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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."
Seems like a reasonable idea. The wikipedia article has more info than the TFA. There have been a couple of much smaller systems build world wide but little info on how well they work or stand up. I'm a little concerned about the 'limited maintenance' claim. It's a big structure in a hostile environment and has lots of moving parts. One wonders just how optimistic their financial spreadsheets are and how far they will diverge from reality.
Faster! Faster! Faster would be better!
You grow plants at the periphery of the collector where it's warm, not hot and less windy. At least, that is the plan. Nearer to the turbines will serve as a training ground for Arrakis.
Faster! Faster! Faster would be better!
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.
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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This is a ridiculous idea. The only structure that is taller than 2600 ft is the Burj Khalifa (Burj Dubai), which is 2717 ft.
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.
Curious what the effect of launching a stream of hot air a half mile up will have on local weather patterns. Would suck big time if this upwelling of hot air caused a localized artificial high pressure zone that shifted the natural weather patterns. Just say'n