Abstract: A subterranean energy storage system configured to store and subsequently release potential energy. Storage of potential energy is achieved by the transfer of a pseudo fluid from a first storage tank to a second storage tank located above the first storage tank, and is subsequently released by the transfer of the pseudo fluid from the second storage tank to the first storage tank. To transfer the pseudo fluid between the first and second storage tanks, the subterranean energy storage system comprises at least one continuous conveyor mechanism extending through at least one transport shaft, wherein the at least one continuous conveyor mechanism comprises a plurality of vessels arranged along a length of the continuous conveyor mechanism. The subterranean energy storage system further comprises an energy transfer means operably connected to the at least one continuous conveyor mechanism to transfer power to and from the subterranean energy storage system.