A hydrostatically compensated compressed air energy storage system may include an accumulator disposed underground, a gas compressor/expander subsystem in fluid communication with the accumulator interior via an air flow path; a compensation liquid reservoir spaced apart from the accumulator and in fluid communication with the layer of compensation liquid within the accumulator via a compensation liquid flow path; and a first construction shaft extending from the surface of the ground to the accumulator and being sized and configured to i) accommodate the passage of a construction apparatus therethrough when the hydrostatically compensated compressed air energy storage system is being constructed, and ii) to provide at least a portion of one of the air flow path and the compensation liquid flow path when the hydrostatically compensated compressed air energy storage system is in use.

A compressed gas energy storage system may include an accumulator for containing a layer of compressed gas atop a layer of liquid. A gas conduit may have an upper end in communication with a gas compressor/expander subsystem and a lower end in communication with accumulator interior for conveying compressed gas into the compressed gas layer of the accumulator when in use. A shaft may have an interior for containing a quantity of a liquid and may be fluidly connectable to a liquid source/sink via a liquid supply conduit. A partition may cover may separate the accumulator interior from the shaft interior. An internal accumulator force may act on the inner surface of the partition and the liquid within the shaft may exert an external counter force on the outer surface of the partition, whereby a net force acting on the partition is less than the accumulator force.

A system and method for protecting a lightweight pressure vessel capable of airborne and underwater use. The system includes an enclosure and a gas container that is capable of holding pressurized or liquefied gas in sufficient quantity to increase internal pressure of the pressure vessel, so that the internal pressure of the pressure vessel equals an external pressure of the pressure vessel. The system also includes a pressure relief device coupled to the enclosure. The pressure relief device is configured to release the pressurized or liquefied gas from the pressure vessel when the internal pressure exceeds the external pressure by a predetermined amount. The system also includes a gas supply mechanism coupled to the gas container, the gas supply mechanism being configured to allow gas from the gas container into order to increase the internal pressure of the pressure vessel until the internal pressure equals the external pressure.

A compressed gas energy storage system may include an accumulator for containing a layer of compressed gas atop a layer of liquid. A gas conduit may have an upper end in communication with a gas compressor/expander subsystem and a lower end in communication with accumulator interior for conveying compressed gas into the compressed gas layer of the accumulator when in use. A shaft may have an interior for containing a quantity of a liquid and may be fluidly connectable to a liquid source/sink via a liquid supply conduit. A partition may cover may separate the accumulator interior from the shaft interior. An internal accumulator force may act on the inner surface of the partition and the liquid within the shaft may exert an external counter force on the outer surface of the partition, whereby a net force acting on the partition is less than the accumulator force.

A compressed gas energy storage system may include an accumulator for containing a layer of compressed gas atop a layer of liquid. A gas conduit may have an upper end in communication with a gas compressor/expander subsystem and a lower end in communication with accumulator interior for conveying compressed gas into the compressed gas layer of the accumulator when in use. A shaft may have an interior for containing a quantity of a liquid and may be fluidly connectable to a liquid source/sink via a liquid supply conduit. A partition may cover may separate the accumulator interior from the shaft interior. An internal accumulator force may act on the inner surface of the partition and the liquid within the shaft may exert an external counter force on the outer surface of the partition, whereby a net force acting on the partition is less than the accumulator force.

A pressure-compensated rupture disk assembly and method for subsea protection of a pressure vessel. The assembly and method incorporate a piston device, a dynamic piston seal configured to move the piston device when a predetermined pressure is reached; and a rupture disk adjacent the piston device, the rupture disk having a first pressure on a piston side and a second pressure on a second side, the rupture disk being configured to open when a predetermined pressure is exceeded.

A system and method for protecting a lightweight pressure vessel capable of airborne and underwater use. The system includes an enclosure and a gas container that is capable of holding pressurized or liquefied gas in sufficient quantity to increase internal pressure of the pressure vessel, so that the internal pressure of the pressure vessel equals an external pressure of the pressure vessel. The system also includes a pressure relief device coupled to the enclosure. The pressure relief device is configured to release the pressurized or liquefied gas from the pressure vessel when the internal pressure exceeds the external pressure by a predetermined amount. The system also includes a gas supply mechanism coupled to the gas container, the gas supply mechanism being configured to allow gas from the gas container into order to increase the internal pressure of the pressure vessel until the internal pressure equals the external pressure.

A hydrogen gas compression system comprises a hydrogen storage chamber placed at a predetermined water depth in water to communicate with surrounding water; a hydrogen container filled with hydrogen gas by a lower pressure than a hydraulic pressure at the predetermined water depth; a transporting portion configured to guide the hydrogen container that is filled with the hydrogen gas, from above the predetermined water depth to the hydrogen storage chamber; a gas release portion configured to cause the hydrogen gas to be released from the hydrogen container transported to the hydrogen storage chamber and to be stored in the hydrogen storage chamber; a hydrogen recovery device placed above the predetermined depth; and a tube arranged to connect inside of the hydrogen storage chamber with the hydrogen recovery device.

A modular subsea fluid storage unit has a variable-volume inner tank having a rigid top panel and a peripheral wall that is flexible by virtue of concertina formations. The peripheral wall is extensible and retractable vertically while the horizontal width of the tank remains substantially unchanged. A side wall of a lower housing part surrounds and is spaced horizontally from the peripheral wall of the inner tank to define a floodable gap between the peripheral wall and the side wall that surrounds the tank. An upper housing part extends over and is vertically spaced from the top panel of the inner tank and overlaps the side wall to enclose the inner tank. The floodable gap and the upper housing part enhance thermal insulation and trap any fluids that may leak from the inner tank.

A compressed gas energy storage system may include an accumulator for containing a layer of compressed gas atop a layer of liquid. A gas conduit may have an upper end in communication with a gas compressor/expander subsystem and a lower end in communication with accumulator interior for conveying compressed gas into the compressed gas layer of the accumulator when in use. A shaft may have an interior for containing a quantity of a liquid and may be fluidly connectable to a liquid source/sink via a liquid supply conduit. A partition may cover may separate the accumulator interior from the shaft interior. An internal accumulator force may act on the inner surface of the partition and the liquid within the shaft may exert an external counter force on the outer surface of the partition, whereby a net force acting on the partition is less than the accumulator force.