Geothermal - potential to power Perth

Saturday 4 December 2010 12:16PM (view full episode)

Geothermal projects around Perth are being used to heat water for large swimming pools. The hot water comes from a sedimentary aquifer. Klaus Regenauer-Lieb describes the challenges and costs in drilling holes of depths one kilometre of more. He says the hot water available in aquifers around Perth is sufficient to power the city entirely.

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Robyn Williams: Geothermal power it seems is happening right now. Klaus Regenauer-Lieb is a professor of earth sciences at the University of Western Australia. He is also a premier's fellow. As we contemplate hot rocks in South Australia, deep heat in Victoria, the west is already in business.

Klaus Regenauer-Lieb: It has not only got potential but it's the only power that is actually produced at a significant level right now...

Robyn Williams: Right now?

Klaus Regenauer-Lieb: Right now we are using this power for at least five swimming pool projects. Challenge Stadium is the biggest power producer, they are just having a drill hole, down one kilometre around about, and extract hot water on the order of 50 degrees centigrade, and heat their swimming pool with that water through a simple heat exchanger and re-inject the cold water then back underground. So there's no water extracted from the ground, just heat.

Robyn Williams: Is this coming from hot rocks, or what?

Klaus Regenauer-Lieb: It is certainly not hot rocks in the terms that are being used right now, it is actually what is called a hot sedimentary aquifer.

Robyn Williams: Which means what?

Klaus Regenauer-Lieb: A sedimentary rock that is naturally permeable, as conversely to a hot rock which is normally a granite that is actually tight, and you have to engineer it to make it permeable, while the sentiments are already permeable. Basically these are, as we speak, aquifers.

Robyn Williams: So the hot water can go through it very easily, and what you're saying is the water comes up anyway.

Klaus Regenauer-Lieb: If you punch a hole into Australia, into the middle of Australia, you will find that the water is coming up at about 100 degrees without pumping.

Robyn Williams: That's terribly convenient. Surely in a city like Perth with a million people, you could think of providing a substantial amount of energy needs through that.

Klaus Regenauer-Lieb: Definitely. So in the city of Perth in summer we have all these power blackouts, and they are caused by basically switching on the air-conditioning of course. Perth actually uses in summer a peak capacity of 3.3 gigawatt electric, that's what the southwest interconnected system can provide. Then after that we switch off the electricity of course, and we have to suffer the heat. In winter or as a base load we have 2.3 gigawatt electric, so one-third of the power in summer is just used for the cooling.

Robyn Williams: Before we talk about the big scale, on the smaller scale, heating up the swimming pools, surely drilling down something like one kilometre takes an awful lot of technology and investment.

Klaus Regenauer-Lieb: Drilling down to one kilometre does not actually take a lot of investment on the grand scale, it is on the order of $500,000 for a single drill hole, and this is what the Water Corporation right now does for actually getting fresh water from the Perth aquifer.

Robyn Williams: So it's a routine thing?

Klaus Regenauer-Lieb: It's a routine thing. It's done for water as a routine operation.

Robyn Williams: Let's talk about the ways in which it can be scaled up for use for a city to provide a substantial amount, not only of energy, but also of desalination. How would that work?

Klaus Regenauer-Lieb: Okay, the first step would be basically to go down to a temperature that is higher than, say, 50 degrees, which is right now hit at one-kilometre depth. So say we go down to 1.5-kilometre depth, not a major capital investment. But at that temperature we are already in the realm for desalinating seawater. So we could use the hot water from there to evaporate seawater on to a partial vacuum, so that we are actually using the vacuum as a means to lower the evaporation temperature, and that basically allows us to go down to 65 degrees easily with a heat source.

Robyn Williams: Has this been done experimentally in your lab on a smaller scale?

Klaus Regenauer-Lieb: It has been done experimentally in our lab but it has been done commercially at grand scale also, and this is basically being done right now as we speak in the Arabic Emirates, for instance, where we have a power station, a gas-fired power station to produce electricity, and the waste heat from that power station is being fed into a so-called multi-effect distillation plant, which actually uses exactly this kind of technology.

Robyn Williams: So what if you could scale up this technology to supply Perth and its energy needs? How much could you offer?

Klaus Regenauer-Lieb: In my wildest dreams I would actually go around Perth and tap whole aquifers that we have around Perth, so we would just do a sort of drill farm, and extract the hot water, and from the volume of water that is available...because you have to consider it is not only available just at one-kilometre depth, which is the Yarragadee Aquifer, it is available at three-kilometre steps, which is the Lazur Aquifer, and we have a deep layer at down to 15-kilometre depth. We have fresh water...well, not fresh water, at that stage it's saline water, but we have water available that is in permeable sedimentary layers that is in excess of 200 degrees hot, and we could use that water to power Perth entirely.

Robyn Williams: Entire needs?

Klaus Regenauer-Lieb: Entire needs. If we go down ten kilometres, which we have the technology right now, the deepest petroleum well is ten kilometres, we could use geothermal to power the entire city.

Robyn Williams: And you could also drill eventually to 15.

Klaus Regenauer-Lieb: This is something that hasn't been done to date. The Russians actually hold the records right now, and they have spent in excess of 15 years to drill down 12 kilometres. And that was only possible because Russia holds the world record of titanium deposits, so they were able to build very light and strong drilling rigs. So I wouldn't recommend to go down 15 kilometres at this stage, ten kilometres is enough.

Robyn Williams: But in terms of the cost of doing that versus the cost...well, if you like, especially in the east, burning coal, which is incredibly do those financial factors become equivalent?

Klaus Regenauer-Lieb: Geothermal at present is already the cheapest of the renewables. If you look at an unnamed gold mine, for instance, that sits on a volcano, they are producing electricity from the volcano to drive the goldmine at a far cheaper rate than the 10c per kilowatt hour, through geothermal. So it is already there, and it's already cheaper. Now, if you were to go down to ten kilometres and you were to find the technology at this stage to stimulate the rocks...because the natural permeability at depth, I admit, is decreasing because we have very high pressures...but if you were to find that, I think it actually is a technology that is competitive as well, but the enormous capital risk of actually failing this is at present of course preventing us from doing so.

Robyn Williams: What you mean?

Klaus Regenauer-Lieb: Let's take an offshore rig. We are drilling right now, it's perfectly acceptable to go with a ship and drill an exploration well for petroleum at, say, eight kilometre depth on the sea floor, the sea floor being at two kilometre depth, so ten kilometre depth under the sea floor. At the risk of failure...I don't know the figures for this kind of operation, but for the standard petroleum drills, the drilling costs for offshore drilling is a minimum $50 million. It's perfectly acceptable to do that right now.

It is not acceptable to do that for geothermal of course because it's not a technology that has proven itself, but in maybe 20 years time or 10 years time we might be doing the same thing. We might say, okay, we're investing $50 million for a drill hole, and under these circumstances we will not have failure.

Robyn Williams: And could you imagine this working in almost every major Australian city?

Klaus Regenauer-Lieb: If we define Adelaide as a major Australian city, then this is certainly an exception. Adelaide isn't underlined by sedimentary rocks. We could use under Adelaide the so-called hot rock technology that we were speaking about, but that requires an additional scientific breakthrough to be able to stimulate the initially dry rock to be able to pump fluids through it.

Robyn Williams: To send water down or even carbon dioxide, as they're doing in Victoria.

Klaus Regenauer-Lieb: Yes, exactly, so that's basically what we need to achieve before this becomes a reality. And I would actually put the timeframe for these kind of operations at ten years plus. While actually extracting hot water from the ground is available now, we know it is actually there, we know that petroleum companies are bringing up hot water, they are just wasting the water right now, but we can use that energy.

Robyn Williams: And we can use it now. Professor Klaus Regenauer-Lieb is a Premier's fellow at the University of Western Australia, and director of the Centre of Excellence for Geothermal Energy.


Klaus Regenauer-Lieb
Director Geothermal Centre of Excellence
Professor in the School of Earth and Environment
University of Western Australia

Further Information

Geothermal Centre of Excellence


Robyn Williams
David Fisher

Comments (3)

Add your comment

  • Penelope :

    06 Dec 2010 11:30:45pm

    This is so possible! I just read about it in McGraw Hill's new book, " Geothermal HVAC, Green Heating and Cooling".. very exciting technology!... Just Googled "Geothermal book"...

  • Bill :

    07 Dec 2010 12:37:29pm

    Just a slight addition to Robyn's introduction here. The Queensland town of Birdsville has been using geothermal power since the 1990s.

  • roger :

    09 Dec 2010 9:22:37am

    When the petroleum sector started drilling wildcat wells the success was low due to the lack of subsurface data. Geothermal in basins should have a lot more success than the earlier petroleum exlporers. Unfortunately many geothermal explorers believe they need to create new techniques to find hot subsurface water. Why spend millions of dollars exploring the top 300 metres to measure precision temperatures that reflect 10,0000 year averaged temperatures that are influenced by surface temperature changes. What about ice ages.

    Instead the geothermal explorers could use proven techniques that are accurate to no decimal points instead of techniques that measure 5 decimal points that have errors of many 100s of metres and why so they ignore billions of dollars in data that give them accuracy. Anyone can drill to 4 one in a soft basin and get a good geothermal resource at the right temperature if there is water.

    The money should be spent on understanding deep acquirers using the billions of dollars of data already available.