A Demonstrated Reconciliation of Top-Down and Bottom-Up Methane Measurements to Derive Verified Emission Intensities

Oil and gas companies striving to attain the OGMP2.0 “Gold Standard” for methane Measurement, Reporting, and Verification (MRV) are required to find and measure individual methane sources across all their operating assets, and in particular, to verify total emissions using an independent "top-down" measurement.  The process of comparing source-level and top-down measurements is termed “reconciliation” and is an essential part of meeting the “Gold Standard”.  However, to date, there is no prescriptive OGMP 2.0 protocol on how to reconcile site and source-level measurements, and there are key knowledge gaps regarding calculation methods, required sample sizes, and uncertainty protocols.

This study demonstrates a novel framework for reconciling on site source measurements with independent source-resolved aerial survey data to derive corporate methane emissions and intensity data sufficient to meet or exceed the OGMP 2.0 Gold Standard certification requirements. Critically, the protocol allows for direct analysis of measurement uncertainties.  In partnership with an oil and gas producer operating in Canada, a source-level inventory is first created based on extensive ground measurements and company-specific emission factors.  Independent source-resolved measurements, covering 100% of the company’s operating assets, are then conducted using Bridger Photonics Inc.’s Gas-Mapping LiDAR (GML).  Multi-pass aerial data are analyzed using detailed probability of detection models, which consider the conditions of each pass, and integrated with the bottom-up data to account for unmeasured sources.  The result is a comprehensive, verified inventory of total methane emissions for the company.  As part of this demonstration, the analysis is repeated using up to four independent aerial surveys, providing real-world insights to the importance of temporal variability in emissions and its influence on required sample sizes for accurate reconciliation.  The results have important implications for creating MRV protocols that ensure reported emissions adequately represent the variable nature of emissions, particularly when sample sizes are small because measurements are limited to assets from a single operator as is the case under OGMP2.0 reporting.