In Pictures: The World’s Largest Solar Thermal Power Plant

http://www.technologyreview.com/energy/40460/?p1=A1

by olalonde • 14 years ago

36 27 14 years ago

sinsear• 14 years ago

I can't help myself to think of "Fallout: New Vegas".. you know, a massive solar-power plant near Last Vegas with mirrors "aiming" for a huge tower.. :D. Other than that, really interesting read :)

ivarious• 14 years ago

Makes me wonder if crop circles were the remnants of some sort of solar energy-tapping constructions.

buo• 14 years ago

What I'd like to know is, what is the temperature at the tower, where all beams converge?

mchannon3• 14 years ago

They probably keep it at under 1000 degrees by circulating a molten salt at whatever rate is necessary to carry away the heat.

No matter what the target is made out of, without that circulation to withdraw heat, it wouldn't get much hotter before it vaporized and there was no target. No doubt it'd be possible to get a much higher temperature if that was the goal.

sp332• 14 years ago

Also, each mirror is motorized. A computer monitors the temperature and will de-focus some mirrors if the temps get too high.

glabifrons2• 14 years ago

Maybe, if you mean Celsius. Salt melts at 1474F (801C), so it'd have to be kept above that or it'd crystallize.

I've always wondered what they do if the conditions don't provide a high enough temperature... seems they'd have to drain it entirely of it's salt before it solidifies, or they'd never be able to get it restarted. That is, unless they have some form of heater all the way through the plumbing to melt the salt so it'll flow.

I first read about using salt this way back in (Popular Science? in) the early/mid-'80s with a parabolic reflector heating the salt to be pumped to a Stirling engine. They didn't address that question then either.

robertp• 14 years ago

I went past the construction site on my way to vegas last week. It looks like all 3 towers are at the full height.

It looks really crazy from the highway with the large towers and circles below.

yumraj• 14 years ago

Personally, I think this is the most ridiculous concept. I have not seen the math but in order to achieve any meaningful scale it needs to be huge, but on the flip side the farther you get from the center the efficiency reduces drastically.

Moreover, this is a dusty desert, what are their plans for cleaning those mirrors, at such a huge scale. The only guy who will make money in this is the one with that contract.

The inventor had tried this earlier, I believe in Israel, but that had failed.

Oh well, with federal loan guarantees that it has, we have another Solyndra on our hands.

redwood2• 14 years ago

You an see an early version of one of these in Barstow, if that's what you're thinking of. There is a functional one in Spain as well (http://en.wikipedia.org/wiki/PS10_solar_power_tower)

Anyway you may be right that the tower concept isn't going to last long, but the troughs have been shown to last decades (see Victorville, California) and obviously they have the same issue of dust... so there must be a known solution for that engineering challenge.

thangalin• 14 years ago

Possibly hydro- and oleophobic mirrors plus elbow grease.

leoedin2• 14 years ago

> I have not seen the math but in order to achieve any meaningful scale it needs to be huge

How can you make a statement like that? If you're not aware of the mathematical basis for the plant then you can't quantify "huge". You're either regurgitating something you read elsewhere without any real understanding, or you're simply making untrue statements.

If this is a ridiculous concept, what do you propose instead? Further oil exploration? More coal? This project is making a meaningful step towards reducing our dependence on fossil fuels. If you want to criticise, fine, but please at least take the time to properly understand the costs involved and the alternative options.

redwood2• 14 years ago

Very cool stuff. I have to say I'm very impressed to see a project like this actually getting off the ground. After working for a few years in California's energy regulatory sphere you can become very cynical about the ability to build much of anything, especially when environmental impact statement proceedings can be used by NIMBY (or any other) concerns to stonewall just about any project for just about any reason, if they've got money.

Looks like Brightsource found the right location where there aren't too many folks worried about the development, and whether or not solar thermal will indeed become a growth industry they've at least set a precedent for this kind of work (and regulatory process) in the 21st century, which is an important development.

I hope Brightsource's decision not to go public was only a good rational choice rather than a sign of a company going under.

thrownaway2424• 14 years ago

I love the juxtaposition of this facility with the absurd desert golf resort. A good contrast of America's disastrous 20th century with a glimmer of hope for the future.

trothamel• 14 years ago

I wish that, when quoting the maximum output of a power plant, news articles would also quote the capacity factor - basically, the percent of the maximum output that a plant achieves long-term.

This plant is likely to have around a 40% capacity factor, which is much better than the 20% or so photovoltaic solar achieves, but it's much lower than the 85-90% that baseload plants achieve.

excuse-me• 14 years ago

If it's peak capacity syncs with peak demand for air-conditioning that might work.

Environmentally you would probably do much better (energy wise) by covering the roofs of building in Las Vegas with similar mirrors to lower their albedo and reduce air conditioning use.

mchannon3• 14 years ago

Capacity factor is location- and weather-dependent, and not always known for certain with a new technology (or in this case a known technology this much larger).

Concentrated solar thermal also allows for storage, making the capacity factor percentage adjustable, and allowing for on-peak optimization, which would have a lower capacity factor but a significantly higher benefit to the power company.

truebosko• 14 years ago

Clean energy in a vast open space that will be ripe for greenery and natural wildlife as soon as the construction crews are out of there.

makmanalp• 14 years ago

Does anyone know how they handle the problem of the mirrors tarnishing and getting dirty over time?

edj• 14 years ago

Don't know about tarnishing, but for cleaning they most likely use water.

From an article on solar thermal plants in the Middle East [1]:

But harsh desert conditions in parts of the MENA region generate large amounts of airborne dust which collects on the solar panels used in CSP systems, reducing their efficiency. They need regular cleaning, which consumes large amounts of water.

1: http://m.scidev.net/en/climate-change-and-energy/renewable-e...

glabifrons2• 14 years ago

Most impressive... I wonder how it looks from the air.

It's 74 times as powerful as this one I spotted while flying into Albuquerque several years back. http://maps.google.com/?ll=34.962827,-106.509635&spn=0.0... I'm pretty sure that is this one: http://energy.sandia.gov/?page_id=1267

anusinha• 14 years ago

Basic thermodynamics: converting heat into work is inefficient. A photovoltaic can go straight from the energy of the photons (admittedly restricted to a particular band that they were designed for) with less loss.

leoedin2• 14 years ago

That's a slightly glossed over interpretation of thermodynamics. Perhaps photovoltaics have a higher theoretical efficiency than a thermal cycle plant, but in practice they don't. Thermal cycle power plants are the mainstay of our power generation - nuclear, coal, gas, geothermal - all those power sources make use of a steam based heat to work cycle. We've got 100 years of experience in developing thermal cycle power. Peak photovoltaic efficiency is currently ~20%, while most affordable cells are closer to 10-15%. A simple cycle thermal plant might have an efficiency of 30-40%. It'll be some time before photovoltaics are more efficient for a given area of collecting space.

Cost is a different question. Photovoltaics have fallen dramatically in cost recently. As the space taken up by a solar plant isn't really an issue (the collecting area could take up 10 times more space without really impacting anything), the winner in solar energy will be the cheapest option per kWh.

mparlane• 14 years ago

Does anyone know the long (really long?) term effects of turning sun energy in to electrical? I refuse to beleive it has a zero impact. We take heat energy away from the ground, so the ground gets cooler right ? And over a long period the ground is no longer heated the same as it use to, so that cools the top crust, which would cool the crust below etc. Thoughts? (I am nowhere near qualified to ask these questions)

underwater• 14 years ago

The amount of energy extracted is minuscule. Digging coal an uranium out of the ground aren't side effect free either.

borism• 14 years ago

Indeed. The geological effects of mining are much more serious than solar energy, which are not zero still (you need mining to produce solar panels/mirrors).

Most side effects are focused on local biosphere I'd guess.

In Pictures: The World’s Largest Solar Thermal Power Plant

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