Geodynamics hits bedrock of hot energy

Weekend Australian
Saturday 3/5/2008 Page: 5

RENEWABLE energy companies have flocked to South Australia to tap the world's hottest underground rocks. The potential of so-called "hot rocks" electricity --- pumping water into rocks kilometres under the surface of the earth and using the resulting steam to generate electricity - is so great that 11 listed companies have launched exploration projects in the state.

Federal and state governments have backed the sector with millions in start-up assistance, and the private sector has strongly backed the firms in recent months. Leading hot rocks company Geodynamics is set to turn the tragic tale of explorers Burke and Wills on its head. Robert Burke and William Wills died of exposure and hunger on the banks of the Coopers Creek in the far north-east corner of South Australia in 1861..

The remote site of the their deaths is now expected to become a symbol of South Australia's ability to adapt to the harsh realities of global warming - by generating hot rocks power. The township of Innamincka - which grew up next to the site of Burke and Wills' death - sits on the sprawling geological plate of Cooper Basin, which contains the world's hottest rocks at a depth of 4km.

Geodynamics has promised to provide its first power to the historic township. The company this year proved it could pump water down a 4km well and recover the resultant steam from a second well nearby. It has planned a pilot electricity, plant in the next 12 months,- followed by a ramp-up to provide. base-load power to the grid by 2011 The concept behind hot rocks energy is simple and attractive -- massive amounts of base-load power generated with no emissions and no waste.

To make it work, deep wells must be drilled into the earth's crust to access rocks that have been heated to more than 200C, due to the heating effect of radioactive elements deeper in the ground. Electricity is generated by a simple steam turbine and the water is recycled back into the ground.

While the hot rocks are expected to cool with time, companies plan to drill dozens of wells and rotate their use to ensure continuous power generation. Geodynamics shares received a boost in April when two new investors moved to acquire 11.8 per cent of the stock at a considerable premium to the share price. The investors, Sentient Group and Sunsuper, will join large energy players Origin Energy and Woodside Petroleum as backers of the company.

Besides the sprawling Cooper Basin in the state's northeast, locations identified as leading to hot rocks projects include the plains and valleys north or Adelaide, the Riverland and desert country north from Spencer Gulf. This year hot rocks firm Eden Energy drilled a 512m-deep exploration hole outside Renmark, a major centre on the Murray River. After temperatures in the hole stabilise, Eden will reveal if ground temperatures can warm up to commercially attractive levels. Eden Energy has raised $3 million through a share placement to investors in Australia and Britain.

Torrens Energy has upgraded its temperature expectations at its Torrens project, east of the dry Lake Torrens, north of Port Augusta. Final heat flows from exploration drilling late last year showed temperatures of 248C at 5000m. The results are higher than temperatures being exploited for hot rock projects in Europe. Listed hot rocks company Petratherm intends to drill two wells at its Paralana geothermal energy project, east of Roxby Downs in the state's north, by the second half of next year.