A multistage cryogenic liquefied gas expander having at least two stages for transforming the energy of a pressurized liquefied gas into electric energy each stage having a pressure containment vessel with an inlet flow entrance located at the lower part of the pressure containment vessel and an outlet flow exit located at the upper part of the pressure containment vessel, the pressure containment vessel enclosing a hydraulic assembly, an electric induction generator and a drive shaft, the drive shaft transferring rotational torque energy from the hydraulic assembly to the electric induction generator, and the drive shaft capable of rotating at a constant speed or a variable speed, wherein the hydraulic assembly consists of a hydraulic assembly housing enclosing a nozzle ring that provides an entrance for the pressurized liquefied gas from within the pressure containment vessel into the hydraulic assembly, the nozzle ring having a plurality of fixed position guide vanes that directs the pressurized liquefied gas to a radial inflow turbine runner, the radial inflow turbine runner is affixed to and provides a first portion of the rotational torque energy to the drive shaft, and directs the pressurized liquefied gas to a jet exducer, the jet exducer is affixed to and provides a second portion of the rotational torque energy to the drive shaft and directs a liquefied gas transformed from the pressurized liquefied gas to the outlet flow exit of the pressure containment vessel, characterized in that: said multistage cryogenic liquefied gas expander capable of operating at variable speeds having at least two stages where only the first stage has a non-rotating nozzle ring having a plurality of adjustable position guide vanes, each adjustable position guide vane having an outer end and an inner end, the outer end having a sliding groove formed therein where the outer end adjoins movably to a rotatable ring base, the inner end pivotally adjoined to a non-movable base, the outer end of each adjustable position guide vane capable of being repositioned by a guide vane adjustment mechanism, the guide vane adjustment mechanism having a gear screw affixed to the rotatable ring base, a gear screw rod engaged to the gear screw, and a handle engaged to the gear screw rod, where rotation of the handle causes the gear screw to move the rotatable ring base, each pair of the adjustable position guide vanes forming a channel extending from the outer end to the inner end of each pair of adjustable position guide vanes, wherein movement of the rotatable ring base results in the outer end of each adjustable position guide vane to move altering a width of the channel between adjacent inner ends of each pair of adjustable position guide vanes. said multistage cryogenic liquefied gas expander capable of operating at variable speeds having at least two stages where only the first stage has a non-rotating nozzle ring having a plurality of adjustable position guide vanes, each adjustable position guide vane having an outer end and an inner end, the outer end having a sliding groove formed therein where the outer end adjoins movably to a rotatable ring base, the inner end pivotally adjoined to a non-movable base, the outer end of each adjustable position guide vane capable of being repositioned by a guide vane adjustment mechanism, the guide vane adjustment mechanism having a gear screw affixed to the rotatable ring base, a gear screw rod engaged to the gear screw, and a handle engaged to the gear screw rod, where rotation of the handle causes the gear screw to move the rotatable ring base, each pair of the adjustable position guide vanes forming a channel extending from the outer end to the inner end of each pair of adjustable position guide vanes, wherein movement of the rotatable ring base results in the outer end of each adjustable position guide vane to move altering a width of the channel between adjacent inner ends of each pair of adjustable position guide vanes.