Wednesday, 3 July 2013

Local firm leads energy future
17 May 2013

Geothermal energy could provide 9% of Australia's energy needs by 2035.

Milton firm GeoDynamics has used steam produced by boiling water tapped five km underground to generate electricity in an Australian first. Experts predict this geothermal energy gathered from turbines driven from the steam of boiling underground water will provide 9% of Australia's energy needs by 2035.

Queensland has already identified 11 high-priority sites-in southwest Queensland, near Surat, near Julia Creek and Cape York-from 33 potential targets. This month GeoDynamics successfully produced electricity to power its own test project in the South Australian desert at Innaminka, near Moomba. It now plans to provide electricity from its one MW pilot project to mining companies in the Cooper Basin by way of a longer-term commercial trial.

Managing director Geoff Ward said their plant was one of only three enhanced geothermal energy (EGS) plants worldwide at the trial stage and the first in Australia. ''What we are doing here is opening up the prospect of being able to use geothermal power in the long term, in the next 30, 40 years, 100 years in a whole lot of areas where you probably couldn't do so now,'' Mr Ward said.

GeoDynamics is running the successful Engineered Geothermal Systems trial from its Habanero well at Innaminka where is drawing boiling water from Innamincka granite deep underground. After 100 days of the pilot trial, it will move to a commercial trial over an extended period. ''We will take the results of the pilot plant trial and put together a 5 or 10 MW plant in a commercial project,'' he said. That will provide power to nearby mining companies.

Santos and Chevron are likely customers given their exploration of unconventional gas reserves nearby Moomba Mr Ward said. ''We are hoping to put together a scheme so that we can sell power, or direct heat to local gas producers or other industries in the Cooper Basin,'' he said. While geothermal enegy was first used in Italy in 1908 and tentatively explored around the geysers of Wyoming around World War II.

Traditional geothermal energy taps into volcanic conditions in places like California, New Zealand and Iceland and the Phillipines, where heavy rainfall run into the fault-lines and seeps underground. ''So you get a system where a lot of heat is bought to the surface and a lot of water that cuiculates quite quickly so generate the ability to generate a lot of heat,'' he said. ''That is the conventional geothermal system.''

But Australia is drier and different. That is why it encourages ''enhanced'' geothermal energy. ''What we do have is some of the world's hottest deep rocks,'' he said. GeoDynamics is exploring 1000 km² of Innaminka granite in central Australia, which is between seven and eight km thick, four km below ground. ''And extends seven to ten km, we think, below that.''

The boiling hot brine is tapped to the surface by steel-encased drill wells at temperatures of 240° celcius, tapped into turbines to produce steam which drive generators. Geoscience Australia estimates that 1% of Australia's geothermal energy shallower than five km and hotter than 150° Celsius, could supply Australia's energy requirements for 26,000 years.

Electricity produced from geothermal energy produces about one-tenth of the CO₂ per MW of electricity from brown coal, Mr Ward said. brown coal produces 1200kg of carbon per MW, gas around 600kgs per MW, while geothermal energy produces around 120kgs per MW, he said.