Summary The paper explores the critical role of combining source-level (Level 4) and site-level (Level 5) measurements to improve methane emissions reporting in the oil and gas sector. With methane being a potent greenhouse gas and the energy sector a major emitter, the study emphasizes the importance of accurate, verifiable emissions data to support global reduction efforts. Using case studies from Harbour Energy's offshore and onshore assets, the research applies direct measurement technologies, including Optical Gas Imaging, High Flow Samplers, and drone-mounted sensors like Aeromon's BH-12, to quantify emissions across various operational scenarios. The reconciliation process aligns detailed bottom-up inventories with independent top-down assessments to validate findings, identify discrepancies, and reduce uncertainty. Key insights include the need for synchronized timing of measurements, high spatial granularity, and clear understanding of operational conditions to accurately capture emissions. Uncertainty analysis is highlighted as central to credibility, with methodologies tailored to each data source and environmental condition. The study finds that reconciliation is not a one-off task but a continuous improvement process that strengthens regulatory compliance (notably with OGMP 2.0 and EU methane regulation) and supports more effective mitigation strategies. Ultimately, the integration of multi-level data enhances transparency, ensures data reliability, and enables informed decision-making for methane reduction across complex energy assets.
Verhoeven et al. (Tue,) studied this question.