WO2014100151A2 - Large access port to subterranean chamber - Google Patents

Abstract

The invention relates to a large access port to a subterranean chamber of a compressed air energy storage system and a method for forming the same. The access port has a liner with a proximal end near ground level and a distal end near the subterranean chamber to provide fluidic communication between the compressed air energy storage system and the subterranean chamber. Separate pipes are located within the liner and extend from the proximal end to beyond the distal end of the liner to provide fluidic communication with fluid in the subterranean chamber. Support structure couples the liner to the separate pipes for support.

Description

LARGE ACCESS PORT TO SUBTERRANEAN CHAMBER

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Patent

Application Number 61/739,359 entitled "Large Access Port to Subterranean Chamber" filed on December 19, 2012, the entirety of which is incorporated by reference herein.

FIELD OF THE INVENTION

[0002] The present invention relates generally to a compressed air energy storage system, and, more specifically, to structures and methods for accessing compressed air in a subterranean chamber.

BACKGROUND OF THE INVENTION

[0003] Compressed air energy storage (CAES) may rely on solution-mined caverns to store high value compressed gases and hydrocarbons. CAES is primarily directed to energy storage by means of accumulating a significant volume of compressed air in a large underground volume. Traditional compressed air energy storage (TCAES) systems often use drilling technologies common to the gas and oil industry to access and communicate with the underground volume. These systems tend to rely on standard sizes and gages of pipe that are cost effective in those industries, but end up restricting power output from compressed air energy storage to a few megawatts. For example, drilled bore penetrations, casing, and pipe sizes and gages tend to be between 6 inches and 38 inches in diameter, which is the range of pipe sizes that are common to the gas and oil industry. Much of the value is derived from the high value of the product being moved in and out of the cavern, and not from the generation of power.

[0004] Drilling has inherent cost uncertainties associated with the geology and geotechnical characteristics of a given site. These uncertainties can be significant in comparison to other forms of construction. Boring multiple holes at a site does not significantly lessen the uncertainty because of the random and uncontrollable environment and events that are associated with drilling each hole. Additionally, the directional uncertainty of drilling and geotechnical concerns with the strength of caverns with multiple penetrations discourage more than a few penetrations from being attempted. Therefore, achieving more cross-sectional flow area by drilling multiple holes tends not to be desirable because they impose significant cost uncertainty into a construction project.

[0005] Techniques for drilling large-diameter blind shafts are known in the mining and construction industries, though typically these applications end at depths well above those common for solution-mined caverns. Accordingly, smaller diameter bores are used to access the caverns. The mining industry has traditionally excavated shafts with slow, expensive, labor intensive, and dangerous mechanical methods that fracture the rock with hammers, treadmills or explosives and muck the debris with buckets to the surface. In the gas and oil industry, rotary drilling is common as it can be done from the surface and uses drilling mud that removes cuttings, lubricates the drilling, cools the drill bit, and stabilizes the bore hole. However, rotary drilling is difficult at larger diameters because the weight of the drill string becomes difficult to manage, the drilling torque becomes large, and mud recirculation becomes ineffective.

[0006] The use of caverns for compressed air storage often requires the handling of air and liquid to displace volume not occupied by the air to control pressure in the cavern. For effective control, air and liquid are transported in separate pipes and in different manners. This means there must be at least two supply paths, one for air and one for liquid, into/out of the cavern. In traditional, solution-mined caverns established with gas and oil drilling

technologies, a single bore with a concentric pipe arrangement providing two paths for fluid flow with a central pipe/annulus arrangement, or multiple bores drilled into a common cavern or some combination of multi-bore/ concentric pipe arrangement are used. Concentric pipe arrangements allow the co-location of two fluid paths, but since the overall bore diameter is restricted to available pipe size, flow restrictions become a serious consideration for compressed air storage applications.

[0007] FIG. 1A illustrates a typical configuration of a solution-mined cavern with a penetration established using existing gas and oil drilling technologies. Although any number of configurations is possible, the cavern 10 illustrated in FIG. 1A has one penetration 12 with pipe sizes and gages common to the gas and oil industry. The figure shows a compressed air cavern 10 with a liquid volume used to control pressure and volume of the air in the cavern. The penetration 12 into the cavern 10 has two concentric pipes: a casing pipe 1 1, which is geotechnically coupled to the drilled hole in the earth, and a central pipe 13. The liquid or brine 16 depicted at the bottom of the cavern 10 is connected with the surface 15 via the central pipe 13. The annulus 19 established between the casing pipe 1 1 and the central pipe 13 carries compressed air to and from the top of the cavern 10. The control of the air and the liquid flow at the surface 15 is accomplished with a manifold 18 that is attached to the casing 11 and that supports the central pipe 13 down the hole. The manifold 18 segregates the liquid flow in the central pipe 13 from the air flow in the annulus 19.

[0008] A conventional pressure compensation strategy for a storage volume often requires establishing a brine stand pipe 17 between the surface brine reservoir and the brine volume 16 at the bottom 14 of the storage volume. The brine stand pipe 17 is a continuous pipe string that hangs from the brine well head 18 and extends to the bottom 14 of the storage volume. The hanging brine pipe 17 may have to be removed and reinstalled several times during the lifetime of the storage facility for maintenance and inspection requirements. The size and weight of this hanging brine pipe 17 can be an important consideration in the cost of facility maintenance and operation.

[0009] Often a pipe string is removed from a bore with a makeover rig designed for such removal and reinstallation in the field. These rigs are typically portable, and therefore, tend to be limited in the size and weight of pipe they can handle. The size and weight limitations of available makeover rigs can be critical design considerations in determining the size and number of brine pipes to be used with a storage facility. The maximum pipe diameter and gage of a brine pipe 17 may be limited by the length required, and also by the size and weight limitations of the makeover rig. Larger brine pipes 17 exceeding these capabilities have generally been considered not economically viable to maintain. For high power facilities that require large brine cross-sectional flow area, many pipes sized within the makeover rig limitations are installed.

[0010] For compressed air energy storage applications, the power rating of a storage facility is critical to the economic viability of a venture. Achieving a much greater desired power rating from the compressed air energy storage tends not to be cost effective when using the gas and oil technologies. The relatively small pipe sizes present obstacles to effective exploitation of compressed air energy storage. For example, the small cross-sectional area of the pipe imposes high pressure loss and flow loss that waste energy; and the cost of multiple small penetrations into a cavern becomes prohibitively expensive very quickly, in part due to cost of boring separate holes as well as the cost of separate pipe strings. [0011] The flow of compressed air and pressure compensating fluids into and out of a cavern can be key drivers in achieving a greater power rating. To overcome the pipe size limitations, air and other fluids transported into and out of the cavern may need to flow at extreme velocity and require significant power to overcome friction to maintain required flow rates. The frictional losses and the pressure required to enable high flow rates can result in a significant loss of energy, thereby compromising the economic benefit of compressed air energy storage. To achieve a favorable economic return, the size of pipes into a cavern may be much larger than the equipment commonly associated with the gas and oil industry and TCAES.

[0012] TCAES systems store the pressure and volume work energy of compressing air, but reject the heat energy of compression, which is not otherwise stored. To achieve economically feasible recovery of energy, TCAES systems often reintroduce heat during air expansion during energy recovery such that only a portion of energy generated comes from the stored compressed air. Heat can be added in a number of ways, but most often through the combustion of natural gas. TCAES systems can be considered to store the work of compression of a future Brayton cycle generation of energy and may be considered a hybrid between a power cycle and an energy storage system. Because the majority of the expansion that is required in a Brayton cycle is achieved through the heating of the compressed air from energy consumed from combustion heating, the standard pipe sizes and gages of the gas and oil industry tends not to restrict operation significantly. The expansion work achievable from the mass flow of compressed air is multiplied many fold by combustion.

[0013] As stated above, TCAES systems are a hybrid between power generation and energy storage. Accordingly, there exists a need for a compressed air energy storage system that stores both pressure/volume and heat energy, and where energy recovery comes primarily from the stored heat energy.

SUMMARY OF THE INVENTION

[0013] Embodiments of the present invention address issues in existing technologies by providing systems and methods for storing compressed air energy where both pressure/volume and heat energy storage is achieved, sometimes in a substantially reversible thermodynamic process, and where energy recovery may come primarily from the storage energy, e.g., "polytropic" energy storage from compressed air (PCAES), which range from adiabatic to isothermal systems, including the GCAES systems described herein. In such a system, the rate of energy production (power) may be directly related to the mass flow of air that can be extracted from a cavern, which has previously been greatly restricted by pipe size and gage limitations. Performance may be measured by the round-trip efficiency of applying reversible processes, e.g., the cumulative efficiency of the compression and expansion processes. In contrast, TCAES performance is measured by thermodynamic efficiency of its power cycle.

[0014] The bore size limitation may be addressed by providing a large-diameter bore.

Because of the significant mass flow requirements to support the desired power output from the cavern, the flow paths of the air and the liquid may need large cross-sectional areas, including up to 5x (and greater) when compared to traditional TCAES systems. These cross-sectional areas can be achieved with one pipe or several pipes, and, by using larger diameter pipes, can reduce the number of penetrations. The cavern may be provided with several air pipes and several liquid pipes for the handling of fluids, but in some embodiments a single large-diameter bore may be sufficient to allow many fluid paths to be placed and configured as required for cavern operations, thereby eliminating the cost of drilling more than one bore into the cavern while enabling relatively large flow cross-sections and providing flexibility in the configuration of the independent flow paths.

[0015] A large-diameter bore as contemplated above is considered impractical for gas and oil technology because it requires pipe sizes that are well beyond standard pipe sizes and gages that are supported by drilling technology in those industries, and because the weight of the requisite drill pipe and casing and drilling torque would be expected to exceed the capabilities of the largest drilling rigs available today. The use of mining technologies that are sized and adapted from the drilling of large-diameter shafts may be used instead. As few as one penetration into the cavern may enable power up to hundreds of megawatts, considered unachievable with a smaller bore. Given that many caverns, e.g., salt caverns, have been built or otherwise exploited for the storage of compressed fluids and hydrocarbons, the larger bore may be used to modify an existing cavern to be more suitable for a PCAES system. There are also opportunities in accessing and/or expanding the capabilities of caverns that are not actively used for such a purpose with the large-diameter bore.

[0016] Embodiments of the invention relate to means and methods for achieving high power from underground storage with a single large-diameter penetration, including the use of hanging brine pipes that are within makeover size and weight restrictions. Embodiments of the invention also relate to the method and means to create a large cross-sectional area penetration into and out of a cavern to facilitate a high power rating with negligible losses. More specifically, certain embodiments provide for high volume flow paths into and out of the cavern, while avoiding some of the limitations of oil field drilling technology, such as flow paths with small diameters, heavy drill strings, and blind operations in deep penetrations. Utility scale implementation, e.g., > 20 MW, of the invention may use larger than standard sizes, relying on more specialized hardware. While embodiments described generally relate to large volume caverns relying largely on hydrostatic pressure, other uses of the large-diameter bore, such as pressurized caverns, are also contemplated.

[0017] According to one aspect, the invention relates to a large access port to a subterranean chamber of a compressed air energy storage system. The access port has a liner with a proximal end near a ground level surface and a distal end near the subterranean chamber to provide fluidic communication between the compressed air energy storage system and the subterranean chamber. The access port also has multiple separate pipes located within the liner and extending from the proximal end beyond the distal end of the liner to provide fluidic communication with fluid in the subterranean chamber and support structure connected to the liner for supporting the pipes.

[0018] In some embodiments, the subterranean chamber is a cavern, and may range in size from having a diameter similar in size to the diameter of the bore to very large naturally occurring and/or manmade spaces. The liner may have a diameter between about 5 feet and at least about 20 feet, and the distal end of the liner may be located above the subterranean chamber. In certain embodiments, the distal end of the liner is cemented in position to form a shoe. The liner may be adapted for cyclic exposure to compressive and tensile stresses. In additional embodiments, the support structure comprises a cap. The cap may be located at the proximal end of the liner. Multiple pipes may hang from the cap, which in some embodiments is a dome. The multiple pipes may be connected to a brine pond, which may be at atmospheric pressure or pressurized above atmospheric pressure.

[0019] According to another aspect, the invention relates to a method of connecting a compressed air energy system to a subterranean chamber. The method includes forming a large-diameter bore from a ground level surface to a depth proximate the subterranean chamber, inserting a liner with a proximate end near the surface and a distal end near the subterranean chamber into the bore, and coupling a plurality of separate pipes to the liner, the pipes extending from the proximal end beyond the distal end into the subterranean chamber.

[0020] In some embodiments, the subterranean chamber is a cavern, and may range in size from having a diameter similar in size to the diameter of the bore to very large naturally occurring and/or manmade spaces. The liner may have a diameter between about 5 feet and at least about 20 feet. The inserting step may include stopping the distal end of the liner above the subterranean chamber, and may include cementing a distal end of the liner to form a shoe. In certain embodiments, the liner is adapted for cyclic exposure to compressive and tensile stresses. The liner may be connected to the compressed air energy system, which may be useful when the method includes pressurizing the subterranean chamber with output form the compressed air energy storage system. The method may also include using pressure in the subterranean chamber to operate the compressed air energy storage system.

[0021] In other embodiments, the method includes installing a cap connected to the liner. The cap may be located at the proximal end of the liner. The multiple pipes may be connected to the liner via the cap, and the pipes may hang from the cap. In some embodiments, the cap is a dome. In additional embodiments, the method includes connecting the pipes to a brine pond. The brine pond may be at or pressurized above atmospheric pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings: [0023] FIG. 1 A depicts a conventional penetration of a solution-mined cavern established using conventional gas and oil drilling technologies;

[0024] FIG. IB depicts a top (plan) view of concentric pipes with an annular space therebetween;

[0025] FIG. 2 depicts a notional temperature-entropy diagram with GCAES energy storage reversible paths;

[0026] FIG. 3 depicts a notional temperature-entropy diagram comparing a TCAES with the GCAES of FIG. 2;

[0027] FIG. 4 depicts the relationship between the diameter or air and brines pipes and

GCAES power;

[0028] FIG. 5 depicts drilling costs as a function of bore diameter and depth in accordance with the prior art;

[0029] FIG. 6 depicts workover rig weight limits applied to pipe strings of various depths and diameters in accordance with the prior art;

[0030] FIG. 7 depicts illustrative embodiments of air (FIG. 7A and FIG. 7C) and brine penetrations (FIG. 7B and FIG. 7E) for a separate-pipe configuration (FIG. 7D) in accordance with some embodiments of the invention;

[0031] FIG. 8 depicts illustrative power levels and pipe costs per KW for a single separate air and multiple brine pipe (less than 24-in. diameter) configuration;

[0032] FIG. 9 depicts illustrative power levels and drilling cost uncertainty for multiple holes or brine pipes;

[0033] FIG. 10 depicts illustrative embodiments of air and brine penetrations (FIG. 10A and IOC) for an annulus/central pipe configuration (FIG. 10B) in accordance with some embodiments of the invention; [0034] FIG. 1 1 depicts illustrative power levels and configuration costs per KW for an unconstrained annulus/central pipe configuration;

[0035] FIG. 12 depicts illustrative power levels and configuration costs per KW for a constrained annulus/central pipe (less than 24-in. diameter) configuration;

[0036] FIG. 13 depicts illustrative power levels and drilling cost uncertainty for multiple holes for an annulus/central pipe configuration;

[0037] FIG. 14 depicts a top (plan) view of geotechnical and other factors affecting penetration locations with respect to the subterranean cavern;

[0038] FIG. 15 depicts an illustrative embodiment of a cap for a large-diameter bore and liner in accordance with the invention;

[0039] FIG. 16 depicts an illustrative embodiment of the large-diameter bore and liner in FIG. 15 in use at a solution- mined cavern in accordance with the invention;

[0040] FIG. 17A depicts an illustrative embodiment of a large-diameter bore set in rock above a proposed cavern location for solution-mining a new cavern in accordance with the invention;

[0041] FIG. 17B depicts an illustrative embodiment of the large-diameter bore of FIG.

17A further solution-mining a new cavern in accordance with the invention;

[0042] FIG. 18A depicts an illustrative embodiment of a large-diameter bore set in rock near but distant from an existing cavern location for penetrating and expanding the capacity of the existing cavern in accordance with the invention;

[0043] FIG. 18B depicts an illustrative embodiment of the large-diameter bore of FIG.

18A having penetrated and performed further solution-mining to expand the capacity of the existing cavern in accordance with the invention; [0044] FIG. 19 depicts an illustrative embodiment of a large-diameter bore and liner using pressure compensation beyond hydrostatic pressure in accordance with the invention;

[0045] FIG. 20 depicts an illustrative embodiment of a top (plan) view of a large- diameter bore at the cap in accordance with the invention;

[0046] FIG. 21 depicts illustrative power levels and configuration costs per KW for a big-bore diameter configuration;

[0047] FIG. 22 depicts illustrative power levels and construction cost uncertainty for multiple holes for a big-bore diameter configuration;

[0048] FIG. 23 depicts a summary of the cost plus standard deviation comparison between the various configurations; and

[0049] FIG. 24 depicts a summary of the relationship between the number of holes and

GCAES power for the various configurations.

DETAILED DESCRIPTION OF THE INVENTION

[0050] The invention may be better understood by reference to the following detailed description, taken in conjunction with the drawings. For the sake of simplicity, one embodiment of the invention is described below in relation to a large subterranean chamber, e.g., cavern, with liquid, e.g., brine, at the bottom. Other configurations and variants will be apparent to those skilled in the art from the teachings herein.

[0051] For a PCAES application, as described herein, separate flow paths for compressed air and brine may be used in order to control cavern pressure. This may be achieved by moving brine into or out of the cavern to compensate for changes in air volume. This method of both volume and pressure control will be referred to as "pressure

compensation," which is described in U.S. Patent Application No. 13/350,050 entitled "Pressure Compensated Caverns," which is incorporated herein by reference in its entirety. In order to control the flow of brine into or out of the cavern a pipe, or multiple pipes, may extend from the surface down to the brine volume in the cavern. The vertical length of this brine pipe can establish a head pressure that is equal to the distance between the surface and the top of the brine volume within the cavern. When there is no flow into or out of the cavern, the pressure within the cavern equals the sum of the head pressure and the pressure of the brine pipe at the surface. If the brine pipe at the surface is connected to an open reservoir at atmospheric pressure, i.e., gage pressure of zero, the pressure of the cavern (assuming no air flow) will be the gage pressure of the brine head. This configuration of brine pressure compensation will be referred to as "hydrostatic pressure compensation." If the brine pipe at the surface has a positive gage pressure, the configuration of cavern pressure compensation is referred to as "pumped pressure compensation." The cavern pressure in this case (assuming no air flow) is the sum of the brine head plus the brine pressure at the surface.

[0052] Embodiments of the system may be operated using either hydrostatic pressure compensation or pumped pressure compensation and may also include embodiments in which the pressure is allowed to fluctuate. Although the illustrations relate to brine pressure compensation, the principles described can be applied to the various configurations. Brine pressure compensation generally requires a greater cross-sectional area for liquid flow than other configurations.

[0053] A variety of possible cavern configurations is possible, including some with multiple penetrations, some with a single fluid, some with multiple fluids, and some with differing flow arrangements between penetrations and various regions of the cavern. Many of the exemplary illustrations depict a single penetration into a cavern for conveying compressed air and brine, but the principles described herein are applicable to multiple penetrations and/or single fluid systems as well. The various configurations may have large cross-sectional area flow paths into and out of the cavern. The cavern may be a wide range of sizes, including as small as or less than the diameter of the bore, as great as or greater than some of the largest naturally occurring and/or manmade spaces, and all volumes in between. A single penetration into a cavern is usually less expensive, and therefore more desirable, if it does not restrict other functions or performance of the cavern. Handling multiple fluids with a single penetration is technically challenging as it requires the configuration of multiple flow paths and the pressure containment of more than one fluid.

[0054] Minimizing the frictional losses of fluids flowing into and out of a cavern is important in maintaining a high efficiency and, ideally, flow losses as near to zero as practical. Often, air and brine pipes are sized to maintain flow power loss at less than 1% of a power rating for a given project. When using conventional oil and gas pipe sizes, this limitation typically restricts the power rating to below 5 MW for a single traditional air/brine penetration. Another difficulty is that drag from brine flow is much higher than compressed air flow due to the higher viscosity of brine in comparison to compressed air. Therefore, to meet a given power rating based on compressed air flow requirements, the cross-sectional area for brine flow may be much greater than that for air flow, e.g., 2x to 4x greater. A system with an increased brine flow area allows for greater air flow, leading to possible power ratings much greater, e.g., lOx to 20x greater, than conventional methods. The system and methods described herein enable flow cross-sectional areas of up to and even greater than several square meters for brine (and air), allowing for power ratings on par with common utilities, e.g., » 10 MW, such as 20 MW. Conventional methods tend not to provide this kind of cross-sectional flow area, thus greatly restricting the power rating.

[0055] Traditional compressed air energy storage (TCAES) power plants store energy in the form of compressed air in underground volumes. This compressed air is typically utilized at a later time to generate power in combination with a heat source applied to a thermodynamic power cycle. Accordingly, TCAES may be considered primarily a power generation strategy, rather than an energy storage strategy, that achieves some economic advantage by compressing air at a time different from the time of power generation. The thermodynamic power cycle of a TCAES facility invests power into the compression of air before the application of heat and the subsequent power producing expansion. TCAES facilities may compress and store air independent of their power generation periods. This "time-phasing" of air compression and storage may introduce thermodynamic losses into the overall power generation cycle.

[0056] In contrast, highly-reversible energy storage with compressed air (GCAES) described herein may generate power from the energy it has stored, as compressed air, without the addition of an external heat source. This may be accomplished by using reversible thermodynamic processes for energy storage and energy recovery, rather than relying upon thermodynamic power cycles requiring external heat addition. FIG. 2 illustrates a notional Temperature - Entropy (T-S) chart showing the storage and recovery paths of a GCAES. This figure illustrates how GCAES follows reversible thermodynamic paths to compress air from Point A to Point B in order to store energy. An energy storage path 21 comprising a series of adiabatic 22 and isothermal processes 23 is used because these processes are reversible. In the ideal case, these paths can be reversed to achieve complete energy recovery. In the adiabatic processes 22, energy is stored as heat and pressure-volume (PV) work in the compressed air. In the isothermal process 23, energy is stored as PV work in compressing the air and as heat removed during the process in a separate heat reservoir. This energy is recovered by expanding the air to recover its PV work in both the adiabatic 22 and isothermal processes 23, and by transferring stored heat into the expanding air during the isothermal process 23. By following reversible thermodynamic processes, energy storage can be considered distinct from a thermodynamic power cycle.

[0057] Existing TCAES systems tend to rely on such a thermodynamic power cycle.

TCAES systems typically temporally separate when air is compressed and expanded during the cycle, rather than perform the power cycle continuously. Most power cycles transfer work and heat between the various thermodynamic processes of the cycle. TCAES systems consume work to compress air during the initial compression phase of their cycles. This compressed air is often stored in a cavern as a means to interrupt and delay the power cycle. Using this approach, the TCAES power cycle allows for compression during periods when energy is inexpensive and plentiful. At a later time, TCAES systems continue the power cycle process by heating and expanding the stored compressed air. FIG. 3 illustrates a temperature-entropy (T-S) diagram of a notional TCAES cycle 30. This diagram illustrates the TCAES cycle 30 tends not to follow reversible processes, which would be vertical or horizontal depicting, respectively, constant entropy, i.e., AS = 0, and isothermal, i.e., ΔΤ =0, conditions. In short, the TCAES cycle 30 is a power cycle and is not a method for storing or recovering energy with near perfect round trip efficiency. Indeed, typically, TCAES systems consume heat from an external source to drive the overall cycle and generate power. The power generated may be equal to or greater than the energy initially stored as compressed air, but significant energy from a fuel or other heat source is consumed to generate this power.

[0058] High power GCAES systems use high flow rates into and out of the compressed air storage volume. These flow rates generally are not considered feasible with TCAES equipment at similar power ratings. Further, the TCAES equipment may not be adaptable to GCAES systems. Non-traditional PCAES systems, which do not require heat addition from an external source, such as the GCAES, may also have high mass flow rates. Such PCAES systems can be described as polytropic, and range from near-isothermal i.e., ΔΤ =0, to near- adiabatic, i.e., AS = 0. The power generated by an ideal PCAES system is thermodynamically represented with the following equation:

where n is the polytropic exponent, which approaches 1 for a near-isothermal process and approaches 1.4 for a near-adiabatic process. For the same power level, the relative air mass flow between a near-isothermal PCAES system and a traditional TCAES system is -2.43 (for a 1 to 100 bar pressure range with an initial temperature of 293K). Additionally, for the same power level, the relative air mass flow between a near-adiabatic PCAES system and a traditional TCAES system is -1.64 for the same conditions. This demonstrates how the mass flow for PCAES (including GCAES) can be substantially greater than for traditional TCAES.

[0059] Polytropic processes are also reversible, and hence a pressure loss in a PCAES system can be a loss to its overall round-trip efficiency between storage and recovery. For a given loss budget in a round-trip efficiency, flow losses may have a greater impact on PCAES systems in comparison with TCAES systems.

Loss_CAES

5. 6

L0SSCAE<I_ poly— near Iso

Loss_CAES

= 10. 1

L0SScAE<i_ poly- near Adia

[0060] Applying the same reasoning as before, it follows that the PCAES systems may benefit from large cross-sectional flow areas to limit losses in the system's round-trip efficiency, wherein: D near— isothermal 2^, 0 D^^g

^neai— adiabatic— 1- 9 DcAES

[0061] As such, the large-diameter bore (D) described herein is highly useful for

PCAES systems, extending from near-isothermal and near-adiabatic. Note that the comparison making use of the Darcy-Weisback flow equation assumes that fo is invariant with volumetric flow and cross-sectional area. For high flow rates, such as those required by compressed air energy storage systems, this approximation is nominally correct.

[0062] GCAES air and brine pipe diameters leading to the storage volume may be relatively large when more than a few MWs of power are desired. FIG. 4 is a chart illustrating exemplary pipe diameters for GCAES facilities up to 100MW in scale. In this case, it is assumed that the air flow and brine flow of the facility is accomplished with two penetrations into a cavern.

[0063] This chart also shows the nominal standard pipe diameters that are industrial standards. Note that GCAES facilities over 30 MW are expected to need brine pipes 41 above standard pipe sizes 45, and facilities over 90 MW are expected to need a non-standard pipe size for the air pipe 42. Large, non-standard pipe sizes may present technical and economic challenges to a project. Use of pipes with large-diameters present potential problems during the construction and operational phases of establishing a GCAES storage facility, including: 1) introducing costs and cost uncertainties when drilling additional penetrations into the storage volume, and 2) adding the weight of the brine pipe string during construction and maintenance phases.

[0064] A major cost component of constructing an air storage cavern is the cost of drilling the holes for the pipes. Representative costs for bores of various diameters and depths are illustrated in FIG. 5. This chart shows that drilling costs increase with both bore diameter and bore depth.

[0065] Cost increases with increases in diameter and depth because the size and amount of equipment required for drilling a larger and deeper bore tends to increase and the energy required to fracture, lift, and remove earth increases with the depth and volume of the bore. Larger diameter bores also tend to require higher drilling torque, necessitating more energy and heavier equipment. Deeper holes may require more energy to lift material out of the hole and also require more drill pipe and casing to support the drilling operation at depth. Deeper and larger diameter bores require the drilling equipment to handle more weight and to supply more energy in support of the drilling operation.

[0066] Related to the cost of drilling a bore is the uncertainty of the costs that will be encountered during the drilling operations. Blind shaft boring is full of geologic, geotechnical, design, operational, and economic uncertainties. The geology of a drilling site will almost always have significant uncertainty. The precise characteristics of the earth strata at a site can vary significantly over short distances, making interpolation between known well logs uncertain. The geotechnical characteristics of rock in various strata are highly variable. The movement and existence of geo-fluids should be controlled and are often not known before hand with much certainty. Accordingly, a bore design should be highly adaptable and adjustable to provide a robust solution for creating a bore. The operational means and methods for drilling should also be adaptable and adjustable to help ensure completion of a bore. The nature of drilling can result in additional costs and schedule uncertainties, particularly when protecting against drilling problems and unforeseen adjustments in the design of the bore.

[0067] The cost and availability of drilling equipment and labor can also lead to problems. Generally, the greater the weight and power required, the larger the drilling rig needed. Larger rigs tend to be more expensive to purchase, lease or hire and, generally, require proportionally greater levels of supplies, fuel, and labor to operate. Larger rigs can also be more difficult to schedule because of limited supply. All of these uncertainties contribute to the variable cost of drilling. Cost estimates for drilling operations tend to deviate between 10% and 20% between estimates. Reducing the number of penetrations may provide greater cost certainty and may help make a project easier to manage.

[0068] A typical method of constructing a drilled hole includes, after completing cementing of the casing, removing the drilling rig, equipment, and materials from the drill site. A smaller rig, known as a workover/makeover rig or completion rig, is then moved over the well bore to be used for the remaining completion operations. The workover rig can also be used during maintenance and inspection operations over the lifetime of the cavern to remove and replace the brine pipes. Workover rigs are often smaller and less expensive (and also more limited) than the original drilling rig used to drill the primary, cased hole. As the original drilling rig is larger and more capable, it can drill almost any size bore and handle almost any size casing to establish the bore. Thus, it tends not to be cost effective to have this type of drill rig revisit the site for normal and frequent maintenance and inspection events. Accordingly, it is desirable to use a workover rig when possible.

[0069] A workover rig is typically portable but, often, limited in the weight and size of pipe it can handle. By designing pipe configurations within the capability of available workover rigs, the workover rig may be used in a more robust capacity. The largest workover rigs that are commonly available tend to have a load capability of about 200,000 lbs. FIG. 6 illustrates an exemplary design of how the depth of a storage volume and the diameter of a brine pipe may be limited by the workover weight limit. If it is assumed that the workover rig load limit is 200,000 lbs. and that the bottom of a storage cavern is 2000 ft., then the diameter of an ASTM & API Schedule PE brine pipe should not exceed 24 in.

[0070] According to this workover limit, the separate-pipe configuration illustrated in

FIG. 4 should not be able to exceed a power of 10 MW without exceeding a brine pipe diameter of 24 in. To establish a higher power configuration, the flow requirements of the brine pipe should be distributed among multiple pipes, each of which should be less than 24 in. in diameter.

Separate Air and Brine Pipe Configuration

[0071] FIG. 7 illustrates exemplary air 72 (FIG. 7A and FIG. 7C) and brine penetrations

74 (FIG. 7B and FIG. 7E) in a separate-pipe configuration (FIG. 7E) cavern arrangement 70. The air bore 72 may be connected to the top of the cavern 75 and located within a clement cased bore 71 , as installed by the original drilling rig. A workover rig may only be used in association with the air bore 72 to handle inspection equipment and instruments, as the air bore 72 tends not to have workover limitations that need to be considered during design and construction. This means the air bore 72 can generally be made as large as required to achieve a flow target. The size and depth of the air bore 72 tend only to be limited by the size and capability of the original drilling rig. As a result, a single air bore 72 can be expected to handle the flow of the facility.

[0072] For GCAES facilities over 10 MW multiple brine pipe holes 74 may be used to keep the pipes within the workover limits. For example, in FIG. 7 each brine penetration 74 is a cased hole to the top of the cavern 75, much like the air pipe 72, with the brine pipe 78 hanging from the well head 77 to the bottom of the cavern 79.

[0073] FIG. 8 depicts characteristics of a separate air and multiple brine pipe configuration having brine pipe diameters of less than 24 in. (assuming a single air pipe). FIG. 9 illustrates the number of brine pipes that may be used at various power levels. The number of drilled holes for this configuration includes a single hole for the air pipe and a hole for each of the brine pipes. The calculated diameter of the air pipe fluctuates mathematically as the number of brine pipes increases incrementally.

[0074] As the number of holes to be drilled increases, the cumulative uncertainty of the construction cost can become significant. Starting with a nominal drilling cost deviation of 10% per hole, as the number of holes increases, the root sum square propagation of the cost uncertainty can become extremely large with relatively low increases in the numbers of holes. FIG. 9 also illustrates the increase in construction cost uncertainty as the power of the project, and therefore the number of bores, increases. In the previous FIG. 8, the cost plus one standard deviation 81 is plotted with the mean cost estimate. This cost uncertainty is one reason fewer penetrations are desired. Also, the practicality of greater numbers of penetrations, e.g., more than six penetrations, is questionable. With increased number of holes, more pipe connections and fluid management are required. Such a configuration, i.e., a single air pipe and multiple brine pipes, may be limited to power levels below 50 MW.

Annulus/Central Pipe Configuration

[0075] An illustrative embodiment of an annulus/central pipe configuration is shown in

FIG. 10. This configuration 100 may be applied to storage caverns where two or more fluids are handled. FIG. 1 1 illustrates the relationship between pipe size and GCAES power as well as the construction cost per KW when the size of the annulus and the center pipe are configured to limit flow loss and minimize pipe material without, however, constraints being placed upon the pipe size. In contrast, FIG. 12 depicts how applying the workover load limit to the brine pipe 78 (FIG. 10), i.e., assuming an exemplary limit of 24 in. diameter. It should be noted that with this configuration and the 24-in. diameter constraint, GCAES power may be limited to about 13MW from a single hole. Above 13 MW, a brine pipe 78 is expected to exceed 24 in.

[0076] The annulus/central pipe configuration 100 (FIG. 10) may have advantages over the previously described separate-pipe configuration 70 (FIG. 7). For example, the cost of the annulus/ central pipe configuration 100 may be less and the cost uncertainty may be reduced in comparison, at least partially from the reduction in the number of holes that need to be drilled. When multiple holes are drilled, they should be spaced laterally from each other a sufficient distance to avoid interfering with each other. Drilling operations often result in bores that deviate from vertical. Depending upon the accuracy of the drilling technique, the bores must be spaced from each other an amount that will preclude unintentional intersection as the holes are drilled. Geotechnical considerations also impact the spacing of drilled holes to limit the chance they could interact structurally in a manner that could threaten the integrity of the bores and the cavern. Limiting the number of holes bored can accordingly limit risk at a storage site.

[0077] Because the number of holes can be dictated by desired brine flow, each hole should have direct access to the bottom of the cavern 79. Considering FIG. 10, if brine pipes 78 are placed off-center there is increased likelihood the brine pipe 78 will not have direct plum-line access to the bottom of the cavern 79, and may not access all the brine in the cavern. However, although it may be desirable to group the bores near the centerline of the cavern, the geotechnical concerns of bores closely spaced together tend to discourage grouping the bores. FIG. 14 depicts how the grouping of penetrations 1401, the geometry of the cavern 1400, and the geotechnical spacing requirements 1402 interact to impose a practical limit on the number of penetrations 1401 a cavern 1400 can accommodate. For these reasons, there tends to be a practical upper limit on the number of bores, e.g., four, depending upon the bore size, the cavern size, and the geotechnical characteristics of the site. Based on FIGS. 8 and 9, GCAES power available from the separate-pipe configuration 70 may be limited to about 30 MW whereas, in comparison, FIGS. 11-13 show that the GCAES power limit for the annulus/central pipe configuration 100 may be about 50 MW.

[0078] Regardless of the number of penetrations, having more than one penetration may be a technical and economic risk. Geotechnical uncertainties drive regulatory restrictions that come into play when a site is seeking construction permits, which can be more cumbersome with additional holes. Further, each drilling operation is already risky in terms of time and money. When design of a hole is constrained by the close proximity of other bores, another technical risk is imposed that heightens the overall risk of a drilling task. Designs that require multiple penetrations into a cavern are generally not desirable, but sometimes necessary.

Embodiments of the present invention enable high power from a single penetration.

[0079] In recent years, the mining industry has developed methods for drilling large- diameter shafts to depths required to access the top of subterranean caverns or Halite deposits from which caverns can be solution-mined. Shaft drilling techniques now use methods originally developed for tunnel boring machines in which rolling cutters are used to crush rock. These techniques tend to reduce the weight of the drill bit, minimize drilling torque, and allow for rotary drilling of larger diameter bores. Reverse-recirculation may be used as a more reliable method for cutting removal at larger diameters. With large-diameter rotary reverse- recirculation drilling methods, the mining industry has been able to drill shafts up to 20 feet in diameter and up to 2500 feet in depth.

Installation

[0080] Typically, once a large-diameter bore, e.g., about 5 feet to about 20 feet in diameter (although bore diameters both greater and smaller are contemplated), is excavated, a liner pipe or casing, which may have approximately the same diameter of the bore, may be placed in and secured to the bore in a manner that addresses the geotechnical requirements for strength and support between the liner and the bore. The geotechnical stabilization of rock and earth of the bore for establishing a shaft may be accomplished by constructing casing of the bore or installing the liner in a segmented manner. A segmented approach may allow the required lifting weight and material size handling to be kept within the capability of available cranes and equipment. A distal end of the liner may be cemented in position to establish the "shoe" of the casing bore. This "shoe" may be used to transfer pressure loads to the surrounding rock formations and provide a sealing barrier to compressed air, geo-fluids, or brine from traveling to voids between the liner and the rock bore. The liner is a pressure vessel that is adapted to provide a flow path for compressed air between the cavern and the surface. Because of the various forces acting radially on the liner, including the compressed air pushing out and the ground forces pushing in, the liner should be able to handle and perform during cyclic exposure to compressive and tensile stresses. Handling these cyclic pressures may be especially important if flow through the liner is reversed several times daily. Liners known in the geotechnical, mechanical, and civil engineering fields may be used to satisfy this requirement, along with the related connection methods.

[0081] The liner may be sealed with a cap that provides for an air connection so that compressed air can flow into or out of the cavern. For example, referring to FIG. 15, a cap 1500 also supports multiple brine pipes, i.e., two or more, 1502, 1504 which hang from the cap 1500 down to the bottom of the cavern 79, thereby providing a support structure to couple the pipes 1502, 1504 to the liner 1510. The cap 1500 may be a dome or have a similar shape to optimize weight distribution and provide flexibility in arranging the pipes 1502, 1504. Putting the dome at a proximal and of the liner 1510 enables easier access to the pipes 1502, 1504. The pipes 1502, 1504 may hang freely for several thousand feet from the cap 1500 to the brine in the bottom of the cavern 79. The combined cross-sectional flow area of the brine pipes 1502, 1504 should provide a sufficient flow of brine such that it will not restrict the desired air flow rate. As previously described, because of differences in viscosity, the brine flow area must be greater than the compressed air flow area, e.g., about 2x to about 4x greater. Connecting manifolds to the air pipe 1506 and to the brine pipes 1502, 1504 provide flow of air to and from the compressed air energy storage equipment and brine to and from the brine reservoir.

[0082] The relationship of the bore, liner, and piping with respect to a solution-mined cavern is depicted in FIG. 16. The brine pipes 1502, 1504 hang down from the cap 1500 into the cavern to communicate with the brine at the bottom of the cavern 79. The compressed air at the top 75 of the cavern is able to flow up the bore, between and around the hanging brine pipes 1502, 1504, and flow out the air connection 1506 in the cap 1500.

[0083] The system and methods described herein are applicable to new caverns, as well as to existing caverns to be modified to have a large-diameter bore. For mining new caverns, once a large-diameter bore is established, solution-mining as is known in the prior art may be used to create a cavern. It is also possible to solution mine with an initial smaller diameter bore, then creating the large-diameter bore thereafter. FIGS. 17A and a7B depict two of the early steps in the solution-mining excavation of a cavern using a large-diameter bore. In FIG. 17A, the large-diameter bore and liner 1702 have been established in the overburden and rock above the Halite formation 1710 in which a cavern is to be excavated. The large-diameter bore and liner 1702 are complete at this point. A shoe 1704 may be established and the bore is structurally able to support the pressures and flow of a compressed air cavern. At this point, the large-diameter bore and liner 1704 are used as a passage for drilling a solution mining pilot hole 1706 into the Halite formation 1710 and to hang various pipe strings into the mining volume to facilitate the excavation process. FIG. 17B depicts an early phase of solution mining in which water flows into the formation 1710 and brine flows out of the formation 1710. The excavation process may proceed according to known methods.

[0084] In cases in which an existing cavern requires modification, e.g., to accommodate a greater flow area, a slightly different construction sequence may be used. For example, as shown in FIG. 18A, a large-diameter bore and liner 1800 may be installed in the terrain adjacent to a penetration 1802 to an existing cavern and a shoe 1804 may be established. In some variations of the procedure, the large-diameter bore and corresponding liner 1800 may stop at a desirable elevation above the cavern. Thus, the large-diameter bore and liner 1800 and shoe 1804 are formed before a connection is made with the existing cavern. The liner may be installed in the ground above, or very near, the cavern, but may not penetrate into the cavern. The shoe 1804 formed at the distal end of the liner may not contact the cavern. During deployment of the liner, it must be installed in the bore and fastened to the geology to ensure proper structural performance.

[0085] Once the bore is formed and the liner installed and ready to handle compressed air, a connection can be made between the bore and the cavern. As shown in FIG. 18B, a neck 1808 is drilled into the cavern, which is solution-mined to establish communication between the cavern and the large-diameter bore and liner 1800. Advantageously, with the new large- diameter bore and liner 1800, the cavern can be expanded and its shape adjusted with solution mining to further accommodate the new penetration.

[0086] FIG. 19 depicts another embodiment of a large-diameter bore that relies on pressure compensation beyond just hydrostatic pressure. In this embodiment, the brine reservoir is pressurized, e.g., at the surface, so that the brine in the cavern is at an increased pressure. Advantageously, pressurizing the reservoir enables storage of a similar volume of compressed air in a smaller/shallower cavern than if only hydrostatic pressure were used. [0087] The cap 1500 depicted in FIG. 20 helps achieve the positive attributes of the annulus/central pipe configuration 100, but providing higher power and flow by combining multiple brine pipes 2002 in a single large-diameter bore 2000. This reduces the drilling operations to boring a single bore, thereby eliminating the complications and problems of multiple bores. Because multiple smaller brine pipes 2002 hang from the cap 1500, a workover rig may be used to handle the pipes.

[0088] FIG. 21 shows the characteristics of a large-diameter bore configuration with 24 in. diameter limitation for the brine pipes 2002. FIG. 22 shows the relationship between available GCAES power as a function of the number of drilled holes. Cost uncertainty may be low because only one hole is drilled. The cost uncertainty as a percentage of the overall costs may actually drop due to lesser drilling and pipe steel material costs in conjunction with an increased power output. FIGS. 23 and 24 summarize, respectively, the GCAES power associated with the construction costs of each configuration described above and the GCAES power associated with the number of drilled holes for each configuration described above.

[0089] As can be appreciated by those having skill in the art, embodiments of the present invention provide numerous capabilities beyond the limitations of the existing art. These benefits may include some or all of the following: providing high flow capabilities, enabling higher power output from caverns, addressing special needs of pressure compensation air storage in which air and another liquid, e.g., brine or water, are handled during operation, enabling larger penetrations into the ground, breaking the flow area into multiple pipes in a single penetration, sizing pipes for use with existing field equipment, e.g., workover rigs, providing multiple brine pipes for pressure compensation within a single drilled hole, avoiding geotechnical problems and restrictions of multiple drilled holes, enabling the ganging of pipes near the centerline of a cavern, enabling power outputs beyond 50 MW, and allowing drilling of a single oversized hole which can accommodate anticipated growth.

Calculations

[0090] Following are several calculations that illustrate the relationship between exemplary CAES and GCAES systems. The power generated by an ideal CAES system can be thermodynamically represented as:

[0092] Reasonable CAES assumptions include:

Maximum Turbine Inlet Temperature, T_MTI = 1800°#i

i800°ftr

For Air: γ = 1.4

[0093] The idealized thermodynamic efficiency of a CAES system is expressed with:

[0094] Applying the Loss parameter to this efficiency formulation:

CAES

CAES _Δ

1-γ

CAES

[0095] The sensitivity of the CAES cycle to pressure loss can be described with:

[0096] Using exemplary values: AE — " Loss

[0097] Assuming a pure adiabatic case:

[0098] Based on the exemplary assumptions:

^^lAda— 1- 65 TthcAES

[0099] Accordingly, a GCAES system may use greater pressure flows than CAES systems so that pressure flow losses have a lesser impact. When other variables are held constant, the cross-sectional area of GCAES flow systems may therefore be larger than CAES systems and GCAES flow systems may be larger than CAES designs more generally.

[00100] As previously described, GCAES systems follow thermodynamic reversible processes, which may be considered distinct from a power cycle. Pressure flow losses can impact the overall round trip efficiency between storage and recovery.

[00101] Using exemplary values

GCAES-Adia ~~ ^""■ 780 LOSS

[00102] Therefore, for example, a 1% flow loss may be expected to result in a .780% drop in round trip efficiency.

AES ____ i GCAES-Adia

* GCAES-Adia ^arlcAES

[00103] This indicates that the round trip efficiency drop of an adiabatic process may be expected to be approximately 10.13 times the efficiency drop seen by a CAES cycle for an equal amount of pressure drop from flow losses. Accordingly, GCAES systems may be designed to minimize flow pressure drops for reversible energy storage concepts in comparison to CAES, which is a power cycle type of energy storage concept and tends not to address (nor needs to address) similar pressure drop levels.

[00104] The cross-sectional flow area of GCAES systems may be made larger in comparison to CAES systems in order to avoid loss in the systems' round trip efficiencies. For comparison, the Darcy-Weisbach flow equation can be written in terms of pressure loss:

[00105] Using this equation in conjunction with the previous calculated loss ratio between CAES and GCAES, the impact on GCAES cross-sectional area may be calculated as: pQ and A =

[00106] Continuing the example for a GCAES near adiabatic system:

^GCAES-Adia ~~ V ^:

D GCAES- Adia ~~ *^■ ^^UCAES

^GCAES-Adia ⁼ 3- 77A_CAES

[00107] Illustrative calculations for purely iso-thermal:

[00108] Using the example assumptions:

sot

[00109] Concerning flow losses:

GCAES- isot

[00110] Using exemplary values: ktlGCAES-isot— ^34 LOSS

[00111] Therefore, for example, a 1% flow loss may be expected to result in a .434% drop in round trip efficiency for a GCAES system.

[00112] Relative target diameters between a GCAES system and a CAES system may be calculated, as follows: - 64 (2. 44)²D_CAES

2. 02D_CAES

[00113] The terms and expressions employed herein are used as terms and expressions of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof. In addition, having described certain embodiments of the invention, it will be apparent to those of ordinary skill in the art that other embodiments incorporating the concepts disclosed herein may be used without departing from the spirit and scope of the invention. The compositions, components, and functions can be combined in various combinations and permutations, to achieve a desired result. For example, all materials for components (including materials not necessarily previously described) that are suitable for the application are considered within the scope of the invention. Accordingly, the described embodiments are to be considered in all respects as only illustrative and not restrictive. Furthermore, the configurations described herein are intended as illustrative and in no way limiting. Similarly, although physical explanations have been provided for explanatory purposes, there is no intent to be bound by any particular theory or mechanism, or to limit the claims in accordance therewith.

Claims

1. A large access port to a subterranean chamber of a compressed air energy storage

system, the access port comprising: a liner having a proximal end near a ground level surface and a distal end near the subterranean chamber providing fluidic communication between the compressed air energy storage system and the subterranean chamber;

a plurality of separate pipes disposed within the liner and extending from the proximal end beyond the distal end of the liner providing fluidic communication with fluid in the subterranean chamber; and

support structure coupled to the liner for supporting the plurality of pipes.

2. The system of claim I, wherein the plurality of pipes includes at least one air flow pipe and at least one brine flow pipe.

3. The system of claim 2, wherein each of the at least one air flow pipe and the at least one brine flow pipe has a flow area in which the combined flow areas of the at least one brine flow pipe is about two to about four times the combined flow areas of the at least one air flow pipe.

4. The system of claim 1, wherein the liner comprises a diameter between about 5 feet and at least about 20 feet.

5. The system of claim 1, wherein the distal end of the liner is located above the

subterranean chamber.

6. The system of claim 1, wherein the distal end of the liner is cemented in position to form a shoe.

7. The system of claim 1, wherein the liner is adapted for cyclic exposure to compressive and tensile stresses.

8. The system of claim 1, wherein the support structure comprises a cap.

9. The system of claim 8, wherein the cap is disposed at the proximal end of the liner.

10. The system of claim 8, wherein the plurality of pipes hang from the cap.

1 1. The system of claim 8, wherein the cap comprises a dome.

12. The system of claim 1, wherein the plurality of pipes are coupled to a brine pond.

13. The system of claim 12, wherein the brine pond is at atmospheric pressure.

14. The system of claim 12, wherein the brine pond is pressurized above atmospheric

pressure.

15. A method of connecting a compressed air energy system to a subterranean chamber comprising the steps of: forming a large-diameter bore from a ground level surface to a depth proximate the subterranean chamber;

inserting a liner into the bore, the liner having a proximate end near the surface and a distal end near the subterranean chamber; and

coupling a plurality of separate pipes to the liner, the pipes extending from the proximal end beyond the distal end into the subterranean chamber.

16. The method of claim 15, wherein the plurality of pipes includes at least one air flow pipe and at least one brine flow pipe and each of the at least one air flow pipe and the at least one brine flow pipe has a flow area in which the combined flow areas of the at least one brine flow pipe is about two to about four times the combined flow areas of the at least one air flow pipe

17. The method of claim 16, wherein the combined flow areas of the at least one air flow pipe and at least one brine flow pipe facilitate high mass flow rates into and out of the subterranean chamber.

18. The method of claim 15, wherein the liner comprises a diameter between about 5 feet and at least about 20 feet.

19. The method of claim 15, wherein the inserting step comprises stopping the distal end of the liner above the subterranean chamber.

20. The method of claim 15, wherein the inserting step further comprises cementing a distal end of the liner to form a shoe.

21. The method of claim 15, wherein the liner is adapted for cyclic exposure to compressive and tensile stresses.

22. The method of claim 15 further comprising installing a cap coupled to the liner.

23. The method of claim 22, wherein the cap is disposed at the proximal end of the liner.

24. The method of claim 22, wherein the plurality of pipes are coupled to the liner via the cap.

25. The method of claim 24, wherein the plurality of pipes hang from the cap.

26. The method of claim 22, wherein the cap comprises a dome.

27. The method of claim 15 further comprising coupling the plurality of pipes to a brine pond.

28. The method of claim 27, wherein the brine pond is at atmospheric pressure.

29. The method of claim 27 further comprising pressurizing the brine pond above

atmospheric pressure.

30. The method of claim 15 further comprising coupling the liner to the compressed air energy storage system.

31. The method of claim 30 further comprising pressurizing the subterranean chamber with output from the compressed air energy storage system.

32. The method of claim 31 further comprising utilizing pressure in the subterranean

chamber to operate the compress air energy storage system.