Environment

Australia's vast geothermal energy resources represent thousands of years worth of untapped power

Temperature readings taken in existing oil and gas bore holes indicate a huge amount of geothermal energy below the surface of Australia.
Temperature readings taken in existing oil and gas bore holes indicate a huge amount of geothermal energy below the surface of Australia.
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Geothermal energy: cool water is pumped down into the hot rock, heated up and then drawn back to the surface to power steam turbines for electricity generation.
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Geothermal energy: cool water is pumped down into the hot rock, heated up and then drawn back to the surface to power steam turbines for electricity generation.
Geothermal power plant: clean and reliable energy.
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Geothermal power plant: clean and reliable energy.
Temperature readings taken in existing oil and gas bore holes indicate a huge amount of geothermal energy below the surface of Australia.
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Temperature readings taken in existing oil and gas bore holes indicate a huge amount of geothermal energy below the surface of Australia.

Australia is sitting on top of some of the world's most potent geothermal energy sources, according to government estimates. Just one percent of the hot rock energy less than 5 km under the surface would be enough to meet the whole country's entire power needs for 26,000 years if it was tapped. So why aren't we seeing more movement on it?

Geothermal energy is a very handy, virtually inexhaustible clean energy source for those areas lucky enough to find themselves on top of it. Massive amounts of hot rock just below the Earth's surface can be used to heat water and drive steam turbines for reliable electricity generation with virtually no emissions or environmental impact.

Where wind and solar tend to generate power at inconvenient or uncontrollable times, geothermal can be easily regulated and is ready to go 24/7. Surveys testing the available heat in existing bore holes down to a depth of 5 km (3 miles) below the surface indicate that Australia is sitting on some seriously large hot rock resources, as shown in our lead image.

So why is this enormous resource apparently so underdeveloped?

Part of the answer is geographic. Much of Australia's hot rock is simply not conveniently located close to major cities. The big red splotch of prime red geothermal activity to the centre right of the map is more or less on top of a large, barren desert area several hundred kilometres from Sydney or Adelaide, and large scale power transmission can be an expensive proposition.

Geothermal energy: cool water is pumped down into the hot rock, heated up and then drawn back to the surface to power steam turbines for electricity generation.
Geothermal energy: cool water is pumped down into the hot rock, heated up and then drawn back to the surface to power steam turbines for electricity generation.

Another part is geological. Australia has a ton of hot rock, but not a lot of the highly porous rock that makes for easy power extraction. To generate power, you need to be able to pump large amounts of water into a deep rock hole and let the water filter through pores and cracks in the rock, picking up heat as it goes, and then pump the heated water back to the surface on the other side.

Much of Australia's hot rock isn't porous enough to let a good flow of water through, which means in order to set up a geothermal power plant, engineers need to forcibly crack the rock, slowly pumping water into an underground rock reservoir at high pressure, to create the appropriate kinds of cracks and channels. It's a costly process, and it's a bit hit and miss.

Geothermal power plant: clean and reliable energy.
Geothermal power plant: clean and reliable energy.

A final problem facing all renewable energy sources may be political. While the fossil fuel energy industries enjoy some AU$4 billion in direct subsidies and tax breaks, the Australian government has allocated just AU$50 million to geothermal development.

On top of that, the current conservative government has succeeded in slashing Australia's 2020 renewable energy target from 41,000 gigawatt hours by about 20 percent down to 33,000 – and managed to include the burning of scrap wood in the "renewable" target at the same time.

Australian Prime Minister Tony Abbott has made his beliefs on renewable energy clear, saying "Coal is good for humanity… Essential to the prosperity of the world," while describing wind farms as "ugly… noisy and they may have all sorts of other impacts… It's right and proper that we're having an enquiry into the health impacts of these things." Abbott's treasurer Joe Hockey has also described wind generators as "utterly offensive."

Still, the Australian Geothermal Energy Association views both State and Federal governments as "very supportive" to the handful of operators currently working on developing geothermal projects. So perhaps there's a cleaner future in store for a country that currently ranks as the 10th highest carbon polluter per capita in the world.

13 comments
Bruce Schuck
Australains pay 0.38143 AU per litre in fuel taxes. Thats a tax, not a subsidy.
MD
Bruce you are forgetting GST. that is a tax, just like excise. Subsidies and tax breaks are more than just making a hit (+/-) on consumers pocket with Transport fuel costs.
Jérémy Henriquel
There is also some technical problems that hampers geothermal in every country, namely: The heat is quite low grade (inferior at 300°C) and so the heat-to-electricity conversion is quite low too (around 20-30% with a steam turbine). Add the energy intensive and very expensive machinery that pumps water at a hundred bar into the ground and consumes about a third to a half of the energy produced and you only have 10-20% of the primary energy converted to electricity. That means that geothermal needs to produce a lot of electricity to recoup its initial high cost and so it must quite big from the beginning, increasing again its cost. Also, I don't know the flow rate needed for such a plant but it should be very big, so quid of finding all this water in a desert. This water also don't come out clean from the ground below, it carries nasty gas (H2S, CO2, NH3) and elements (As, Hg, Pb) from deep inside the Earth, and they must be removed or it could become environmentally damaging if released outside.
Robert Walther
No chance! The rabid tree huggers will freak. Survival is not environmentally friendly.
Freyr Gunnar
> Just one percent of the hot rock energy less than 5 km under the surface would be enough to meet the whole country's entire power needs for 26,000 years if it was tapped. It's interesting that the media constantly use the nebulous word "power" where they really mean "electricity". And since 98% of transport is done with *oil*, renewable energy does absolutely nothing to overcome peak oil. With all the uranium and the low population it has, it'd make more sense for Australia to build 60GW worth of nuclear power plants instead of spending money on geothermal.
Don Duncan
Fact: The govt. allots 1.25% of its energy subsidy to geothermal, its competitor, fossil fuels, gets the rest. Rhetoric: The govt. claims it is "very supportive" of geothermal. Authors's conclusion: "...there's a cleaner energy future in store..." I make the opposite conclusion, based on the facts, not govt. BS.
Douglas Bennett Rogers
The Naval Air Warfare Center, China Lake was going to use extensive local geothermal to power Selene, a laser system to power satellites. This was probably for grid independence.
GoForward
Geothermal energy seems to be an excellent way to satisfy energy demand. Perhaps some type of refrigerant could be used with vertical and lateral lines in a closed system instead of the open system as shown in the diagram. If the system can be simplified and reinforced so that 360 C temperatures can be accommodated, then the cooling tower and other cooling devices shown might be able to be removed from the design. Moreover, 360 C is ample for steam creation since water boils at 100 C, so you are already three times over what is needed. EVs can satisfy the needs of the transportation sector. So, now not only do you have solar, wind, and ocean/wave power available to Australia, you have another great source of energy with geothermal. Kudos to all of the leaders who are helping to transition the world to these clean energy sources, as all of these are freely available and don't pollute the air or release CO2. Simple example: say you had to provide power for your own house, without the grid. Would you rather have solar, wind, or geothermal energy generation, which are all zero emission sources or a coal-burning generator in front of your house, with all of its maintenance requirements, toxic emissions and dirty air that requires you to clean off the black soot from your house every week? Would you like your children to play next to this coal generator too and breathe in the toxic air? I think the majority would say no and just go with solar/wind/geothermal.
SamB
What Jeremy said with the following addition. Hot rocks in this Australian context is another name for saying 'fairly well radioactive'. When you pump water down into it, it will come back with all sorts of other elements and will also be mildly radioactive. It's one thing to look at temperature gradients and say "we can make this work", it's a whole other thing to do it safely and economically. Geothermal is rightly in research stage in its development. Personally I don't see it ever escaping this.
christopher
The "utterly offensive" comment, by the TREASURER, spoke to the current ECONOMICS of windfarms as compared with coal (of course, duh, he's the treasurer). That is a 100% accurate assessment when not removed from the actual context of the actual quote... but this is green politics, so it's much easier to pull 2 words out of an unrelated sentence, then pretend he meant something else to further your agenda. Truth has no place when the "higher goal" of forcing green down everyone's throats is in play. No matter how green your views might be, you can't deny that coal costs less money right now. @Robert said it best: "Survival is not environmentally friendly!"
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