Table 1 Results of Monte Carlo aggregation of component-based emissions in the Barnett Shale.

From: Super-emitters in natural gas infrastructure are caused by abnormal process conditions

Component Emissions (kg CH 4 per hour per site) Percent of total emissions Max. emissions (kg CH 4 per hour per site) Number of sites where contribution of individual component is >26kg CH4 per hour
Pneumatic controllers 0.53 (0.52–0.54) 46% 9.5 (7.6–13) 0
Chemical injection pumps 0.18 (0.17–0.18) 15% 6.7 (5.0–9.3) 0
Equipment leaks 0.15 (0.14–0.15) 13% 9.0 (6.8–13) 0
Compressors 0.10 (0.10–0.11) 8.7% 18 (14–22) 0
Water tank flashing 0.084 (0.083–0.085) 7.3% 22 (19–26) 0
Condensate/oil tank flashing (60% control efficiency) 0.073 (0.045–0.11) 6.3% 160 (68–340) 10 (5–17)
Liquid unloadings 0.040 (0–0.18) 3.5% 530 (0–2,600) 2 (0–4)
Dehydrators 3 × 10−4 (2 × 10−4–3 × 10−4) 0.03% 0.44 (0.17–0.50) 0
Total 1.2 (1.1–1.3) 100% 600 (90–2,600) 13 (7–20)
  1. Table shows average emissions per site due to each component, contribution to total emissions and maximum expected emissions from each component (95% CI shown in parentheses). Also shown are the average number of sites where individual components produce emissions greater than the 99th percentile of site-based emissions from Zavala-Araiza et al.21 (wherein 174 sites emit >26 kg CH4 per hour and produce 44% of total emissions).