Measurement-Based Methane Inventory for Upstream Oil and Gas Production in Alberta, Canada Reveals Higher Emissions and Starkly Different Sources than Official Estimates

Abstract

Abstract As a signatory of the Global Methane Pledge, Canada has committed to > 75% reductions in oil and gas sector methane emissions by 2030. Regulations are being developed to meet this critical objective, but are hampered by uncertainty in true levels of emissions and source breakdowns. This paper presents a measurement-based, source-resolved, hybrid top-down/bottom-up methane inventory for conventional upstream oil and gas operations in Canada’s largest oil and gas-producing province, Alberta. The derived 2021 inventory of 1338 kt/y is approximately 1.8× the most recent official federal inventory and matches independent top-down aerial mass-balance and satellite estimates within measurement uncertainties. Moreover, the breakdown of major sources is starkly different from those assumed in the federal inventory, with venting (e.g., uncontrolled tanks, pneumatics, unlit flares) responsible for almost two-thirds of emissions implying important opportunities for mitigation. Derived methane intensities are similar to basins in the U.S.A. but approximately 4× those in the neighbouring province of British Columbia. Quantified methane intensities of individual anonymized companies reveal order-of-magnitude differences in performance at directly comparable facility types, highlighting the need for independent monitoring, reporting, and verification (MRV) to ensure collective success in reducing emissions.