Fluid storage in compressed-gas energy storage and recovery systems

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.

What is claimed is: 
     
         1 . A method of fabricating a lined underground reservoir, the method comprising:
 excavating rock at a site location to form an open shaft extending below ground level;   assembling within or above the shaft a fluid-impermeable liner substantially enclosing an interior volume for containing at least one of compressed gas or heat-transfer liquid, the interior volume being smaller than a total volume of the open shaft, wherein the liner comprises:
 an invert section enclosing a bottom of the interior volume, 
 a dome section enclosing a top of the interior volume opposite the bottom, and 
 a sidewall section substantially gaplessly spanning the invert and dome sections, wherein after assembly, the liner is disposed within the shaft below ground level; 
   disposing a surround material to at least partially fill a gap between an outer surface of the liner and an inner surface of the shaft around at least a portion of the outer surface of the liner;   after assembly of the liner and disposal of the surround material so as to form a surrounded liner, disposing an overfill material over the surrounded liner to fill at least a portion of a space between the ground level and the surrounded liner; and   fluidly connecting the interior volume enclosed by the liner to a fluid source or fluid sink external to the surrounded liner, thereby forming the lined underground reservoir.   
     
     
         2 . The method of  claim 1 , wherein the surround material comprises concrete or metal-reinforced concrete. 
     
     
         3 . The method of  claim 1 , wherein the liner comprises at least one of steel or plastic. 
     
     
         4 . The method of  claim 1 , wherein the overfill material comprises at least one of rock, concrete, or metal-reinforced concrete. 
     
     
         5 . The method of  claim 1 , wherein the overfill material comprises a volume of heat-transfer liquid. 
     
     
         6 . The method of  claim 1 , further comprising, prior to disposing the overfill material, forming within the shaft a plug shaped to laterally distribute upward-acting forces resulting when the liner contains pressurized fluid, wherein a width of the shaft around the plug is larger than a width of the shaft around the surrounded liner. 
     
     
         7 . The method of  claim 6 , wherein a cross-section of the plug in a plane approximately perpendicular to ground level is substantially trapezoidal or hexagonal. 
     
     
         8 . The method of  claim 1 , further comprising, prior to disposing the surround material, disposing a spacer on the liner that defines at least a portion of the gap between the outer surface of the liner and the inner surface of the shaft around at least a portion of the outer surface of the liner. 
     
     
         9 . The method of  claim 1 , further comprising:
 disposing within the interior volume of the liner a mechanism for generating a foam or droplet spray;   fluidly connecting the mechanism to a source of heat-transfer fluid external to the surrounded liner; and   fluidly connecting an area within the interior volume of the liner proximate the invert section to a sink of heat-transfer fluid external to the surrounded liner.   
     
     
         10 . The method of  claim 1 , wherein assembling the liner comprises:
 supporting a first portion of the liner above a bottom surface of the shaft such that a top surface of the first portion of the liner is proximate ground level;   disposing a second portion of the liner on the top surface of the first portion of the liner to form an at least partially assembled liner; and   lowering the at least partially assembled liner such that a top surface of the second portion of the liner is proximate ground level.   
     
     
         11 . The method of  claim 10 , wherein supporting the first portion of the liner comprises floating the first portion of the liner on a liquid within the shaft. 
     
     
         12 . The method of  claim 11 , wherein lowering the at least partially assembled liner comprises removing liquid from the shaft. 
     
     
         13 . The method of  claim 1 , further comprising, during disposal of the surround material, at least partially filling the interior volume of the liner with a liquid such that a top surface of the liquid is approximately coplanar with a top surface of the surround material. 
     
     
         14 . The method of  claim 1 , wherein (i) the sidewall section of the liner comprises a plurality of substantially cylindrical segments, and (ii) each cylindrical segment comprises a plurality of discrete curved portions connected at interfaces therebetween. 
     
     
         15 . The method of  claim 14 , further comprising welding the plurality of discrete curved portions together at the interfaces to form each of the substantially cylindrical segments. 
     
     
         16 . The method of  claim 1 , wherein the fluid source or fluid sink external to the surrounded liner is a compressed-gas energy storage and recovery system configured to store gas in the interior volume after compression thereof and extract gas from the interior volume before expansion thereof. 
     
     
         17 . The method of  claim 1 , further comprising disposing between the outer surface of the liner and the inner surface of the shaft a network of drainage pipes for channeling liquid away from the liner. 
     
     
         18 . The method of  claim 17 , further comprising spraying concrete on the network of drainage pipes. 
     
     
         19 . The method of  claim 1 , wherein a portion of the surround material is disposed over the dome section of the liner. 
     
     
         20 . The method of  claim 1 , wherein the surround material comprises a concrete layer and, disposed between the concrete layer and the liner, a viscous layer for mitigating force on the liner. 
     
     
         21 . The method of  claim 20 , wherein the concrete layer comprises therewithin a network of metal. 
     
     
         22 . The method of  claim 1 , wherein the shaft is substantially vertical. 
     
     
         23 . The method of  claim 1 , wherein, during assembly of the liner and disposal of the surround material, the site location is free of sub-surface access tunnels having a sufficiently large size and sufficiently shallow slope to accommodate vehicular traffic. 
     
     
         24 . The method of  claim 1 , wherein excavating rock comprises:
 (a) excavating one or more holes at the site location where the shaft is to be formed;   (b) placing an explosive in the one or more holes;   (c) detonating the explosive to pulverize the rock;   (d) removing the pulverized rock; and   (e) optionally, repeating steps (a)-(d).   
     
     
         25 . The method of  claim 1 , wherein excavating rock comprises:
 (a) pulverizing rock with a cutting mechanism mounted on a translatable telescoping boom to form at least a portion of the shaft;   (b) removing the pulverized rock; and   (c) optionally, lowering the cutting mechanism and boom into the at least a portion of the shaft and repeating steps (a) and (b).   
     
     
         26 . The method of  claim 1 , wherein (i) the surrounded liner is configured to contain a fluid pressure of at least 200 bar, and (ii) the rock at the site location has a rock mass rating of at least 50. 
     
     
         27 . The method of  claim 1 , wherein (i) the rock at the site location has a rock mass rating RMR, and (ii) the surrounded liner is configured to contain a maximum fluid pressure P in MPa defined by P≦(RMR×0.83)−25. 
     
     
         28 . The method of  claim 1 , wherein (i) a thickness of the liner is insufficient to withstand a maximum internal fluid pressure of the lined underground reservoir, and (ii) the lined underground reservoir is configured to withstand the maximum internal fluid pressure, notwithstanding the insufficient thickness of the liner, via at least one of the overfill or rock surrounding the surrounded liner withstanding a portion of the internal fluid pressure.