Autonomous Mobile Methane Measurements Units

The quantification of methane concentrations in air is essential for the quantification of methane emissions, which in turn is necessary to determine absolute emission and the efficacy of emission mitigation strategies. These are essential if countries are to meet climate goals. Since their development in the late 1980s, cavity ring-down spectrometers (CDRS) are accepted as the gold standard for measuring methane concentrations. However, large scale deployment of CRDS analyzers across the thousands of oil and gas production sites, landfills, and wastewater facilities would be prohibitively expensive. As a result, lower-cost instrumentation has been recently developed but it is unclear how cheaper instrumentation will affect measurement resolution or accuracy. To test the use of lower cost instrumentation, Autonomous Mobile Methane Measurements Units (AMMMUs) have been developed as part of the re-development of Colorado State University’s Methane Emission Technology Evaluation Center. Here, we report on the instrumentation used inside the AMMMUs, which comprises metal oxide sensors, a non-dispersive infrared sensor, an integrated infrared sensor, and a tunable diode laser absorption spectrometer. All sensors tested detect methane to different upper/lower thresholds, with different levels of precision, and respond at different rates to changes in methane concentrations. This report provides a comprehensive guide on how to build and integrate low-cost off the shelf methane sensors in the AMMMUs along with all necessary code.