Geothermal Energy

Geothermal energy is considered to be a renewable and clean energy source, and is already being harnessed in many places throughout the world. Sources of geothermal energy are heated groundwater and hot dry rocks. Water heated by rocks in the ground can be used directly for heating or, if the water is hot enough, to create electricity (hydrothermal energy). Hot dry rocks can also be used to manufacture electricity by pumping water into the ground and converting the extracted steam. Hot dry rock projects in Australia include the Birdsville geothermal power station in Queensland and a test project in the Cooper Basin, South Australia. The demonstration plant in the Cooper Basin is expected to derive energy from 240–270 degrees Celsius granite at a cost that is cheaper than, or comparable to, other green energy sources (see link to Chopra and Wyborn paper below).

The heat is derived from radiogenic elements in the rocks (particularly granite) and trapped by layers of sediment that act as blankets.

To find Australia’s hot rocks, researchers at the Australian National University (ANU) have compiled well-temperature data into a database called Austherm (see link to Chopra and Holgate, Proceedings World Geothermal Congress 2005, below). Austherm05 data were used to create the thermal images in Figure 1 (below). Western Australia’s Canning Basin is a suitable target for hot dry rocks with geothermal-energy potential, and areas of the Perth Basin may also be prospective.

Figure 1
 

Crustal temperature image (AGD66)

View the reports below to discover more about these topics, and geothermal energy in general.

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The following books can be viewed or downloaded from GeoDocs

Report 43
An evaluation of the hydrocarbon potential of the onshore northern Perth Basin, Western Australia
by A. CROSTELLA
Book (1995): $38.50

Record 1982/6
The potential for geothermal-energy development in Western Australia
by T. T. BESTOW
Book: $8.80
Microfiche: $7.00

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