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CA's First Molten Salt Energy Plant Approved
An anonymous reader writes "This year we've seen molten salt power plants start to pick up steam around the world, and now the technology is heating up stateside — California just approved its first molten salt energy plant. Designed by SolarReserve, the plant uses heliostats to focus thermal energy on a power tower filled with salt, which is able to reach very high temperatures (over 1000 degrees Fahrenheit) and can hold heat for an extraordinary length of time. Heat from this reserve of molten salt can then be pumped through a steam generator to provide on-demand energy long after the sun has set."
http://en.wikipedia.org/wiki/Solar_power_plants_in_the_Mojave_Desert
Only if you ignore Solar II that ran from 1996 to 1999....
---In a time of Chimpanzees I was a Monkey.
It took me 4 reads just to find the two puns that you appear to be so steamed over.
Distributed Denial of APK: It takes 15 seconds to reply to him anonymously, but wastes tons of his time if we all do it.
Nothing from or controlled by Computer Associates should be trusted with warm water, much less molten salt.
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
Yep, even I get annoyed by Slashdot summaries pretty often, but this one didn't even trip my detector. Had to go over carefully to see the two at the beginning. Sorry, lower your sensitivity, because you're making us intolerants look tolerant in comparison!
Way to pour salt on his wound.
meep
Eliminate that make-believe accuracy, as the original was probably rounded at least +/-50 F to the round 1000 figure. 800 Kelvin is plenty accurate here.
Slightly off-topic (or on-topic considering the bigger picture). Can this method of heat concentration be used in the refinement of silicon. My understanding is that silicon production is expensive because of the energy needed to generate heat for the process.
http://en.wikipedia.org/wiki/Silicon#Production
Does anyone know exactly how long the reservoir tanks will keep the molten salt at a high enough temp to be useful? It says it can run for 24 hours but should an abnormally long string of cloudy days occur would this inhibit its usefulness? I realize it's California so it should be fairly sunny year round but I'm not familiar with the area it's being built at. Looked up the salt as well. (Had a hard time thinking it would be sodium chloride...) It's a mixture of sodium and potassium nitrate. I was a bit worried as nitrates tend to be violently reactive/explosive but this would only be with reducing agents. (so it should be relatively fairly safe if there was a leak.) However when potassium nitrate is heated above 560C (as it would in this plant) it turns to potassium nitrite and gives off oxygen. I'm curious if this would be an issue or if the sodium nitrate or something else in the mixture inhibits this. I imagine the oxygen would either stick in the solar collector part as a gas bubble or just be dissolved in the molten salt mixture. Anyone know? (My expertise is more in biochemistry than inorganic/industrial chemistry)
Realistically? No. The thermal mass required to keep a steam turbine running 24/7 is not something you want in your house. This is large scale industrialized energy production. The only personal scale applications are solar hot water heaters and greenhouses, and in those cases your goal is to take advantage of the stored heat directly instead of converting it to electricity.
Besides that it is also a "trivial geometry" case. If you assume the collector constant the more obtuse the angle of reflection requires a bigger mirror. If the receiver is low, you end up with an obtuse angle out of necessity. The higher it is, the easier to obtain that magic 90 degrees that minimises the mirror size and from there cost and everything else.
Baker's Law: Misery no longer loves company. Nowadays it insists on it
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Yes, lord knows the solar energy people don't want to literally make a pillar of salt.
It would drive the Fundies nuts, that they could then equate solar energy with Sodom and Gomorrah.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
You RTFA? I’m sorry, but I’ll have to take that claim with a grain of salt.
Distributed Denial of APK: It takes 15 seconds to reply to him anonymously, but wastes tons of his time if we all do it.
What happens when a bird flies too near to the tower?
A republican will pretend to care about the environment long enough to sound like a complete asshole.
I tell ya, if I had a NaCl for every pun on here...
It is a solemn thought: dead, the noblest man's meat is inferior to pork.
I'm beginning to suspect the Mythbusters intentionally blow it once in a while just to give the geeks something to argue about. That gets them more buzz.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
It takes several days and nights of little to no sunlight for the salt to cool down enough to no longer be molten and useful.
Efficiency is going to directly impact the size of the collector you need for a given application, and thus cost. So yes, efficiency is quite important in solar power, as it is in every other renewable energy source. It is less important than with other energy sources, yet still quite important. And it could easily mean that below a certain size of application, the technology is economically infeasible.
The enemies of Democracy are
I didn't see anywhere in the article where they say that Sodium Chloride (i.e. table salt) was going to be used. I thought power plants typically used a different kind of salt (Sodium Nitrate?) to store thermal energy?
Since the diagram in the article shows the "cold" tank being at 550 degF, then they must not be using sodium chloride or it would be a solid in that tank.
1 horsepower isn't enough to run a house. And smaller heat engines are inherently less efficient than larger ones. And a smaller reservoir will loose heat faster than a larger one that has proportionally less surface area.
You still don't want the thermal mass in or near your house. A thousand degrees is enough to make paper and wood instantly catch fire. It is enough to melt aluminum and damage commercial bricks and concrete. It is enough to cause 3rd degree burns in seconds.
Efficiency directly affects cost.
If you're trying to argue that modifying some technology to make it more efficient will necessarily make it cost less per unit of energy, then that is patently false. I can make any thermoelectric device more efficient by making it out of diamonds and gold, but that won't make it cheaper. Any technology with a different efficiency is a different technology, full stop. If all we care about is cost/energy, there are lots of factors more important than efficiency to consider.
smaller turbines are less efficient
With CHP systems, turbine efficiency doesn't matter. You can heat your house or your hot tub with the 20% more waste heat that a small turbine generates. In fact, a small system can be more efficient as well as cheaper than a larger one by utilizing the 60% waste heat produced.
Smaller components can be built on assembly lines, using automated processes, instead of in a one-off fashion. This can make them less expensive and more reliable. Smaller components can be sourced from multiple producers, leveraging market forces to lower costs and increase quality. Smaller systems are also easier to finance, and can be more resistant to fraudulent investment schemes, legal barriers and market manipulation.
These are all more important factors to consider with renewable energy than mere efficiency. But cost is clearly the biggest factor. And it should be plainly obvious that the relationship between cost and efficiency is tenuous at best.
"I assumed blithely that there were no elves out there in the darkness"
Looks like saltpeter (sodium nitrate and potassium nitrate) with a bit of calcium nitrate mixed in is the currently preferred mix with a ~220C melting point.
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