Quantification of Methane Emissions from Natural Gas Losses in the Urban Region of Boston, Massachusetts with an Atmospheric Measurement Network and Modeling Framework

Kathryn McKain, Harvard University, kmckain@fas.harvard.edu (Presenter)
Adrian Down, Duke University, adrian.down@duke.edu
Steve M. Raciti, Boston University, raciti@bu.edu
John Budney, Harvard Univesity, jwbudney@seas.harvard.edu
Lucy R. Hutyra, Boston University, lrhutyra@bu.edu
Cody Floerchinger, Aerodyne, Inc, cfloerchinger@aerodyne.com
Scott C. Herndon, Aerodyne, Inc, herndon@aerodyne.com
Thomas Nehrkorn, AER, Inc, tnehrkor@aer.com
Mark S. Zahniser, Aerodyne, Inc, mz@aerodyne.com
Robert Jackson, Duke University, jackson@duke.edu
Nathan Phillips, Boston University, nathan@bu.edu
Steven Wofsy, Harvard University, wofsy@fas.harvard.edu

Fugitive emission from natural gas is an important source of methane, with most recent analyses focusing on emissions from the natural gas production sector. Methane emissions from the entire natural gas supply chain must be quantified to evaluate the full environmental impacts of natural gas, and to develop and assess the efficacy of emission reduction strategies. As a case study, we quantified the natural gas emission rates for the one year in the urban region of Boston, MA using a comprehensive atmospheric measurement and modeling framework with three main components. First, continuous methane observations from four stations were combined with a high-resolution transport model to quantify the regional average emission rate. Next, simultaneous observations of atmospheric ethane were compared with the ethane to methane ratio in the pipeline gas delivered to the region to estimate the fractional contribution of natural gas to the total methane flux. Lastly, government statistics and geospatial data on energy consumption were used to relate the average methane emission rate to a fractional loss rate to the atmosphere from all downstream components of the natural gas system in the urban region. We find that natural gas accounts for the majority of the methane emissions in the Boston urban region, and that the natural gas loss rate is several times larger than those implied by the most closely comparable emission inventories. Our results suggest that natural gas consuming regions with older infrastructure, and possibly more broadly, may be larger sources of methane to the atmosphere than is currently estimated and represent areas of significant resource loss. We discuss possible explanations for the disagreements between inventory- and atmosphere-based methods found in this study, and general principles and challenges for applying this methodological framework to other urban areas.

Presentation Type:  Poster

Session:  Carbon Monitoring System (CMS) Posters   (Mon 1:30 PM)

Associated Project(s): 

• Friedl, Mark: 4-D Modeling of the Regional Carbon Cycle in and Around Urban Environments: An Interdisciplinary Study to Advance Observational and Modeling Foundations ...details
• Hutyra, Lucy: Quantifying Carbon Signatures Across Urban-To-Rural Gradients: Advancing the Capacity for Monitoring, Reporting, and Verification Through Observations, Models, and Remote Sensing ...details
• Nehrkorn, Thomas: Prototype Monitoring, Reporting and Verification System for the Regional Scale: The Boston-DC Corridor ...details
• Wofsy, Steve: Source attribution, emission monitoring and treaty verification by combining remote sensing and suborbital data ...details

Poster Location ID: 130