GreenLITE Measurements to Quantify Emissions from Oil Sands Processing: Alberta Case Study

Measurements from the Greenhouse-gas Laser Imaging Tomography Experiment (GreenLITE™) system have been used to estimate methane (CH₄) and carbon dioxide (CO₂) emissions from an oil sands tailings pond. Oil sands are a natural mixture of sand, water, and bitumen that can be refined to produce unconventional crude oil using processes that produce tailings – a mixture of water, sand, clay, and residual bitumen. Tailings are stored in large engineered dam systems called tailings ponds which are known emission sources of CH₄, CO₂, and volatile organic compounds (VOCs). Provincial and federal requirements dictate that facilities with relatively large emissions of specific gases must report those facility-scale emissions on an annual basis. Methods of assessing facility emissions may include use of emissions factors, flux chamber measurements, and/or mass balance calculations. A major challenge in measuring and monitoring emissions from oil sands processing facilities is that such facilities are dynamic by nature and tailings ponds in particular vary in composition both spatially and temporally. An assortment of other factors can substantially impact pond emissions such as pond inversion, pumping of the pond content, or storms. As a result, emissions between ponds and even from a given pond will vary significantly in both spatial and temporal domains – clearly reducing the effectiveness and accuracy of point and/or intermittent measurement approaches. A continuous monitoring system with broad spatial coverage would be ideal for this purpose. A candidate technology to meet this need is GreenLITE™, a system that uses high precision intensity modulated continuous wave (IMCW) lidar transceivers and a series of retroreflectors to measure the atmospheric density of CH₄ and/or CO₂ along horizontal columns of air. The system has been deployed in several configurations to test its ability to measure and map gas concentrations over areas ranging from 0.04 to 25 km² (~200 m X 200 m, up to ~5 km X 5 km). Such deployments include a year-long demonstration in the city of Paris, France, in 2016, and deployment as part of a pilot program at an industrial oil and gas facility in 2017. Here we present the results from a 2019 case study that provided estimates of CH₄ and CO₂ emissions using GreenLITE™ measurements at a tailings pond in Alberta, Canada. This presentation includes a brief overview of GreenLITE™, a description of the integrated approach developed to provide time varying estimates of emissions based on continuous measurements of concentration and coincident in situ atmospheric state data, and a review of the results which estimate CH₄ and CO₂ emissions that are comparable to other published studies and demonstrate a viable approach to monitoring emissions at oil sands processing facilities.