If I got the article right, the plan is to use underground carbon stores like a battery, “charging” it by pushing carbon under that has been pulled from the air

If I got the article right, the plan is to use underground carbon stores like a battery, “charging” it by pushing carbon under that has been pulled from the air, and “discharging” by pulling it up later? That has to be one of the most inefficient ways of storing energy imaginable.