A thermal storage subsystem may include at least a first storage reservoir configured to contain a thermal storage liquid at a storage pressure that is greater than atmospheric pressure. A liquid passage may have an inlet connectable to a thermal storage liquid source and configured to convey the thermal storage liquid to the liquid reservoir. A first heat exchanger may be provided in the liquid inlet passage and may be in fluid communication between the first compression stage and the accumulator, whereby thermal energy can be transferred from a compressed gas stream exiting a gas compressor/expander subsystem to the thermal storage liquid.

A hydraulic compressed air energy storage system includes air and liquid tanks, each of which includes interdependent volumes of liquid and air. Each tank includes dedicated passages through which incoming air may be fed, forcing outflow of liquid, or incoming liquid may be fed, forcing outflow of air. Compressed air tanks are connected to a first group of the air and liquid tanks. The system further includes a pump and a liquid turbine, the liquid turbine being electrically connected to a generator for generating electric power. During charging of the system, liquid is pumped through the first group of air and liquid tanks, and air is expelled from the first group of air and liquid tanks and compressed in the compressed air tanks. During discharging of the system, compressed air is released from the compressed air tanks, and said compressed air pumps liquid through the liquid turbine, thereby generating electricity.

An apparatus in the form of a subterranean storage container configured to store a volume of a small molecular gas, such as hydrogen or methane. In some embodiments, a casing is arranged to extend into a subterranean formation. A top end of the casing is connected to a top cap structure. The top cap structure includes an adapter flange connected to an inner liner which extends within the casing and is separated therefrom by a circumferentially extending annulus. The annulus is configured to be filled with a fluid at a predetermined pressure. The fluid may be an uncompressible liquid such as propylene glycol. The small molecular gas is stored within an interior of the inner liner at a selected pressure, such as above 1000 pounds per square inch (psi).

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.

An intelligent fuel storage system can consist of a storage pod connected to a storage module with the storage pod having a plurality of separate storage vessels each residing below a ground level. The storage pod may concurrently store a first volume of a first fuel and a second volume of a second fuel prior to altering the first and second volumes in accordance with a performance strategy generated by the storage module to provide a predetermined blend of the first fuel and second fuel with at least a threshold volume and at least a threshold pressure.

Various embodiments are generally directed to a casing connected to a top cap structure that consists of an adapter flange extending to an adapter barrel that is configured to fit wholly within the casing. The adapter barrel can be separated from the casing by an annulus that is filled to a predetermined annulus pressure while an internal chamber defined by the adapter barrel contains a gas having a small molecular size at a storage pressure that is greater than the predetermined annulus 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.

The present invention is a tank for storing pressurized gas. The tank comprises at least one tubular element (1) having a wall comprising a layer of prestressed concrete (6), at least one circumferential mechanical reinforcing layer (8), at least one axial mechanical reinforcing layer (7) and a sealing layer (5). The concrete from which the layer of prestressed concrete is made is chosen from ultra high performance fiber-reinforced concretes.

A method of processing a stream of compressed air travelling between a gas compressor/expander subsystem and an underground accumulator in a compressed air energy storage system may include directing a thermal storage liquid through the first liquid flow path in a liquid charging flow direction from a thermal source reservoir toward a thermal storage reservoir whereby at least a portion of the thermal energy in the compressed air is transferred from the compressed air into the thermal storage liquid within the first reversible heat exchanger; including redirecting the compressed air through the first gas flow path in a gas discharging flow direction that is opposite the gas charging flow direction and redirecting the thermal storage liquid through the first liquid flow path in a liquid discharging flow direction whereby at least a portion of the thermal energy in the thermal storage liquid is returned into the compressed air.

A thermal storage subsystem may include at least a first storage reservoir configured to contain a thermal storage liquid at a storage pressure that is greater than atmospheric pressure. A liquid passage may have an inlet connectable to a thermal storage liquid source and configured to convey the thermal storage liquid to the liquid reservoir. A first heat exchanger may be provided in the liquid inlet passage and may be in fluid communication between the first compression stage and the accumulator, whereby thermal energy can be transferred from a compressed gas stream exiting a gas compressor/expander subsystem to the thermal storage liquid.