"Surely if it's buried, as seems to be the general consensus for cheapest mode of safe deployment, then it doesn't shake?"
The ground occasionally shakes, depending on where you are.
The Earth also rotates on its axis. And with the speeds and energies with which grid storage flywheels operate, that's a significant engineering concern.
The real killer though is cost / KWh of energy storage. For Beacon's designs it's about $10,000/KWh capacity (not $1000/Wh as I wrote above). Which is high. Liquid metal or molten salt batteries, or simple thermal storage (again, likely salt) could likely compete with this.
> The Earth also rotates on its axis. And with the speeds and energies with which grid storage flywheels operate, that's a significant engineering concern.
You can align the angle of the flywheel to match the angle of the earth at your latitude, which helps with that. However if you do that the flywheel is titled, so the bearings are uneven, and then you need some shielding above the flywheel - you can't just have the earth be the walls.
But it means that the bearings experience much less force, so it can be worth it.
The ground occasionally shakes, depending on where you are.
The Earth also rotates on its axis. And with the speeds and energies with which grid storage flywheels operate, that's a significant engineering concern.
The real killer though is cost / KWh of energy storage. For Beacon's designs it's about $10,000/KWh capacity (not $1000/Wh as I wrote above). Which is high. Liquid metal or molten salt batteries, or simple thermal storage (again, likely salt) could likely compete with this.