Hydrostatically Compensated Compressed Gas Energy Storage System

A compressed gas energy storage system comprising:

• a) an accumulator having a primary opening, an upper wall, a lower wall and an accumulator interior at least partially bounded the upper wall and lower wall, the accumulator for containing a layer of compressed gas atop a layer of liquid when in use;
• b) a gas compressor/expander subsystem spaced apart from the accumulator and a gas supply conduit having an upper end in communication with the 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;
• c) a shaft having a lower end adjacent the primary opening, an upper end spaced apart from the lower end, and a shaft sidewall extending upwardly from the lower end to the upper end and at least partially bounding a shaft interior for containing a quantity of a liquid, the shaft being fluidly connectable to a liquid source/sink via a liquid supply conduit;
• d) a partition covering the primary opening and separating the accumulator interior from the shaft interior, the partition having an outer surface in communication with the shaft interior and an opposing inner surface in communication with the accumulator interior;
• e) wherein at least one of the layer of compressed gas and the layer of liquid bears against and exerts an internal accumulator force on the inner surface of the partition and the quantity of liquid within the shaft bears against and exerts an external counter force on the outer surface of the partition, whereby a net force acting on the partition while the compressed gas energy storage system is in use is a difference between the accumulator force and the counter force and is less than the accumulator force.

A compressed gas energy storage system comprising:

• a) an accumulator having a primary opening, an upper wall, a lower wall and an accumulator interior at least partially bounded the upper wall and lower wall, the accumulator for containing a layer of compressed gas atop a layer of liquid when in use;
• b) a gas compressor/expander subsystem spaced apart from the accumulator and a gas conduit having an upper end in communication with the gas compressor/expander subsystem and a lower end in communication with accumulator interior for conveying compressed gas between the compressed gas layer in the accumulator and the compressor/expander subsystem;
• c) a shaft having a lower end adjacent the primary opening, an upper end spaced apart from the lower end, and a shaft sidewall extending upwardly from the lower end to the upper end and at least partially bounding a shaft interior for containing a quantity of a liquid, the shaft being fluidly connectable to a liquid source/sink via a liquid supply conduit;
• d) at least a first compression heat exchanger that is configured to exchange heat between gas being conveyed into the gas compressor/expander subsystem and the quantity of liquid contained within the shaft;
• e) a partition covering the primary opening and separating the accumulator interior from the shaft interior, the partition having an outer surface in communication with the shaft interior and an opposing inner surface in communication with the accumulator interior;
• wherein at least one of the layer of compressed gas and the layer of liquid bears against and exerts an internal accumulator force on the inner surface of the partition and the quantity of liquid within the shaft bears against and exerts an external counter force on the outer surface of the partition, whereby a net force acting on the partition while the compressed gas energy storage system is in use is a difference between the accumulator force and the counter force and is less than the accumulator force.

A compressed gas energy storage system comprising:

• a) an accumulator having a primary opening, an upper wall, a lower wall and an accumulator interior at least partially bounded the upper wall and lower wall, the accumulator for containing a layer of compressed gas atop a layer of liquid when in use;
• b) a gas compressor/expander subsystem spaced apart from the accumulator and a gas conduit having an upper end in communication with the gas compressor/expander subsystem and a lower end in communication with accumulator interior for conveying compressed gas into the compressed gas layer;
• c) a shaft having a lower end adjacent the primary opening, an upper end spaced apart from the lower end, and a shaft sidewall extending upwardly from the lower end to the upper end and at least partially bounding a shaft interior containing a quantity of a liquid, the shaft being fluidly connectable to a liquid source/sink via a liquid supply conduit;
• d) a thermal storage subsystem provided in fluid communication between the gas compressor/expander subsystem and the accumulator, whereby thermal energy is extracted from the compressed gas exiting the gas compressor/expander subsystem at an exit temperature and stored in the thermal storage subsystem and the temperature of the gas exiting the thermal storage subsystem is reduced to a storage temperature that is less than the exit temperature;
• e) a partition positioned at the lower end of the shaft and covering the primary opening and separating the accumulator interior from the shaft interior, the partition having an outer surface in communication with the shaft interior and an opposing inner surface in communication with the accumulator interior;
• wherein at least one of the layer of compressed gas and the layer of liquid bears against and exerts an internal accumulator force on the inner surface of the partition and the quantity of liquid within the shaft bears against and exerts an external counter force on the outer surface of the partition, whereby a net force acting on the partition while the compressed gas energy storage system is in use is a difference between the accumulator force and the counter force and is less than the accumulator force.

A compressed gas energy storage system comprising:

• a) an accumulator having a primary opening, an upper wall, a lower wall and an accumulator interior at least partially bounded the upper wall and lower wall, the accumulator containing a layer of compressed gas atop a layer of liquid;
• b) a gas compressor/expander subsystem having a least a first compressor that is spaced apart from the accumulator and a first expansion stage,
• c) a first gas conduit having an upper end in communication with the first compression stage and a lower end in communication with a first location in the accumulator interior for conveying compressed gas into the compressed gas layer;
• d) a shaft having a lower end adjacent the primary opening, an upper end spaced apart from the lower end, and a shaft sidewall extending upwardly from the lower end to the upper end and at least partially bounding a shaft interior containing a quantity of a liquid, the shaft being fluidly connectable to a liquid source/sink via a liquid supply conduit;
• e) a partition positioned at the lower end of the shaft and covering the primary opening and separating the accumulator interior from the shaft interior, the partition having an outer surface in communication with the shaft interior and an opposing inner surface in communication with the accumulator interior;
• wherein at least one of the layer of compressed gas and the layer of liquid bears against and exerts an internal accumulator force on the inner surface of the partition and the quantity of liquid within the shaft bears against and exerts an external counter force on the outer surface of the partition, whereby a net force acting on the partition while the compressed gas energy storage system is in use is a difference between the accumulator force and the counter force and is less than the accumulator force.