER can also be calculated through other approaches, such as IPCC, which is not site-specific but a regional estimation that considers different factors, such as average temperature, manure typology, storage site, etc.…”

Methane Emissions from Abandoned Oil and Gas Wells in Alberta and Saskatchewan, Canada: The Role of Surface Casing Vent Flows

“…Aerial or vehicle-based surveys can reduce site access issues and potentially increase the number of wells screened and identify more superhigh emitters. Nevertheless, direct component-level and site-level measurements are still needed to measure lower flow rates ( ≤ 10 4 mg/h) and to differentiate between collocated sources, , such as surface casing vent and non-surface casing vent emissions.…”

“…We measured all sites that could be measured according to site access and configuration and did not consult provincial surface casing vent flow or gas migration databases during site selection to limit potential bias. We quantified methane flow rates at each well site using a two-step process including chamber-based measurements, ,, which are described in the Supporting Information.…”

Methane Exchange Flux Monitoring between Potential Source Sewage Inspection Wells and the Atmosphere Based on Laser Spectroscopy Method

“…In addition, we also need to consider the impact of temperature and other factors on the monitoring accuracy. At present, typical gas flux measurement methods include the static gas chamber method [19,20], the eddy covariance method [21], the imaging Fourier transform infrared spectrum telemetry method [22], data analysis based on a space-borne spectrometer [23], and so on. Among these, the static gas chamber method obtains flux information by measuring the change in the target gas concentration with time in an airtight space.…”