Outback yields new energy hope
Engineers are about to trigger a series of earthquakes in Australia’s outback in a bid to find a major new source of renewable energy.
The scientists will test if ancient rocks outside the town of Innimincka, near Adelaide, can unleash “green” energy at volumes equivalent to about half of Kuwait’s oil reserves.
If they are successful Innimincka’s Habanero Well could deliver a major new renewable energy source to compete with natural gas.
Bertus de Graaf, managing director of Geodynamics Ltd, says the geothermal resource below is so large it can potentially generate massive amounts of zero emission energy.
It all may sound a little like Jules Verne’s “Journey to the Centre of the Earth”, but hot dry rock (HDR) geothermal energy is one of the great hopes of renewable energy.
Earth energy
Generating electricity from the earth’s heat isn’t new.
Countries such as Italy, Iceland, New Zealand and Japan have been doing it for up to a century – using naturally occurring steam to generate up to 150 megawatts capacity, enough to power a large town.
But HDR geothermal energy has the capacity to supply larger volumes of power.
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“The key point from the economic point of view is to have heat at accessible depth and that’s what we’ve got here… It’s certainly the best spot in the world”
Bertus de Graaf, Geodynamics Ltd |
“A lot of people ask ‘is the earth going to shrink when you do that or something?’, but I’m confident it will have no ill effects…essentially we’re just skimming the heat off the top,” says Geodynamic geoscientist and granite specialist Doone
Wyborn.
The key to the process lies in special hot granite rocks with temperatures of more than 250C which are located no more than five km below the earth.
Commercial production
In a process called hydraulic stimulation, water is initially pumped down through a well at extremely high pressure, causing seismic action in a network of existing joints and fractures.
This helps the water to flow through the fractures and is followed by low pressure circulation between two or more wells to transfer heat from the rocks to the water.
Global research began about 20 years ago but so far there has been no commercial production, although the world’s first HDR power station is now being built in France.
Sheik Rahman, from the University of New South Wales School of Petroleum Engineering, is cautiously optimistic about the new technology.
“We know we have the resource and the technology, but the problem is we’ve got to have a fracture network that works properly…so we are relying on Mother Nature as well,” he said.
Geological freak
The Australian team believes nature has produced a geological freak at Innimincka – large quantities of hot dry rocks in good shapes and good locations.
And smack in the middle of the Cooper Basin, one of Australia’s most important gas provinces.
“The key point from the economic point of view is to have heat at accessible depth and that’s what we’ve got here,” de Graaf says.
“It’s certainly the best spot in the world.”
Innimincka, home to just 16 permanent residents, might soon have a sensational new attraction if the Geodynamics project gets past the next critical stage of testing.
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“But I think the informed energy market players see this as something that has the potential to change the landscape”
Clive Donner, Rothschild Venture Capital |
Pipedream
Their plan is to install a 13 megawatt demonstration plant which could deliver enough power for 250,000 homes.
Beyond that, Geothermal has rights to extract heat in the Cooper Basin from an area which could yield the thermal energy equivalent to 50 billion barrels of oil.
“That’s more than 20 times larger than the known Australian oil reserves and about 40 years worth of current Australian black coal production,” de Graaf says.
Rothschild Venture Capital chief executive Clive Donner acknowledges many people still regard HDR geothermal energy as a pipedream like so many wildcat oil wells.
“But I think the informed energy market players see this as something that has the potential to change the landscape,” he said.