5 ms·

A Tower of Molten Salt Will Deliver Solar Power After Sunset

63 points by robszumski 11y ago

robszumski 11y ago
The most interesting part of a facility like this is that it takes up the same amount of space as a regular field of solar, but it much more efficient. The trade off though, is the huge tower, which doesn't lend itself to more populated areas.
- dredmorbius 11y ago
  CSP works best where your sunlight is intense and rarely obstructed by clouds, fog, haze, dust, etc. Pretty much desert. Which is precisely where you don't find a whole lot of people. Cooling systems (for the cold end of your Carnot cycle) are a challenge if water's limited, though there's no reason generally nonpotable water, even salt water, could be used for the open loop.
Animats 11y ago
It will be interesting to see how the numbers work out. This has been proposed before, but not built at full scale.
- IndianAstronaut 11y ago
  This technology is actively in use in Spain. http://www.economist.com/node/13725855 http://www.economist.com/node/13725855
lifeisstillgood 11y ago
Fantastically the UK just signed an agreement with China to let China build a fission plant in the most populous south east, with the usual capital cost and total lack of realistic decommissioning plans, and still the price planned for the next thirty years is already above all our other sources Nice to know the govt. is still on the ball /sarcasm
cinquemb 11y ago
That is, unless declining battery costs make storing PV power more economical. James Nelson, a California-based energy modeler with the Union of Concerned Scientists, says this intrasolar race will be good for the environment: “I’m glad we have multiple technologies that can help the transition from gas power plants.” I agree with his remarks in principle, but really, there is far more abundant Na/K in the earths crust than the currently touted Li. And the Li would probably go to better use in ~65C melting point salts(by weight LiNO3 5%,NaNO3 6%,KNO3 23%,CsNO3 44%, Ca(NO3)2 19%, although the Cs would be the limiting resource if the competition for Li usage wasn't there)[0]. [0] http://moscow.sci-hub.bz/9b519cf6102a9b10fc60ce9035594865/raade2011.pdf?download=true http://moscow.sci-hub.bz/9b519cf6102a9b10fc60ce9035594865/ra...
dredmorbius 11y ago
In a world of _very_ poor options for energy storage, molten salt seems to be, from very rough calculations, something which might scale to what Tom Murphy ("Do the Math") refers to as a "nation-scale battery" -- up to two weeks of stored generation capacity. My own very naive and rough back-of-the-napkin calculations suggest that a total thermal storage facility roughly comparable with existing US oil storage tanks in Oklahoma could provide that capacity. More generally, the strength of molten salt is to even out supply to variability in either demand or incident sunlight. Note also that concentrated solar power requires _concentration_ -- you cannot focus _diffuse_ light (e.g., hazy or overcast conditions), though PV still delivers some power under such circumstances. But PV is instantaneous, and other storage options -- batteries, pumped hydro, compressed air energy storage (CAES), flywheels -- are either limited by material and/or sites, or by costs or engineering challenges. Salts are plentiful, as are insulating options. Thermal energy systems are well understood. The concept is inherently distributable (no need to put it all in one spot), and, modulo spills, generally environmentally benign. https://www.reddit.com/r/dredmorbius/comments/1viied/grid_scale_thermal_energy_storage_this_might_work/ https://www.reddit.com/r/dredmorbius/comments/1viied/grid_sc...
- david-given 11y ago
  That's electricity only, though, right? The last time I looked at numbers that was a third of actually energy consumption, the rest going for heat and transport. (That was for the UK.) Not that I'm saying liquid-salt batteries is are a bad thing; if they work, they'll fill a much-needing-filling hole in our energy infrastructure. But they only solve a small part of the problem.
  - tedsanders 11y ago
    Right, hot thermal storage is used to store electricity. And yes, hot thermal storage does not solve the world's energy problems by itself. To your point about electricity being 1/3 of energy consumption, I still think it's important to celebrate and invest in technologies that store electricity. Even though electricity is just one part of the energy picture, electricity is far more expensive to store than other kinds of energy such as liquid fuel (which can be stored in barrels and tanks), natural gas (which can be stored in the ground or in tanks), or solid energy sources like coal or nuclear (which can just sit in a box).
talos 11y ago
Yes, they're finally building the solar plant from SimCity 2000!
- Terr_ 11y ago
  Even on turtle-speed, the sun always shines -- must be a city-ordinance.
Gustomaximus 11y ago
There is a plant using molten salt storage in Spain since 2009 if interested; https://en.wikipedia.org/wiki/Andasol_Solar_Power_Station https://en.wikipedia.org/wiki/Andasol_Solar_Power_Station

63 points by robszumski 11y ago

The most interesting part of a facility like this is that it takes up the same amount of space as a regular field of solar, but it much more efficient. The trade off though, is the huge tower, which doesn't lend itself to more populated areas.

dredmorbius 11y ago
CSP works best where your sunlight is intense and rarely obstructed by clouds, fog, haze, dust, etc. Pretty much desert. Which is precisely where you don't find a whole lot of people. Cooling systems (for the cold end of your Carnot cycle) are a challenge if water's limited, though there's no reason generally nonpotable water, even salt water, could be used for the open loop.

Animats 11y ago

It will be interesting to see how the numbers work out. This has been proposed before, but not built at full scale.

IndianAstronaut 11y ago
This technology is actively in use in Spain. http://www.economist.com/node/13725855 http://www.economist.com/node/13725855

lifeisstillgood 11y ago

Fantastically the UK just signed an agreement with China to let China build a fission plant in the most populous south east, with the usual capital cost and total lack of realistic decommissioning plans, and still the price planned for the next thirty years is already above all our other sources Nice to know the govt. is still on the ball /sarcasm

cinquemb 11y ago

That is, unless declining battery costs make storing PV power more economical. James Nelson, a California-based energy modeler with the Union of Concerned Scientists, says this intrasolar race will be good for the environment: “I’m glad we have multiple technologies that can help the transition from gas power plants.” I agree with his remarks in principle, but really, there is far more abundant Na/K in the earths crust than the currently touted Li. And the Li would probably go to better use in ~65C melting point salts(by weight LiNO3 5%,NaNO3 6%,KNO3 23%,CsNO3 44%, Ca(NO3)2 19%, although the Cs would be the limiting resource if the competition for Li usage wasn't there)[0]. [0] http://moscow.sci-hub.bz/9b519cf6102a9b10fc60ce9035594865/raade2011.pdf?download=true http://moscow.sci-hub.bz/9b519cf6102a9b10fc60ce9035594865/ra...

dredmorbius 11y ago

In a world of _very_ poor options for energy storage, molten salt seems to be, from very rough calculations, something which might scale to what Tom Murphy ("Do the Math") refers to as a "nation-scale battery" -- up to two weeks of stored generation capacity. My own very naive and rough back-of-the-napkin calculations suggest that a total thermal storage facility roughly comparable with existing US oil storage tanks in Oklahoma could provide that capacity. More generally, the strength of molten salt is to even out supply to variability in either demand or incident sunlight. Note also that concentrated solar power requires _concentration_ -- you cannot focus _diffuse_ light (e.g., hazy or overcast conditions), though PV still delivers some power under such circumstances. But PV is instantaneous, and other storage options -- batteries, pumped hydro, compressed air energy storage (CAES), flywheels -- are either limited by material and/or sites, or by costs or engineering challenges. Salts are plentiful, as are insulating options. Thermal energy systems are well understood. The concept is inherently distributable (no need to put it all in one spot), and, modulo spills, generally environmentally benign. https://www.reddit.com/r/dredmorbius/comments/1viied/grid_scale_thermal_energy_storage_this_might_work/ https://www.reddit.com/r/dredmorbius/comments/1viied/grid_sc...

david-given 11y ago
That's electricity only, though, right? The last time I looked at numbers that was a third of actually energy consumption, the rest going for heat and transport. (That was for the UK.) Not that I'm saying liquid-salt batteries is are a bad thing; if they work, they'll fill a much-needing-filling hole in our energy infrastructure. But they only solve a small part of the problem.
- tedsanders 11y ago
  Right, hot thermal storage is used to store electricity. And yes, hot thermal storage does not solve the world's energy problems by itself. To your point about electricity being 1/3 of energy consumption, I still think it's important to celebrate and invest in technologies that store electricity. Even though electricity is just one part of the energy picture, electricity is far more expensive to store than other kinds of energy such as liquid fuel (which can be stored in barrels and tanks), natural gas (which can be stored in the ground or in tanks), or solid energy sources like coal or nuclear (which can just sit in a box).

talos 11y ago

Yes, they're finally building the solar plant from SimCity 2000!

Terr_ 11y ago
Even on turtle-speed, the sun always shines -- must be a city-ordinance.

Gustomaximus 11y ago

There is a plant using molten salt storage in Spain since 2009 if interested; https://en.wikipedia.org/wiki/Andasol_Solar_Power_Station https://en.wikipedia.org/wiki/Andasol_Solar_Power_Station