Massive Solar Tower Planned For Arizona 407
inkscapee writes "It's simple, clean, low-maintenance, and cost-effective: using hot air on a large scale to generate electricity. No, this not a plan to use Congress to generate power, though that would certainly be an endless supply — EnviroMission will use air rising up a tall tower to generate 200 megawatts of electricity. The concept is simple: a giant greenhouse at the base of the tower warms the air. The warmed air rises through the tower and turns turbines, which generate electricity. The taller the tower, the faster the air moves, which increases power output. This structure will be a monster at over 2600 feet tall. It works in all weather, and if there is a feasible water source, food could be grown in the greenhouse."
Sounds great in theory (Score:3, Funny)
But too bad - the greenhouse effect is a myth, as we all know.
Re:Sounds great in theory (Score:4, Insightful)
That's not the only myth they are tackling
Hmmm... What plants grow at those temperature?
Maybe in cooler climes it can be used to grow stuff colder climes (or seasons), however at the locations where it'll be warmer and have more stable temperatures, it's gonna get awful damn windy... That means, amongst other things, rugged plants, lots of soil loss (going straight into the turbines or filters that will need to be replaced!) , and lot of moisture loss.
It's looks like an interesting concept for an energy source, but as for green growing space... doubt it.
Re:Sounds great in theory (Score:5, Insightful)
Re:Sounds great in theory (Score:4, Insightful)
the problem is, at those locations, it would only be useful in moderate climes anyway, that don't need greenhouses much.
Also, if you are doing this in the desert, the problem is water, which the greenhouse will not serve to conserve, since there is a constant airflow.
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Awesome Dune reference. Frank Herbert would be proud.
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lots of soil loss
Where's that soil end up? On the greenhouse glass, of course. If the wind flow is enough to toss heavy rocks 2500 feet up (size and weight of hailstones?) then they'll make quite a dent when they hit the glass below.
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Hmmm... What plants grow at those temperature?
Locally mix in some cold air during the winter, it'll be nice.
Kind of like asking, if my natural gas furnace burns a 2500 degree blue flame, how can I use it to keep my house at 72 degrees in the winter?
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Re:Sounds great in theory (Score:4, Informative)
I am guessing you have never spent the night outside in the Desert.
I live in the AZ desert, and have a green house for 3 reasons. 1) the birds, rabbits, etc even eat the hot pepper plant northern rabbits wont touch. 2) Cold nights, day to night swings of 30F are the norm, northern plants seam confused by this, and don't grow (but don't die either.) 3) Humidity, normal plants lose way too much humidity without a enclosure. My roof panels auto open at 90 degrees, and the misters turn on at 95 then close up to maintain overnight.
#1 seams to apply here, #2, probably be good dual purpose for Nov to March.#3 the moisture should settle out on the way up as it gets cooled. Thus if captured would be available. However I would guess the cooling affect of the water down low, would reduce the efficiency, and thus not be desired.
Re:Sounds great in theory (Score:4, Insightful)
It's the typical "we want a federal grant" spiel. It will cut your grass for you and cure cancer, as well as produce cheap reliable clean energy. Of course there's no logistical problems involved in keeping plants at the optimal temperature, watering them, etc. Nah, some dufus in a lab coat who has never seen a vegetable outside a supermarket said "hey, we could probably grow plants there too".
Of course it would make a hell of a gnomon for a giant desert sundial. That would keep future archaeologists guessing for quite a while. Just to fuck everyone up they should align the doors with compass directions.
Tower design (Score:2)
So you are saying the tower is constructed only by increasing carbon dioxide in an open chamber?
Odd, I thought it used heat trapped by passing through glass.
"Twice the hieght of the Empire State" (Score:5, Funny)
The mammoth 800-plus meter (2625 ft) tall tower will instantly become one of the world's tallest buildings.
Compensating for something there, Arizona?
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Don't be ridiculous.
It's an Australian based company erecting this thing.
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The mammoth 800-plus meter (2625 ft) tall tower will instantly become one of the world's tallest buildings.
Compensating for something there, Arizona?
No, they're just really excited about clean energy.
Decent idea. (Score:2, Informative)
So even if it's silly, go for it, Ariz
Re:Decent idea. (Score:5, Insightful)
Re:Decent idea. (Score:5, Informative)
lots of moving parts
Maybe in absolute terms, but virtually any other means of electrical power generation has more. The only moving parts here are the turbines. Not only do we have plenty of experience with running turbines (since every other power source uses them), but they should all be independent from one another, so a failure of one doesn't lead to damage or require a shutdown, it just means you're putting out a little less power.
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I was under the impression that the turbines surrounded the base of the tower at ground level. Every diagram of systems like this show the same layout.
Re:Decent idea. (Score:5, Informative)
It's kind of like putting a hose in a tub, running it out the window and sucking on the hose a bit to get the water started.
The hot air raising up the tube creates a vacuum that pulls in more cold air around the base which is heated by the sun through the glass. The higher it goes, the more air it needs to pull in the bottom. If you cut the tube off, the vacuum is reduced because the hot air is not being used fully and being released too soon.
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The turbines are on the ground, not in the tower. There is no need to insulate anything. The tower is just a very tall chimney.
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You demonstrate a remarkable ignorance of fluid mechanics and failure at reading comprehension. From the article:
Nowhere in all of this is there mention of a need for insulation or any nonsense of hauling multi-ton turbines to the top of the tower. The point of the tower is that the air does
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This was my thought too. An 800m tower is a pretty big target for winds, but I'm pretty sure Arizona isn't all that hostile an environment, though, when I think about it. Very few/ no storms (dustorms maybe), I don't think it gets earthquakes, next to no rain. And the only moving parts, as far as I understand it, are the turbines, which isn't really "a lot". Any power plant is going to have maintenance costs of some kind. This needs no fuel, and supposedly can work at night. It doesn't use rare, expensive,
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I'm kind of annoyed when people say "empty desert." The problem with this is a desert isn't empty and the animals that do live there need more area to hunt out edible plants and other creatures than more rain prone climates.
Don't get the idea that I'm some cactus hugger, it's just I live in the arizona desert and people think it's all sand when there is quiet an abundant variety of life that can only be found in an area that's already relatively small.
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The big problem is the 0.5% efficiency quoted by Wikipedia. Not only does this waste a lot of nice desert land, but it make the economics difficult. I'd rather see 20% efficient concentrated solar with molten salt storage. Less land and, I'll bet, cheaper in the long run.
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Agreed. It has moving parts (turbines), and needs some architecture on a vast scale, but if done right, we (meaning scientists) may learn some technological abilities from this to make it useful in other areas.
I wonder how this compares by price compared to just taking the same amount of area and laying down photovoltac cells either actively tracking the sun, or just passively facing south. Passive tracking gets less sunlight, but doesn't require the presence of moving parts.
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I like this tech too, really look like it has solid potential!
This was in the works since 2001 so a decade seems about right. [enviromission.com.au]
Re:Decent idea. (Score:5, Insightful)
Re:Decent idea. (Score:4, Informative)
FTA:
The output has already been pre-sold - the Southern California Public Power Authority recently signed a 30-year power purchase agreement with EnviroMission that will effectively allow the tower to provide enough energy for an estimated 150,000 US homes. Financial modelling projects that the tower will pay off its purchase price in just 11 years - and the engineering team are shooting for a structure that will stand for 80 years or more.
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FTA:
The output has already been pre-sold - the Southern California Public Power Authority recently signed a 30-year power purchase agreement with EnviroMission that will effectively allow the tower to provide enough energy for an estimated 150,000 US homes. Financial modelling projects that the tower will pay off its purchase price in just 11 years - and the engineering team are shooting for a structure that will stand for 80 years or more.
Financial modelling at the rate they're getting--which will be above market rates for electricity, via government subsidies/mandates that a certain percentage of power generation be green. It's still good, but their financial modelling won't reflect true cost.
Re:Decent idea. (Score:4, Interesting)
Imagine we'd only just discovered oil - we'd probably be shouting down some lunatic scheme to build a huge floating platform, tow it out into deep, windy, wavy waters and then drill several kilometers into poorly understood geology to tap a pressurised well of highly flammable oil and explosive gas.
In engineering and financial terms, this is easy.
Re:Decent idea. (Score:5, Informative)
The tower is rated for 200 MW, with an estimated utilization of 60%. So the average power output is about 120 MW.
Wholesale electricity prices in the United States are 40-100 $ / MWhr. This should be able to provide most of its power during peak usage, which is great from a business model. Plus they can command a bit of a premium from the California ISO because it is renewable, and California has a 33% renewable mandate. Let's assume 60 $/MWhr.
In each year there are 24 * 365 = 8760 hours. So the company's annual revenue should be in the ballpark of $65 M/yr.
The estimated cost to build the thing is $750M, and their estimated payback period is 11 years. That doesn't quite jive with the numbers I've come up with, and doesn't take into account net-present-value calculations, financing costs, operating expenses, etc. But, even so, you should certainly be able to pay for the thing over its many-decades-long lifetime.
Hmmm. Transporting relatively hot air (Score:2)
into cooler air, higher up. I wonder what the weather will be like near that tower after it goes into operation? This could be a neat experiment!
Re:Hmmm. Transporting relatively hot air (Score:4, Funny)
It's in Arizona, what do they have to lose? :-P
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Food and efficiency (Score:2)
At "176-194 F", I'm not familiar with any plants that grow well.
The efficiency of a heat engine depends on the difference between input and output temperatures, so this can't be very efficient, though efficiency is less important when the input is so cheap.
Some can (Score:2)
Yellowstone has some bacteria that grow at those temperatures, perhaps they could be molded into colorful bacon strips.
Re:Some can (Score:4, Funny)
At those temperatures, we can just put pigs in the bottom to get bacon strips.
Yep, they cook then get drawn into the turbine, it'll be raining bacon strips for mile downwind.
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At "176-194 F", I'm not familiar with any plants that grow well.
The sad part is that is well done for beef. I prefer medium well, myself, around 155 F.
Perhaps on a cloudy day you could stampede cattle under the greenhouse, and have a rather large steak dinner a couple hours later.
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Beef jerky factory.
Good old Slashdot (Score:2, Troll)
No, this not (sic) a plan to use Congress to generate power, though that would certainly be an endless supply
Yep, another old, tired, stupid and vacuous panning in the summary that you'd expect from a 14 year old who thinks he's massively clever. This is is what Slashdot has become.
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The only thing taller.. (Score:5, Informative)
This is a ridiculous idea. The only structure that is taller than 2600 ft is the Burj Khalifa (Burj Dubai), which is 2717 ft.
http://en.wikipedia.org/wiki/List_of_tallest_structures_in_the_world [wikipedia.org]
The idea that we would build the 2nd tallest structure in the world for 200 MW is ridiculous. This doesn't even come CLOSE to being a top producer of energy per power plant. The top 10 power plants in the world all produce more than 6000 MW. Even the largest biofuel, geothermal and tidal plants currently exceed 200MW.
http://en.wikipedia.org/wiki/List_of_largest_power_stations_in_the_world [wikipedia.org]
-molo
Re:The only thing taller.. (Score:5, Insightful)
Taller doesn't necessarily mean more expensive. It's a big metal tube, not the same as a full building. It doesn't even need to be habitable. Structures of similar heights have been built for radio transmission you know.
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Who said anything about more expensive? As for "similar heights", the largest radio tower was the Warsaw Radio Mast [wikipedia.org], which was 2164 ft before it collapsed. The currently tallest radio mast is the KVLY-TV mast [wikipedia.org] which is 2063 ft. This would be 26% taller than KVLY, would be free-standing (unguyed), and would be solid (wind cannot blow through it). This tower is more comparable to a occupied structure.
The current highest capacity wind turbines are 7.6 MW. I haven't been able to find figures on the area pro
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Nobody is living inside the tower.
It will be significantly easier to build this than any building for occupation at half that size.
Re:The only thing taller.. (Score:5, Insightful)
The complexity of a giant hollow tube doesn't really compare well to an office and apartment building designed to safely hold tens of thousands of humans at a time.
As for the cost, the average US nuclear power plant puts out very close to one gigawatt, and costs on the order of 6-9 billion dollars to build and another 30 billion in expenses over its lifetime. This tower has an estimated construction cost of 750 million dollars, and although I can't find any estimates of the maintenance cost, I'm going to go out on a limb here and say "a hell of a lot less than completely rebuilding it every 3 years of its spec'd lifetime".
Sounds like at the very least a better-than-breakeven proposition vs nuclear, IMO - With no waste or risk of disaster.
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Average nuclear reactor output in the U.S. is
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Re:The only thing taller... (Score:2)
It's not habitable. With a payback period of 11 years, it's doing pretty well, particularly for a renewable energy plant.
Thermocouple? (Score:2)
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Aside from being stupidly expensive, anything you took out via thermocouple at the base wouldn't come out as power through the top.
Moreover, the heat differential wouldn't be nearly the same.
In essence, you'd be spending much much more money to make much less power.
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What would the thermocouple be doing? Facilitating the opening/closing of vents?
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Other Heat Islands? (Score:2)
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Yes, but it would also make the heat worse.
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Part of the solar tower system is a greenhouse at the base that traps heat (over your city's heat island) and funnels the hot air into the tower.
Rain, etc. (Score:3, Interesting)
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Well the tower being dirty shouldn't cause any problems, the greenhouse roof being dirty would reduce efficiency, I don't know if it's self-cleaning. Rain would be no problem at all, when the desert sun comes up the water will disappear reeaall fast...
They failed to predict the future before (Score:2)
In 2005 EnviroMission said that the first solar tower would be up and running before year 2008 in Australia. That never happened.
Now in 2011 they say that it will be ready at the start of 2015 in Arizona. I hope they succeed this time.
I'm sure it would work (Score:2)
to generate electricity, but isn't a major hurtle for projects like this one the distance from where the electricity will be consumed? They're confining this to the desert, because of the daytime temps, but most power is being used on either coast, thousands of miles away.
Cost (Score:2)
That depends (Score:3)
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Depend if you need a B-2 bomber, a few 747s, a large cruise ship, or a power plant.
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How beneficial is a large cruise ship in delivering ordinance deep in enemy territory through air defense networks?
The money spent on a B-2 doesn't evaporate into the ether. It becomes paychecks, purchases of materials (from alloys to paper clips), stock dividends for retirement funds and so on. Those paychecks pay mortgages, rent, car payments, groceries, trips to Disney World, condoms, computers....
Serious Question... (Score:5, Interesting)
I get it... turbine generators have really good efficiency and we've refined their use for over a century. But it seems to me that every worth-while method of power production uses them...
Solar Cells, and Lightning Rods seem to be the only methods I can think of that produce electricity without the use a turbine/generator combo but neither are viable for wide spread use. It seems to me that we'd do well to invest in methods of converting heat directly into electricity (giant Peltiers?) without the use of a turbine/generator. I would think doing so would theoretically make a number of our existing methods that much more efficient and perhaps open the door for other methods of power production.
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Is there a form of viable power production that doesn't require a mechanical generator of some sort?
Radioisotope thermoelectric generator [wikipedia.org]
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There are magnetohydrodynamic approaches. You make a lot of hot plasma, cool it by allowing to expand in one direction and then use a big magnet to separate the positive ions and negative electons, which impact different electrodes. I don't think it's terribly efficient (to put it mildly) and the wear on the electrodes is something chronic, but if you want a LOT of power (GW) for short periods (seconds to minutes) for some reason it might be usable. I think Jerry Pournells has a laser launcher powered tha
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FTA:
In the video after the jump, EnviroMission CEO Roger Davey explains the solar tower technology, the Arizona project and why he couldn't get it built at home in Australia.
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This is in the middle of the desert, so no chance of hurricanes there. Also, its just a hollow tube, you could easily reinforce it to withstand high winds like that. Because is is hollow you have the option of putting louvers all over the sides. If a storm pops up, open them all and let the wind pass through the tower, problem solved.
ARIZONA (Score:2)
We're talking Arizona. Not much threat of hurricanes there.
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My initial question would be what happens when a hurricane lands near a 2600 foot tower perched on a giant greenhouse? Somehow the mirrors (concentrators) and water/oil tank configuration of solar power seems like a more resilient structure, if only for the fact that the mirrors are smaller and closer to the ground and you dont need a massively tall tower.
I rather doubt that Arizona has seen a hurricane in quite some time.
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I don't think hurricanes are much of a concern in Arizona.
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But it could happen! See, you smarty-pants engineers calculate what could happen based on what happens around Arizona in the past, but what happens if the San Andreas fault lets go and most of California sinks into the ocean? Then Arizona ends up right next to the coast and could be affected by hurricanes! What then, Mr. Smarty Pants?!
(The above is sarcasm, by the way)
Seriously, though, I assume the GP meant "tornado" as hurricanes tend not to "land," though they do make land-fall. Tornados "touch down"
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not many hurricanes in Arizona, but seeing as this is as tall as the tallest building in the world, the Burj Khalifa in Dubai, I can't seeing this being economical at only 200 MW.
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Because a chimney is a hotel? (Score:2)
Because the dubai tower is a hotel with needs lots and lots of cooling and other luxeries compares with a hollow tube that generates power not consume it and needs to compete with other powerplants that need fuel or hydro plants which needs enormous lakes...
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When was the last time a hurricane hit Arizona?
I really don't know which type of solar plant is better, I have looked strongly at solar concentrators with a heat reservoir and they are an excellent option, but I don't know that much about these passive solar towers.
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Hurricanes don't end up in Arizona.
What does happen is that a Hurrican travels up the Colorado River and loses steam as it comes inland.
By the time it reaches Arizona, the hurricane is, at most, a tropical storm with gusty winds that are manageable.
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Hurricanes hit coastal area's and sometimes a little inland before they die, but there is no way in hell that Arizona is going to be hit by a hurricane.
For a hurricane to hit Arizona it would have to traverse the gulf of Mexico, pass over both Texas and New Mexico. Moving across land seriously diminishes a hurricanes strength, there is no way a hurricane would even reach New Mexico let alone Arizona.
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Dude, this is Arizona. In the middle of a desert. How, pray tell, is a hurricane going to hit there?
Re:How stable is that 2600 foot tower? (Score:4, Insightful)
More generally: site selection and engineering for the weather are surely taken into account before they break ground. The tower is freestanding and attached to the ground - the greenhouse is built around it, not the other way around. Even if the company glosses over stability in inclement weather, it should be caught in the permitting process. And even if it isn't accounted for during permitting, you can bet the insurers and underwriters will want good answers. Even so, this probably isn't ideal technology for, say, coastal Florida.
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Tornados are also extremely rare in that part of the US. Here is a map of tornado occurrence: http://en.wikipedia.org/wiki/File:Tornado_Alley.gif [wikipedia.org]
However, they do have haboob wind storms with wind speeds up to 30 mph and lots of flying sand. http://en.wikipedia.org/wiki/Haboob [wikipedia.org] I guess these and thunderstorms are the most extreme weather that the struc
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Re:They should catch it on the way back down (Score:4, Insightful)
The idea is interesting, but it seems to me that a substantial portion of the solar energy is going towards gravitational potential energy - that is, lifting tons of air mass hundreds of feet in the air.
At some point, that air mass cools off, the air will want to drop back down towards the earth because of gravity. Seems like, in addition to generating 200MW on the 'exhaust' stack, they could build a second "cool air return" stack that generated power from the force of gravity pulling the cooled air back down to ground level?
-1 parent. The exhaust air at the top of the tower is going to keep rising because it will still be hotter than the ambient air. The cold air that falls to offset the rising mass is called the atmosphere. It's big, it's going to be moving slower than the air you just used to spin a turbine, and it's not cost effective to try to make electricity from it until it enters the greenhouse, gets heated, and funnels into the turbines that are already in the design (the one place where air is moving fast in the whole design.
Re:They should catch it on the way back down (Score:5, Informative)
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Actually, that effect you mention is the mechanism by which they *capture* the solar energy. Of course they don't capture *all* that energy, but that's not the point. The point is the energy you take out as a function of investment and operational costs. The tower component is bound to be pretty expensive, but the system has no moving parts other than the turbines and it can be scaled up by building out over cheap land.
It's the NPV of all the inputs per kw/h that matters, and if the figures come out compe
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One of the engineer on this project is obviously an Atari fan.
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Upper troposphere? The height of this is nothing compared to any atmospheric layers. I'd be surprised if any climate effects will be measurable outside of the immediate vicinity.
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Not sure why they even bothered mentioning growing food in the greenhouse, they stated the temperature may hit 176 to 194 Fahrenheit.
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Are you talking land value? In the desert, land is cheap. Are you talking about the amount of glass needed to make the "green house?" What would make the size of the base a deterrent?
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What does the relationship between the radius of the greenhouse and the height of the tower have to do with anything? More of either one is better.