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

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: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.

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

[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]

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.

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?

Can we still make fun of him in 2010?

[LostCluster]

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

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: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."