Australia Pushes Geothermal Energy

_martini_ writes writes to tell us Reuters is reporting that several Australian firms are experimenting with taking geothermal energy mainstream. Geodynamics Ltd. will be making an investment decision on their first geothermal power station in early 2006. From the article: "Mother Nature has been kind to us. Australia could be the world leader within the next couple of years given the geological anomalies present in South Australia," says Peter Reid, chief executive of another explorer, Petratherm Ltd."

Comments

Geothermal Is Expensive

[geomon]

There are several problems that geothermal energy will have to overcome before it can be used for any large-scale power production. First of all, geothermal solutions are terribly corrosive and the pipes are subject to scaling. The maintenance costs associated with keeping the plumbing working are high.

These are just a few of the problems associated with geothermal energy: the variable nature of the reservoirs and fluids; the depth, location, orientation, number and type of wells; the type and size of power plant; the method of disposal of the spent geothermal fluid and the need to conform with local environmental regulations.

Re:Geothermal Is Expensive

[ian_mackereth]

This is quite different to most geothermal installations, though. Most of them utilise vulcanism, with all the attendant sulfur and such to cause the corrosion and scaling. This scheme is in granite that contains low-level radioactivity and should be relatively clean to pump water through. The basic idea is to force water/steam into one hole to open up some fissures, then pump water through those fissures to generate steam that goes up an outlet pipe to drive a turbine. The water's reclaimed and re-pumped down the feed bore.

Environmental impact should be minimal, and there's hardly any ecosystem there to affect anyway. This region was chosen for the Woomera rocket range for exactly this reason. Australia's about 90% of the area of the continental USA, and much of it looks exactly like this area; arid or semi-arid rocky plains.

There's a transcript of an article with quite some depth (ahem.) here. http://www.abc.net.au/rn/science/ockham/stories/s1 440622.htm

Re:Geothermal Is Expensive

[Timbotronic]

There needs to be a distinction drawn between regular geothermal power from volcanic areas (such as Iceland, NZ, Yellowstone etc) and hot dry rock geothermal power which is what Geodynamics are pursuing.

HDR Geothermal works by passing water through hot, fractured granite. The granite is hot because of the radioactive decay of trace elements in the granite (too low in concentration for any radioactive waste concerns). A thick layer of sediment above the granite effectively creates a heat blanket, allowing the temperature to build to 200-300 hundred degrees C - ideal for heating water without building up extreme pressure.

I'm not a geologist, but I imagine that problems with pipe scaling would be much lower for HDR geothermal than in regular geothermal power, where you've got a lot of salts, sulphur and all sorts of muddy crap bubbling through. The water in HDR geothermal is kept in a closed loop so there's no waste to dispose of. The heat is extracted via a heat exchanger which boils a more volatile fluid such as ammonia and this fluid is used for the power generation. So you've got no impurities going through your generation facility.

Geodynamics say they have enough heat to power Australia at current levels of consumption for 70 years. Unlike solar or wind, the power is constant and can be ramped up or down at will. I'm surprised this has been off everyone's radar for so long.

Energy creation or energy storage?

[dada21]

I was reading on a link from LRC about Nature's Nuclear Reactor, so the timing of this /. post comes just as I was thinking about the potential energy inside the ground.

I've ran the numbers for solar cells and windmill generators and can't see the overall savings. Taking into account the manufacturing, installation and maintenance costs, are these techniques better for the environment or any cheaper?

Geothermal seems like it would work well, if you can store the energy or throttle back the generation during lulls in need. The setup costs seem huge and I wonder how often they'll tap out a given dig's heat (if ever).

I think money will be better spent in more efficient storage of energy. Batteries, salts and event heat tanks all interest me. I'm not seeing any long term viability of anything but coal, gasoline and natural gas until the storage exceeds the unit per dollar ratio of the 3 gases mentioned.

Big anomaly

[Neo-Rio-101]

.... given the geological anomalies present in South Australia

You mean the city of Adelaide?

Re:Big anomaly

[Frogbert]

Quite frankly I'm surprised there is anything at all in South Australia.

Re:Big anomaly

[The Nine]

You're thinking of Western Australia. :p I'm still not convinced Perth actually exists. I mean, sure, it's on the maps, but when was the last time you ever heard anything about Perth on the news, or met anybody from Perth, or had Perth's existence validated in any other way?

Isn't This Dangerous

[MBCook]

Is this dangerous? I heard this on the radio today and that was what struck me.

So if we use this to power Australia like they suggest, what are the consequences. That would mean stealing a lot of heat from the Earth that is trapped in these geothermal "deposits" (since it sounds like they found concentrated areas of heat higher up than usual). If we cool those down (which is what will happen when we extract heat from them) then what will happen? Will it effect the ground in any way? I'm thinking of towns where they used to mine salt or coal or something and the ground later started to collapse because the stuff was gone. While they are not removing rock, would removing the heat cause problems later? For example: remove the heat -> things cool down -> rocks contract from cooling -> empty space -> fissues?

Anyone know? I realize this would probably be a long-term problem (not something that would show up for a long time). Would this not be a problem because the ground could slowly adjust as we removed the heat, or would the heat stay high until the last minute then plummet (sorta like batteries do) causing problems?

Re:Isn't This Dangerous

[HotNeedleOfInquiry]

No. It's not dangerous and it's not new technology. I know firsthand that it is used in California and the Sierra Madres of Mexico. Most of the homes in Klameth Falls, Oregon are heated via geothermal energy. I'm sure it's used in a lot of other places, so I'm a little surprised this is even news. I've not heard of any sort of accident or danger, other than the possible release of poisionous hydrogen sulfide gas, and that only during the exploration stage.

There are issues, but nothin insurmountable.

Re:Isn't This Dangerous

[palndrumm]

Will it effect the ground in any way?

Not really, no. We're talking about big solid lumps of granite, which at the sort of temperatures they're at to start with won't undergo any significant thermal contraction even if cooled to atmospheric temperature. Plus we're only able to extract a relatively small proportion of the overall amount of heat in these deposits, so the overall temperature of the rock won't change a whole lot.

Here on the Ring of Fire...

[Repton]

I'm sure we can lend them some expertise — NZ's first geothermal plant was commissioned in the '50s...

(apparently, we get 18% of our primary energy from geothermal sources)

Re:Here on the Ring of Fire...

[nathanh]

I'm sure we can lend them some expertise -- NZ's first geothermal plant was commissioned in the '50s... (apparently, we get 18% of our primary energy from geothermal sources)

NZ has a different area of expertise. NZ has naturally occuring hot water springs. Tapping those is relatively easy. That's why NZ has had geothermal energy for so long. Iceland was in a similar fortunate position and they also have geothermal.

Australia is drier than Oscar Wilde's wit. There are no naturally occuring hot water springs. The technology being researched in Australia is Hot Dry Rock. The rocks are dry and you pump fluids down into the rocks. The water is forced through naturally occuring horizontal fissures in the rocks and collected by a second bore. This only works when there are insulating rocks above, below and around the fissures. Otherwise the fluid disperses and you never collect back enough water to make the system economical.

When it does work it's brilliant. The system powers itself and the only significant issue is dealing with scale buildup on the pipes. The energy output is enormous and the capital investment is modest. A single plant can power a small city with almost no pollution and no (as yet known) environmental impact.

Say NO to geothermal

[jnadke]

This is just another attempt at Mother Nature to monopolize the energy market. First coal, then oil, now renewable engeries???

We must rise up to defeat this threat. Say NO to Mother Nature.

Re:Yellowstone

[Bad D.N.A.]

"I wish that they would do more around the yellowstone area" NO... leave yellowstone alone. And while your there, please catch and release.

Ah, geothermal

[localman]

I just visited Iceland a couple months back, and I have to say that it made me wonder why geothemal isn't more popular.

My favorite iceland moment: I went to the blue lagoon, which is a spa next to a geothermal powerplant. Basically you've got this cloudy blue mineral water in a huge black volcanic rock basin, at one end you've got the spa, where you get in, and the water is probably just over 80 degrees. Then on the other end of the basin you've got geothermal runoff water boiling in. You can get as close as you like to the inlet, but when you get within 30 feet or so you're nearly getting cooked. There's also some silica mud and waterfalls along the sides. The view is dramatic with the industrial steamstacks on one end, a classy spa structure on the other, and the natural volcanic pool in the middle. Highly recommended.

But the point is: you're bathing in powerplant runoff. And it's supposed to be good for you. Now that's pretty amazing: I want that kind of powerplant in my back yard. And looking up in Wikipedia, the largest geothermal installation in the world is actually in California. And it doesn't put out some wussy windmill sized power, we're talking 2000 Megawatts -- that's nuclear plant territory, if I understand correctly.

Reykjavik is reputedly the least polluted city in Europe, and most of the heating and power is provided by geothermal -- they just run hot pipes through the houses. Iceland has some pretty unique geographic properties that lend itself well to the process, but it's hard to believe that this can't be harnessed elsewhere to good effect. I mean, I understand the startup costs are very high. And I understand the technology needs work. But we're talking about a nearly limitless source of energy that is clean, safe, and politically sound. It seems like a pretty wise investment.

Cheers.

Granite is radioactive.

[TapeCutter]

Australia does not have any major fault lines, no volcanoes and has some of the oldest (most stable) bedrock on the planet. The heat in the Granite is not from magma, it is from the low level radioactivity in the rock itself. A big enough chunk of granite will get hot all by itself. Check out the CSIRO, they have been working on this kind of "geothermal" for at least 10yrs. Their numbers say that one site with two deep wells (500m apart) would remain hot enough to replace the largest power plant in NSW for 50yrs. Intrestingly the site they got those numbers from was just a few miles from said power station.

The biggest problem in Oz is that coal is not only sprinkled everwhere so as to convieniently fuel our current power stations, it is also a major export. These two things combine to make the coal industry fat, lazy and influential.

Re:I'm a geothermal geek

[Anthony]

I am studying at the ANU dept of Earth and Marine Sciences that is doing a lot of the research in this. This is not hydrothermal. You are right, there are no active margins and no active hotspots. This is using 3-4km deep drill holes, injecting plentiful artesian water down, fracturing the rock at depth and the heated water returning. The anomaly is a large intrusion that is near enough to the surface to make the project feasible. Sorry I haven't the paper at hand. Look at Geodynamics or look for papers by Prame Chopra. The "limited life" they are projecting is 300 years.