Deployment of Unmanned Aerial Vehicle during surface CO2 release experiments at the Ginninderra greenhouse gas controlled release facility H. Berko (CO2CRC, Geoscience Australia), F. Poppa (The Australian National University), U. Zimmer (The Australian National University) and A. Feitz (CO2CRC, Geoscience Australia) Lagrangian stochastic (LS) forward modelling of CO2 plumes from above-surface release experiments conducted at the GA-CO2CRC Ginninderra controlled release facility demonstrated that small surface leaks are likely to disperse rapidly and unlikely to be detected at heights greater 4 m; this was verified using a rotorcraft to map out the plume. The CO2 sensing rotorcraft unmanned aerial vehicle (RUAV) developed at the Australian National University, Canberra, is equipped with a CO2 sensor, a GPS, lidar and a communication module. It was developed to detect and locate CO2 gas leaks; and estimate CO2 concentration at the emission source. The choice of a rotor-craft UAV allows slower flight speeds compared to speeds of a fixed-wing UAV; and the electric powered motor enables flight times of 12 min. In experiments conducted at the Ginninderra controlled release facility, gaseous CO2 (100 kg per day) was released from a small diffuse source located in the middle of the paddock, and the RUAV was flown repeatedly over the CO2 source at a few meters height. Meteorological parameters measured continuously at the site at the time of the flight were input in the LS model. Mapped out horizontal and vertical CO2 concentrations established the need to be close to the ground in order to detect CO2 leakage using aerial techniques. Using the rotorcraft as a mobile sensor could be an expedient mechanism to detect plumes over large areas, and would be important for early detection of CO2 leaks arising from CCS activities.

The CO2CRC has been leading the international development and application of atmospheric techniques for CO2 leak detection and quantification for CCS. CSIRO's atmospheric monitoring program at the CO2CRC Otway Project demonstrated world's leading practice for atmospheric monitoring at geological storage sites. The GA-CO2CRC Ginninderra controlled release facility has enabled development and testing of a new atmospheric tomography approach for accurately quantifying CO2 emissions using atmospheric techniques. A scaled-up version of the technique using an array of more cost effective (but less accurate) sensors was applied at a larger scale at the Otway Stage 2B controlled release. Additional techniques have been developed including data filtering to optimize the detection of emitted gases against the ecosystem background and Bayesian inverse modeling to locate and quantify a source. GA and CSIRO operate a joint baseline atmospheric station in the Bowen Basin and have been independently investigating the sensitivity of CO2 leak detection through coupling of measurements taken in a sub-tropical environment with simulated leakage events. An outcome from this body of work is the importance of good quality, calibrated measurements, a long baseline record and the development and application of techniques using atmospheric models for quantifying gaseous emissions from the ground to the atmosphere. These same measurement requirements and quantification techniques have direct application to fugitive methane emissions from open cut coal mines, coal seam gas, tight gas, and conventional gas emissions. Application is easier for methane: the background signal is lower, sensors are available at affordable cost, and the emissions are measureable now. The Bowen Basin site, for example, is detecting fugitive methane emitted from open cut coal mining activities tens of kilometres away. An example of the sensitivity of atmospheric techniques for the detection of fugitive emissions from a simulated methane source will be presented.

Lagrangian stochastic (LS) forward modelling of CO2 plumes from above-surface release experiments conducted at the GA-CO2CRC Ginninderra GHG controlled release facility demonstrated that small surface leaks are likely to disperse rapidly and unlikely to be detected at heights greater 4 m; this was verified using a rotorcraft to map out the plume. The CO2 sensing rotorcraft unmanned aerial vehicle (RUAV) developed at the Australian National University, Canberra, is equipped with a CO2 sensor (3 ppm accuracy and 2 s response time), a GPS, lidar and a communication module. It was developed to detect, locate and quantify CO2 gas leaks. The choice of a rotorcraft UAV allows slower flight speeds compared to speeds of a fixed-wing UAV; and the electric powered motor enables flight times of 12 min. During the experiments, gaseous CO2 (100 kg per day) was released from a small diffuse source located in the middle of the paddock of the controlled release facility, and the RUAV, flying repeatedly over the CO2 source at a few metres height, recorded CO2 concentrations up to 85 ppm above background. Meteorological parameters measured continuously at the site were input in the LS model. Mapped out horizontal and vertical CO2 concentrations established the need to be close to the ground in order to detect CO2 leakage using aerial techniques. Using the rotorcraft as a mobile sensor could be an expedient mechanism to detect plumes over large areas, and would be important for early detection of CO2 leaks arising from CO2 geological storage activities.

Fugitive methane emissions, in particular relating to coal seam gas (CSG),has become an emerging issue in Australia over the last few years. There has been significant controversy in US regarding the magnitude of fugitive emissions during production from unconventional gas wells, with large differences in emissions reported between studies using different measurement approaches. . Preliminary research into a small number of Australia's unconventional fields suggest the average fugitive emissions per well are lower than that found in the US. The primary challenge is that the techniques for quantifying methane leakages are still at an early stage of development. Current methods for the small to medium scale use chamber based approaches or vehicles installed with fixed sampling lines and high precisions gas analysers. These technologies are promising, but generally have not been ground truthed in field conditions against known emission rates to estimate effectiveness. They also have limited application in environments where vehicle access is not possible. The Ginniderra facility is being upgraded to support a methane controlled release experiment in 2015. This will enable testing of and verifying methods and technologies for measuring and quantifying methane emissions. To address the absence of suitable techniques for emmission measurement at medium scales, several BOREAL lasers will be deployed which work at scales of 20-1000 m. It is also envisaged airborne techniques utilising laser and hyperspectral will be deployed, along with tomography work utilising multiple concurrent concentration measurements.

Two shallow sub-surface CO2 controlled release experiments were conducted at the Ginninderra test site during 2012. The theme of the first experiment was CO2 detection in the soil and surface emissions quantification. The theme for the second experiment was investigating sub-surface migration and broad scale detection technologies. Our objective overall is to design cheaper monitoring technologies to evaluate leakage and environmental impact in the shallow sub-surface. Over 10 different monitoring techniques were evaluated at the site against a known CO2 release. These included soil gas, soil CO2 flux, soil analysis, eddy covariance, atmospheric tomography, noble gas tracers, ground penetrating radar, electromagnetic surveys, airborne hyperspectral, in-field phenotyping (thermal, hyperspectral and 3D imaging), and microbial soil genomics. Technique highlights and an assessment of the implications for large scale storage are presented in the following corresponding talks.

Eddy Covariance (EC) is considered a key atmospheric technique for quantifying CO2 leakage. However the complex and localised heterogeneity of a CO2 leak above the background environmental signal violates several of the critical assumptions made when implementing the EC technique, including: - That horizontal gradients in CO2 concentration are zero. - That horizontal and vertical gradients in the covariance of CO2 and orthogonal wind directions are zero. The ability of EC measurements of CO2 flux at the surface to provide information on the location and strength of CO2 leakage from below ground stores was tested during a 144 kg/day release event (27 March - 13 June 2012) at the Ginninderra controlled release facility. We show that the direction of the leak can be ascertained with some confidence although this depends on leak strength and distance from leak. Elevated CO2 levels are seen in the direction of the leakage area, however quantifying the emissions is confounded by the potential bias within each measurement through breaching of the assumptions underpinning the EC technique. The CO2 flux due to advection of the horizontal CO2 concentration gradients, thought to be the largest component of the error with the violation of the EC technique's assumptions, has been estimated using the modelling software Windtrax. The magnitude of the CO2 flux due to advection is then compared with the measured CO2 flux measured using the EC technique, to provide an initial assessment of the suitability of the EC technique to quantifying leakage source rates.

Results from the first pass application of the tomography technique using low accuracy sensors is presented and limitations of the sensors and technique discussed. BUll. Seismol. Soc. AM.

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No abstract available

The TCRM Stochastic Event Catalogue contains artificially generated tropical cyclone tracks and wind fields representing 10000 years of tropical cyclone activity. The catalogue is stored by year, with a track file and wind field file. The wind field file contains the maximum wind speed from all events occuring in the corresponding track file (i.e. it represents annual maximum wind speeds).