Hot rocks have potential to fuel competitive, emission free and renewable electricity for centuries to come. This potential is stimulating Hot Rock projects worldwide, calling upon integrated expertise from the petroleum, minerals and power industries.

Converting just 1% of the Australia's estimated crustal energy from depths between 150°C and 5 km (190 million PJ) to electricity would supply 26,000 years of Australia's 2005 primary power use, and that neither takes into account the renewable characteristics of hot rocks, nor resources below 5,000m.

Factors that distinguish Australian Hot Rock resources are:

  1. Very radioactive granites are abundant, as in South Australia where the mean heat flow is 92µWm-2 compared to a global continental average of 51µWm-2. Areas of recent volcanic activity and hot aquifers above hot granites also constitute targets; and

  2. Australia is converging with Indonesia on a plate scale – giving rise to common, naturally occurring sub-horizontally fractured basement rocks that are susceptible to hydraulic fracture stimulation.

Most projects are focused on hot rocks to develop Enhanced (Engineered) Geothermal Systems (EGS) to fuel binary power plants. Roughly 80 percent of these projects are located in South Australia. Australian government grants have focused on reducing critical, sector-wide uncertainties and equate to roughly 25% of the cost of the private sector's field efforts to date. A national hot rock resource assessment and a road-map for the commercialisation of Australian hot rock plays will be published by the Australian Government in 2008.

Portfolio management methods can usefully be adapted to underpin decision-making by companies and governments seeking to respectively push and pull hot rock energy supplies into markets.

This paper describes the challenges and prospects for hot rock projects in Australia as a proxy for projects anywhere in the world.

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