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Sable-Keech t1_j1d3ygb wrote

That’s called concentrated solar power, and it uses a lot of mirrors to focus the sun’s heat onto a bunch of salt to melt it down and use it to generate electricity.

Apparently its efficiency is similar to that of solar panels. But it should be cheaper since you don’t need expensive materials for all the solar panels, only normal mirrors.

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Phat_Potatoes OP t1_j1d4ljk wrote

Why isn't it more hyped and spread?

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Sable-Keech t1_j1d4sk0 wrote

It doesn’t scale down well. 1 solar panel can generate power, but for the CSP it needs a very large central heat engine and lots of mirrors surrounding it to focus light at the center.

It’s also very water intensive, which is seen as a waste because it needs to be put in places with a lot of sun, which tend to be dry and water scarce.

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Kowaluu t1_j1dke0v wrote

I would imagine CSP plants to be operating as ORC Organic rankine cycle) plants as they can achieve evaporation in lower temperatures and dont need water in their circulation.

CSP plants also have added benefit that can be used in some sort of heat storage solutions which would enable production in cloudy/ night times. I remember reading that the material heated in focal towers is some salt that actually melts there.

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kilotesla t1_j1fxjsd wrote

There was a lot of interest and excitement about it a while ago, maybe 15 years ago. What made people generally turn away from it was simply that silicon solar cells and panels got less expensive really fast, so even though when solar thermal electric power projects looked like they'd be competitive, by the time they were finished, the silicon solar cells were so much cheaper that they were no longer competitive.

However, the need for storage is leaving to renewed interest: storing heat can be cheaper than storing electricity.

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