alt Hacker NewsI just don't see it with thermal. You have to pay the Carnot tax, and you also need humongous amounts of material.
E.g. 100 GWh (4 days of 1GW thermal power) with a 100C temperature swing (you can't go down all the way to room temperature) will need around 3.6*10^4 tons of sand. That's a lot.
Honestly, power-to-gas sounds like the only reasonable way for now. In theory, with SOFC (Solid Oxide Fuel Cells) for power generation, it can beat the steam cycle.
Replies
Panzer04 • today at 1:06 AM
36000 tons... doesn't actually sound like that much? That's a ~30x30m cube of dirt.
But I have no reference for the cost of setting up such a storage and how it compares to battery or hydro.
➕ show 2 replies
The temperature swing can be much greater than 100 C. Heat can be extracted as a wave passing through the store, then heat added back by reversing the flow. It would operate like a counterflow heat exchanger.
View another way: if we hook several piles in series, then lukewarm air from a first mostly discharged pile can be directed into later piles for more heating. In the continuous limit this is the concept I described above.