DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
The reply filed on 26 February 2026 has been entered. Claims 1-20 are pending in the application.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1-9 and 11-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over WO 2020/160670 A1 to Young et al. (Young) in view of US 2003/0021631 A1 to Hayashi et al. (Hayashi).
In reference to claim 1, Young discloses a hydrostatically compensated, compressed gas energy storage system comprising: a) an accumulator (12; Figs. 1-4) disposed underground and comprising an interior containing a layer of compressed gas above a layer of compensation liquid, the layer of compressed gas being at an accumulator pressure that is between about 20 bar and about 90 bar; b) a compressor and expander subsystem (100) in fluid communication with the accumulator interior via a gas flow path (22) and configured to selectably convey compressed gas into the accumulator and to extract gas from the accumulator; and c) a compensation liquid reservoir (150) spaced apart from the accumulator and a compensation liquid flow path (40, 54, 58) extending between the compensation liquid reservoir and the layer of compensation liquid within the accumulator, the system being operable in at least a charging mode in which the compressor and expander subsystem conveys gas into the layer of compressed gas thereby displacing a corresponding volume of compensation liquid from the layer of compensation liquid within the accumulator out of the accumulator via the compensation liquid flow path thereby maintaining the layer of compressed gas at substantially the accumulator pressure during the charging mode (“being operable” is interpreted as a recitation of intended use; Young is capable of the use, see pars. 0095-0096 and Figs. 4A, 4B, and therefore meets the limitation of the claim), but fails to explicitly disclose the compensation liquid (13; Fig. 2) having a density of at least 1500 kg/m3.
However, Hayashi discloses a similar hydrostatically compensated compressed gas energy storage system that utilizes a compensation liquid having a density of at least 1500 kg/m3 (par. 0034, Table 1: materials with a specific gravity of 1.6 and above). It would have been obvious for a person of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the high-density compensation liquid disclosed by Hayashi into the system of Young. A person of ordinary skill would have been motivated to do so, with a reasonable expectation of success, as the liquid advantageously provides for sealing of the walls of the accumulator thereby preventing release of compressed gas, as taught by Hayashi (par. 0036).
In reference to claim 2, the modified Young teaches the system of claim 1, wherein the system is operable in a discharging mode in which the compressor and expander subsystem extracts gas from the layer of compressed gas as a corresponding volume of compensation liquid flows from compensation liquid flow path into the layer of compensation liquid within the accumulator thereby maintaining the layer of compressed gas at substantially the accumulator pressure during the discharging mode (“is operable” is interpreted as a recitation of intended use; Young is capable of the use, see pars. 0098-0099, and therefore meets the limitation of the claim).
In reference to claim 3, the modified Young teaches the system of claim 1, wherein the compensation liquid is a slurry comprising solid particles suspended in water (Hayashi, par. 0034).
In reference to claim 4, the modified Young teaches the system of claim 3, wherein the solid particles comprise particles formed from at least one of clay (Hayashi, par. 0034, bentonite), ore, sand, rocks, magnetite, limestone, iron ore (Hayashi, par. 0034, hematite), copper concentrate.
In reference to claim 5, the modified Young teaches the system of claim 4, wherein the solid particles comprise one of magnetite, limestone, iron ore (Hayashi, par. 0034, hematite), and copper concentrate.
In reference to claims 6-8, since the modified Young uses the same compensation liquid (a slurry of clay or iron ore) with the same density (under 2400 kg/m3) as claimed, the compensation liquid would inherently have the same properties and suspension times claimed.
In reference to claim 9, the modified Young teaches the system of claim 1, wherein the compensation liquid density is less than 2400 kg/m3 (Hayashi, par. 0034, Table 1).
In reference to claim 11, the modified Young teaches the system of claim 1, wherein the accumulator pressure is at least 50 bar (par. 0086).
In reference to claim 12, the modified Young teaches the system of claim 1, wherein the accumulator is disposed at an accumulator depth that is between about 200m and about 700m (par. 0088).
In reference to claim 13, the modified Young teaches the system of claim 12, wherein the accumulator depth is less than 500m (par. 0088).
In reference to claim 14, the modified Young teaches the system of claim 1, wherein: a) the compensation liquid flow path comprises a shaft (18) having a lower end adjacent the accumulator (12), 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 the compensation liquid (see Figs. 1, 4), the shaft interior being fluidly connected to the compensation liquid reservoir (via 58); and b) further comprising a partition (24) separating an interior of the accumulator from the shaft interior, the partition having an outer surface in contact with the quantity of compensation liquid within the shaft interior and an opposing inner surface in contact with the layer of compressed gas and the layer of compensation liquid, whereby at least one of the layer of compressed gas and the layer of compensation liquid bears against and exerts an internal accumulator force (41) on the inner surface of the partition and the quantity of liquid within the shaft bears against and exerts an external hydrostatic counter force (46) on the outer surface of the partition, so that a partition force acting on the partition while the compressed gas energy storage system is in use is a difference between the accumulator force and the hydrostatic counter force and is less than the accumulator force (par. 0072).
In reference to claim 15, the modified Young teaches the system of claim 14, wherein the shaft interior is fluidly connected to the layer of compensation liquid by a liquid supply conduit (40) so that the compensation liquid can flow between the shaft interior and the layer of liquid in the accumulator in response to changes in the pressure of the layer of compressed gas.
In reference to claim 16, the modified Young teaches the system of claim 15, wherein the liquid supply conduit (40) passes thorough the partition (24) or beneath the partition.
In reference to claim 17, the modified Young teaches the system of claim 14, wherein a liquid supply conduit (40) extends between a first end that is proximate the outer surface of the partition (24) and is in fluid communication with the shaft (18) and a second end that is in communication with the layer of compensation liquid (16) and remains fluidly isolated from the layer of gas when the compressed gas energy storage system is in use (see Figs. 1, 4).
In reference to claim 18, the modified Young teaches the system of claim 1, wherein the gas flow path comprises a gas supply conduit (22) configured to convey compressed gas between the layer of compressed gas and the compressor and expander subsystem (100), and wherein at least a portion of an outer surface of the gas supply conduit is in contact with the compensation liquid in the compensation liquid flow path (inside shaft 18).
In reference to claim 19, the modified Young teaches the system of claim 18, wherein the gas supply conduit (22) passes through a partition (24).
In reference to claim 20, the modified Young teaches the system of claim 1, wherein the gas flow path comprises a gas supply (22; Fig. 4) conduit that is external to the liquid flow path and is configured to convey compressed gas between the layer of compressed gas and the compressor and expander subsystem (see Fig. 4).
Claim(s) 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over the modified Young as applied to claim 1 above, and further in view of US 3,064,436 A to Loofbourow et al. (Loofbourow).
In reference to claim 10, the modified Young teaches the system of claim 1, but fails to explicitly disclose an agitation system. However, Hayashi teaches one of the advantages of using a bentonite slurry as a compensation liquid is that it aids in sealing the underground cavern. Loofbourow discloses utilizing bentonite to seal an underground cavern and utilizes an agitating system (57; Fig. 4) configured to agitate the liquid within the compensation liquid reservoir to help keep solid particles suspended in water (col. 3, line 71 - col. 4, line 2). It would have been obvious for a person of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the agitating system disclosed by Loofbourow into the system of the modified Young. A person of ordinary skill would have been motivated to do so, with a reasonable expectation of success, as it would advantageously maintain the suspension of particles, thereby ensuring its sealing properties, as taught by Loofbourow.
Response to Arguments
Applicant’s arguments with respect to claim(s) 1-20 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JONATHAN MATTHIAS whose telephone number is (571)272-5168. The examiner can normally be reached Monday-Wednesday 10am - 6pm Pacific Time.
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/JONATHAN R MATTHIAS/Primary Examiner, Art Unit 3746
18 March 2026