Abstract: Disclosed herein is an isothermal liquid piston natural gas compression and expansion system for storing and retrieving energy in large quantities that employs an existing infrastructure embodied in the natural gas pipeline and storage system, including the natural gas as a medium for the storage and retrieval of pressure energy for large scale sustainable energy storage.

Abstract: Disclosed herein is an isothermal liquid piston natural gas compression and expansion system for storing and retrieving energy in large quantities that employs an existing infrastructure embodied in the natural gas pipeline and storage system, including the natural gas as a medium for the storage and retrieval of pressure energy for large scale sustainable energy storage.

Abstract: Disclosed herein is a system including a generator/motor subsystem configured to interchangeably impart and receive mechanical force; a stiff DC bus; and power conditioning circuitry electrically connected between the generator/motor subsystem and the stiff DC bus, the power conditioning circuitry conditioning electrical power received from the stiff DC bus to control the angular speed of a rotor of the generator/motor subsystem when imparting mechanical force, and also conditioning electrical power generated for provision to the stiff DC bus by the generator/motor subsystem when receiving mechanical force.

Abstract: Disclosed herein is a system for storing and releasing energy, comprising a generator/motor subsystem; a hydraulic pump for pumping hydraulic fluid between first and second pump ports in response to force applied by the generator/motor subsystem and also capable of imparting force to the generator/motor subsystem in response to hydraulic fluid being caused to flow between the first and second pump ports; a first compression/expansion vessel for exchanging hydraulic fluid with the hydraulic pump via the first pump port; a second compression/expansion vessel for exchanging hydraulic fluid with the hydraulic pump via the second pump port; a gas storage subsystem for selectively storing gas from, or releasing gas to, the first and second gas compression/expansion vessels; an internal heat exchanger within each of the first and second compression/expansion vessels for exchanging heat between the hydraulic fluid and the gas therein, each internal heat exchanger having a very large thermal mass relative to the mass

Abstract: Disclosed herein is a system for storing and releasing energy, comprising a generator/motor subsystem; a hydraulic pump for pumping hydraulic fluid between first and second pump ports in response to force applied by the generator/motor subsystem and also capable of imparting force to the generator/motor subsystem in response to hydraulic fluid being caused to flow between the first and second pump ports; a first compression/expansion vessel for exchanging hydraulic fluid with the hydraulic pump via the first pump port; a second compression/expansion vessel for exchanging hydraulic fluid with the hydraulic pump via the second pump port; a gas storage subsystem for selectively storing gas from, or releasing gas to, the first and second gas compression/expansion vessels; an internal heat exchanger within each of the first and second compression/expansion vessels for exchanging heat between the hydraulic fluid and the gas therein, each internal heat exchanger having a very large thermal mass relative to the mass