A cavern pressure control method includes storing compressible and possibly incompressible fluids in an underground storage volume, removing a portion or introducing additional incompressible fluid into the underground storage volume, possibly removing a portion or introducing additional compressible fluid into the underground storage volume, thereby producing a net pressure increase rate (P.sub.inc) within the underground storage volume, wherein P.sub.inc is maintained at less than a predetermined maximum increase value (PI.sub.max).

Disclosed herein are methods and systems for storing and withdrawing a light gas such as helium or hydrogen in an underground formation. The method includes pumping a cryogenic liquid stream to produce a pumped liquid stream, and vaporizing the pumped liquid stream to produce a first-high pressure gas steam. The method further includes feeding the first high-pressure gas stream to a gas storage cavern.