Massive Solar Updraft Towers Planned For Arizona

MikeChino writes "Australia-based EnviroMission Ltd recently announced plans to build two solar updraft towers that span hundreds of acres in La Paz County, Arizona. Solar updraft technology sounds promising enough: generate hot air with a giant greenhouse, channel the air into a chimney-like device, and let the warm wind turn a wind turbine to produce energy. The scale of the devices would be staggering — each plant would consist of a 2,400 foot chimney over a greenhouse measuring four square miles. The Southern California Public Power Authority has approved EnviroMission as a provider, although there’s still plenty of work to be done before the $750 million, 200 megawatt project can begin."

Comments

A better location

[n0tWorthy]

They should build it in Washington DC

I can't help but wonder...

[Rei]

these couldn't be built for a small fraction the price by using an atmospheric vortex engine instead of a tower.

Re:I can't help but wonder...

[dkf]

Seems like an interesting idea, replacing the tall tower with an air vortex. But I think the risks have to be researched beforehand. What you create here is a giantic tornado, so how is it guaranteed that this tornado won't suddenly rip off the base and start wandering around?!

Pack trailer parks around the base. That'll keep that tornado fixed firmly in place.

Re:Plenty of consulting dollars to be spent

[yobjob]

I've been watching Enviromission not build a solar tower in regional Victoria (Australia) for a decade now. Not building one in the United States is a real step up for these guys.

Efficiency

[pete-classic]

Is there some efficiency to be gained by building a four square mile device over, say, 2560 one acre devices? Energy efficiency? Cost? It seems like there's a lot of risk in building one giant unit.

-Peter

Re:Efficiency

[Rei]

Is there some efficiency to be gained by building a four square mile device over, say, 2560 one acre devices? Energy efficiency? Cost?

Yes. Yes.

Re:Efficiency

[dbIII]

Is there some efficiency to be gained by building a four square mile device over, say, 2560 one acre devices?

Yes, by the bucketload. Thermal solutions of all kinds scale up - that is twice the size gives you a lot more than twice the energy. One example is that you can have an enormous rotor that works at low wind speeds because there is so much moving air while a small one can't move at all. Another is in large units where you get power from steam several turbines can be used to get a lot more energy out of the steam while in small units you can only spin one.
Photovoltaics don't scale up - double the area and you only get double the power. That's why the nuke lobby liked comparing their 1960s dinosaurs to photovoltaics since eventually there has to be a scale where nearly anything thermal will pull ahead.

Re:Plenty of consulting dollars to be spent

[s0litaire]

Hm.. My first thought was "Perfect for one big ass Pot farm..." ^__^

Re:Yeah!

[CyberBill]

This DOES (essentially) reduce thermal energy in the atmosphere.

Typically, the solar energy just heats up the ground, and also bounces around in the atmosphere and heats it up. This thing works by trapping the energy in a small area (greenhouse) and then using some of that heat to generate electricity. By the time the air is pumped out into the open atmosphere, it has less heat energy than if the thing wasn't there to begin with.

This really boils down to being just like a photovoltaic panel. Rather than the Sun wasting its energy heating up the atmosphere, we use the energy to make electricity... which we then waste by turning electricity back into heat which heats up the atmosphere. :)

Nuclear Would Use Less Land with Higher Output

[Anonymous Coward]

A nuclear plant would use maybe 50 acres and produce a gigawatt. I think the capital expense is comparable. What is the benefit here?

Regards,
Jason

Re:Nuclear Would Use Less Land with Higher Output

[bmk67]

It doesn't generate a shitload of radioactive waste, perhaps?

Re:Nuclear Would Use Less Land with Higher Output

[wizardforce]

Most of the nuclear waste in the US is recyclable. The amount of waste produced for a given amount of power is small compared to coal, pil and other fossil fuels. Thorium reactors produce even less waste than Uranium/Plutonium reactors do and is more common as well. There is also the problem of low carnot efficiency of solar updraft towers relative to other solar thermal designs because of the relatively small thermal gradient. The larger the thermal gradient, the higher the efficiency.

Re:Nuclear Would Use Less Land with Higher Output

[Chris Burke]

Land use is not exactly a big issue in Arizona...

Re:Nuclear Would Use Less Land with Higher Output

[QuoteMstr]

The total volume is waste is tiny, and it's not that dangerous. It's not more dangerous than the output of other industrial sites like oil refineries and solvent plants. Considering that the carbon footprint of the nuclear power cycle is staggeringly low (even taking into account plant construction and uranium mining), nuclear power is the best and most obvious solution to climate change. We don't even need thorium reactors. There's enough conventional nuclear fuel to last millennia even without reprocessing. We can extract the stuff from seawater.

The issue here is political: the general populace is frightened of political power due to a 40 year standoff involving nuclear weapons and one terrible Russian nuclear accident. The waste "problem" is fear-mongering.

How can you tell? Ask a nuclear opponent what his criteria for "solving" the waste problem are. What containment technology would win him over, even in principle? You'll find he won't accept anything short of the magical transformation of nuclear waste into hemp.

Education and sanity are slowly winning, but it will be a long time until nuclear power is accepted again here. Until then, we're going to be stuck with coal power slowly strangling our planet.

Re:Nuclear Would Use Less Land with Higher Output

[QuoteMstr]

So tell me then, why did the price of Uranium go up?

Because that's how it works. You start with some initial reserves. You mine them cheaply. When you start to run out of reserves, prices go up. The high prices cause exploration. New mines open up, and prices go down. Repeat ad infinitum.

Also, we've actually been using decommisioned nuclear weapons as fuel, which is cheaper than anything else because the uranium there is already mined and enriched.

Regardless, the actual cost of fuel is such a small part of a nuclear power plant's budget that the price could rise twentyfold before you'd notice it at the meter.

the good stuff is scarce

It's called enrichment. Besides, if you're willing to use heavy water (which is non-toxic), you can even use natural uranium in a reactor.

The "good stuff" isn't scarce, and the article I linked to provided plenty of numbers that support my position. Why don't you come up with some of your own?

Re:Nuclear Would Use Less Land with Higher Output

[QuoteMstr]

How big are uranium mines, the roads used to transport the uranium, the refining plants, the reprocessing plants, and the mountain that is needed to store the waste for several millenia?

Well, let's see. Coal has an energy density of about 24 megajoules per kilogram, and uranium has a density of 560 megajoules per kilogram. Uranium comes from its ore uraninite, which is UO2 (78% uranium by weight). So let's adjust uranium's energy density to 441 megajoules per kilogram to make up for it.

The density of coal is about 1.05 g/cm^3, while the density of uraninite is 8.725 g/cm^3, that is, uraninite is 8.3 times denser than coal on a weight basis. It also has 18.375 times as much energy.

So, taking into account both the higher density and higher energy density of nuclear fuel, we need 1/(8.3 * 18.375), or 1/152 the infrastructure we need to mine the equivalent amount of coal.

Let me repeat that: for the same amount of energy, we need 153 times as much infrastructure to get it from coal instead of uranium.

Other turbine proposals...

[catalina]

Back in the 70s there was a proposal to build a very tall cylinder (1 mile or so), inject water mist at the top, and let the resulting downdraft drive a turbine a ground level. Interesting idea, fairly well developed and into the engineering stage. Of course, nobody funded actually building one. The engineer who designed it couldn't overcome the skeptics, and nobody thought it would be competitive with cheap natural gas/oil-fired generators.....

Re:Yeah!

[wizardforce]

We should be trying to extract the thermal energy we already have

What precisely do you think they're trying to do? Where do you think this thermal difference comes from exactly? Every single process that generates usable electrical power generates thermal energy. Simple thermodynamics dictates that a process must be less than 100% efficient and must create more disorder than order. So instead of converting coal and air into CO2, electrical power and heat; we're converting solar thermal energy into electrical power and waste heat. The thermal energy is already there and is going to waste otherwise.

the american way...

[Anonymous Coward]

No, no, no, you have it all wrong!

Amerika will pay Australia to buy from an American corporation. The American corporation will in turn import all the raw materials from china and help the Australian firm find a bunch of minimum wage mexicans to build the thing.

The only question is... which south american country will supply the hookers and blow for this project?

Re:Do a small scale pilot first

[jittles]

A 4 square mile greenhouse in the middle of the dessert?

I, for one, will not stand up to these people interrupting dessert!

Can we still make fun of him in 2010?

[LostCluster]

George W. Bush is already scheming how to dodge the updraft.

Re:Do a small scale pilot first

[Locke2005]

Coal plants make up the vast majority of the power plants in the US and are definitely the most environmentally damaging form of energy production on the planet. Fixed that for you. Coal plant emit more radioactive material (radon) than nuclear plants, in addition to sulphur, other pollutants, and carbon dioxide. Some of this could be cleaned up through better smokestack scrubbers, but from an environmental impact standpoint coal is definitely the most expensive energy source.

Re:dumb question?

[Weedhopper]

Many, if not most wastewater (sewage) treatment plants in the US produce a net energy surplus, which is then returned to the grid.

Re:Hot air injection at 2400 feet?

[Lije Baley]

I'm guessing it will kill every rabbit and turtle up there.

Re:Why can't we address the human factor first?

[QuoteMstr]

I don't accept your premise.

(Or, I find your lack of faith disturbing.)

Though science, we can provide a first-world lifestyle for all those people. We can build enough nuclear plants to provide enough energy to supply them all with power, and desalinate seawater, and still have plenty left over.

Nuclear fuel is that abundant. You can even extract it from seawater. Growth problems go away with the application of enough electricity.

Besides: population growth is self-limiting. Affluent people have fewer children. As we see more people enjoy a first world lifestyle, with its education and contraceptives, we'll see worldwide population sizes level off just as it they have in first world nations.

Re:Plenty of consulting dollars to be spent

[pesho]

You vastly underestimate them. In addition to their US and Australian projects they are also not building one in Namibia .

The Namibian project is more ambitious as it will be used also to grow food in the hot and windy conditions under their greenhouse.

Re:dumb question?

[cptdondo]

Yup, we do this... We generate about 1/2 of our power from the methane off our digesters. (I work for a wastewater plant).

We still burn off a lot of methane - it's not cost effective yet to bring on another generator.

I've been toying with a waste methane coop and buy the extra methane from the WWTP. It would cost about $1/W to buy in, and then you'd be responsible for your share of O&M, and anything extra would be sold back to the grid.

I need about 200 investors at $3K ea. Think of all the green credits you get.

Re:Linear thinking

[ChrisMaple]

The numbers in TFA work out to an efficiency of 1.9% for 4 square miles and a 2000 foot chimney. That's probably the limit for what can be economically built. Even if they could get better efficiency for a larger system, it's not going to scale up much. They're already fighting serious problems with airflow resistance. Photovoltaics routinely exceed 20%.

In their favor, storing an hour or more of heat shouldn't be too difficult, so the output will be more regular that photovoltaics.

Re:Why can't we address the human factor first?

[General Wesc]

Human population will reach 9 billion this year.

6.9 billion, perhaps. We're nearly to 6.8 billion right now and the high UN projection is to hit 9 billion around 2030. Medium projection is 9 billion around 2050, and low is never reaching it. (Source)

The solution is simple -- before fucking with the planet and spending billions of dollars on green efforts, work to limit the population growth.

The good news is that we can actually do multiple things at once. There's no need to completely ignore one issue just because there's another one that you see as more pressing.

Re:Green Energy?

[The End Of Days]

Maybe there's something I'm missing, but I'm pretty sure all the energy that the sun will dump into these greenhouses was going to end up there anyway...

The desert isn't a wasteland

[sp3d2orbit]

The project will decimate 2000 acres of desert habitat for 200 megawatts output. Palo Verde nuclear power plant, also in Arizona, spans 4000 acres of desert and produces 3.2 gigawatts.

Nuclear power is 8x more efficient in land use alone.

Re:Why can't we address the human factor first?

[Nefarious Wheel]

This sort of news upsets me... Why do we spend countless dollars on searching for more energy if the basic problem is not addressed first: There are too many humans and until we figure out how to control human population growth we are doomed sooner or later. ...we'll be able to reduce human population to something that Earth can sustain.

Course manouvers. The Universe is infinite, space is big, and it's all out there for us to tap. And considering the scale of the playpen, I have utterly no qualms about invading it with our polluting presence. We could grow to a population of quintillions or more and not even be noticed on the cosmic scale. I refuse to feel sorrow over our biological imperatives. Far from feeling any sort of sorrow, I take a sunny fresh joy in watching people discussing ways to allow us to live and thrive while using what we have in the most efficient possible way, until the time comes for us to leave the nest and fly. Go Technology!

Re:Green Energy?

[CyDharttha]

Good luck solving any problems without causing new ones. Unfortunately for the human race, perfect foresight is fictional.

After reading the earlier comment regarding urination problems (I should have passed it by), I unfortunately read 'foresight' as 'foreskin'. Sigh.

Re:Super Flux Capacitor

[fuzzyfuzzyfungus]

Impractical. Lightning is dramatic(in large part because it wastes most of its energy in hard-to-collect light and sound); but doesn't actually contain that much energy, compared to the needs of even a modestly sized city.

The combination of "hardly enough energy to bother with, once you've averaged it out over the year" and "peak energy high and fast enough to blow a hole through anything not specifically engineered to take it" just isn't very exciting...

Re:Wet toilet seats a problem?

[The Snowman]

Anyone with carpet in their bathroom deserves whatever debris gets trapped in their penis.

I hate to nitpick grammar, but I am pretty sure that "penis" is always masculine singular, i.e. "his penis."

Re:Green Energy?

[SEWilco]

2400 feet is not high in the atmosphere. 2400 feet is similar to the height of the newly created world's tallest building, so construction obviously will be somewhat challenging. But in the scale of the atmosphere, 24,000 or 48,000 feet would be more impressive. But even those are routine for thunderstorm convection, so are hardly unusual.

Re:Green Energy?

[gyrogeerloose]

Construction of a simple tube that tall should be considerably simpler.

It was interesting how, in the artist's conceptual drawings, the whole thing looked slick and clean and modern while in the photograph of the real, working power station, it was rough and industrial-looking. And notice the guy wires supporting the chimney that weren't included in the drawing.

Don't get me wrong, I think this is a pretty cool thing. I just find the somewhat deceitful methods often used by corporations to sell things to the public by not telling the whole truth rather...fascinating. The Sutro Tower (a 700+ foot high TV antenna tower) in San Francisco is a case in point. The original plans called for a rather futuristic single needle. The actual tower as built was a brutally expedient latticework that San Franciscans hate to this day.

Re:Green Energy?

[fbjon]

A giant greenhouse, designed to heat massive ammounts of air, and dump it into the cold upper atmosphere... So we have given up and are going to proactively warm the earth's atmosphere directly now?

Dumping hot air into the upper atmosphere cools the Earth. As air is circulated higher up it more readily radiates energy out into space, bypassing some fraction of the greenhouse gases of the atmosphere.

Re:Plenty of consulting dollars to be spent

[imakemusic]

Ass Pot: It's the good shit.