A group of West Australian scientists is working on a project to turn saline groundwater into fresh, drinking quality H20 and it appears the answer to doing so is right under their feet.
Geothermal energy is the energy that’s derived from the heat that’s stored within the earth and its uses, from heating swimming pools to producing electricity, are already well established.
Since 2004, Challenge Stadium in Perth has used the technology to heat its swimming pools.
The stadium uses a geothermal supply that runs about 700 to 1000 meters below the ground.
Now, a group from the WA Geothermal Centre of Excellence, CSIRO and the State Government is looking at whether WA could use geothermal energy to desalinate groundwater.
If successful, the technology could be used by regional communities and mining companies that currently pay large sums to pipe water in.
The director of the WA Geothermal Centre at the University of Western Australia, Professor Klaus Regenauer-Lieb, is leading the investigation.
“It really has a potential to make Western Australia a new industrial hub in clean energy technology and water production,” he said.
Although it’s very early days, the 52-year-old Winthrop professor says the heat could revolutionize Australia’s access to clean water.
“It will help to reduce competition for scarce fresh water resources in those parts of Australia where geothermal energy can be economically used to improve water quality,” he said.
“Its potential is very exciting.”
How it works
Researchers say that, roughly speaking, the deeper you drill into the earth the hotter it is.
Every kilometre closer to the core corresponds to a temperature increases of about 20 degrees celsius.
However, in some places including WA, it’s closer to 50 degrees per kilometre.
“Through using this heat you can evaporate groundwater,” said Professor Regenauer-Lieb.
During this stage pure water separates from the salt and pollutants and forms a clean steam.
“Then all you need to find is a cool source to condense the steam so it creates water.
“You can use the feed [waste] water that you want to evaporate to cool.”
The process is repeated until the water reaches the desired quality.
So: heat, evaporate, condense, repeat.
Geothermal energy is best suited for rural communities and remote industry where the cost of water and energy is far higher due to its scarcity.
Prof Regenauer-Lieb says, at the moment, the energy is not feasible for metropolitan areas but could drastically reduce costs for regional communities and mining companies which pipe water in.
With this in mind, the group is mapping out sites across regional WA that have available but unused groundwater and geothermal energy within close range.
Finding those locations is something CSIRO hydro-geologist and regional coordinator of the investigation, Don McFarlane, admits will be a challenge.
“We realise what we’re trying to do is pretty speculative,” he said.
“The opportunities if we can crack it, then we don’t need to have pipelines going into areas, we don’t need to have to have power lines going into areas, we can actually have water resources in-situ using local energy sources,” he said.
“That would be fantastic.”
Innovative opportunities
Mr McFarlane says as drier conditions prevail across WA, the state needs to move towards innovative practices to boost the water supply.
“We’ve got extensive water resources, some of them fresh, some of them brackish and some of them saline but we’ve also got a potential energy source in those sediments,” he said.
Because geothermal energy sources its power from the heat generated within the earth, it’s considered a sustainable energy.
“It is actually a very clean and in long-term, very environmentally friendly operation,” said Professor Regenauer-Lieb.
He says since the heat of the earth is continuous, so is geothermal energy output.
“It’s a matter of flicking on a switch and letting it run 24/7 because the energy source is constant,” he said.
Many involved in the investigation admit it may take a few years before it breaks into the market.
“At the moment it’s all a bit theoretical and the fact that it hasn’t caught on in other parts of the world tells us we’ve got a long way to go,” Mr McFarlane said.
Although largely supportive of geothermal energy, WA Greens representative Robin Chapple echoes a similar message.
“Look, certainly geothermal is one of the technologies of the future but it’s not quite there yet,” he said.
“Once it’s up and running it’s not too bad but the technology in getting high-value steam from deep underground still has some glitches.”
Mr Chapple, who has a background in engineering, believes the process is more difficult than many perceive.
“It does seem quite simple: drill a hole in the ground, put water down to generate steam but the depths we’re working at and the pipe work to control the pressures is very complex,” he said.
“Once the system is proven, it will be one of the most significant suppliers of classic, non-carbon based energy that we could actually ever think of.”
Possibilities
Mr Chapple supports geothermal energy but not its connection with cleaning water.
“Geothermal is great, desalination isn’t,” he said.
“Desal, by its very nature, is a catch-up structure because we don’t manage our water very well in the first place.
“We end up making artificial water because we can’t manage our own water supply.”
Mr Chapple believes the key setback for geothermal energy is the large amount of capital required for initial exploration and development.
“Most of the geothermal money is not actually spent on producing the steam but is actually doing the exploration work and finding suitable grounds so it’s very capital intensive,” he said.
“It’s similar to the mining industry and yet basically gets no government support and yet the mining industry is doing virtually the same thing - drilling holes.”
Despite the difficulties, interest in the technology is growing with a small geothermal power station operating in Birdsville, western Queensland, from water derived deep from the Great Artesian Basin.
Its well plunges 1230 meters below the earth’s crust and generates over 100 kilowatts of power.
There is also growing interest in South Australia and New South Wales as trials are carried out in a bid to introduce geothermal energy power stations.
Professor Klaus Regenauer-Lieb hopes support will grow for what he believes is an energy that could provide water for generations to come.
“Some time in the future this technology will break through,” he said.
“You need to remember the decisions that we make now can still be operational for many, many years.
“If we don’t make the right decisions now, in 20 years time it will bite us.”
