Advancing methane emission quantification: a robust methodology for site-level measurements

The Oil and Gas Methane Partnership 2.0 (OGMP 2.0), led by the United Nations Environment Programme (UNEP) and supported by the European Commission, is currently the only measurement-based international reporting framework for the oil and gas sector. OGMP 2.0 aims to standardize and enhance the accuracy of methane emission reporting, enabling the industry to systematically quantify and reduce emissions.

This study introduces a robust methodology to meet OGMP Level 5 requirements, which call for site-level methane measurements integrated with specific Emission Factors (EF) and Activity Factors (AF) for individual sources. Previously, emissions reporting relied solely on inventory data, but independent site-level measurements now reconcile source-level inventories (Level 4) and thus enhance confidence in reported emissions.

The Dutch oil and gas sector serves as a case study. In 2023, the Dutch Emission Registration reported 639 kton of methane emissions nationally, which 17 kton (2.7%) attributed to the oil & gas sector. As part of this study, we measured emissions at over hundred oil and gas production and distribution sites.

We demonstrate the application of the Tracer Dispersion Method (TDM) to quantify methane emissions at the site level. This approach involves releasing a tracer gas with a known emission rate and measuring its concentration, along with methane, downwind of the facility with a specially equipped measurement truck. We determine the concentration of various gaseous components, allowing us to differentiate the emissions to the various types of sources that may be present. We drive by at multiple occasions along a predetermined route downwind of the site, enabling us to capture data under various meteorological and operational conditions. This ensures robust data collection and facilitates the automatic determination of the site-level emission factor, significantly reducing associated uncertainties.

This methodology not only complements source-level measurements but also improves the detection of previously unidentified emission sources, enhancing the overall reliability of emission inventories. We will discuss the requirements, advantages, and limitations of the TDM approach and outline next steps for further refinement.

By providing a scalable and accurate methodology for site-level methane quantification, this work contributes to the global effort to achieve transparent and actionable emission reduction strategies in the oil and gas sector.