South West Hub: a carbon capture and storage project

Abstract

The South West CO2 Geosequestration Hub (the South West Hub) is located in South West Western Australia in proximity to industrialised regions around Kwinana, Kemerton, and coal mining and power production facilities around Collie. Recognition that there is a potentially suitable geosequestration site in the region near extensive emission sources led to the formation of the South West Hub and its submission as a potential Flagship under the Australian Federal Clean Energy Initiative (CEI). An area with geosequestration potential was identified based on data from years of active research in the region to investigate oil and gas potential, ground-water resources and more recently for geothermal energy potential and now carbon storage. Three interesting factors stand out regarding this site: (1) the storage site relies primarily on residual and dissolution trapping, (2) some of the CO2 will be sequestered by mineralisation during the amelioration of bauxite residue from some nearby alumina plants, and (3) the subsurface storage area can be tested at a relatively early stage by accessing significant pilot-scale quantities of high-purity CO2 from existing industry in the Kwinana area. CO2 is already being captured and vented at a site in Kwinana, and a proposed pipeline will transport the CO2 to the alumina plants with the remainder of the gas used for a pilot-scale test. The upfront capital costs are therefore reduced to the pipeline cost rather than for a full-scale capture-ready power plant. In preparation for an investment decision (to drill a new data well addressing the main criteria for characterising carbon storage potential of the proposed Lesueur site) a series of studies have increased the understanding of the geology of the area. Modelling studies suggest that up to 6.4 million tonnes per annum could be stored in the Triassic aged Lesueur Sandstone, with total capacity estimates of 200–260 million tonnes of CO2 over the lifetime of the project. This paper primarily discusses the evolution of the geological understanding of the Lesueur Sandstone and associated formations in and around the Harvey Ridge structure, which falls within the Lesueur study area, as well as how the Collie coal users and producers and other local industries and government have become engaged in the project. Recent activities in the project have included seismic data acquisition and the drilling, coring and logging of a data well that will allow significant reductions in geological uncertainties for the project.