| Popis: |
Methane emissions from >100 tank battery sites in the Permian Basin of west Texas were quantified using two different aircraft-based measurement platforms deployed asynchronously, but within a 5-day period. Emissions were detected by aircraft with rates ranging from 0.71 kg/hr to >750 kg/hr. On-site emission measurements were also made using a drone-based technology at a representative sample of 33 sites and were compared to engineering estimates of emission rates. A large fraction of total emissions from the sites sampled by the aircraft systems (90%±6%) were accounted for by sites with emissions greater than 10 kg/hr, when engineering estimates of emissions were assigned to sites with no emissions detected by aircraft. At least half of the sites with emission rates above 10 kg/hr had emissions that did not persist longer than a few days, and consequently, site by site comparisons of asynchronous aircraft measurements showed poor agreement. The two aircraft systems differed in their estimates of total emissions from the ensembles of sites sampled, and in the percentage of sites with emissions greater than 10 kg/hr. The differences in frequencies of detection between the two aircraft based platforms are attributed to a combination of factors, however, both aircraft-based emission measurement systems attribute a large fraction of emissions to sites with emission rates >10 kg/hr. |
