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. Presented at the 2013 CO2CRC Research Symposium

Hot Rocks in Australia - National Outlook Hill, A.J.1, Goldstein, B.A1 and Budd, A.R.2 goldstein.barry@saugov.sa.gov.au hill.tonyj@saugov.sa.gov.au Petroleum & Geothermal Group, PIRSA Level 6, 101 Grenfell St.Adelaide SA 50001 Anthony.Budd@ga.gov.au Onshore Energy & Minerals Division, Geoscience Australia, GPO Box 378 Canberra ACT 26012 Abstract: Evidence of climate change and knowledge of enormous hot rock resources are factors stimulating growth in geothermal energy research, including exploration, proof-of-concept appraisals, and development of demonstration pilot plant projects in Australia. In the six years since the grant of the first Geothermal Exploration Licence (GEL) in Australia, 16 companies have joined the hunt for renewable and emissions-free geothermal energy resources in 120 licence application areas covering ~ 67,000 km2 in Australia. The associated work programs correspond to an investment of $570 million, and that tally excludes deployment projects assumed in the Energy Supply Association of Australia's scenario for 6.8% (~ 5.5 GWe) of Australia's base-load power coming from geothermal resources by 2030. Australia's geothermal resources fall into two categories: hydrothermal (from relatively hot groundwater) and the hot fractured rock i.e. Enhanced Geothermal Systems (EGS). Large-scale base-load electricity generation in Australia is expected to come predominantly from Enhanced Geothermal systems. Geologic factors that determine the extent of EGS plays can be generalised as: - source rock availability, in the form of radiogenic, high heat-flow basement rocks (mostly granites); - low thermal-conductivity insulating rocks overlying the source rocks, to provide thermal traps; - the presence of permeable fabrics within insulating and basement rocks, that can be enhanced to create heat-exchange reservoirs; and - a practical depth-range, limited by drilling and completion technologies (defining a base) and necessary heat exchange efficiency (defining a top). A national EGS resource assessment and a road-map for the commercialisation of Australia's EGSs are expected to be published in 2008. The poster will provide a synopsis of investment frameworks and geothermal energy projects underway and planned in Australia.

Monitoring is an important aspect in verifying the integrity of the geological storage of greenhouse gases. Geoscience Australia is working with CSIRO, the CO2CRC, the Australian National University, the University of Adelaide and the University of Wollongong to develop and evaluate new techniques to detect and quantify greenhouse gas emissions.

Hydrothermal and hot fractured rock (HFR) resources are prevalent in Australia. This, and evidence of risks posed by climate change are factors stimulating growth in geothermal energy exploration, proof-of-concept and demonstration power generation projects in Australia. In the six years since the grant of the first Geothermal Exploration Licence (GEL) in Australia in 2001, 16 companies have joined the hunt for renewable and emissions-free geothermal energy resources in 122 licence application areas covering ~ 68,000 km2. The associated work programs correspond to an investment of $570 million, a tally which excludes up-scaling and deployment projects assumed in the Energy Supply Association of Australia's scenario for 6.8% (~ 5.5 GWe) of Australia's base-load power coming from geothermal resources by 2030. Most investment is focused on HFR for enhanced geothermal systems (EGS) to fuel binary power plants. At least two companies are also focused on hydrothermal resources, also to fuel binary power plants. A national EGS resource assessment and a road-map for the commercialisation of Australian EGS are expected to be published in 2008. Geoscience Australia's preliminary work suggests Australia's hot rock energy between 150oC and 5 km is roughly 1.2 billion PJ (roughly 20,000 years of Australia's primary energy use in 2005), without taking account of the renewable characteristics of hot rock EGS plays. The presentation will provide up-to-date accounts of: 1. Exploration, proof-of-concept and demonstration projects on the path to commercializing hot rock resources in Australia; 2. Government designed investment frameworks that aim to attract and facilitate progress to commercializing hot rock resources in Australia; 3. Methods adopted by regulators to meet community expectations that only safe operations (including EGS projects) will be approved by regulators; and 4. Proposed methods for the portfolio management of EGS projects vying for funding within companies, and competing for research and demonstration grants from governments.

Having techniques available for the accurate quantification of potential CO2 surface leaks from geological storage sites is critical for regulators, public assurance and for underpinning carbon pricing mechanisms. Currently, there are few options available that enable accurate CO2 quantification of potential leaks at the soil-atmosphere interface. Integrated soil flux measurements can be used to quantify CO2 emission rates from the soil and atmospheric techniques such as eddy covariance or Lagrangian stochastic modelling have been used with some success to quantify CO2 emissions into the atmosphere from simulated surface leaks. The error for all of these techniques for determining the emission rate is not less than 10%. A new technique to quantify CO2 emissions was trialled at the CO2CRC Ginninderra controlled release site in Canberra. The technique, termed atmospheric tomography, used an array of sampling sites and a Bayesian inversion technique to simultaneously solve for the location and magnitude of a simulated CO2 leak. The technique requires knowledge of concentration enhancement downwind of the source and the normalized, three-dimensional distribution (shape) of concentration in the dispersion plume. Continuous measurements of turbulent wind and temperature statistics were used to model the dispersion plume.

Geological storage of greenhouse gases is one approach that the Australian Government is pursuing to assist Australia, and the world, to reduce greenhouse gas emissions into the atmosphere. Understanding the geology of Australia's sedimentary basins and their potential for greenhouse gas storage is an important component of Geoscience Australia's work in supporting emission reductions.

A short animation of an atmospheric simulation of methane emissions from a coal mine (produced using TAPM) compared to actual methane concentrations detected by the Atmospheric Monitoring Station, Arcturus in Central Queensland. It illustrates the effectiveness of both the detection and simulation techniques in the monitoring of atmospheric methane emissions. The animation shows a moving trace of both the simulated and actual recorded emissions data, along with windspeed and direction indicators. Some data provided by CSIRO Marine and Atmospheric Research.

Many industries and researchers have been examining ways of substantially reducing greenhouse gas emissions. No single method is likely to be a panacea, however some options do show considerable promise. Geological sequestration is one option that utilises mature technology and has the potential to sequester large volumes of CO2. In Australia geological sequestration has been the subject of research for the last 2? years within the Australian Petroleum Cooperative Research Centre's GEODISC program. A portfolio of potential geological sequestration sites (?sinks?) has been identified across all sedimentary basins in Australia, and these have been compared with nearby known or potential CO2 emission sources. These sources have been identified by incorporating detailed analysis of the national greenhouse gas emission databases with other publicly available data, a process that resulted in recognition of eight regional emission nodes. An earlier generic economic model for geological sequestration in Australia has been updated to accommodate the changes arising from this process of ?source to sink? matching. Preliminary findings have established the relative attractiveness of potential injection sites through a ranking approach. It includes the ability to accommodate the volumes of sequesterable greenhouse gas emissions predicted for the adjacent region, the costs involved in transport, sequestration and ongoing operations, and a variety of technical geological risks. Some nodes with high volumes of emissions and low sequestration costs clearly appear to be suitable, whilst others with technical and economic issues appear to be problematic. This assessment may require further refinement once findings are completed from the GEODISC site-specific research currently underway.

A shallow vertical CO2 injection test was conducted over a 21 day period at the Ginninderra Controlled Release Facility in May 2011. The objective of this test was to determine the extent of lateral CO2 dispersion, breakthrough times and permeability of the soil present at the Ginninderra site. The facility is located in Canberra on the CSIRO agricultural Ginninderra Experiment Station. A 2.15m deep, 15cm stainless steel screened, soil gas sampling well was installed at the site and this was used as the CO2 injection well. The CO2 flow rate was 1.6 L/min (STP). CO2 soil effluxes (respiration and seepage) were measured continuously using a LICOR LI-8100A Automated Soil CO2 Flux System equipped with 5 accumulation chambers spaced 1m apart in a radial pattern from the injection well. These measurements were supplemented with CO2 flux spot measurements using a WestSystems portable fluxmeter. Breakthrough at 1m from the injection point occurred within 6 hrs of injection, 32hrs at 2m and after almost 5 days at 3m. The average steady state CO2 efflux was 85 ?mol/m2/s at 1m, 15 ?mol/m2/s at 2m and 5.0 ?mol/m2/s at 3m. The average background CO2 soil respiration efflux was 1.1 - 0.6 ?mol/m2/s. Under windy conditions, higher soil CO2 efflux could be expected due to pressure pumping but this is contrary to the observed results. Prolonged windy periods led to a reduction in the CO2 efflux, up to 30% lower than the typical steady state value.

Approximately one quarter of Australia's CO2 emissions come from southeast and central Queensland. This poster presents the geoscientific interpretations which lead to constructing a simplified 3-D model of a potential geological storage site for CO2. The Bowen Basin is located in northeast Australia, approximately 200 to 500 km from major CO2 emission hubs in southeast Queensland. The resources of the Bowen Basin include coal, oil and gas, and there are water resources within the overlying Great Artesian Basin. Defining trap integrity within the Bowen Basin is important to ensure that none of these resources are compromised. The Wunger Ridge area has been the focus of petroleum exploration for hydrocarbons. Geological, geophysical, hydrodynamic, petrological, petrophysical and seal capacity interpretations of datasets from the area were undertaken. These interpretations indicate that the Triassic fluvial - deltaic Showgrounds Sandstone is the most suitable for CO2 storage and injection as it is permeable and saturated with brackish to saline water except where hydrocarbons have accumulated. Geological profiles were developed using sequence stratigraphic concepts and combined with rock properties, measured from core, to produce simplified 3-D models with the goal of assessing parameters for CO2 injection and migration. Simulation runs using simple models, based on a coarse-scale grid, suggest that either one horizontal or two vertical wells are required to inject at the proposed rate. Geological heterogeneity increases injection pressure around the wellbore and reduces injection rates compared to homogeneous models, resulting in the need for more injection wells.