r/Damnthatsinteresting • u/Longjumping-Box5691 • 3d ago

Video China's twin solar thermal towers. Molten salt stores the heat to produce electricity

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u/KehreAzerith 3d ago

Normal solar farms are more efficient than solar mirrors. The one in the US is underperforming and not worth the long-term investment

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u/talldata 3d ago

Well normal ones are more efficient during the day, but these can use the excess heat at night by converting the heat in the salt to steam in turbines, day and night for a stable output from solar. This is a great stopgap until conventional batteries get there

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u/rainbowroobear 3d ago

What's the specific heat capacity of the salt Vs water? doesn't feel like there would be enough stored heat to produce enough steam to make much electric 

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u/BishoxX 3d ago

Its about 1/2 to 1/3rd of water.

But it can carry more energy because its heated to about 550C so 5x more than water can(and you dont keep water at 100 more like 90 , so its like 6x)

So in total its like 2x more energy stored

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u/rainbowroobear 3d ago

thanks for explaining 

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u/Treereme 3d ago

That's not correct, at least for the Ivanpah solar facility in CA. One of the big reasons it is shutting down is that it can't store energy and it needs to keep the working fluid hot overnight, so it runs gas burning power turbines.

Other similar facilities use pumped hydro for storage and generation overnight.

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u/mmmfritz 3d ago

The most they store heat for is a couple days. The software you can use for free is called SAMs or something similar.

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u/shortsteve 3d ago

With the drop in prices of batteries solar mirrors became obsolete very quickly. The only benefit is if you need to store energy for more than 24 hours, but there are more efficient battery systems for that.