How to Use Solar Energy at Night

[kristopher]

Near Granada, Spain, more than 28,000 metric tons of salt is now coursing through pipes at the Andasol 1 power plant. That salt will be used to solve a pressing if obvious problem for solar power: What do you do when the sun is not shining and at night?

The answer: store sunlight as heat energy for such a rainy day.

Part of a so-called parabolic trough solar-thermal power plant, the salts will soon help the facility light up the night—literally. Because most salts only melt at high temperatures (table salt, for example, melts at around 1472 degrees Fahrenheit, or 800 degrees Celsius) and do not turn to vapor until they get considerably hotter—they can be used to store a lot of the sun's energy as heat. Simply use the sunlight to heat up the salts and put those molten salts in proximity to water via a heat exchanger. Hot steam can then be made to turn turbines without losing too much of the original absorbed solar energy.

The salts—a mixture of sodium and potassium nitrate, otherwise used as fertilizers—allow enough of the sun's heat to be stored that the power plant can pump out electricity for nearly eight hours after the sun starts to set. "It's enough for 7.5 hours to produce energy with full capacity of 50 megawatts," says Sven Moormann, a spokesman for Solar Millennium, AG, the German solar company that developed the Andasol plant. "The hours of production are nearly double power plant without storage and we have the possibility to plan our electricity production."

Using ...
http://www.sciam.com/article.cfm?id=how-to-use-solar-energy-at-night

[Nederland]

1. How much does it cost?

Specifically, how much does it add to the cost of a building a 100 MW plant?

[kristopher]

3. Perhaps you missed it when you read the article, but it's there.

[Nederland]

4. Yeah, I'm lazy

"$50 per kilowatt-hour to install"

And that doesn't even include the cost of 2000 acres of land.

[pleah]

2. K&R Wow. That is very interesting!

I am going to read more about this. Thanks.

I wonder if, at least, the East and West coasts could put this to use.

[OKIsItJustMe]

5. Actually, the DoE facility "Solar Two" used this technology in the 1990's

http://www.energylan.sandia.gov/sunlab/Snapshot/STFUTURE.HTM

…

Solar Two represents a new generation of solar energy technology, capable of producing clean, cost-effective, dispatchable electric power on a very large scale, without harmful pollutants or carbon emissions. Solar Two was conceived and built on the site of its predecessor, Solar One, by a consortium of U.S. utilities and industry and the Department of Energy (DOE). Over its three years of operation, Solar Two achieved its overall goal of demonstrating advanced molten-salt power tower technology developed over the past decade at a scale sufficient to allow follow-on commercialization of the technology. Plant operations successfully proved that solar energy could be collected efficiently over a broad range of operating conditions and that the low-cost energy storage system operated reliably and efficiently. This unique storage capability allowed solar energy to be collected when the sun was shining and high-value, dispatchable electric power to be generated at night or whenever demanded by the utility, even when the sun was not shining.

…

(More information):
http://www.nrel.gov/docs/fy01osti/28751.pdf
http://www.nrel.gov/docs/fy99osti/24643.pdf
http://en.wikipedia.org/wiki/The_Solar_Project#Solar_Two
http://www1.eere.energy.gov/solar/thermal_storage.html

The Spanish plant uses the technology pioneered in the US by Solar Two.

For information on a US company that's planning to use the technology, check out SolarReserve:
http://www.solar-reserve.com

[NNadir]

6. The moron Amory Lovins called this bone headed idea "just around the corner" in 1976.

That's just what we need.

A brazillion dumb millions of tons of salt sitting over a brazillion solar plants with low energy density over the world's water supplies.

Now mind you, I support molten salt nuclear reactors, but the energy density of a nuclear reactor is millions of times higher, the economics a million times better, and therefore the maintainence a million times easier.

In general, every "renewables will save us" idea is sort of like the old joke where the space program of a purported dumb country proposes a mission to the sun, preventing the heat problem by going at night.

Since there are ZERO "renewables will save us" advocates who have even passing acquaintance with the laws of thermodynamics, they all seem to have (predictably) ignored that any energy storage plan has huge external costs.

But it is also generally true that renewables will save us advocates couldn't care less about risk for their stupid little "save our cars" schemes. There are ZERO "renewbles will save us" advocates who give a rat's ass about the more than 200,000 people who died at the Banqiao dam failures in 1976, but just about everyone them has a fetish about the less than 50 who died in 1986 at Chernobyl.

[Sirveri]

7. Do you show up just to bash everything that isn't nuclear?

I mean seriously now. Parabolic mirrors and steam piping feed a steam turbine and also dump heat into a heat battery for later use at night. This is a good thing. Nuclear is nice, but that too will run out in time, we'll need everything we can get in the future once nat gas gets really expensive.

[druidity33]

9. yes.

he does.

:shrug:

[HamdenRice]

10. He is DU's most one trick of all one trick ponies

That is literally all he does. The only thing missing is he didn't say, "I note with contempt..." his one trick pony catch phrase.

[glitch]

11. From your perspective "moron" is high praise indeed. nt

[jpak]

13. The charlatan New Jersey molten salt breeder reactor is a sick delusional fraud

:rofl:

[formercia]

8. There are low temperature solutions to the problem

Utilizing the heat of crystallization and heat of hydration of some soluble salts in water, heat can be stored and extracted in a manner that creates, in effect a thermal 'battery.' Sodium and Potassium Nitrate are very corrosive and can create a fire hazard.

[DCKit]

12. Gasoline is highly dangerous too, but everyone drives around with far more...

than it would take to kill them.

The S.O. and I have a running joke: All the cars that explode three (or more) times in movies are American made, the others are cheesy imports and only ever explode once, if at all.

On Edit:

The higher the temperature, the more efficient heat exchange becomes. It's science and I think they understand the risks.

[Sirveri]

14. that's not necessarily true. It does provide higher carnot efficiency though.

It all depends on the effiency and losses to entropy., however a higher carnot value is more likely to produce a more efficient cycle. All said and done it doesn't take into account maintenance costs and how they would impact $/kwh.

[wtmusic]

15. Debunked.

"With molten salt energy storage electricity can be generated at night. Biello tells us how much electricity Andasol 1 produces - 50 MWs - the number of hours it can produce electricity - 7.5 - and its cost - $380 million. But then something goes very wrong in Biello's account. Solar Millennium AG, Andasol'sbuilder acknowledges that Andasol is currently remunerated with a feed-in tariff of just under € 0.27/kWh.

That is $0.34 a KWh. Indeed capital cost of the Andasol 1 facility is $7600 per KW, a 50% priemium over thye current high end estimate of the cost of conventional nuclear power.

Biello does not reveal this shocking cost to his readers. instead he inserts a completely misleading statement from National Renewables Energy Laboratory engineer Greg Glatzmaier suggesting that "Electricity from a solar-thermal power plant costs roughly 13 cents a kilowatt-hour, according to both with and without molten salt storage systems". This is of course utter nonsense, as anyone who would make the effort to check on the cost and generating capacity of recently constructed or proposed solar facilities."

http://nucleargreen.blogspot.com/