An energy storage system comprises at least one cryogen storage device that includes a subcooling loop and that is configurable to store a cryogen with or without boil-off losses. The system also comprises a cryoplant configured to interact with a power source and with the subcooling loop of the at least one cryogen storage device. The system also includes a control system configured to control the interaction of the cryoplant with the power source and the at least one cryogen storage device. The control system is configured to control interaction of the cryoplant with the power source and the at least one cryogen storage device according to a plurality of operational modes, including: a cooling mode, a passive storage mode, a fuel cell backup mode, and a liquefaction mode.