Engineering360: "Long-duration renewable energy storage is cost-competitive"

Tremors? Earthquakes? Intrinsically, this process would raise and lower the earth (not Earth) and I would be surprised if there were not side effects similar to the issues where the earth in California's central valley is sinking due to the removal of water from the aquifers for irrigation.

Sounds similar to compressed air energy storage, which has been around for awhile but doesn't seem to have caught on.

The fundamental flaw with compressed air storage is the thermodynamic issues with pressurization and de-pressurization and resultant energy losses. There have been some very complicated schemes to try to use/recover the heat, but again, this concept violates the KISS principles and is impractical to implement in other than academic exercises.