Ginninderra sub-surface CO2 release: Experiment 3 October 2013 - January 2014

Ivan Schroder1, Andrew Feitz1, Henry Berko1, Padarn Wilson2, Hui Zhang3, Ulrike Schacht4, Charles Jenkins5 and Steve Zegelin5

CO2CRC Report No: RPT16-5601

1 Geoscience Australia and CO2CRC Ltd 2 ANU 3 China Geological Survey 4 University of Adelaide and CO2CRC Ltd 5 CSIRO and CO2CRC Ltd

CO2CRC Limited Level 1, 700 Swanston Street, bldg. 290 The University of Melbourne Victoria 3010 Australia www.co2crc.com.au

Ivan Schroder, Andrew Feitz, Henry Berko, Padarn Wilson, Hui Zhang, Ulrike Schacht, Charles Jenkins and Steve Zegelin (2016) Ginninderra sub-surface CO2 release: Experiment 3, October 2013 - January 2014, CO2CRC Limited, Melbourne, Australia, CO2CRC Publication Number RPT16-5601. 27 pp

© CO2CRC 2016

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CO2CRC acknowledges and appreciates the strong relationships it has with industry, community, government, research organisations, projects and agencies in Australia and around the world.

Industry ANLEC R&D (on behalf of ACALET)

Chevron Australia

Coal 21

Global CCS Institute

INPEX Browse Ltd

J-POWER

Shell Development (Australia) Pty Ltd

Community Landowners near site

Moyne Shire

Nirranda South

Government Australian Government: Department of Education and Training

Australian Government: Department of Industry, Innovation and Science

CarbonNet Project

NSW: Department of Industry

SA: The Department for Manufacturing, Innovation, Trade, Resources and Energy (DMITRE)

Victoria: Department of Economic Development, Jobs, Transport and Resources

WA: Department of Mines and Petroleum

Research Australian National University

Charles Darwin University

CSIRO

Curtin University

Federation University Australia

Geoscience Australia

GNS Science

Imperial College of London

Korea Institute of Geosciences & Mineral Resources

Lawrence Berkeley National Laboratory (LBNL)

Petroleum Technology Research Centre (PTRC)

University of Adelaide

University of Edinburgh

University of Melbourne

University of NSW

University of Queensland

University of Western Australia

UK CCS Research Centre

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Contents EXECUTIVE SUMMARY ............................................................................................................................ 2

1. EXPERIMENT DESCRIPTION ............................................................................................................. 3

AIMS ........................................................................................................................................ 3

SITE DESCRIPTION ................................................................................................................... 4

1.2.1. Crop type ......................................................................................................................... 5

1.2.2. Soil properties ................................................................................................................. 5

1.2.3. Weather and climate ...................................................................................................... 6

1.2.4. Groundwater ................................................................................................................... 8

CONTROLLED RELEASE OF CO2, Kr AND He ............................................................................. 9

1.3.1. CO2 gas supply and release ............................................................................................. 9

1.3.2. Kr gas supply and release .............................................................................................. 10

1.3.3. He gas supply and release ............................................................................................. 10

2. MONITORING AND ASSESSMENT TECHNIQUES ........................................................................... 11

SOIL GAS ................................................................................................................................ 11

2.1.1. Soil gas surveys ............................................................................................................. 11

2.1.2. Sampling method .......................................................................................................... 12

2.1.3. Sample analysis ............................................................................................................. 13

EDDY COVARIANCE ............................................................................................................... 14

GROUNDWATER DEPTH ........................................................................................................ 17

2.3.1. Manual measurements ................................................................................................. 17

2.3.2. Automated diver measurements .................................................................................. 17

LINE CO2 CONCENTRATIONS ................................................................................................. 18

SOIL FLUX .............................................................................................................................. 18

2.5.1. Equipment used ............................................................................................................ 18

2.5.2. Manual soil flux surveys ................................................................................................ 20

AIRBORNE HYPERSPECTRAL SURVEYS................................................................................... 21

ELECTRO-MAGNETIC SURVEYS .............................................................................................. 22

2.7.1. Electro-magnetic 31 ...................................................................................................... 22

2.7.2. Electro-magnetic 38 ...................................................................................................... 22

MOBILE CO2 SURVEYS ........................................................................................................... 22

PLANT ANALYSES ................................................................................................................... 23

3. ACKNOWLEDGEMENTS ................................................................................................................. 25

4. REFERENCES .................................................................................................................................. 25

5. INSTRUMENT MANUALS ............................................................................................................... 26

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EXECUTIVE SUMMARY This report provides background information about the Ginninderra controlled release Experiment 3 including a description of the environmental and weather conditions during the experiment, the groundwater levels and a brief description of all the monitoring techniques that were trialled during the experiment.

The Ginninderra controlled release facility is designed to simulate CO2 leakage through a fault, with CO2 released from a horizontal well 2 m underground. Two previous subsurface CO2 release experiments have been conducted at this facility in early and late 2012, which have helped guide and develop the techniques that have been applied herein.

The aim of the third Ginninderra controlled release experiment was to further the development of detection and quantification techniques, and investigate seasonal effects on gas migration. Particular focus was given to plant health as a diagnostic detection method, via physical, biochemical and hyperspectral changes in plant biomass in response to elevated CO2 in the shallow root zone.

Release of CO2 began 8 October 2013 at 4:45 PM and stopped 17 December 2013 at 5:35 PM. The CO2 release rate during Experiment 3 was 144 kg/d CO2. Several monitoring and assessment techniques were trialled for their effectiveness to quantify and qualify the CO2 that was released. The methods are described in this report and include:

• soil gas

• eddy covariance

• mobile surveys

• line CO2 concentrations

• groundwater levels and chemistry

• plant biochemistry

• airborne hyperspectral

• soil flux

• electromagnetic (EM-31 and EM-38)

• meteorology

This report is a reference guide to describe the Ginninderra Experiment 3 details. Only methods are described in this report, with the results of the experiment published in conference papers and journal articles.

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1. EXPERIMENT DESCRIPTION The third controlled sub-surface release of carbon dioxide (CO2) conducted at the Ginninderra controlled release facility was carried out between 8 October 2013 and 17 December 2013. The experiment involved a number of different monitoring and assessment techniques in order to detect and quantify the CO2 that was released.

Details about the construction of the site, the sub-surface CO2 pipe and installation of the CO2 supply tank can be found in the Ginninderra Greenhouse Gas Controlled Release Facility: Installation Report (Berko and Feitz, 2012). Details of the methods utilised in the first and second controlled release experiment can be found in the Ginninderra sub-surface release: Experiment 1 (Kuske et al., 2014a) and Ginninderra sub-surface release: Experiment 2 (Kuske et al., 2014b) reports.

This report aims to provide background information about the experiment including a description of the environmental and weather conditions during the experiment, the groundwater levels and a brief description of all the monitoring techniques that were trialled during the experiment. Results of the assessment techniques will not be reported here and have been published as journal papers (Feitz et al., 2014a; Feitz et al., 2014b), with the data released as open access in late 2016.

AIMS

The aim of the Ginninderra Experiment 3 controlled release was to simulate the leakage of CO2 along a line source, to represent leakage through a fault. Multiple methods and techniques were then trialled in order to assess their abilities to:

• identify that a leak was present

• identify the location of the leak

• identify the strength of the leak

• assess the effects a leak may have on plant health

• assess seasonal controls on gas migration

This experiment had a focus on plant health indicators to assess the aims listed above, in order to evaluate the effectiveness of monitoring plant health.

Most of the assessment techniques began collecting data or operating prior to the start date of the CO2 release in order to identify a good baseline understanding of the site’s background conditions. Many techniques also monitored the length of time it took for the environment to return to background conditions, or, at least, until the effects of the released CO2 were below detection.

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SITE DESCRIPTION

The Ginninderra controlled release facility is located at the CSIRO Ginninderra Experiment Station, 10 km northwest of Canberra city centre (Figure 1). Figure 2 shows the research site in more detail with monitoring equipment and sample site locations superimposed to indicate the experiment layout.

Figure 1 Location of the Ginninderra controlled release facility, Canberra, ACT.

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Figure 2 Ginninderra controlled release facility Experiment 3 layout showing location of the release well and monitoring and sampling locations. Green squares = plant sampling sites, Blue triangles = 1 m soil gas wells, Green stars = eddy covariance towers, Green circles = Groundwater wells, Red cross and circles = laser and reflectors respectively, Yellow circles = Permanent soil flux chambers.

1.2.1. Crop type

Two crops were utilised in this experiment, with the western half of the field sown with field peas, and the eastern half of the field sown with wheat. The crops were sown on 3 July 2013. Field peas were planted late in their growing season, although this was not observed to deleteriously affect the plants.

1.2.2. Soil properties

Soils have been characterised as sandy loams and clays with coarse gravel. It is thought that the site consists of a paleo-fluvial system, leading to a highly heterogeneous soil system across the field. The site has been characterised as having deep red and yellow podzolic soils with the subsoil containing predominantly kaolinite with subdominant illite (Sleeman, 1979). X-ray diffraction (XRD) analyses

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indicate that soils comprise quartz with K and Na feldspars, illite/muscovite, clays and trace amounts of ankerite. A more detailed soil analysis including XRD and Portable Infrared Mineral Analyzer (PIMA) results can be found in the Ginninderra Greenhouse Gas Controlled Release Facility: Installation Report (Berko and Feitz, 2012).

1.2.3. Weather and climate

A weather station (Campbell Scientific Inc.) has been operating at the site since September 2009 (Figure 3). Variables that are measured include; temperature, relative humidity, wind speed, wind direction, solar radiation, barometric pressure and rainfall. These variables are important for determining site conditions that might affect both plant health and conditions as well as how the CO2 might disperse once in the atmosphere.

Figure 3 Weather station permanently deployed at the Ginninderra controlled release facility.

Over the measurement period weather statistics were compared to monthly mean statistics calculated from a 53 year dataset (Bureau of Meteorology data statistics for Ginninderra CSIRO - Station 70169) (Figure 4). Total rainfall for the month of October was 19.8 mm, considerably below

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the average for October of 67.1 mm. This resulted in the site having very dry conditions at the beginning of the experiment, and a low water table (below the level of the CO2 release pipe). November had above average rainfall of 100.4 mm (average November rainfall is 68.3 mm), while December and January both were far below average rainfall for the area with 19.6 mm (average December rainfall is 57.8 mm) and 7.4 mm (average January rainfall is 59.0 mm) of rain respectively.

Figure 4 Monthly total rainfall (2013-14) and 53-year mean total at Ginninderra for September to February.

Temperatures at the site ranged between 4.0°C and 20.3°C during the month of October, between 6.8°C and 23.1°C during November and between 10.9°C and 28.4°C during December. The predominant wind direction during the experiment was northwest (Figure 5), which is consistent with past meteorological measurements made at the site. Winds are often observed to calm soon after midday and shift more easterly, while at night there is typically little to no wind.

0

20

40

60

80

100

120

Sep Oct Nov Dec Jan Feb

Rain

fall

(mm

)

Month

Release 3 2013-14

53-year mean

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Figure 5 Wind rose plot for Ginninderra Experiment 3 showing frequency of wind directions and wind speeds (m/s) for the duration of the experiment.

1.2.4. Groundwater

Groundwater levels before the experiment were at normal levels at around 1 to 2 m depth. The lack of rainfall during the experiment led to groundwater levels steadily dropping over the summer, leading to a deep water table by the end of the experiment (>2 m). This means that the CO2 release pipe was above the groundwater level for the duration of the release. Figure 6 shows the record of groundwater levels from mid-2011 to early-2014, with the duration of Experiment 3 indicated by the shaded region.

0.0 - 1.0 1.0 - 2.0 2.0 - 3.0 3.0 - 4.0 4.0 - 5.0 5.0 - 6.0 6.0 - 7.0 >7.0

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Figure 3 Groundwater levels (metres below surface) recorded at the Ginninderra controlled release facility from mid-2011 until early-2014. Shaded zone indicates the duration of Experiment 3. The CO2 release pipe is at a depth of 2 m.

CONTROLLED RELEASE OF CO2, Kr AND He

1.3.1. CO2 gas supply and release

Geoscience Australia managed the continuous supply of CO2 for the experiment. A 2.5 tonne liquid CO2 tank was permanently located at the release facility. The initial pressure inside the tank was 1500 kPa and the tank was refilled every two weeks by BOC for the duration of the experiment. Figure 7 shows a schematic diagram of the horizontal underground pipe installed at the CO2CRC Ginninderra controlled release facility.

CO2 was released from the 100 m slotted HDPE pipe, 2 m underground. 144 kg/d of CO2 was injected into five chambers (B–F) at 10 L/min per chamber using 5 Burkert CO2 flow controllers. Release of CO2 began 8 October 2013 at 4:45 PM and stopped 17 December 2013 at 5:35 PM. On 26 November 2013, Kr at 10 mL/min and He at 50 mL/min were mixed with the B-line CO2 at the mass flow controller unit and released from Chamber B. The release of the gas tracers continued until 5:35 PM 17 December 2013.

The δ13C isotopic signature of the supplied CO2 was determined. The δ13C is particularly useful for confirming the extent of CO2 migration in the sub-surface via soil gas measurements if distinct from the background soil gas signature. Samples were taken in Calibond-5 bags from the line A outlet at the mass controller after several minutes of venting. The samples were then analysed at Geoscience

0

0.5

1

1.5

2

2.5

3

Dep

th (m

)

Date

P2 (east) P4 (west) P1 (north west) P3 (north east)

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Australia’s Organic Geochemistry Laboratory according to the method outlined in Boreham et al (2004). The δ13C for Release 3 had an isotopic signature of -22‰, which was similar to the CO2 supplied during an experiment in 2010, i.e. ~-18 ‰ (Humphries, 2010; Humphries et al., 2012). This suggested that the source of the CO2 was primarily from a biogenic source. BOC source their CO2 from three manufacturers in Australia: from a geological source at Boggy Creek, Victoria; the Manildra ethanol plant; and Kooragang Island’s ammonia plant, which uses methane as the hydrogen source. The -22‰ δ13C CO2 signature suggests that the predominant source of CO2 was from Manildra.

Figure 4 Schematic diagram of the horizontal underground pipe that releases CO2 at the Ginninderra controlled release facility. Chambers are numbered A (western end) through F (eastern end).

1.3.2. Kr gas supply and release

A Sierra Smart-Trak mass flow controller was installed in the Burkert CO2 Flow Controller unit to meter Krypton (Kr) gas. The Kr line from the mass flow controller was connected to a mixing chamber (ss-cylinder, 100 mL) also located in the Burkert unit. The CO2 line to chamber B was connected to the mixing chamber. Kr was injected into chamber B (10 mL/min) as a tracer gas and hence was diluted at a ratio of 1:1000.

1.3.3. He gas supply and release

An additional Sierra Smart-Trak mass flow controller was installed in the Burkert CO2 Flow Controller unit to meter Helium (He) gas. The He line from the mass flow controller was connected to a mixing chamber (ss-cylinder, 100 mL) also located in the Burkert unit. The CO2 line to chamber B was connected to the mixing chamber. He was injected into chamber B (50 mL/min) as a tracer gas and hence was diluted at a ratio of 1:200.

A B C D E F

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2. MONITORING AND ASSESSMENT TECHNIQUES

SOIL GAS

2.1.1. Soil gas surveys

The soil gas sampling grid was developed to cover the study area up to a distance of 30 m away from the horizontal release well (Figure 2 and Figure 8). The soil gas wells were spaced 1 m apart near the release well, in order to better characterise the developing CO2 plume. With increasing distance from the release well the spacing of the soil gas wells was increased. The grid was laid out perpendicular to the horizontal release well. Five rows of monitoring wells were spaced 30 m apart, with the middle row 60 m away from the western and eastern ends of the release well. Soil gas composition was monitored at 1 m depth for all sampling points. Two sets of shallow soil gas wells were installed for Experiment 3, from 0 to 10 m at 2 m intervals, perpendicular to the well and starting from the centre of each crop’s major leakage zone.

Soil gas samples were collected once prior to injection and then repeated six times following the start of the release experiment as well as once post-release, meaning a total of 8 soil gas surveys were performed for this study (Table 1).

Figure 5 Illustration of the soil gas monitoring grid for the 2013 controlled release experiment. The grey squares indicate the locations of the 47 permanent wells at 1 m depth. The blue squares indicate locations of the 12 shallow soil gas wells installed at 30 cm depth for this experiment. Note: the release well runs through the centre of the grid in a west to east direction.

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Table 1 Dates and number of successful samples for all soil gas surveys conducted during Experiment 3.

Survey No. Date of survey No. of successful samples Time (since start of release)

1 3 Oct 2013 46 Baseline (Pre-release)

2 10 Oct 2013 46 24 hours

3 16 Oct 2013 47 1 week

4 7 Nov 2013 47 4 weeks

5 27 Nov 2013 46 7 weeks

6 5 Dec 2013 47 8 weeks

7 17 Dec 2013 46 10 weeks

8 19 Dec 2013 46 40 hours post-release

2.1.2. Sampling method

A direct push soil gas sampling methodology was adopted for the study as it minimised the risk of atmospheric contamination, had minor impact on the soil environment and had a fast, effective soil gas recovery rate (Schacht and Jenkins, 2014). A Post Run Tubing system (PRT) was used to access the soil vadose zone and acquire a sample. O-ring connections ensured that the PRT system had a vacuum-tight seal.

In total 47 PRT probes were permanently installed for the soil gas sampling for Experiment 3 (Figure 8). Each probe consisted of a PRT retractable drive point assembly and PRT retractable drive point holders. Hollow probe rods, 1.2 m long and 2.54 cm thick were used to push the PRT probes approximately one metre into the soil using a 13.6 kg slide hammer. The probe was then jacked up approximately 0.2 m, leaving a 0.2 m deep, 2.54 cm diameter void, which the gas can fill. During the jacking, the PRT retractable drive point falls ~5 cm down the hole, at which point it catches onto the end of the drive point holder, allowing soil gas to enter the probe. A 1.5 m length of polytubing with the PRT adaptor attached to the end is inserted down the inside of the probe and screwed into the retractable drive point holder at the base of the rod, while the hollow probe rods were removed completely. The hole was then filled with screened sand around the alternating small batches of ~50 mL powdered bentonite and water to the surface to create a seal between the tubing and soil. Approximately 150 ml or three times the volume of the polytube is purged from the system via a syringe to remove any atmospheric contaminants. The system is then sealed with a closed luer fitting.

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2.1.3. Sample analysis

All analyses were conducted by the Geoscience Australia’s Isotope and Organic Geochemistry Laboratory. Molecular compositions of the samples, including C1-C5 and C6+ hydrocarbons, O2, N2, CO2, was conducted using a HP7890A gas chromatograph (GC) equipped with an automated 10-port gas sampling valve plumbed with dual sample loops (1 ml each) in a heated valve oven at 90°C and two 1/8” SS packed columns. The column outlets were connected together using a 1/8” tee and the outlet flow directed to a TCD in-series with a FID/methanizer. Helium (He) and hydrogen (H2) were determined using an Agilent 6890 gas chromatograph equipped with a series of 1/8” columns. The detection limit for all the above mentioned components is 0.002 mole percent. Calibration was carried out against two Certified Reference Materials. Measurements were corrected for response factors from gas standards, and any introduced N2 and O2 during analysis. The variation of measured percentage is within 5%.

A subset of survey samples was analysed for krypton (Kr) using a Hewlett Packard 6890 gas chromatograph interfaced to a Hewlett Packard 5973 mass selective detector. In order to determine absolute concentrations Kr a calibration curve was derived using a gravimetric standard of Kr and by varying injection volumes. The detection limit for Kr is 16 ppb, with the variation of measured percentage being within 2%.

A smaller subset of samples was analysed for δ13C of CO2 by continuous flow gas chromatography (GC-C-IRMS) using a Finnigan MAT252 coupled to a combustion III interface and a Fusion GC. A PoraPlot Q fused silica column was used to separate the CO2. All analysis was run in duplicate, at least, to give a range of results with an experimental error of 0.3‰.

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Figure 6 Photograph of a row of soil gas wells across the measurement site at the Ginninderra controlled release facility.

EDDY COVARIANCE

The main eddy covariance (EC) flux tower (Figure 10) measured continuously from 6 September 2013 to 12 February 2014, and was powered by two 80 W solar powered batteries. The EC tower was positioned ~15 m south of the release well at the eastern end, to account for the predominant north-westerly winds at the site, thus maximising the measurements downwind of the release. Using a Campbell Scientific Inc. (CSI) CR3000 data logger, measurements were stored at a frequency of 10 Hz which were used to prepare 15 minute averages. The data were uploaded hourly using the WiFi network at the site.

Table 2 summarises the instruments installed on the flux tower. On 16 October 2013 the WindSonic’s alignment was changed from 355° to 0°. The EC150 was removed on 7 January 2014, and the HMP45 stopped collecting data from 8 January 2014.

Table 2 Details of instruments for the main EC tower deployed during Experiment 3, describing the height above ground at which they were installed and what variables were measured.

Equipment Variables Measured Height above ground (m)

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Vaisala HMP45 RH & Temperature

Relative humidity (RH), Air temperature (Ta) 1.95

Campbell Scientific EC150 IRGA and CSAT3A

Absolute humidity (Ah), CO2 concentration (Cc), Air pressure (ps) Wind direction (Wd), Components to wind direction in the x, y and z dimensions (Ux, Uy, Uz), Wind speed (Ws), Virtual air temperature (Tv)

2.3

Kipp and Zonen CNR4 radiometer

Upwelling longwave radiation (Flu), Upwelling solar radiation (Fsu), Downwelling longwave radiation (Fld), Downwelling solar radiation (Fsd)

2.75

Gill WindSonic 2D sonic anemometer

Backup Wind direction (Wd) and Wind speed (Ws) 2.95

Kipp and Zonen CNR1 net radiometer

Backup Net radiation (Fn) 2.9

Campbell Scientific HFT3 soil heat flux plate

Soil heat flux (Fg) -0.08

3x Campbell Scientific TCav thermocouple probe

Soil temperature (Ts) -0.03, -0.05, -0.1

Campbell Scientific CS616 soil moisture probe

Soil moisture content (Sws) 0 to -0.1

Campbell Scientific EC100 electronics enclosure

1.7

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Figure 7 Eddy Covariance setup at the Ginninderra controlled release facility during Experiment 3.

Another EC tower was deployed from 12 December 2013 to 12 February 2014, approximately 20 m south of the release well on the boundary between the two crops. Details of this second tower are highlighted in Table 3. Table 3 Details of instruments used for the second EC tower deployed in Experiment 3, describing the height above ground at which they were installed and what variables were measured.

Equipment Variables Measured Height above ground (m)

Campbell Scientific EC150 IRGA and CSAT3A

Absolute humidity (Ah), CO2 concentration (Cc), Air pressure (ps) Wind direction (Wd), Components to wind direction in the x, y and z dimensions (Ux, Uy, Uz), Wind speed (Ws), Virtual air temperature (Tv)

1.1

Gill WindSonic 2D sonic anemometer

Backup Wind direction (Wd) and Wind speed (Ws) 2.0

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GROUNDWATER DEPTH

Four groundwater monitoring wells (Figure 11) (50 mm diameter) are located at the Ginninderra site and their locations are indicated in Figure 2.

2.3.1. Manual measurements

Groundwater levels were measured using a plopper tape measure and were recorded during some field site visits. Table 4 lists the dates of measurements dating from pre-experiment, to a few months after the experiment (Figure 6 shows groundwater level results for a longer period).

Table 4 Dates of manual groundwater level readings for Experiment 3.

Date

24 Sep 2013

30 Oct 2013

27 Nov 2013

13 Dec 2013

20 Dec 2013

10 Jan 2014

2.3.2. Automated diver measurements

Four Mini-Divers (Schlumberger Water Services) were installed near the base (2-3.5 m depth below ground) for each of the groundwater wells (P1-P4) from 29 May 2013 to 19 November 2013. These were installed by suspension from the top of the well, by stainless steel cable. A Baro-diver Di500, suspended above the ground, was installed in P4 to apply atmospheric corrections. Data was sampled every 5 mins and stored in instrument memory. Every fortnight the data were downloaded to and reviewed for quality puproses.

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Figure 8 Photograph of a groundwater bore at the Ginninderra controlled release facility.

LINE CO2 CONCENTRATIONS

A Boreal GasFinder2 was deployed on 17 December 2013 for 165 minutes of continuous monitoring. The GasFinder2 was mounted on a scanning platform on a tripod at a height of 1.2 m in the NW corner of the field. The GasFinder2 uses a near-infrared semiconductor diode laser set to a unique absorption wavelength of CO2 gas in air to measure the average CO2 concentration across the path length between the laser and a reflector. It has a sensitivity of 1000 ppm•m for CO2 with an operating temperature range of -20°C to 40°C.

Eight gold-plated retro-reflectors were set-up in an array across the field from 50-120 m away from the laser in an arc spanning bearing of 100°-165° (for locations see Figure 2). Reflectors were firmly cable-tied to star pickets or stable support structures. The laser scanned sequentially through each reflector with a 20 second dwell time.

SOIL FLUX

2.5.1. Equipment used

A West Systems portable flux meter containing a Licor Li840a soil gas analyser was used to measure the flux of CO2 and H2O from sample locations within the site of investigation. The technology uses a double beam infrared sensor with a temperature range of -10°C to 45°C and atmospheric pressure range of 660 to 1060 hPa. The accuracy of the sensor for CO2 is 2%, and repeatability is within +5 ppm when the sensor is set to its full scale range of 20,000 ppmV. The accuracy of the sensor for H2O is 2% and can measure the full range of 0-60 ppt. The CO2 flux meter can measure between 0

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and 600 moles/m2/day, depending on the size of the chamber used during measurements (a smaller chamber is used for small fluxes <1 mole/m2/day, while a larger chamber is used for fluxes up to 600 moles/m2/day). The large chamber (net volume 0.006 m3) was used for this experiment. The accuracy of measuring flux across a survey using the larger chamber depends on the rate of efflux, with the accuracy of background and leak measurements at our site having an accuracy of ±15% and ±10% respectively and leak areas accurate to CO2 fluxes were corrected for temperature and pressure effects and converted into log g/m2/day units.

Li8100 permanent soil flux chambers were installed at 3 locations between 9 October and 12 October 2013 and were operated until 2 February 2014 (Figure 12). Two chambers were installed directly above the well within the wheat, near the major leak pathway, while the third chamber was deployed in a background setting, 30 m away from the pipe. The ground of each chamber site was cleared on deployment, and a collar pushed in, however it was noted some vegetation began growing on the measurement surface as the experiment progressed. The accuracy of the infrared gas analyser of the Li8100 for CO2 is 1.5% of reading up to maximum measurement range of 20,000 ppm.

Figure 9 Permanent soil flux chamber deployed among the wheat crop during Experiment 3.

The chambers were solar powered, taking a measurement every 30 minutes. Each measurement consisted of pre and post purging cycles, accompanied with a measurement period of 60-90 seconds.

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2.5.2. Manual soil flux surveys

Sample points were located in a grid pattern across the location of the subsurface CO2 pipe to help characterise the spread of the CO2 in the soil, out to a maximum distance of 30 m from the pipe. The grid consisted of higher density sampling above the well (2-4 m2), grading to lower density towards the 30 m background (10-20 m2) During the surveys, not all points were always sampled due to time restrictions. However, a good representation across the entire field was always collected in order to develop good survey results to help characterise the amount of CO2 flux from the soil at each point in time. Samples were taken in the ruts between crop rows, thus avoiding the need for ground clearing. A good seal was established and a wheat bag draped around the chamber to reduce the influence of wind at the chamber edge. A linear best fit slope was fitted to the data and the flux and error manually recorded along with the grid position.

A total of 11 soil flux surveys were undertaken to characterise both the background soil flux of the local conditions at the site and to assist with the quantification of the release of CO2 during the controlled release experiment (Table 5). The soil flux survey on December 13 concurrently recorded H2O flux.

Table 5 List of soil flux surveys undertaken during Experiment 3 at the Ginninderra controlled release facility.

Survey No. Date of survey No. of points sampled Observation

1 2 Oct 2013 85 Background

2 15 Oct 2013 122 Leak observed

3 24 Oct 2013 141 Leak observed

4 31 Oct 2013 131 Leak observed

5 6 Nov 2013 129 Leak observed

6 14 Nov 2013 128 Leak observed

7 27 Nov 2013 147 Leak observed

8 4 Dec 2013 134 Leak observed

9 13 Dec 2013 131 Leak observed

10 20 Dec 2013 112 Small leak observed

11 24 Jan 2014 79 Background

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AIRBORNE HYPERSPECTRAL SURVEYS

Two airborne hyperspectral surveys were flown during Experiment 3 in order to assess the ability of this method to detect impacts on plant development during the controlled release of CO2, particularly during various stages of growth.

Hyperspectral data in the SWIR and VNIR bands were collected using a research aircraft from Flinders University - Airborne Research Australia (ARA). A SPECIM AisaEAGLE II hyperspectral scanner (VNIR) (252 spectral bands between 400 and 100 nm) and a SPECIM AisaHAWK (241 spectral bands between 990 and 2494 nm) were mounted in underwing pods of ARA’s ECO-Dimona research aircraft VH-EOS, each one together with its own OXTS RT4003 GPS/IMU navigation and altitude system (Figure 13). Additionally, a FLIR A615 thermal imager, and a Canon 1D Mk 4 DSLR were fitted to collect data. Because the site is so close to Canberra city, data is publically available from multiple GPS base-stations providing suitable data for differential GPS post-processing to provide precise navigational data required for accurate image formation.

Figure 10 The ECO-Dimona research craft which flew the hyperspectral surveys. Pictured in the foreground is the SPECIM HAWK hyperspectral scanner mounted in the underwing pod.

The TERN hyperspectral targets used to acquire the data were deployed in the same paddock as the test crop so they were sampled at the same time and place, and through the same atmosphere. CO2CRC ground teams conducted simultaneous in-situ measurements of plants in the crop, using an ASD FieldSpec3 spectrophotometer. The reflectance spectra of the calibration targets were also measured which are used to calibrate the reflectance spectra from the hyperspectral data during

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processing. An issue in thermal data acquired for the hyperspectral flight on 7 November 2013 resulted in lower thermometric resolution and no absolute calibration available for the dataset.

ELECTRO-MAGNETIC SURVEYS

2.7.1. Electro-magnetic 31

A Geonics EM-31 was used to map shallow (1 to 2 m depth) geological variations and subsurface features such as changes in ground conductivity and magnetic sucseptibility. Table 6 outlines the dates of EM-31 surveys conducted during Experiment 3. Surveys were conducted in both horizontal and vertical dipole operating modes. Surveys were collected with the instrument 1 m above the ground, walking north-south transects in the wheel ruts between crop rows. Position was established using a Trimble Juno GPS device, which also acted as a datalogger. The equipment has an operating frequency of 9.8 kHz, intercoil spacing of 3.66 m, and a measurement accuracy of ~5% of reading.

2.7.2. Electro-magnetic 38

A Geonics EM-38 MK-2 was used for collecting inphase (magnetic susceptibility) and quad-phase (conductivity) measurements with coil separation of 0.5 m and 1.0 m used. The instrument was operated in vertical dipole mode, providing data from effective depth ranges of 0.75 m and 1.5 m respectively. The survey was conducted at 1 m above the ground in the fallow field between Experiment 2 and 3. Position and measurement data logging was obtained from the instrument.

Table 6 List of EM-31 and EM-38 surveys undertaken during Experiment 3 at the Ginninderra controlled release facility.

Survey No. Date of survey Type of Survey

1 12 July 2013 EM-38

2 8 Oct 2013 EM-31

3 6 Dec 2013 EM-31

MOBILE CO2 SURVEYS

A Licor Li8100 CO2 gas analyser was installed on a Trumeter measuring wheel. Gas was pumped through the analyser via tubing from a height of 5 cm above ground, at a rate of 10 L/min, and sampled once a second. Three mobile CO2 surveys were conducted (14 October, 21 October, 21 December) in the morning during low-wind conditions. Surveys were conducted at a slow walking speed of 1.5-2.5

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km/hr along the wheel ruts in between rows, providing 24 north-south transects across the field with a spacing of 2.5-3 m.

PLANT ANALYSES

A goal of this experiment was to identify if changes in plant health, through visual and biochemical changes, can be used as a predictor of a subsurface CO2 leak. Three sampling campaigns were conducted; one baseline survey (8 October), an abridged survey on 25 October, and a full survey on 7 November. For each crop, from within a 0.5 by 0.5 m plot at each location, 20 plants were dug up (including roots). They were measured onsite for plant height, root length, leaf and flower count etc. washed of loose soil and sun-dried, before being weighed (Figure 14). Leaves were harvested from each location, with approximately 20 g samples bagged for analysis and put on ice.

Sampling was restricted to visual counts on 25 October and the wheat was not sampled to minimise the impact of removing vegetation on the other techniques. Light sampling was possible in peas, and involved collection of leaf and fruit from in situ plants without uprooting. For the plant survey on 7 November, wheat leaf samples could not be collected directly above the leak point due to near complete die off of the plants. Average height measurements (with greater standard error) were taken from the stalks of plants within 1 m of the well.

Plant composition was analysed by Southern Cross University with a summary of analysis methods provided in Table 7.

Table 7 Southern Cross University test methods.

Component Test Method

Carotenoids ARL TM-155 (Assay by HPLC* [450 nm], calculated as B carotene)

Chlorophyll Chlorophyll extraction and determination (Poorter & de Jon-Van Berkel, 2011)

Proteins AOAC Official Method 990.03

Nitrogen AOAC Official Method 990.03

Total Sugars ARL TM-179 (Assay by HPLC* [ELSD** detection], calculated as glucose)

*High Performance Liquid Chromatography **Evaporative Light Scattering Detector

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Figure 14 Left: An uprooted pea plant being measured for height, root length and leaf/fruit counts. Right: View to the NE across the release zone showing the area of impact on peas from the CO2 release.

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3. ACKNOWLEDGEMENTS Andrew Feitz and Ivan Schroder publish with the permission of the CEO, Geoscience Australia. All authors acknowledge the funding provided by the Australian Government through the CRC program to support CO2CRC research and funding provided by the Australian Government through the Carbon Capture and Storage – Implementation Budget Measure.

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Feitz, A., Jenkins, C., Schacht, U., McGrath, A., Henry, B., Schroder, I., Noble, R., Kuske, T., George, S., Charles, H., Zegelin, S., Cumow, S., Zhang, H., Sirault, X., Jimenez-Berni, J., Hortle, A. (2014a) An assessment of near surface CO2 leakage detection techniques under Australian conditions. Energy Procedia, 63, pp. 3891-3906

Feitz, A.J., Leamon, G., Jenkins, C., Jones, D.G., Moreira, A., Bressan, L., Melo, C., Dobeck, L.M., Repasky, K., Spangler, L.H. (2014b) Looking for leakage or monitoring for public assurance? Energy Procedia, 63, pp. 3881-3890.

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Kuske, T., Feitz, A., Schacht U., Jenkins, C., Sirault, X., McGrath A., Kemp, C. and Berko, H. (2014). Ginninderra sub-surface CO2 release: Experiment 2. CO2CRC Report RPT14-4883, pp 22.

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