<p>An integral compressor-expander assembly, including a cryogenic expander positioned in an overhung configuration on a central shaft; a multi-stage centrifugal compressor supported on the central shaft between at least two bearings; and a device coupled to the central shaft and configured to either supply rotational power to the central shaft or generate power from rotation of the central shaft, depending upon a current operational mode of the multi-stage compressor.</p>
