Solar tower

lionking · 18th February 2007, 11:00 PM

Australian company Enviromission has announced that it will begin construction of a pilot solar tower this year. The idea is to untimitely build the world's tallest construction, a tower more that a kilometer high. At the base will be a canopy, or hothouse, with a diameter of 5-7 kilometers, heating the air which will rush up the tower equipped with turbines. One of the advantages of this type of solar power generator is that it would work at night as the ground temperature would always be greater than the temperature a kilometer up. I recall reading that construction costs would approximate those of a coal fired or nuclear plant, while producing the same amount of power, but with negligible running costs and no emissions.
I'm sure there will be significant construction difficulties, but the project seems to make sense. Comments?
Link www.enviromission.com.au.

EternalSceptic · 19th February 2007, 02:28 AM

Originally Posted by lionking

Australian company Enviromission has announced that it will begin construction of a pilot solar tower this year. The idea is to untimitely build the world's tallest construction, a tower more that a kilometer high. At the base will be a canopy, or hothouse, with a diameter of 5-7 kilometers, heating the air which will rush up the tower equipped with turbines. One of the advantages of this type of solar power generator is that it would work at night as the ground temperature would always be greater than the temperature a kilometer up. I recall reading that construction costs would approximate those of a coal fired or nuclear plant, while producing the same amount of power, but with negligible running costs and no emissions.
I'm sure there will be significant construction difficulties, but the project seems to make sense. Comments?
Link www.enviromission.com.au.

In the part of Austria where I live there are hundreds of wind power stations (at the end this is also solar energy) and they are pretty successfull. Then there is the gigantic flywheel called "moon" which drives ebb and tide and there are power stations which use this energy. Besides the construction difficulties, which can be managed IMO, I can't see anny reason why it should not work

MRC_Hans · 19th February 2007, 04:09 AM

I think the wors problem if this thing is its size. And I am not referring to construction problems, but something with a diameter of 5-6 kilometers, and a kilometer high, that is a prohibitive amount of real estate to take up or overshadow, in a lot of countries. In Denmark, the prize of the ground needed would be so high that the produced power wouldn't even pay for the mortgage.

I realize this is probably not too big a problem in Australia.....

Hans

Rasmus · 19th February 2007, 04:32 AM

I have read something about this type of generator a long time ago. I think it said that the area underneaht the structure could still be used for farming etc.

On the other hand, the wind would be rather strong. Not sure how various crops cope with that, and I think it was seen as a potential problem as the structure would at best end up moving a lot of dust around.

Either way, I am very excited to hear that someone is trying to build one at this size.

(Oh, it says here that the actual tower will be shorter, and a brief search on the website didn't show me any dimensions?)

Indolent Wretch · 19th February 2007, 06:59 AM

Originally Posted by Rasmus

I have read something about this type of generator a long time ago. I think it said that the area underneaht the structure could still be used for farming etc.

Me too, I'm sure some wind resistant crop could be chosen, and the wind won't be particularly severe at any real distance from the centre.

It's a nice idea this, always liked it. It's simple, some of your generators are low down so they are easy to replace, construction is pretty simple, other than the generators there are no moving parts and the energy creation side needs no fuel transported to the plant.

The world is full of deserts with non-usable land, shed loads of baking sunshine, and they tend to be areas with a very low real estate cost.

However governments seem to be very reluctant to help pony up the cash and actually build a full scale one which is a real shame. I know Bill Gates is busy be couldn't he start getting interested in carbon neutral power generation as well as everything else? After all his operating system burns quite a few unnessecary gigajoules every year.

Hindmost · 19th February 2007, 10:56 AM

It looks feasible, but the power output is low. 200 MW is just not that much power. Building the tallest tower in the world is also not going to be cheap or easy. This is twice the height of the Taipei 101--construction of that size built to meet all the possible weather and earthquake needs should prove interesting. (I don't know if Australia is in a high earthquake zone) Putting it up in the outback would provide a resonable capacity factor due to the favorable weather...for solar power.

glenn

bjornart · 19th February 2007, 10:58 AM

A kilometer high tower is really cool, but how does such a construction compare in cost and efficiency with just covering the same area with solar cells?

I guess there might not be very good numbers on that, but a 1000 m tower has to be a very challenging build, and the two step process of heating air and running it through a turbine can't be all that efficient.

lionking · 19th February 2007, 11:47 AM

Originally Posted by glennmr78

It looks feasible, but the power output is low. 200 MW is just not that much power. Building the tallest tower in the world is also not going to be cheap or easy. This is twice the height of the Taipei 101--construction of that size built to meet all the possible weather and earthquake needs should prove interesting. (I don't know if Australia is in a high earthquake zone) Putting it up in the outback would provide a resonable capacity factor due to the favorable weather...for solar power.

glenn

I'm pretty sure this is the output of the pilot plant only with the real one having much higher generation. No earthquake problems to speak of, and land and sunshine are both plentiful, so if it doesn't work here, it never will.

Molinaro · 19th February 2007, 11:48 AM

As I remember this story, it is to be built in China.

Hindmost · 19th February 2007, 12:06 PM

Originally Posted by lionking

I'm pretty sure this is the output of the pilot plant only with the real one having much higher generation. No earthquake problems to speak of, and land and sunshine are both plentiful, so if it doesn't work here, it never will.

The 200 MW was off the link you provided. The pilot plant--off the same link--indicated it had an output of about 50kW over a period of 7 years. I think the idea is to put 5 towers in the same area to yield 1000MW...that would be equal to a small nuke facility

glenn

Rasmus · 19th February 2007, 12:23 PM

the "tower" shouldn't be too difficult to build, the structure doesn't need much force to keep it up. The structure doesn't need to carry anything, after all. (my first idea would be tons of clingfilm and a couple of ballons to drag it up ...)

I don't think it can be compared to a building where people work and live in. This is assuming that the generators will be set up low in the tower and not be placed in intervals up to the very top.

The tower wouldn't even need much insulation or anything, right?

jimbob · 19th February 2007, 01:45 PM

Originally Posted by lionking

I'm pretty sure this is the output of the pilot plant only with the real one having much higher generation. No earthquake problems to speak of, and land and sunshine are both plentiful, so if it doesn't work here, it never will.

The fewest of any continent.

I have a great idea to stop us being dependent on the Arabs for oil:

Why don't we invest massively in building solar power stations in the world's hot deserts, like in North Africa and the Middle Eas....

Seriously, I do think it is a good idea; much as I like the idea of the technical challenges associated with nuclear fusion and the ITER, I think the best place for a fusion reactor is 150 Gm from here.

You are creating something ten times hotter than the surface of the sun, controlling it with magnetic fields from liquid helium-cooled superconductors (right next to this) and then you are going to use it to DRIVE A STEAM ENGINE??? or something else equivalent.

Don't forget the Beryllium blanket (nice one for the toxicologists).

I'd love to seee it work, I am an engineer, so like the idea of these toys, but I think this, and other forms of solar concentration are probably better (especially for hot-cloudless areas with low populations).

Jim

Soapy Sam · 19th February 2007, 01:58 PM

First I heard of the idea was an SF story at least 20 years ago. Maybe Clarke, but I don't recall for sure.
("Tales from the White Hart" maybe?)
The idea definitely appeared in New Scientist at least once as a serious project.

I think it's one of those ideas that resurface every decade, then die in the funding stage. It would be interesting to see one built. I wonder if it would act as a condenser / water supply as well? That would be a plus in Australia.

fishbob · 19th February 2007, 02:06 PM

Look at the video. If the tower is 1000 meters tall, then the apparent diameter is about 100 to 150 meters. 32 turbines at the base catch the inrushing air at the base.

I took an architecture class in the mid-70s (Univ of Tx) on building with alternate materials - taught by an odd character named Pliny Fisk. Most of the class involved actual construction of various ideas, on his property outside of town. The university wouild not allow him to do this stuff on campus due to the large piles of 'recycled materials (junk) and due to 'safety concerns' (students climbing around 30 feet in the air with hammers and nails).

We made adobe tiles, made used flourescent light tubes into solar heaters, built solar heated walls out of empty beer bottles, and built a solar tower about 35 feet high. The tower was three sided, about 8 feet across, made from sheets of tin that were painted black. The thing had a turbine across the top to measure upflowing air speed. The idea was to dig a trench about 50 yards long, cover it to make a tunnel, connect it to a residence as a fresh air source, and connect the residence to the tower as an air exhaust. Air flowing underground was supposed to be cooled, and reduce the need for air conditioning. This was an ongoing project, and I never found out what the results were, however, I could feel a good breeze inside the tower on a hot Texas day.

Properly engineered, I can see this idea working. The economics will be the difficult part.

lionking · 19th February 2007, 02:38 PM

Originally Posted by glennmr78

The 200 MW was off the link you provided. The pilot plant--off the same link--indicated it had an output of about 50kW over a period of 7 years. I think the idea is to put 5 towers in the same area to yield 1000MW...that would be equal to a small nuke facility

glenn

Thanks, my mistake.

Rasmus · 19th February 2007, 02:49 PM

Originally Posted by bjornart

A kilometer high tower is really cool, but how does such a construction compare in cost and efficiency with just covering the same area with solar cells?

As far as I nkow, solar cells still have a negative energy output, i.e. you put more energy into the production than you will ever receive during the lifetime of the cell.

Hence, plastering the desert in solar cells will buy you a massive net loss in energy.

Rasmus · 19th February 2007, 02:54 PM

Originally Posted by glennmr78

TI think the idea is to put 5 towers in the same area to yield 1000MW

The higher the tower the better.

I would like to see the tradeoff between ground area covered and tower hight. I suspect there's a reason they intend to have the tower so high rather than just cover an even bigger patch of desert.

Modified · 19th February 2007, 03:32 PM

Could one of these things be built up the side of a mountain? It would obviously be less efficient, but a lot easier to build.

lionking · 19th February 2007, 04:46 PM

Originally Posted by Modified

Could one of these things be built up the side of a mountain? It would obviously be less efficient, but a lot easier to build.

The only problem would be that the hothouse would be in the shade of the mountain for part of the day, and besides, there would not be too many suitable mountains in the desert.

Hindmost · 19th February 2007, 04:58 PM

Originally Posted by Modified

Could one of these things be built up the side of a mountain? It would obviously be less efficient, but a lot easier to build.

The mountain might affect the operation significantly that it would not be practical. Less solar input and possible unfavorable air currents and temperature inversions--but I am just speculating.

It will be interesting to see if or how this progresses. Since the pilot plant operated back in the 80s, there obviously hasn't been any rush to scale up. Energy prices may be making it cost effective.

glenn

CapelDodger · 19th February 2007, 05:01 PM

Originally Posted by MRC_Hans

I think the wors problem if this thing is its size. And I am not referring to construction problems, but something with a diameter of 5-6 kilometers, and a kilometer high, that is a prohibitive amount of real estate to take up or overshadow, in a lot of countries. In Denmark, the prize of the ground needed would be so high that the produced power wouldn't even pay for the mortgage.

I realize this is probably not too big a problem in Australia.....

Hans

In Denmark you have tide and wind, so don't complain. In Australia there's lots of desert without the kind of storms we get in these parts. Horses for courses, as the saying goes.

I hope this project goes ahead, it'll be fascinating to watch. I read about the concept years ago, probably in SciAm, and thought it intriguing. And challenging. But not ludicrous.

CapelDodger · 19th February 2007, 06:18 PM

Originally Posted by Modified

Could one of these things be built up the side of a mountain? It would obviously be less efficient, but a lot easier to build.

That might not be a bad idea. If you've got some serious gradient available - and I'm thinking mostly the Andes here - with plenty of sunlight and water you could build everyday, low-tech greenhouses with vents feeding into a tube-generator tacked on to the local mountain range. Moisture could be recovered and recycled as drinking-water in the process. No new engineering would be required - and so it's not terribly sexy. But potentially useful.

CapelDodger · 19th February 2007, 06:36 PM

Originally Posted by lionking

The only problem would be that the hothouse would be in the shade of the mountain for part of the day, and besides, there would not be too many suitable mountains in the desert.

Note to self : buy options in the Atlas Mountains. Also check out the Chilean Coastal Desert - in the rain-shadow of the Andes (serious natural gradient), plenty of sunshine, and low-lying enough that desalination for greenhouse irrigation is economically feasible. And currently worth pennies-an-acre.

lionking · 19th February 2007, 07:40 PM

Originally Posted by CapelDodger

Note to self : buy options in the Atlas Mountains. Also check out the Chilean Coastal Desert - in the rain-shadow of the Andes (serious natural gradient), plenty of sunshine, and low-lying enough that desalination for greenhouse irrigation is economically feasible. And currently worth pennies-an-acre.

I knew about the Andean Desert, but without looking it up, didn't think it would have been hot enough. But I suppose that the important thing is the temperature difference between the base and the top of the tower, so it would probably work.

Mangafranga · 19th February 2007, 09:52 PM

The real reason this project was scrapped, Drop Bears. Imagine the range they would get on this thing. Add to that the possibility of cannonballing into the largest mostly invisible lake in Australia. Can you just imagine what that invisible wave of water would do? The Drop Bears have just made this project too dangerous.

lionking · 19th February 2007, 11:06 PM

Originally Posted by Mangafranga

The real reason this project was scrapped, Drop Bears. Imagine the range they would get on this thing. Add to that the possibility of cannonballing into the largest mostly invisible lake in Australia. Can you just imagine what that invisible wave of water would do? The Drop Bears have just made this project too dangerous.

It's bad enough that potential visitors to Australia know about our sharks, snakes, jellyfish, crocodiles and spiders. Now you have to spill the beans on our carniverous, aggressive marsupial.

Cuddles · 20th February 2007, 05:08 AM

There's a nice article about this here. Cost-wise it is not such a bad idea. Assuming the estimates are correct (not always a great idea for construction) it is cheaper than current photo-votaics and comparable to some other renewables, although wind turbines and hydro-electric are cheaper. It also has the big advantage that the power is generated continuously and smoothly. The main problem is its experimental nature. Smaller towers have been tested with some success, but building the tallest structure in the world is always going to be a challenge. Since this is such a big project it takes a lot of resources. If it succeeds it'll be great, if not it will be a big blow for renewable energies in Australia.

bjornart · 20th February 2007, 12:05 PM

Originally Posted by Rasmus

As far as I nkow, solar cells still have a negative energy output, i.e. you put more energy into the production than you will ever receive during the lifetime of the cell.

Hence, plastering the desert in solar cells will buy you a massive net loss in energy.

The wikipedia article on solar cells has articles going both ways, but the cite for solar cells having negative output is relatively old, and it appears it's main point for negating other calculations is that they assume all power produced will be used, which is not the case for the off grid solar cell installations that make up most of the installations in place. But that argument wouldn't be valid for an on-grid installation.

rjh01 · 20th February 2007, 10:50 PM

Would one advantage of the Solar tower is that it generates AC rather than DC power?

18th February 2007, 11:00 PM	#1
lionking In the Peanut Gallery Join Date: Jan 2007 Location: Melbourne Posts: 29,650	Solar tower Australian company Enviromission has announced that it will begin construction of a pilot solar tower this year. The idea is to untimitely build the world's tallest construction, a tower more that a kilometer high. At the base will be a canopy, or hothouse, with a diameter of 5-7 kilometers, heating the air which will rush up the tower equipped with turbines. One of the advantages of this type of solar power generator is that it would work at night as the ground temperature would always be greater than the temperature a kilometer up. I recall reading that construction costs would approximate those of a coal fired or nuclear plant, while producing the same amount of power, but with negligible running costs and no emissions. I'm sure there will be significant construction difficulties, but the project seems to make sense. Comments? Link www.enviromission.com.au.

19th February 2007, 04:09 AM	#3
MRC_Hans Penultimate Amazing Join Date: Aug 2002 Location: Whithin earshot of the North Sea Posts: 16,600	I think the wors problem if this thing is its size. And I am not referring to construction problems, but something with a diameter of 5-6 kilometers, and a kilometer high, that is a prohibitive amount of real estate to take up or overshadow, in a lot of countries. In Denmark, the prize of the ground needed would be so high that the produced power wouldn't even pay for the mortgage. I realize this is probably not too big a problem in Australia..... Hans
	__________________ Don't. Just don't.

19th February 2007, 04:32 AM	#4
Rasmus Philosopher Join Date: Jul 2005 Posts: 6,138	I have read something about this type of generator a long time ago. I think it said that the area underneaht the structure could still be used for farming etc. On the other hand, the wind would be rather strong. Not sure how various crops cope with that, and I think it was seen as a potential problem as the structure would at best end up moving a lot of dust around. Either way, I am very excited to hear that someone is trying to build one at this size. (Oh, it says here that the actual tower will be shorter, and a brief search on the website didn't show me any dimensions?)
Rasmus Philosopher Join Date: Jul 2005 Posts: 6,138

19th February 2007, 06:59 AM	#5
Indolent Wretch Scholar Join Date: Jan 2006 Posts: 100	Originally Posted by Rasmus I have read something about this type of generator a long time ago. I think it said that the area underneaht the structure could still be used for farming etc. Me too, I'm sure some wind resistant crop could be chosen, and the wind won't be particularly severe at any real distance from the centre. It's a nice idea this, always liked it. It's simple, some of your generators are low down so they are easy to replace, construction is pretty simple, other than the generators there are no moving parts and the energy creation side needs no fuel transported to the plant. The world is full of deserts with non-usable land, shed loads of baking sunshine, and they tend to be areas with a very low real estate cost. However governments seem to be very reluctant to help pony up the cash and actually build a full scale one which is a real shame. I know Bill Gates is busy be couldn't he start getting interested in carbon neutral power generation as well as everything else? After all his operating system burns quite a few unnessecary gigajoules every year.
Indolent Wretch Scholar Join Date: Jan 2006 Posts: 100

19th February 2007, 10:58 AM	#7
bjornart Master Poster Join Date: Nov 2002 Posts: 2,395	A kilometer high tower is really cool, but how does such a construction compare in cost and efficiency with just covering the same area with solar cells? I guess there might not be very good numbers on that, but a 1000 m tower has to be a very challenging build, and the two step process of heating air and running it through a turbine can't be all that efficient.
bjornart Master Poster Join Date: Nov 2002 Posts: 2,395	__________________ Well, I DON'T CARE WHAT YOU LIKE TO BELIEVE, GODDAMMIT! I DEAL IN THE FACTS! -Cecil Adams

19th February 2007, 02:28 AM	#2
EternalSceptic Critical Thinker Join Date: Feb 2007 Location: Bernhardsthal, Austria (Europe) Posts: 256	Originally Posted by lionking Australian company Enviromission has announced that it will begin construction of a pilot solar tower this year. The idea is to untimitely build the world's tallest construction, a tower more that a kilometer high. At the base will be a canopy, or hothouse, with a diameter of 5-7 kilometers, heating the air which will rush up the tower equipped with turbines. One of the advantages of this type of solar power generator is that it would work at night as the ground temperature would always be greater than the temperature a kilometer up. I recall reading that construction costs would approximate those of a coal fired or nuclear plant, while producing the same amount of power, but with negligible running costs and no emissions. I'm sure there will be significant construction difficulties, but the project seems to make sense. Comments? Link www.enviromission.com.au. In the part of Austria where I live there are hundreds of wind power stations (at the end this is also solar energy) and they are pretty successfull. Then there is the gigantic flywheel called "moon" which drives ebb and tide and there are power stations which use this energy. Besides the construction difficulties, which can be managed IMO, I can't see anny reason why it should not work

19th February 2007, 10:56 AM	#6
Hindmost Guest Join Date: Jan 2006 Location: Draco Tavern Posts: 3,317	It looks feasible, but the power output is low. 200 MW is just not that much power. Building the tallest tower in the world is also not going to be cheap or easy. This is twice the height of the Taipei 101--construction of that size built to meet all the possible weather and earthquake needs should prove interesting. (I don't know if Australia is in a high earthquake zone) Putting it up in the outback would provide a resonable capacity factor due to the favorable weather...for solar power. glenn

19th February 2007, 11:47 AM	#8
lionking In the Peanut Gallery Join Date: Jan 2007 Location: Melbourne Posts: 29,650	Originally Posted by glennmr78 It looks feasible, but the power output is low. 200 MW is just not that much power. Building the tallest tower in the world is also not going to be cheap or easy. This is twice the height of the Taipei 101--construction of that size built to meet all the possible weather and earthquake needs should prove interesting. (I don't know if Australia is in a high earthquake zone) Putting it up in the outback would provide a resonable capacity factor due to the favorable weather...for solar power. glenn I'm pretty sure this is the output of the pilot plant only with the real one having much higher generation. No earthquake problems to speak of, and land and sunshine are both plentiful, so if it doesn't work here, it never will.

19th February 2007, 11:48 AM	#9
Molinaro Illuminator Join Date: Dec 2005 Location: Toronto Posts: 3,027	As I remember this story, it is to be built in China.
	__________________ 100% Cannuck!

19th February 2007, 12:06 PM	#10
Hindmost Guest Join Date: Jan 2006 Location: Draco Tavern Posts: 3,317	Originally Posted by lionking I'm pretty sure this is the output of the pilot plant only with the real one having much higher generation. No earthquake problems to speak of, and land and sunshine are both plentiful, so if it doesn't work here, it never will. The 200 MW was off the link you provided. The pilot plant--off the same link--indicated it had an output of about 50kW over a period of 7 years. I think the idea is to put 5 towers in the same area to yield 1000MW...that would be equal to a small nuke facility glenn

19th February 2007, 12:23 PM	#11
Rasmus Philosopher Join Date: Jul 2005 Posts: 6,138	the "tower" shouldn't be too difficult to build, the structure doesn't need much force to keep it up. The structure doesn't need to carry anything, after all. (my first idea would be tons of clingfilm and a couple of ballons to drag it up ...) I don't think it can be compared to a building where people work and live in. This is assuming that the generators will be set up low in the tower and not be placed in intervals up to the very top. The tower wouldn't even need much insulation or anything, right?
Rasmus Philosopher Join Date: Jul 2005 Posts: 6,138

19th February 2007, 01:45 PM	#12
jimbob Uncritical "thinker" Join Date: Jan 2007 Location: Derbyshire, UK Posts: 5,165	Originally Posted by lionking I'm pretty sure this is the output of the pilot plant only with the real one having much higher generation. No earthquake problems to speak of, and land and sunshine are both plentiful, so if it doesn't work here, it never will. The fewest of any continent. I have a great idea to stop us being dependent on the Arabs for oil: Why don't we invest massively in building solar power stations in the world's hot deserts, like in North Africa and the Middle Eas.... Seriously, I do think it is a good idea; much as I like the idea of the technical challenges associated with nuclear fusion and the ITER, I think the best place for a fusion reactor is 150 Gm from here. You are creating something ten times hotter than the surface of the sun, controlling it with magnetic fields from liquid helium-cooled superconductors (right next to this) and then you are going to use it to DRIVE A STEAM ENGINE??? or something else equivalent. Don't forget the Beryllium blanket (nice one for the toxicologists). I'd love to seee it work, I am an engineer, so like the idea of these toys, but I think this, and other forms of solar concentration are probably better (especially for hot-cloudless areas with low populations). Jim

19th February 2007, 01:58 PM	#13
Soapy Sam NLH Join Date: Oct 2002 Posts: 25,885	First I heard of the idea was an SF story at least 20 years ago. Maybe Clarke, but I don't recall for sure. ("Tales from the White Hart" maybe?) The idea definitely appeared in New Scientist at least once as a serious project. I think it's one of those ideas that resurface every decade, then die in the funding stage. It would be interesting to see one built. I wonder if it would act as a condenser / water supply as well? That would be a plus in Australia.
Soapy Sam NLH Join Date: Oct 2002 Posts: 25,885

19th February 2007, 02:06 PM	#14
fishbob Seasonally Disaffected Join Date: Jan 2003 Location: Chilly Undieville Posts: 5,666	Look at the video. If the tower is 1000 meters tall, then the apparent diameter is about 100 to 150 meters. 32 turbines at the base catch the inrushing air at the base. I took an architecture class in the mid-70s (Univ of Tx) on building with alternate materials - taught by an odd character named Pliny Fisk. Most of the class involved actual construction of various ideas, on his property outside of town. The university wouild not allow him to do this stuff on campus due to the large piles of 'recycled materials (junk) and due to 'safety concerns' (students climbing around 30 feet in the air with hammers and nails). We made adobe tiles, made used flourescent light tubes into solar heaters, built solar heated walls out of empty beer bottles, and built a solar tower about 35 feet high. The tower was three sided, about 8 feet across, made from sheets of tin that were painted black. The thing had a turbine across the top to measure upflowing air speed. The idea was to dig a trench about 50 yards long, cover it to make a tunnel, connect it to a residence as a fresh air source, and connect the residence to the tower as an air exhaust. Air flowing underground was supposed to be cooled, and reduce the need for air conditioning. This was an ongoing project, and I never found out what the results were, however, I could feel a good breeze inside the tower on a hot Texas day. Properly engineered, I can see this idea working. The economics will be the difficult part.
	__________________ When you believe in things you don't understand, then you suffer . . . " - Stevie Wonder "Stupidity - a callow indifference to facts or data" - Stuart Firestein -neuroscientist. I hate bigots. Last edited by fishbob; 19th February 2007 at 02:15 PM.

19th February 2007, 02:38 PM	#15
lionking In the Peanut Gallery Join Date: Jan 2007 Location: Melbourne Posts: 29,650	Originally Posted by glennmr78 The 200 MW was off the link you provided. The pilot plant--off the same link--indicated it had an output of about 50kW over a period of 7 years. I think the idea is to put 5 towers in the same area to yield 1000MW...that would be equal to a small nuke facility glenn Thanks, my mistake.

19th February 2007, 02:49 PM	#16
Rasmus Philosopher Join Date: Jul 2005 Posts: 6,138	Originally Posted by bjornart A kilometer high tower is really cool, but how does such a construction compare in cost and efficiency with just covering the same area with solar cells? As far as I nkow, solar cells still have a negative energy output, i.e. you put more energy into the production than you will ever receive during the lifetime of the cell. Hence, plastering the desert in solar cells will buy you a massive net loss in energy.
Rasmus Philosopher Join Date: Jul 2005 Posts: 6,138

19th February 2007, 02:54 PM	#17
Rasmus Philosopher Join Date: Jul 2005 Posts: 6,138	Originally Posted by glennmr78 TI think the idea is to put 5 towers in the same area to yield 1000MW The higher the tower the better. I would like to see the tradeoff between ground area covered and tower hight. I suspect there's a reason they intend to have the tower so high rather than just cover an even bigger patch of desert.
Rasmus Philosopher Join Date: Jul 2005 Posts: 6,138

19th February 2007, 03:32 PM	#18
Modified Illuminator Join Date: Sep 2006 Location: SW Florida Posts: 4,062	Could one of these things be built up the side of a mountain? It would obviously be less efficient, but a lot easier to build.

19th February 2007, 04:46 PM	#19
lionking In the Peanut Gallery Join Date: Jan 2007 Location: Melbourne Posts: 29,650	Originally Posted by Modified Could one of these things be built up the side of a mountain? It would obviously be less efficient, but a lot easier to build. The only problem would be that the hothouse would be in the shade of the mountain for part of the day, and besides, there would not be too many suitable mountains in the desert.

19th February 2007, 04:58 PM	#20
Hindmost Guest Join Date: Jan 2006 Location: Draco Tavern Posts: 3,317	Originally Posted by Modified Could one of these things be built up the side of a mountain? It would obviously be less efficient, but a lot easier to build. The mountain might affect the operation significantly that it would not be practical. Less solar input and possible unfavorable air currents and temperature inversions--but I am just speculating. It will be interesting to see if or how this progresses. Since the pilot plant operated back in the 80s, there obviously hasn't been any rush to scale up. Energy prices may be making it cost effective. glenn

19th February 2007, 05:01 PM	#21
CapelDodger Penultimate Amazing Join Date: Sep 2001 Location: Cardiff, South Wales Posts: 16,741	Originally Posted by MRC_Hans I think the wors problem if this thing is its size. And I am not referring to construction problems, but something with a diameter of 5-6 kilometers, and a kilometer high, that is a prohibitive amount of real estate to take up or overshadow, in a lot of countries. In Denmark, the prize of the ground needed would be so high that the produced power wouldn't even pay for the mortgage. I realize this is probably not too big a problem in Australia..... Hans In Denmark you have tide and wind, so don't complain. In Australia there's lots of desert without the kind of storms we get in these parts. Horses for courses, as the saying goes. I hope this project goes ahead, it'll be fascinating to watch. I read about the concept years ago, probably in SciAm, and thought it intriguing. And challenging. But not ludicrous.
	__________________ It's a poor sort of memory that only works backward - Lewis Carroll (1832-1898) God can make a cow out of a tree, but has He ever done so? Therefore show some reason why a thing is so, or cease to hold that it is so - William of Conches, c1150

19th February 2007, 06:18 PM	#22
CapelDodger Penultimate Amazing Join Date: Sep 2001 Location: Cardiff, South Wales Posts: 16,741	Originally Posted by Modified Could one of these things be built up the side of a mountain? It would obviously be less efficient, but a lot easier to build. That might not be a bad idea. If you've got some serious gradient available - and I'm thinking mostly the Andes here - with plenty of sunlight and water you could build everyday, low-tech greenhouses with vents feeding into a tube-generator tacked on to the local mountain range. Moisture could be recovered and recycled as drinking-water in the process. No new engineering would be required - and so it's not terribly sexy. But potentially useful.
	__________________ It's a poor sort of memory that only works backward - Lewis Carroll (1832-1898) God can make a cow out of a tree, but has He ever done so? Therefore show some reason why a thing is so, or cease to hold that it is so - William of Conches, c1150

19th February 2007, 06:36 PM	#23
CapelDodger Penultimate Amazing Join Date: Sep 2001 Location: Cardiff, South Wales Posts: 16,741	Originally Posted by lionking The only problem would be that the hothouse would be in the shade of the mountain for part of the day, and besides, there would not be too many suitable mountains in the desert. Note to self : buy options in the Atlas Mountains. Also check out the Chilean Coastal Desert - in the rain-shadow of the Andes (serious natural gradient), plenty of sunshine, and low-lying enough that desalination for greenhouse irrigation is economically feasible. And currently worth pennies-an-acre.
	__________________ It's a poor sort of memory that only works backward - Lewis Carroll (1832-1898) God can make a cow out of a tree, but has He ever done so? Therefore show some reason why a thing is so, or cease to hold that it is so - William of Conches, c1150

19th February 2007, 07:40 PM	#24
lionking In the Peanut Gallery Join Date: Jan 2007 Location: Melbourne Posts: 29,650	Originally Posted by CapelDodger Note to self : buy options in the Atlas Mountains. Also check out the Chilean Coastal Desert - in the rain-shadow of the Andes (serious natural gradient), plenty of sunshine, and low-lying enough that desalination for greenhouse irrigation is economically feasible. And currently worth pennies-an-acre. I knew about the Andean Desert, but without looking it up, didn't think it would have been hot enough. But I suppose that the important thing is the temperature difference between the base and the top of the tower, so it would probably work.

19th February 2007, 09:52 PM	#25
Mangafranga Thinker Join Date: Dec 2006 Posts: 222	The real reason this project was scrapped, Drop Bears. Imagine the range they would get on this thing. Add to that the possibility of cannonballing into the largest mostly invisible lake in Australia. Can you just imagine what that invisible wave of water would do? The Drop Bears have just made this project too dangerous.
Mangafranga Thinker Join Date: Dec 2006 Posts: 222

19th February 2007, 11:06 PM	#26
lionking In the Peanut Gallery Join Date: Jan 2007 Location: Melbourne Posts: 29,650	Originally Posted by Mangafranga The real reason this project was scrapped, Drop Bears. Imagine the range they would get on this thing. Add to that the possibility of cannonballing into the largest mostly invisible lake in Australia. Can you just imagine what that invisible wave of water would do? The Drop Bears have just made this project too dangerous. It's bad enough that potential visitors to Australia know about our sharks, snakes, jellyfish, crocodiles and spiders. Now you have to spill the beans on our carniverous, aggressive marsupial.

20th February 2007, 05:08 AM	#27
Cuddles Decoy Moderator Join Date: Jul 2006 Location: A magical land full of pink fluffy sheeps and bunnies Posts: 16,579	There's a nice article about this here. Cost-wise it is not such a bad idea. Assuming the estimates are correct (not always a great idea for construction) it is cheaper than current photo-votaics and comparable to some other renewables, although wind turbines and hydro-electric are cheaper. It also has the big advantage that the power is generated continuously and smoothly. The main problem is its experimental nature. Smaller towers have been tested with some success, but building the tallest structure in the world is always going to be a challenge. Since this is such a big project it takes a lot of resources. If it succeeds it'll be great, if not it will be a big blow for renewable energies in Australia.
	__________________ I am not a little teapot.

20th February 2007, 12:05 PM	#28
bjornart Master Poster Join Date: Nov 2002 Posts: 2,395	Originally Posted by Rasmus As far as I nkow, solar cells still have a negative energy output, i.e. you put more energy into the production than you will ever receive during the lifetime of the cell. Hence, plastering the desert in solar cells will buy you a massive net loss in energy. The wikipedia article on solar cells has articles going both ways, but the cite for solar cells having negative output is relatively old, and it appears it's main point for negating other calculations is that they assume all power produced will be used, which is not the case for the off grid solar cell installations that make up most of the installations in place. But that argument wouldn't be valid for an on-grid installation.
bjornart Master Poster Join Date: Nov 2002 Posts: 2,395	__________________ Well, I DON'T CARE WHAT YOU LIKE TO BELIEVE, GODDAMMIT! I DEAL IN THE FACTS! -Cecil Adams

20th February 2007, 10:50 PM	#29
rjh01 Gentleman of leisure Tagger Join Date: May 2005 Location: Planet Earth Posts: 17,178	Would one advantage of the Solar tower is that it generates AC rather than DC power?