The disclosed device is for storing energy by means of a flywheel. The device comprises a solid rotor having embedded permanent magnets along its outer surface, with flywheels attached at each end. The rotor is suspended by magnetic bearings within a housing. The housing comprises electromagnets that are sequentially charged in order to cause the rotor to spin due to the interaction of the electromagnets with the facing permanent magnets on the rotor. The spinning of the rotor causes the flywheels to spin, which results in the storage of rotational energy. The flywheels, which include magnets, turn through sets of coils on either end of the housing, thereby operating as an electrical generator to convert the flywheel rotational energy into electrical energy output from the device.