A company in Australia has completed a production well for deep, dry geothermal energy for electricity generation. Sources say the well’s success will allow the proof of concept that could lead to further development of the resources worldwide. A report published last year by the Massachusetts Institute of Technology found that similar resources in the U.S. alone could generate up to 100,000 MW of power.
Brisbane, Australia-based Geodynamics Ltd. reached the target depth of 4,221 meters for Habanero 3 in the state of South Australia on Jan. 22 and completed the well on Feb. 5. “The Habanero 3 and the associated developments of the Cooper Basin system” to produce and deliver hot fractured-rock (HFR) energy would be a significant advance, says Jefferson W. Tester, professor of chemical engineering at MIT.
About 9,000 MW of conventional geothermal power is installed globally, but commercial-scale HFR systems have not been conclusively demonstrated. Tester led a study for the U.S. Energy Dept. that found mining the huge amounts of heat in deep granite layers of Earth’s crust could supply a substantial portion of U.S. electricity, probably at competitive prices.
Tester applauds the Australians for “an ambitious program at a time when the U.S. had largely killed its program” for engineered geothermal resources. “They may be able to show us the way,” he says.
HFR mines Earth’s heat with wells up to 10 km deep into hot rock, connecting the wells to a fractured-rock region that has been stimulated to let water flow through it. This creates a heat exchanger that can produce large amounts of hot water or steam to run electric generators on the surface. It requires little fuel and emits no carbon dioxide. “This would be a breakthrough if they’re able to produce hot fluid at a sustained production flow rate that exceeds what has been achieved before,” says Tester.
Geodynamics Ltd.
50-mw powerplant is planned.
The Cooper Basin contains the largest HFR resource in Australia. Its central part is underlain by granite with temperatures between 235°C and 250°C at its top at depths of less than 4 km. The region is regarded as the hottest known spot on Earth outside of volcanic centers.
Geodynamics aims to complete open circulation testing at its Habanero wells early this year, followed by closed circulation testing. This proof of concept will demonstrate the viability of heat extraction from the deep-heat reservoir. By the end of this year, the company expects to be able to use geothermal energy from a 1-MW pilot power station to power its field operations. The company also plans this year to finalize its preferred design for a 50-MW powerplant, which is expected to be in operation in 2012.
The expected cost of power from the Cooper Basin is 3¢ per kilowatt-hour, says Geodynamics non-executive director Prame Chopra.
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