A preliminary regional geothermal assessment of Victoria, Australia

Abstract

In 2005, the State of Victoria passed the Geothermal Energy Resources Act, which provides a new framework for the large-scale commercial exploration and extraction of geothermal energy in the State at depths greater than 1 000 m and at temperatures greater than 70 °C. Small-scale projects, such as balneology, ground heat pumps and aquaculture, are excluded, and these will continue to be regulated by existing planning, environmental and water legislation. The first stage of a regional geothermal assessment is the collection and integration of all relevant geological, geophysical and geochemical data from previous studies on the water, minerals and petroleum resources in the study area. Previous studies have attempted to map the geothermal prospectivity in Victoria, though the reliability of the data collected, and the sources of the data used in these studies, have often been questionable. Consequently, GeoScience Victoria has attempted to identify and collate all open-file geothermal data collected to date in Victoria. In addition, where possible, all of the published data have been traced to their original sources and quality-assessed. The resulting temperature database is considered robust and has been used to construct a preliminary `depth to 150°C' map for the Gippsland and Otway basins.