Comment by Panzer04
10 hours ago
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.
10 hours ago
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.
The ~grid scale design of this for reference is somewhere around 200mx200mx50m for above ground, or ~100m cube (or bigger) for quarry infill. Such a design is going to get crushed by battery/hydro over the hours/days, but wins on cost for seasonal usage.
The cost of putting dirt in a pile is $1-2/ton.
so $36-72k for days of 1GW of power? Sounds pretty cheap to me ...
They also state the cost per kWh(th) of storage capacity is about $0.10, or $100,000/GWh(th). This is thermal energy, which is converted to work at maybe 40% efficiency, mind you. There are costs over and above the dirt (for example, pipes laid through the dirt to carry heat in/out).
The biggest expense will be the pipework inside that pile. That you won't be able to service easily. And you'll also need a LOT of insulation around it to prevent heat from leaking out too quickly.
Thermal storage benefits from the square/cube scaling, so the amount of insulation goes down as you scale up the storage.
The insulation is just more dirt.
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