camelot-forum.co.uk

This looks interesting. 2-4$/kWh of storage

https://cleantechnica.com/2021/08/31/us ... re-energy/

That, on the face of it, looks an excellent, scalable, readily achievable solution. There’s plenty of Silica sand (or used to be) in Cheshire, so maybe it’s a solution that we could be self sufficient in.

An interesting idea... I would be concerned about it bridging in the silos (fancy freeing up that hot sand with a poking stick?) and the life expectancy of the heat exchangers in a jet or flow of hot sand! They will have to get quite a high flow through them to get the "steam" output needed to drive their turbines...
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The bridging is something I thought about too. It can be a big problem in grain silos. Is it a solved problem yet?

I’ve had experience of hot powder bridging (900 degrees Celsius) and have witnessed the effects of hot leaking fluidised powders. Most sand is basically silica, but I expect they are talking fairly pure silica sand for this.

26GWh is a lot of (heat) energy (compare to Dinorwig at 9.1GWh gravitational) and is about the equivalent size (cannot expect to operate the turbines in closed circuit? I wonder how much sand that would required to be stored for that (yes I could work it out!), but certainly quite a lot.

Certainly not a domestic system - but there was a high temperature heat store described on the recent fully charged series of home energy storage.

An interesting concept…