Transmission and Distribution Pipeline Leak Identification and Characterization by Walking Survey and Soil Flux Measurements
Year: 2024
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide We identified fugitive methane (CH 4 ) leaks within natural gas transmission and distribution pipeline rights of way (ROWs) around Pittsburgh, PA, and Baltimore, MD, by means of a walking survey while measuring ambient methane and ethane (C 2 H 6 ) mixing ratios. We used the methane time series to determine discrete leaks using a simple algorithm and verified that the methane was fossil in origin via the methane-to-ethane ratio. For transmission ROWs, we found an average of 23 leaks (range of 12 to 47) over 20.1 total km, corresponding to an activity factor (AF) of 1.1 leaks/km (range 0.60 to 2.3 leaks/km). We also quantified total methane emissions for a subset ( N = 5) of the identified leaks using a soil flux measurement chamber. The mean leak emission rate (ER) was 172 g/h/leak (range 17 to 452 g/h/leak). Our AF is higher than the Environmental Protection Agency’s Greenhouse Gas Inventory (GHGI) estimate for transmission pipelines, which is 0.02 leaks/km. Our mean ER is also larger than the GHGI estimate for protected steel pipelines (44 g/h/leak). This study provides a model for making AF and ER measurements in vegetated environments with difficult terrain and suggests fugitive emissions from transmission pipelines may be a more significant source of atmospheric methane than is currently outlined in the GHGI.
Source: ACS ES&T Air
Authors: Ellis S. Robinson, Peter F. DeCarlo
Institutions: University of Arizona, Johns Hopkins University
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
SDG: Climate action
Open Access status: hybrid
Estimated APC paid: $4,500
OpenAlex ID: W4405716425