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.

Australia has embarked on a process of potential commitment through the Kyoto Protocol to contain growth in greenhouse gas emissions to 8% between 1990 and the reporting period of 2008 - 2012. The target is well below the estimated growth of about 28% under the `business as usual' condition. Australia's greenhouse gas inventory estimates that 502 million tonnes of carbon dioxide equivalents were emitted in the base year of 1990. This report examines over 175 candidate options for reducing greenhouse gas emissions to identify their technical feasibility, cost per tonne of carbon dioxide avoided and capability to reduce emissions under Australian conditions. The candidate options were not intended to represent an exhaustive list but they encompass major and some lesser options being canvassed in Australia and overseas. Preferred options were selected on their performance towards the criteria of technical feasibility, cost and capability.

A Bayesian inversion technique to determine the location and strength of trace gas emissions from a point source in open air is presented. It was tested using atmospheric measurements of nitrous oxide (N2O) and carbon dioxide (CO2) released at known rates from a source located within an array of eight evenly spaced sampling points on a 20 m radius circle. The analysis requires knowledge of concentration enhancement downwind of the source and the normalized, three-dimensional distribution (shape) of concentration in the dispersion plume. The influence of varying background concentrations of ~1% for N2O and ~10% for CO2 was removed by subtracting upwind concentrations from those downwind of the source to yield only concentration enhancements. Continuous measurements of turbulent wind and temperature statistics were used to model the dispersion plume. The analysis localized the source to within 0.8 m of the true position and the emission rates were determined to better than 3% accuracy. This technique will be useful in assurance monitoring for geological storage of CO2 and for applications requiring knowledge of the location and rate of fugitive emissions.

In July 2010 Geoscience Australia and CSIRO Marine & Atmospheric Research jointly commissioned a new atmospheric composition monitoring station (' Arcturus') in central Queensland. The facility is designed as a proto-type remotely operated `baseline monitoring station' such as could be deployed in areas that are likely targets for commercial scale carbon capture and geological storage (CCS). It is envisaged that such a station could act as a high quality reference point for later in-fill, site based, atmospheric monitoring associated with geological storage of CO2. The station uses two wavelength scanned cavity ringdown instruments to measure concentrations of carbon dioxide (CO2), methane (CH4), water vapour and the isotopic signature (?13C) of CO2. Meteorological parameters such as wind speed and wind direction are also measured. In combination with CSIRO's TAPM (The Air Pollution Model), data will be used to understand the local variations in CO2 and CH4 and the contributions of natural and anthropogenic sources in the area to this variability. The site is located in a region that supports cropping, grazing, cattle feedlotting, coal mining and gas production activities, which may be associated with fluxes of CO2 and CH4. We present in this paper some of the challenges found during the installation and operation of the station in a remote, sub-tropical environment and how these were resolved. We will also present the first results from the site coupled with preliminary modelling of the relative contribution of large point source anthropogenic emissions and their contribution to the background.

Quantification of leakage into the atmosphere from geologically stored CO2 is achievable by means of atmospheric monitoring techniques if the position of the leak can be located and the perturbation above the background concentration is sufficiently large for discrimination. Geoscience Australia and the CO2CRC have recently constructed a site in northern Canberra for the controlled release of greenhouse gases. This facility enables the simulation of leak events and provides an opportunity to investigate techniques for the detection and quantification of emissions of CO2 (and other greenhouse gases) into the atmosphere under controlled conditions. The facility is modelled on the ZERT controlled release facility in Montana. The first phase of the installation is complete and has supported an above ground, point source, release experiment (e.g. simulating leakage from a compromised well). Phase 2 involves the installation of a shallow underground horizontal well for line source CO2 release experiments and this will be installed during the first half of 2011. A release experiment was conducted at the site to explore the application of a technique, termed atmospheric tomography, to simultaneously determine the location and emission rate of a leak when both are unknown. The technique was applied to the release of two gas species, N2O and CO2, with continuous sampling of atmospheric trace gas concentrations from 8 locations 20m distant from a central release point and measurement of atmospheric turbulence and dispersive conditions. The release rate was 1.10 ± 0.02 g min-1 for N2O and 58.5 ± 0.4 g min-1 for CO2 (equivalent to 30.7 ± 0.2 tonnes CO2 yr-1). Localisation using both release species occurred within 0.5 m (2% error) of the known location. Determination of emission rate was possible to within 7% for CO2 and 5% for N2O.

Note: A more recent version of this product is available. This point dataset contains the major power stations in Australia including all those that feed into the electricity transmission network.

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.

Recent national and state assessments have concluded that sedimentary formations that underlie or are within the Great Artesian Basin (GAB) may be suitable for the storage of greenhouse gases. These same formations contain methane and naturally generated carbon dioxide that has been trapped for millions of years. The Queensland government has released exploration permits for Greenhouse Gas Storage in the Bowen and Surat basins. An important consideration in assessing the potential economic, environmental, health and safety risks of such projects is the potential impact CO2 migrating out of storage reservoirs could have on overlying groundwater resources. The risk and impact of CO2 migrating from a greenhouse gas storage reservoir into groundwater cannot be objectively assessed without knowledge of the natural baseline characteristics of the groundwater within these systems. Due to the phase behaviour of CO2, geological storage of carbon dioxide in the supercritical state requires depths greater than 800m, but there are no hydrochemical studies of such deeper aquifers in the prospective storage areas. Geoscience Australia (GA) and the Geological Survey of Queensland (GSQ), Queensland Department of Mines and Energy, worked collaboratively under the National Geoscience Agreement (NGA) to characterise the regional hydrochemistry of the Denison Trough and Surat Basin and trialled different groundwater monitoring strategies. The output from this Project constitutes part of a regional baseline reference set for future site-specific and semi-regional monitoring and verification programmes conducted by geological storage proponents. The dataset provides a reference of hydrochemistry for future competing resource users.

A metadata report for the atmospheric monitoring station installed in Arcturus, south of Emerald in central Queensland. The station was installed for baseline atmospheric monitoring to contribute to emission modelling spanning 2010-2014. The station included compositional gas analysers, supporting meteorological sensors and an eddy covariance flux tower. The metadata covered in the report include: the major variables measured by each instrument, the data duration and frequency, data accuracy, calibration and corrections, the location the data is stored, and the primary contact for the data.

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.