This assumes that there is excess power at some point. This will soon become unrealistic: we either need power for data centers during the day or charging vehic

This assumes that there is excess power at some point. This will soon become unrealistic: we either need power for data centers during the day or charging vehicles during the night. The solution works only to keep a steady production of electricity, but if the demand would require full output all the time then these "mechanical batteries" don't help.