Quantifying Uncertainty in Methane Emission Measurements
Category: Research Poster
Author(s): Annie Hartshorn
Presenter(s): Annie Hartshorn
Mentors(s): Alexandra Taylor
Leaks from natural gas (NG) distribution pipelines are important safety hazards and contribute to climate change as NG is primarily composed of methane (CH4), a potent greenhouse gas. NG distribution pipelines, which provide gas in residential areas, are known emission sources. They are routinely surveyed for leaks by technicians using handheld methane sensing equipment, and the maximum concentration of the leak, measured in parts per million (ppm), indicates leak severity. However, potential error between instrument measurements and true NG leak flow rates is largely unquantified. This study aims to evaluate how well measured gas concentrations estimate true leak flow rates. In this study, I simulated NG pipeline leaks by drilling very fine holes into closed-system PVC pipes. I ran high-purity CH4 through these pipes at a variety of flow rates and measured the ‘leaks’ using an IRwin SX Gas Leak Detector. Then, I quantified the differences between expected and observed measurements. In theory, measured methane concentration should increase proportionally with flow rate, but gas leak dispersion is unpredictable, potentially complicating this relationship. In my presentation, I will discuss the results of this work, highlighting the strengths and limitations of this approach for estimating gas leak flow rate.