Abstract: In various embodiments, lined underground reservoirs and/or insulated pipeline vessels are utilized for storage of compressed fluid in conjunction with energy storage and recovery systems.

Abstract: The invention relates to systems and methods for rapidly and isothermally expanding and compressing gas in energy storage and recovery systems that use open-air hydraulic-pneumatic cylinder assemblies, such as an accumulator and an intensifier in communication with a high-pressure gas storage reservoir on a gas-side of the circuits and a combination fluid motor/pump, coupled to a combination electric generator/motor on the fluid side of the circuits. The systems use heat transfer subsystems in communication with at least one of the cylinder assemblies or reservoir to thermally condition the gas being expanded or compressed.

Abstract: In various embodiments, lined underground reservoirs and/or insulated pipeline vessels are utilized for storage of compressed fluid in conjunction with energy storage and recovery systems.

Abstract: In various embodiments, foam is compressed to store energy and/or expanded to recover energy.

Abstract: In various embodiments, lined underground reservoirs and/or insulated pipeline vessels are utilized for storage of compressed fluid in conjunction with energy storage and recovery systems.

Abstract: In various embodiments, efficiency of energy storage and recovery systems compressing and expanding gas is improved via heat exchange between the gas and a heat-transfer fluid.

Abstract: In various embodiments, cylinder assemblies are coupled in series pneumatically, thereby reducing a range of force produced by or acting on the cylinder assemblies during expansion or compression of a gas.

Abstract: In various embodiments, energy is stored or recovered via super-atmospheric compression and/or expansion of gas in conjunction with substantially adiabatic compression and/or expansion from or to atmospheric pressure.

Abstract: In various embodiments, dead space and associated coupling losses are reduced in energy storage and recovery systems employing compressed air.

Abstract: In various embodiments, compressed-gas energy storage and recovery systems feature one or more valves, which may be disposed within end caps of cylinder assemblies in which gas is expanded and/or compressed, for admitting fluid to and/or exhausting fluid from the cylinder assembly.

Abstract: In various embodiments, energy-storage systems are based upon an open-air arrangement in which pressurized gas is expanded in small batches from a high pressure of, e.g., several hundred atmospheres to atmospheric pressure. The systems may be sized and operated at a rate that allows for near isothermal expansion and compression of the gas.

Abstract: In various embodiments, foam is compressed to store energy and/or expanded to recover energy.

Abstract: In various embodiments, gas is compressed to store energy and/or expanded to recover energy to or from high pressures, and the gas is exchanges heat with a heat-exchange fluid that is thermally conditioned at low pressures.

Abstract: In various embodiments, energy is stored or recovered via super-atmospheric compression and/or expansion of gas in conjunction with substantially adiabatic compression and/or expansion from or to atmospheric pressure.

Abstract: In various embodiments, efficiency of energy storage and recovery systems compressing and expanding gas is improved via heat exchange between the gas and a heat-transfer fluid.

Abstract: In various embodiments, a mechanical assembly and/or storage vessel is fluidly coupled to a circulation apparatus for receiving pressurized heat-transfer fluid from an outlet at a first elevated pressure, boosting a pressure of the heat-transfer fluid to a second pressure larger than the first pressure, and returning heat-transfer fluid to an inlet at a third pressure.

Abstract: In various embodiments, cylinder assemblies are coupled in series pneumatically, thereby reducing a range of force produced by or acting on the cylinder assemblies during expansion or compression of a gas.

Abstract: In various embodiments, valve efficiency and reliability are enhanced via use of hydraulic or magnetic valve actuation, valves configured for increased actuation speed, and/or valves controlled to reduce collision forces during actuation.

Abstract: In various embodiments, valve efficiency and reliability are enhanced via use of hydraulic or magnetic valve actuation, valves configured for increased actuation speed, and/or valves controlled to reduce collision forces during actuation.

Abstract: In various embodiments, valve efficiency and reliability are enhanced via use of hydraulic or magnetic valve actuation, valves configured for increased actuation speed, and/or valves controlled to reduce collision forces during actuation.