Flaring efficiencies and NO_<i>x</i> emission ratios measured for offshore oil and gas facilities in the North Sea

Abstract. Gas flaring is a substantial global source of carbon emissions to atmosphere and targeted as route mitigating the oil gas sector footprint due waste resources involved. However, quantifying from resource-intensive, no studies have yet assessed for offshore regions. In this work, we present dioxide (CO2), methane (CH4), ethane (C2H6), NOx (nitrogen oxide) data 58 emission plumes identified flaring, measured during aircraft campaigns over North Sea (UK Norway) in 2018 2019. Median combustion efficiency, efficiency with which flared converted CO2 plume, was 98.4 % when accounting C2H6 or 98.7 only CH4. Higher efficiencies were Norwegian compared UK sector. Destruction removal (DREs), an individual species combusted, 98.5 CH4 97.9 C2H6. ratios be 0.003 ppm ppm−1 0.26 CH4, median C2H6:CH4 ratio 0.11 ppm−1. The highest observed floating production storage offloading (FPSO) vessels, although could potentially presence alternative sources on board, such diesel generators. measurements work used estimate total 1.4 Tg yr−1 CO2, 6.3 Gg 1.7 3.9 NOx.