Current Use in Australia

Electricity Generation
Geothermal energy is currently produced at one small binary power station at Birdsville in western Queensland, supplemented by diesel-powered generators.  The fluid is 98°C and derives from the Great Artesian Basin (also referred to as the Eromanga Basin) that overlies the Cooper Basin. 

The water is run through a gas filled Organic Rankine cycle heat exchanger (shown below) which heats and pressurises the gas which drives a turbine and alternator to produce electricity. The partly cooled water is channelled into a pond for further cooling and reticulation into the town’s water supply and the lagoon.

The gross capacity of the plant is 120 kW and has 40kW parasitic losses, which equates to a net output of 80kW. The plant was shutdown from December 2004 to December 2005 for upgrading to meet compliance of Australian Standards regarding handling of isopentane and is now operating. Total power generation in 2006 was 2 034 615 kWh of which 715 182 kWh was provided by the geothermal power plant.  This equates to 35% of total power output. 

In November 2006 Ergon Energy commenced a feasibility study into whether it can provide Birdsville’s entire power requirements and relegate the existing LPG and diesel-fuelled generators to be used only as a back-up at peak times such as the annual Birdsville races which attract large crowds for several days.  The feasibility report is due by the end of March 2007.

Organic Rankine Cycle Turbine and Oil Separator, Birdsville, Queensland. Courtesy of Ergon Energy.

Direct Use
Direct use of geothermal waters has been an important source of energy in the city of Portland in western Victoria. Water pumped from a 1400 metre deep bore at a temperature of 58°Celsius at rates of approximately 60 litres per second with a nominal capacity of 3600 kW and is used to heat many of the municipal buildings and public facilities.  Direct use of this resource has been temporarily suspended pending the outcome of restorative operations on the bore which are in the planning phase.

Geothermal waters are also used for spas at Moree, near Barradine and at Lightning Ridge in New South Wales and at Hastings in south east Tasmania.  There are also two developments in Victoria on the Mornington Peninsula, south of Melbourne and another spa resort in Gippsland, Victoria.  There are no available estimates of the amount of energy being produced at these locations. 

Ground source heat pumps are also finding increased use in Australia in both commercial and residential applications.