Probably a stupid car question...

[kandrathe]

Except you're probably doing more environmental harm by doing this because it takes power being produced somewhere else that is probably polluting the environment more than if you stored it in a battery system.

Yeah, that is true. Wrapping that into what Pete last wrote above, unless you use local "Green" sources, or "wasted" energy to drive the pumps at night then the value of re-establishing the potential is dubious.

If you think about huge solar power arrays being proposed, it makes more sense for huge solar arrays to store excess power as heat in huge hyper-insulated vats of molten salt.

Generally, anytime you consume a fuel to generate unneeded power, and then attempt to store it for use later you are introducing another layer of inefficiency, and capital expense. Even with "backup power" for computer rooms, battery storage is so expensive that we only have minutes of capacity (10 minutes in our case). In most cases, battery power acts as a buffer for intermittent power dips and spikes, and it gives the backup generator enough time to automatically fire up, alert someone in case of error, and for a local operator to manually intervene to get power restored.

The more SciFy approach I would propose would be to look into the work of Chunlei Guo, and his femtolaser technology. He has developed a laser etching technique where he can cause the surfaces of metals to exhibit capillary action. It should be possible to create mass produce structures of nanotubes that would "pump" the water uphill without need for powered pumps. Although, a side effect would be (the need for) extreme filtration.