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Massive Solar Tower Planned For Arizona
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."
But too bad - the greenhouse effect is a myth, as we all know.
The mammoth 800-plus meter (2625 ft) tall tower will instantly become one of the world's tallest buildings.
Compensating for something there, Arizona?
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
This is, by far, the kind of tech we need to be investing in, preferably starting a decade ago. Genuine renewable, reliable power - are deserts hot? Yes? Let's make power from it! It'll be terribly uneconomical at first, of course, but it can improve given time. And it's worth trying out. It might not pan out, but it's sure as hell a better investment then 1.1 million in legal fees trying to surpress video games or whatever other legal action is popular at the moment.
So even if it's silly, go for it, Arizona - this is a much better investment then your immigration laws. In fact, triple your budget for this.
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!
Paranoia is a Survival Trait!
It's in Arizona, what do they have to lose? :-P
"When information is power, privacy is freedom" - Jah-Wren Ryel
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.
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
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
-molo
Using your sig line to advertise for friends is lame.
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.
For this specific case: not many hurricanes in Arizona, nor in most every desert.
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.
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.
"When information is power, privacy is freedom" - Jah-Wren Ryel
They aren't "lifting tons of air mass" against gravity. Gravity pushing down on the surrounding air is what is pushing the air up in the first place. This tower is a way to focus that downward push of cool air onto a narrow tube of hot air that then floats up and runs the turbines. This isn't any different than boiling small amounts of water at the bottom of a lake. The bubbles will rise quickly and that energy could be harnessed, but it would be pretty useless to try and harness the energy of the resulting water vapour eventually drifting back to the bottom of the lake.
Yes, but it would also make the heat worse.
"When information is power, privacy is freedom" - Jah-Wren Ryel
I know this is in a desert, but it will rain on rare occasions; what will they do with the water that falls on the structure? I imagine it would not be worth while to collect it and transport it somewhere, since it will be so rare. I feel like they probably have considered this, and I just want to know what decision they came to. Put it all in a big gutter, feed it into a huge sump (or a lot of little ones), or what? Also, what about dust buildup - will it get cleared by wind (like the Mars rovers' solar panels) or will someone have to go up there with a giant squeegee to clean it off every now and then? Again, I bet they have thought of it, and I am curious about what ideas they came up with. Maybe they only clean it when it rains? Maybe every time they do clean it, it rains the next day? Who knows?
Just Arizona itself. I consider that a win/win ;-)
People in cars cause accidents....accidents in cars cause people
To put things in perspective...this thing costs less than a single B-2 bomber, and about the same as a few 747s or a large cruise ship. Which is more beneficial?
"and if there is a feasible water source, food could be grown in the greenhouse." Uh, this is the Arizona desert we're talking about here. Any living thing inside a greenhouse outside of December and January is going to be baked to a crisp. :)
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.
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 competitive it doesn't matter if the system is not all that thermodynamically efficient.
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on whether or not there are any contractors for these planes in your district.
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.
Collector's Edition
A few years ago I worked at a power plant that had at one time the worlds tallest smokestack (now fifth) http://en.wikipedia.org/wiki/Mitchell_Power_Plant.
It's about half the height of the proposed tower. The smokestack had a massively wicked updraft at the ground level without any additional heat gathering skirting. There were signs on the doors into the stack warning you to not put you hands near the edges of the doors. The suction made the heavy metal doors slam shut and would take your fingers off if you weren't careful.
Overhead view: http://maps.google.com/maps?q=Cresap,+3,+Marshall,+West+Virginia+26041&hl=en&ll=39.829961,-80.815859&spn=0.010596,0.016029&sll=37.0625,-95.677068&sspn=44.52365,65.654297&geocode=FVD2XwIdi9Uu-w&t=h&z=16
When the power plant was built the answer to air pollution concerns was to build giant smoke stacks so you sent the smoke so high into the atmosphere it would be someone else's problem.
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