Alternative Energy

[den]

I wonder how viable Hot Dry Rock Geothermal Energy is. It looks do-able with the technology we have now. According to the article they showed on Beyond Tomorrow, South Australia has a heat reserve equivalent to half the Kuwaiti oil reserves.

Which is nice.

Comments

[humbleminion.livejournal.com]

Speaking as something of a professional in the field, the final answer is 'maybe'. There's a huge upside, but it goes along with major technical issues in setting up and maintaining the heat exchanger in an extremely harsh environment. Plus, our current government is utterly uninterested in seriously funding such things, for reasons that make people like me bang their heads against the wall.

Apologies for not being more specific. Commercial-in-confidence and such...

[makovette.livejournal.com]

Mmmm SO₂ Mmmm ;-)

Has Iceland beaten that problem yet?

CYa!
Mako

[annbat.livejournal.com]

I'm not sure what the problems or solutions are but Iceland is mostly geothermally powered. They chose geothermal as the best of the three energy sources that can be created locally (the other two being wave energy and wind energy) and they also use the low grade heat from the geothermal for home, industry and greenhouse heating needs...very good systems as far as I can tell. Of course their government is not being lobbied by the oil and gas industries and vehicals are not needed as much on such a small rocky island.

[makovette.livejournal.com]

Sulpher is a biiig problem with geothermal heat sources. It's basically sulpheric acid which trashes the steam powered turbines. Heavy mineral deposits are also a major headache, as what the acid doesn't eat, the deposits clog up (pipes, valves &ct.).

Maintenence and parts costs are far higher than in a regular gas or coal fired generation plant as a result. If anyone has the best geothermal engineering and tech for dealing with those problems, it's gotta be Iceland, which is why I asked.

CYa!
Mako

[dewhitton.livejournal.com]

This group propose to take super-heated water (+250*C) and run it through a heat exchanger to generate steam from a water/ammonia solution, and to pump the hot water back down the bore. The geothermal water won't be vented and the water/ammonia solution is in a closed system.

[makovette.livejournal.com]

PS: Your avatar gave me a good chuckle, you have great taste in icons :-D

CYa!
Mako

[annvole.livejournal.com]

Are you refering to my alternative lj name Ann Bat? If so, you can see I just flipped my Ann Vole avatar and turned the buck teeth into fangs (5 minute job).

"Maybe"

[dewhitton.livejournal.com]

I wondered about that. Everything I read and saw was all "Untapped free energy! NO DOWN-SIDES!" and it made me wonder.

Re: "Maybe"

[lostwanderfound.livejournal.com]

It's also got the same downside as most renewables do: geographically limited static generation sources combined with transmission losses. There's a lot of cable between the central desert hot zones and Sydney.

Most of Australia is actually fairly low-temp, geothermically speaking: being so far from the plate boundaries is wonderfully convenient when it comes to avoiding earthquakes and volcanoes, but it means that we've got a lot of continental crust between us and the mantle.

It's probably still got a part to play, though. It seems likely that it isn't going to be one single source of energy that we rely on in the future; it'll probably be a combination of whatever's viable locally.

Nuclear is probably going to play some part, as well. It's just another short-term fossil fuel in the end; Australia holds about 30% of the world's uranium, but even at the controlled rate that we're digging it up now it'll all be gone within about a hundred years. If there's a significant shift in the world's energy burden from oil to nuclear [1] then that exploitation rate is going to accelerate exponentially, so I'd guess that nuclear power is nothing more than a fifty to seventy year stopgap at best. [2]

And, for those seventy years, Australia effectively becomes Saudi Arabia. Won't that be interesting? [3]

Despite nuclear's limited lifespan, it could provide just enough time for us to get renewables working. It's likely that we're going to have to seriously look at energy usage, as well: the common American conception of air conditioning as a basic human right simply isn't sustainable. There's a limit to how much we can insulate ourselves from the world and survive.

[1] Which there almost certainly will be; we're at the start of the oil crash right now, renewables aren't sufficiently developed yet, and pollution issues make increasing coal use utterly suicidal.

[2] There remains the possibility of finding a lot more uranium somewhere. We'll certainly find some if we concentrate on looking; whether it's enough is another matter. Personally, I'd rather not base the future of the planet on a fuel that "might" be there, and is ultimately going to run out anyway. It's also worth noting that the limit of our uranium isn't "how much is in the planet?", it's "how much can we find and extract without using more energy than we'd produce from it?".

[3] Politically, especially. Australia isn't physically capable of supporting a population large enough to effectively defend it. We're likely to end up even more of a U.S. client state than we are already.

[sjwt.livejournal.com]

I like the 1-10km tall greenhouse turbine my self.

[annbat.livejournal.com]

One thing that is over-looked is that most of your real energy needs involve low grade heat (heat and cool your house, hot water for showers and dishes, even heat for your cooking and most industrial processes). All those temperatures can be gathered by air-heating solar panels and stored in insulated dirt just a few feet below the surface (so plants can be grown on top and appropriate drainage provided to prevent rain water "washing" the heat out of the storage below). With a few air pipes, parking lots and black roofs can be turned into big solar panals.

This can all be done by amatures with low-tech materials so government people think "too good to be true" and business people think "no priority product = no money" and research people think "no interest = no grant money".

It surprises me that they are using very ineffiecient methods of converting the energy into power (use water expantion and the forget steam with all that energy in the conversion, they are using water as the transfer medium for temperatures aroud 200 degrees Celcius - too high for even "dry" steam).

[annbat.livejournal.com]

and I forgot to mention that for house heating and cooling, you do not even need solar panels...just store the heat and cool from the outside air for a few months (easy with all that mass under your house)

[hafoc.livejournal.com]

I've always wondered about an ammonia cycle turbine. This is the sort of thing proposed for OTEC-- Ocean Thermal Energy systems, where they were going to make electricity from the temperature difference between tropical surface water and deeper water.

Now, the deep water would be thirty, forty degrees f and the surface no more than 90. By using ammonia as the medium you can boil it and condense it again using that limited temperature difference. (Water is a strange solvent in a lot of ways. For one thing it has an unusually high boiling point for its molecular weight-- something to do with the molecule's "ionic" structure-- I forget the proper term for it-- with one end of the molecule tending to positive electric charge and the other to negative. Its high boiling point makes it less than ideal as a medium to run turbines, but it's so blasted common we're used to it.)

The reason this is interesting is that downhole temperatures in oil wells are commonly in the 120 f range. Or higher. So presumably you could use a tapped-out oil field as a heat source to evaporate ammonia and run turbines to generate electricity. This is an interesting use for abandoned wells, for one thing. For another, it would allow geothermal energy to be generated with much lower temperature gradients than using water.

I've sent off letters and stuff suggesting this process, but nobody's interested. I presume it wouldn't really work, since nobody's deigned to reply to me-- but I'd like to know WHY it wouldn't work.

[annvole.livejournal.com]

I believe this is how the "electrolux cycle" works in those heat-powered refrigerators (like many bar friges and fuel powered friges for mobile homes). The problem with usig it in a turbine would be the extreemly abrasive nature of water droplets in the vapour (ammonia). If you could "scrub" dry the ammonia vapour good enough, maybe: otherwise you could use a modified hydrolic ram or use a piston like the old steam engines to extract the energy released when condencing the boiling ammonia in the water.

[hafoc.livejournal.com]

Oh, yeah, by the way. Geothermal power is actually NUCLEAR power. Oooooooh, scary! Run away, run away! :D

[oceansedge.livejournal.com]

Geothermal Energy is a VERY exciting field - I saw the show you're talking about, and looks like they're pretty much ready to roll with this particular project.... I'm going to be watching it very carefully in the coming years.