(213d) Development of Continuous Methane Monitors for Detection of Emissions from the Oil & Gas Sector

Natural gas consists mostly of methane, an invisible and harmful greenhouse gas known to have present global warming impact 50 times greater than that of carbon dioxide. The US Environmental Protection Agency (EPA) has proposed to implement regulatory standards for comprehensive emissions monitoring and mitigation from oil and natural gas facilities. To address the urgency of detecting methane emissions in these facilities, a continuous monitoring solution was developed for quantitative mapping of methane leaks via using point sensors that are installed permanently at the periphery of a site, are IoT-enabled, and run on solar power. Our low-cost sensors use calibration models developed using machine learning that account for environmental effects in the sensor response. The monitoring system collects data in real time on methane emissions and meteorological conditions, which are filtered and averaged via edge computing using atmospheric dispersion statistics. The data are then processed using inversion algorithms to estimate leak rates and their positions. These results are displayed in a digital platform where users can visualize methane leaks mapped on their facilities in real time. Our methane emissions detectors have been deployed at a few different oil and gas facilities, including two test sites where their detection accuracies were optimized by using controlled releases of methane with flow rates from 1 to 15 kg/h for several months. The results show that our point sensors can detect methane concentrations with ppm-level accuracy over a wide range of temperature, humidity, and wind speed and direction. From the concentration data, our interpretation algorithms can estimate leak rates and their positions quantitatively, even for complex field sites. Our methane monitoring system can identify leak rates as low as 0.2 kg/h. Its capability to accurately pinpoint methane leaks with no false positives will enable oil and gas operators to intervene and mitigate their emissions to achieve sustainable and cost-effective operations in low-resource settings.