The Ginninderra CH4 and CO2 release experiment: An evaluation of gas detection and quantification techniques
At International Journal of Greenhouse Gas Control , 2018
Recommended citation: Andrew Feitz, Ivan Schroder, Frances Phillips, Trevor Coates, Karita Neghandhi, Stuart Day, Ashok Luhar, Sangeeta Bhatia, Grant Edwards, Stefan Hrabar, Emili Hernandez, Brett Wood, Travis Naylor, Martin Kennedy, Murray Hamilton, Mike Hatch, John Malos, Mark Kochanek, Peter Reid, Joel Wilson, Nicholas Deutscher, Steve Zegelin, Robert Vincent, Stephen White, Cindy Ong, Suman George, Peter Maas, Sean Towner, Nicholas Wokker, David Griffith, The Ginninderra CH4 and CO2 release experiment: An evaluation of gas detection and quantification techniques, International Journal of Greenhouse Gas Control, Volume 70, March 2018, Pages 202-224, ISSN 1750-5836. https://doi.org/10.1016/j.ijggc.2017.11.018
Abstract
A methane (CH4) and carbon dioxide (CO2) release experiment was held from April to June 2015 at the Ginninderra Controlled Release Facility in Canberra, Australia. The experiment provided an opportunity to compare different emission quantification techniques against a simulated {CH4} and {CO2} point source release, where the actual release rates were unknown to the participants. Eight quantification techniques were assessed: three tracer ratio techniques (two mobile); backwards Lagrangian stochastic modelling; forwards Lagrangian stochastic modelling; Lagrangian stochastic (LS) footprint modelling; atmospheric tomography using point and using integrated line sensors. The majority of {CH4} estimates were within 20% of the actual {CH4} release rate (5.8 g/min), with the tracer ratio technique providing the closest estimate to both the {CH4} and {CO2} release rates (100 g/min). Once the release rate was known, the majority of revised estimates were within 10% of the actual release rate. The study illustrates the power of measuring the emission rate using multiple simultaneous methods and obtaining an ensemble median or mean. An ensemble approach to estimating the {CH4} emission rate proved successful with the ensemble median estimate within 16% for the actual release rate for the blind release experiment and within 2% once the release rate was known. The release also provided an opportunity to assess the effectiveness of stationary and mobile ground and aerial {CH4} detection technologies. Sensor detection limits and sampling rates were found to be significant limitations for {CH4} and {CO2} detection. A hyperspectral imager’s capacity to image the {CH4} release from 100 m, and a Boreal {CH4} laser sensor’s ability to track moving targets suggest the future possibility to map gas plumes using a single laser and mobile aerial reflector.