Geothermal power in Australia

Geothermal power in Australia is little used but growing.[1] There are known and potential locations near the centre of the country that have been shown to contain hot granites at depth which hold good potential for development of geothermal energy. Exploratory geothermal wells have been drilled to test for the presence of high temperature geothermal reservoir rocks and such hot granites were detected. As a result, projects will eventuate in the coming years and more exploration is expected to find new locations.

Interpreted Temperature at 5km Depth
Australian radiogenic granite and sedimentary basin geothermal hot rock potential map

Exploration

There is exploration being conducted in all states and the Northern Territory but there is no commercial production of geothermal energy in Australia. Exploration involves finding vast blocks of "hot rocks" with fracture systems that could generate electricity through water being injected, circulated through the fractures, and being returned to surface as steam which could then be used to rotate steam turbines.[2]

There are vast deep-seated granite systems in Central Australia that have high temperatures at depth and these are being drilled by companies such as Panax Geothermal, Geodynamics Ltd, Petratherm, Green Rock Energy and Pacific Hydro to depths of more than four kilometres.

South Australia has been described as "Australia's hot rock haven" and this renewable energy form could provide an estimated 6.8% of Australia's base load power needs by 2030.[2] According to a conservative estimate by the Centre for International Economics, Australia has enough geothermal energy to contribute electricity for 450 years.[3]

Parts of central Tasmania have been identified by KUTh Energy as having the potential to generate up to 280MW of power. Such a resource would be able to supply 25% of Tasmania's electricity needs.[4]

Projects

Paralana

The 30 MW Paralana project is located adjacent to the Beverley Uranium Mine. It is an enhanced geothermal system (EGS) project, based on Petratherm’s "heat exchanger within insulator" model.[5]

Cooper Basin

A 25 MW Cooper Basin demonstration project to assess the potential of hot-rock geothermal energy for zero-emission, base-load power was commenced by Geodynamics. However, the project was abandoned after being assessed as uneconomic due to a combination of the cost of commercialising generation and the remoteness of the site.

"The technology worked but unfortunately the cost of implementing the technology and also the cost of delivering the electricity that was produced to a market was just greater than the revenue stream that we could create," Geodynamics chief executive Chris Murray said.

Professor Martin Hand ran the South Australian Centre for Geothermal Energy Research at the University of Adelaide said, "I think it was talked up too much — it's a very nice concept on the front page of a newspaper, looks very easy to do, and I think it was over-spruiked”

Geodynamics is no longer exploring geothermal power and is instead looking at other green energy initiatives. It has therefore changed its name to ReNu Energy and changed its ASX code to RNE.

Jurien-Woodada

The Jurien-Woodada project, owned by New World Energy Limited, is the most advanced geothermal play in Western Australia for electricity production. The project is adjacent to transmission infrastructure and large resource-driven energy markets in the mid-west region. The project area has the potential to contain both hot sedimentary aquifer and EGS styles and is being assessed for delivery of electricity into Western Australia's South West Interconnected System.

Otway Basin

The Penola Project is part of Panax’s Limestone Coast Project and is the largest of only four known Measured Geothermal Resources in Australia. An independent assessment has estimated the geothermal resource potential at 11,000 petajoules.

The Penola Project has an extensive database with 28 petroleum wells. The deepest petroleum exploration well is approximately 4,000 metres and intersects more than 1,000 metres of the target reservoir, the Pretty Hill Sandstone.

Panax’s Salamander-1 well, drilled in 2010 is the first deep geothermal well drilled in the Otway Basin. It was completed in record time and is the first to demonstrate conventional geothermal technology in Australia. First steam was produced and the well-testing programme was also completed on the project in 2010.

The Salamander-1 well met its primary objectives. At 4,000 metres projected geothermal temperatures were exceeded by more than 10°C and target reservoir rocks met the requirements for the development of a geothermal demonstration plant. An in-house pre-feasibility study found the project has the potential to generate power at $83 per megawatt hour, which is cheaper than wind power. Complications with the well were found during well-testing. Reservoir engineers have been engaged to examine the well and carry out remediation works.

Panax a conventional geothermal technology in Australia with its Salamander-1 well and is securing funding from the Australian Federal Government to progress the Penola Project.

Companies

Company Name Area of operations Furthest project advancement Geothermal only ASX code
Geodynamics Hunter Region, Innamincka Advanced pilot plant development Yes GDY
Earth Heat Resources South Australia Current focus is on foreign developments[6] Yes EHR
Petratherm Paralana, Wooltana Station Resource drilling Yes PTR
New World Energy Pilbara, Perth basin Resource drilling Yes
Green Rock Energy Roxby Downs, Perth basin Resource drilling Yes GRK
Pacific Hydro Tenement appraisals No
Panax Geothermal Limestone Coast Pilot plant production wells Yes PAX
Greenearth Energy Anglesea, Gippsland Pilot plant planning Yes GER
Torrens Energy Parachilna Validation drilling No TEY
Southern Gold Ltd Roxby Downs Temperature mapping No SAU
Hot Rock Ltd Penola, Otway Basin Validation drilling Yes HRL
Origin Energy Joint venture partner No ORG
gTET Winton, Queensland Operational geothermal power generation plant Yes

See also

References

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