Electrical energy storage in form of underground gravitational and buoyancy energy

Abstract

Described herein is the construction of underground facilities for storing electrical energy in the form of gravitational energy and buoyancy energy. In one embodiment, the facility is disposed in a thixotropic fluid beneath the earth surface and houses water for maintaining positive buoyancy and a piston having a greater bulk density than water. In another embodiment, the underground facility is configured as a buoyancy compartment disposed in a cylinder filled with water, where the cylinder is sealed except for an opening in the lower half portion of the cylinder so that water flows from a location inside the cylinder to a location outside the cylinder with little obstruction. In another embodiment, an underground facility is configured as a negative buoyancy bay.

Description

[0001] Inventor: Brian Lane

[0002] Priority claim

[0003] This application claims priority to U.S. Provisional Application No. 63 / 344,638, filed on May 23, 2022, and U.S. Non-Provisional Application No. 181 / 988,55, filed on May 18, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0004] The present disclosure generally relates to constructing underground facilities for storing electrical energy in the form of gravity energy and buoyancy energy. Background Art

[0005] The electricity-producing industrial sector is increasingly relying on renewable energy sources such as wind and solar for electricity generation. The electricity generated from these sources is intermittent, so increasing electricity storage is beneficial in the short, medium and long term.

[0006] Short-term storage can be provided by chemical batteries (more commonly lithium-ion batteries), flywheels, and intermittent fossil fuel generators. But chemical batteries consume energy over time, resulting in energy losses. Long-term storage can be provided by hydroelectric storage. Hydroelectric storage can store large amounts of energy for long periods of time, but it is limited by geographical location.

[0007] It has also been proposed to store electrical energy in the form of gravitational energy. A known solution is to use electrical energy obtained from the grid or other sources to raise and lower a mass by pumping water from the bottom to the top or from the top to the bottom of a closed container. This storage relies on raising the mass to a certain height, keeping it at a higher height, and lowering it at the desired time. The energy stored by raising the mass and the energy released by lowering the mass is the product of the mass, the height raised, and the gravitational acceleration constant. Electrical energy stored in the form of gravitational energy can provide electrical energy with a response time of minutes or hours, for example, it can be cycled multiple times a day or less frequently depending on the renewable energy generation cycle and / or consumer demand. Storing electrical energy in the form of gravitational energy can provide long-term storage without consuming energy.

[0008] There remains a need in the art for large-scale facilities that can be easily and cheaply built at a variety of locations for storing electrical energy in the form of gravity or buoyancy energy, independent of existing configurations at the location, such as the presence of mines or the presence of terrain suitable for forming reservoirs.

[0009] The energy storage facility is located underground so that it can have a sufficiently long life and / or not age prematurely. Preferably, the underground facility is designed to provide medium to large-scale energy storage, on the order of tens to thousands of megawatt hours (MW-hr).

[0010] Alternatively, a secluded and very deep body of water may be a good location for a floating facility, where the facility is constructed of durable materials. Preferably, a floating facility can be configured to be very large in scale, as the construction elements of the facility can be more easily transported to the site from a remote offshore fabrication facility, also with a storage capacity of tens to thousands of megawatt-hours (MW-hr). Summary of the invention

[0011] A modular cylindrical structure suitable for storing electrical energy in the form of gravity energy or buoyancy energy, comprising a cylindrical outer wall, which can be made of steel or reinforced concrete or a composite material of steel and concrete. The longitudinal axis of the cylindrical structure is vertical, the bottom is closed, and includes a pipe connecting the lower and upper ends of the facility, or alternately arranges pipes between the upper and lower ends of the piston, and is supported in a buoyancy, semi-buoyancy or fixed system. As others have proposed, the cylindrical structure surrounds a single or segmented mass body that can move up and down along a vertical longitudinal axis to lift or lower the mass body. When the piston descends, for example, through a process called regenerative loading, the motor can return electrical energy to the power grid or other loads. The piston preferably includes a steel or concrete container filled with soil, rock, a relatively high specific gravity solid material, or in the case of buoyancy energy, a relatively low specific gravity container immersed in a fluid (e.g., an air-filled container).

[0012] The facility can be constructed at any onshore site with reasonable surface conditions, or at an offshore site in deep, sheltered waters connected to a grid. For example, the facility can be constructed as part of a power source, such as near a farm of wind turbines or solar panels that can only generate electricity intermittently. Power sources that combine intermittent generation of electricity with storage of electricity in the form of gravitational energy can provide a more uniform supply of electricity to the grid and / or provide higher peak power to the grid during peak demand. The piston is configured as a solid mass having a volume density much higher than the surrounding fluid.

[0013] Alternatively, the specific gravity of the piston can be much lower than that of the surrounding fluid. In this alternative case, the stored energy can rise against the force of buoyancy rather than against the downward force of gravity. Using a piston with a very low density can reduce material requirements and thus reduce costs, which will reduce the levelized cost of energy storage. A low-density piston can be achieved by forming a hollow capsule or multiple capsules (a "cabin" is a three-dimensional shape composed of a cylinder with flat or hemispherical ends) using high-strength materials, which have a high ability to resist pressure perpendicular to its surface. Alternatively, the capsule can be a solid form of low-density material that can resist hydrostatic pressure perpendicular to its surface with very little deformation. The gravity or buoyancy structure form can be selected based on the availability or cost of materials on site or geological conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings, in which:

[0015] Figure 1 is a cross-sectional, partially cut-away view of a first embodiment of an underground facility suitable for storing electrical energy in the form of gravity energy in accordance with at least some embodiments disclosed herein.

[0016] Figure 2 A cross-sectional, partially cut-away view of a first embodiment of an underground facility suitable for storing electrical energy in the form of gravity energy having a cylinder supported by in situ concrete instead of a foundation in accordance with at least some embodiments disclosed herein.

[0017] Figure 3 Plan and cross-sectional views of a modular facility having eight (8) underground storage facilities at one site for storing electrical energy in the form of gravity energy according to at least some embodiments disclosed herein.

[0018] Figure 4 Detailed cross-sectional view of a subsea floating piston seal suitable for storing electrical energy in the form of gravity energy according to at least some embodiments disclosed herein.

[0019] Figure 5 is a detailed view of a piston in a raised position for periodic seal maintenance, according to at least some embodiments disclosed herein.

[0020] Figure 6 Detailed cross-sectional, partially cut-away view of a first embodiment of an underground facility suitable for storing electrical energy in the form of gravity energy using positive buoyancy chambers in accordance with at least some embodiments disclosed herein.

[0021] Fig. 7A , Figure 7B and Figure 7C Shown are cross-sectional, partially cut-away views of negative buoyancy compartments according to at least some embodiments disclosed herein.

[0022] Figure 8 Detailed cross-sectional, partial cut-away views of pumping systems embedded in a solid piston are shown, according to at least some embodiments disclosed herein.

[0023] Fig. 9 Detailed cross-sectional, partially cut-away views of a pumping system embedded in and attached to a positive buoyancy chamber are shown, in accordance with at least some embodiments disclosed herein.

[0024] Fig.10 sectional view of an underwater floating facility for storing electrical energy in the form of gravity energy incorporating an integral pump and piston arrangement according to at least some embodiments disclosed herein.

[0025] Fig.11 A cross-sectional view of an underwater floating facility for storing electrical energy in the form of gravity energy using positive buoyancy tanks in combination with an integral pump system in accordance with at least some embodiments disclosed herein.

[0026] Fig.12 Detailed cross-sectional, partial cut-away, and detailed plan views of a piston guide system integrating a solid piston and a pump for controlling the deflection movement of the piston and facilitating fluid flow from beneath the piston to the pump are shown according to at least some embodiments disclosed herein.

[0027] Fig.13 Detailed cross-sectional, partial cutaway views of a pumping system depicting a piston and cylinder below the surface of the earth, according to at least some embodiments disclosed herein.

[0028] Fig.14 Detailed cross-sectional, partial cutaway views of pumping systems showing an offset piston and cylinder at or above the surface, according to at least some embodiments disclosed herein.

[0029] Fig.15 A detailed partial cross-sectional view of a pumping system showing offset pistons and cylinders and a manifold system connecting multiple silos to a single pump or multiple pumps according to at least some embodiments disclosed herein.

[0030] Fig.16 A detailed cross-sectional, partially cut-away view of a pumping system shown positioned between a solid piston bottom and a pipe caisson bottom and having a cable retrieval system to accommodate piston movement, according to at least some embodiments disclosed herein. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention will now be described with reference to the accompanying drawings. The same elements in different drawings are identified by the same reference numerals. Each embodiment of the present invention will now be described in detail. These embodiments are provided to explain the present invention, and the present invention is not limited thereto. In fact, it will be understood by those of ordinary skill in the art after reading this specification and viewing the accompanying drawings that various modifications and changes may be made thereto.

[0032] It should be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures or functions of the present invention. Exemplary embodiments of components, arrangements and configurations are described below to simplify the disclosure; however, these exemplary embodiments are provided only as examples and are not intended to limit the scope of the present invention. In addition, without departing from the scope of the present disclosure, the exemplary embodiments presented below may be combined in any manner, that is, any element of an exemplary embodiment may be used in any other exemplary embodiment.

[0033] Figure 1 An underground facility suitable for storing electrical energy in the form of gravity energy is shown. The underground facility includes a deep excavation area filled with a thixotropic fluid 10, which is preferably cylindrical and may include a steel or reinforced concrete or composite steel-concrete liner 12, depending in part on surface and groundwater conditions. The density of the thixotropic fluid will be adjusted to suit the surface conditions near the excavation area, and the buoyancy will support the gravity energy storage cylinder and associated piping without the need for structural support at its bottom. The underground excavation area 12 can be built up to a depth of up to 5000 meters and a diameter of 50 meters depending on the required energy storage capacity. The top cover 14 of the underground facility 16 is located on and supported by the surrounding soil.

[0034] A cylinder 16 of steel or rebar or a steel and concrete composite will be fabricated on top of the filled excavation area and gradually lowered into the thixotropic liquid. Construction techniques will progressively fill the cylinder with water 18 to maintain near neutral but positive buoyancy. A piston 20 will be constructed in a similar manner at the surface and gradually lowered into the water filled piston. The piston will be constructed of concrete and sand or other materials having a bulk density greater than water. The highest bulk densities can be obtained by incorporating relatively high density materials, such as waste depleted uranium hexafluoride, which is present in relatively large quantities in the United States and some other countries. Higher density materials offer the opportunity to reduce the size of the overall facility, thereby reducing the overall cost.

[0035] The outer wall of the apparatus 16 will support symmetrically arranged pipes 22 connecting the water chambers on the bottom side with pumping facilities 28. The pipe system will include submersible valves 24 and semi-submersible pumps 24 to lift water from the lower chamber to the upper chamber. Reverse flow under the action of gravity will force the rising water back to the lower chamber and drive the regeneration pump. Power cables 26 will provide power to the pumps and water pipes, and thixotropic lines 28 will provide replenishing fluid to the system in the event of fluid loss to the surface or evaporation.

[0036] Figure 2 Another arrangement is shown in which a cylinder filled with water 18 is firmly supported in a cast-in-place concrete plug 44. When the piston 20 is at rest in the lowermost position it rests on a structural support 46. This structural support arrangement provides structural support that is independent of the balancing buoyancy from the thixotropic liquid which should be beneficial, given the selected storage facility size and on-site ground conditions.

[0037] Figure 3It shows how multiple facilities can be built on a single site, limited only by the available land surface area and surface conditions suitable for the excavation area and surface support. In addition, the circular arrangement of underground facilities facilitates the sharing of construction, operation and maintenance equipment, helping to ensure low unit storage costs. Spacing of underground facilities at three times the diameter of the excavation area is a conventional approach to foundation configuration, but can be as low as two times the diameter of the excavation area if surface conditions allow for closer spacing.

[0038] Figure 4 A flexible seal 32 is shown disposed between the piston and the cylinder wall at the top of the piston. At least one row but possibly up to three rows of seals should be provided as backup. The seal is secured in the piston by an insert to resist the upward force exerted on the seal by the water pressure and the friction exerted by the outward pressure on the seal pushing against the cylinder. The seal is configured to be durable for the design life but will provide for replacement when the piston is lifted out of the water. Several possible seal types are contemplated, such as O-rings, saddle types, or more flexible flap types, examples of which can be found in industry.

[0039] The inside of the cylinder may be lined with a polyurethane coating, fusion bonded epoxy or thin film epoxy or powder coating to enhance the corrosion protection of the liner and reduce the coefficient of sliding friction, thereby reducing resistance to cylinder movement and minimizing seal wear. The application method will be consistent with the application method of the inner surface of, for example, a steel pipeline used for fluid transportation.

[0040] Figure 4 Also shown is an inflatable bladder 34 located below the seal. The bladder is inflated by water pressure provided by a small diameter pipe 28 connected to the top of the piston 38 and a temporary pump 36, which applies water pressure to the bladder to inflate it to a pressure equal to that required to support the partially submerged piston. Under the action of the water pressure, the inflatable bladder 34 will fill the space between the piston and the cylinder to make a seal, which is different from the inflatable seals commonly used in household plumbing repair tasks. Once the seal is in place, the piston can be lifted above the top of the cylinder for occasional maintenance or replacement of the piston seal. The ability to lift the piston seal above the water surface will be achieved by pumping water 22 into the space below the piston 20.

[0041] Figure 5 The piston is shown lifted a short distance above the surrounding cylinder, enough to expose the seal 32 on the top of the piston 20 above the top of the cylinder. The seal can then be maintained or replaced as needed. This extreme lifting operation will only be done periodically since the cylinder and container will be kept in a clean condition. The bottom of the piston will include guide rollers and lateral springs 40 at the bottom of the piston. These parts cannot be maintained, so strong bearings are installed.

[0042] In the cycle of electrical energy storage and generation, a small amount of energy is dissipated in friction of the seal between the piston and the cylinder, friction losses in the pump motor, friction losses in the pipe inlet, pipe length, and pipe outlet, and cable losses. However, by properly designing the mechanical elements, energy efficiencies of 85% or more can be achieved to achieve round-trip efficiencies of 75% or more, which is consistent with those measured in utility-scale hydroelectric storage schemes. These design elements will be the selection of low friction seals and bearings.

[0043] Figure 6 An alternative to the heavy mass configuration is shown to be the configuration of buoyancy tanks. The buoyancy tanks 40 are arranged in a cylinder filled with water 18, which is a sealed tube except for an opening in the lower half of the cylinder to allow water to flow almost unimpeded from the inside of the cylinder to the outside. The buoyancy tanks 40 rise and fall as water is released or added to the top of the cylinder. Adding water to the top of the cylinder under pressure stores energy, and releasing the water at the top of the cylinder through a turbine recovers the stored energy, minus the energy lost due to friction and mechanical losses.

[0044] Fig. 7A , Figure 7B and Figure 7C A possible configuration of the buoyancy tanks is shown. Fig. 7A A cylindrical chamber 40 of stainless steel or carbon steel or aluminum is shown with internal reinforcement 42 required to resist the pressure differential across the chamber. The reinforced steel chamber can be configured to withstand at least half of the pressure applied to the chamber. When the chamber is located on top of the water-filled cylinder 18, air pressure can be periodically increased and replenished through an air valve 44.

[0045] Figure 7B An alternative arrangement of a PVC or HDPE or other plastic capsule 40 filled with aerated polyvinyl chloride (PVC) or high density polyethylene (HDPE) or other aerated plastic is shown so that the bulk density of the capsule is much less than the density of the water or other fluid in the cylinder. The capsule material is selected to provide the lowest possible density while maintaining sufficient strength to resist the external hydrostatic pressure applied at the maximum depth of the capsule. Such a device is provided in HDPE in the form of a seawater buoy having a rigid HDPE outer layer and an aerated HDPE inner layer of fill material.

[0046] Figure 7C An alternative arrangement of a set of pipes forming a cylindrical chamber 40 is shown. An arrangement of 19 or 37 vertical pipes can ensure that all pipes touch in a circle to ensure optimal lateral stability. The pipes will be gas-tight and water-tight and can be pressurized to reduce stress on the pipes. The hoop strength of the pipes can resist external hydrostatic pressure. Seals are located at the top and bottom of the cylinder with lateral restraint provided by closing plates.

[0047] Figure 8A cross-sectional view of a pumping system mounted in a solid piston is shown. The advantage of this arrangement is that the fluid passes more directly through the seal, thereby reducing losses. Four pumps 48 are provided to ensure redundancy and operate in opposite directions, thereby reducing longitudinal axis rotation of the piston (called deflection). Alternatively, a single pump with deflection compensation can be integrated. The power cable 50 is arranged or telescoped in concertina style, or fed to or from a cable reel to carry out the planned vertical movement of the piston. A pipe 52 is cast into the piston body to allow water to flow through the piston. A pipe valve 54 can be remotely operated to shut off the flow when the piston needs to be maintained at a selected height.

[0048] Fig. 9 A negative buoyancy tank is shown with a pumping system mounted on top of the tank. As above, four pumps 48 are provided and the power cables are arranged or telescoped in concertina fashion to allow for the planned vertical movement of the piston. There are two or four vertical pipes 52 in the tank to allow water to flow through the tank. When the piston needs to be maintained at a selected height, a pipe valve 54 can be remotely operated to shut off the flow.

[0049] The proposed gravity piston solution can be adjusted to suit the required energy storage capacity by, for example, changing the cylindrical outer wall dimensions, piston height dimensions, and piston density. For example, an excavation area with a diameter of about 20 meters and a depth of 536 meters would correspond to an energy storage capacity of 100 MW-hr of gravity energy per facility. On a larger scale, an underground storage facility with an excavation area of ​​about 40 meters in diameter and 2,634 meters deep would correspond to an energy storage capacity of 10,000 MW-hr.

[0050] The proposed buoyancy chamber solution can also be adjusted to suit the required energy storage capacity by, for example, changing the cylindrical outer wall dimensions, piston height dimensions, and supporting fluid density. For example, an excavation area with a diameter of about 20 meters and a depth of 790 meters would correspond to an energy storage capacity of 100 MW-hr of gravity energy per facility. On a larger scale, an underground storage facility with an excavation area of ​​about 38 meters in diameter and 4,124 meters deep would correspond to an energy storage capacity of 10,000 MW-hr.

[0051] Fig.10 A similar arrangement is shown, where the floating alternative concept can be configured to a similar capacity in sheltered waters. It can be installed in seawater or freshwater locations, with its depth and diameter limited only by the water depth and actual buoyancy volume.

[0052] Fig.11 A similar arrangement is shown where a second alternative concept of a floating positive buoyancy piston can be configured to a similar capacity in sheltered waters. It can also be installed in seawater or freshwater locations, with its depth and diameter limited only by the water depth and actual surface volume.

[0053] Fig.12 A gravity piston or buoyancy chamber 20 is shown in a cylinder 16, but the cylinder has two or more vertical sealed chambers 56 arranged to guide the vertical movement of the piston or chamber. The guide chambers prevent the piston or chamber from rotating in the plane, i.e. yaw. The guide chambers are designed in proportion to allow water to flow from the pump / turbine to the bottom of the piston. These chambers are open at a lower height to allow water to flow through. The guide chambers end at a height suitable for supporting the pump 24, and have an appropriate water level above this height to achieve efficient pumping of water from above the piston to below. In addition, the bottom of the piston is backfilled with coarse gravel 70, which provides permeable support for the piston if the piston is at its lowest height.

[0054] Fig.13 The cylinder is shown with a guide chamber (such as Fig.12 The upper water chamber and pilot chamber 56 are hydraulically connected to external piping 58 at a height below the ground outside the silo. The combined pump / turbine is embedded at a height suitable for supporting the pump and having an appropriate water level above this height to achieve efficient pumping of water from above the piston to below.

[0055] Fig.14 Shows that there is Fig.12 The cylinder of the pilot chamber shown in FIG. 1 is a cylinder of a pilot chamber, but the pump is arranged at or above the ground surface for ease of operational access. The water level in the cylinder is raised to a height suitable for supporting the pump and having an appropriate water level above the height to achieve efficient pumping of water from above the piston downward. This requires a closed top of the cylinder 60 and an elevated standpipe 62. The closed top of the cylinder is removable to allow occasional access to lift the piston to perform the aforementioned seal maintenance.

[0056] Fig.15 A multiple silo energy storage facility is shown where several silos 64 are grouped adjacent to a common pump and turbine facility 66 for power consumption and generation. By sharing the common facility, the overall economy, redundancy, and responsiveness of the energy storage facility can be improved. By opening or closing the valves 68 to each silo, the combined pump / turbine facility can be operated at different but graded flow rates.

[0057] Fig.16A positive buoyancy chamber is shown having a pumping system consisting of a set of relatively high volume density pipes with integrally sealed tops and bottoms mounted at the bottom of the chamber. A pump 70 is provided, and the power cable is arranged in a reeled or telescopic form 72 to allow for planned vertical movement of the piston. One or more vertical pipes 74 are provided in the chamber to allow water to flow through the chamber. When the piston needs to be maintained at a selected height, a pipe valve 76 can be remotely operated to shut off the flow. With the pump located at the lower end of the piston, the water level 76 can be lowered to slightly above the upper water level of the piston, thereby maximizing the efficient use of the height of the entire facility. A similar arrangement can be configured with a solid piston instead of a set of pipes. As described above, a similar arrangement of an inflatable bladder below the top seal can be included to occasionally lift to access and maintain the seal.

[0058] The proposed gravity piston scheme can be adjusted to suit the required energy storage capacity by, for example, changing the cylindrical outer wall dimensions, piston height dimensions and piston density.

[0059] The description of various embodiments of the present invention is for illustrative purposes only and is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein are intended to best explain the principles of the embodiments, practical applications, or technical improvements to the technology found on the market, or to enable others or ordinary skill in the art to understand the embodiments disclosed herein.

[0060] When introducing elements of the present disclosure or embodiments thereof, the articles "a / an" and "the" are intended to indicate that there are one or more such elements. Similarly, when used to introduce an element, the adjective "another" is intended to indicate one or more elements. The terms "including" and "having" are intended to be inclusive, such that there may be other elements in addition to the listed elements.

[0061] Although the present invention has been described with a certain degree of particularity, it should be understood that the disclosure is made by way of illustration only and that various changes may be made in the details of construction and arrangement of parts without departing from the spirit and scope of the invention.

Claims

1. A system suitable for storing electrical energy in the form of gravitational energy, the system comprising: an excavation area disposed below the surface of the earth, the excavation area being surrounded by a fluid; a liner surrounding said excavated area; a cylindrical facility having a first side disposed opposite a second side, the first side being above the surface, the second side being disposed in a fluid below the surface, wherein the cylindrical facility contains water for maintaining positive buoyancy and a piston having a bulk density greater than that of water; a piping device connecting the cylindrical facility to a pumping facility disposed above the ground surface; a top cover disposed above the ground surface and covering the first side of the cylindrical facility; Power supply cables located above ground level; and A water pipe and a thixotropic pipe are disposed above the ground surface and are configured to supply fluid to the system.

2. The system of claim 1, wherein the excavation area is cylindrical.

3. The system of claim 1, wherein the fluid comprises a thixotropic fluid.

4. The system of claim 1, wherein the liner comprises a material selected from the group consisting of: steel, reinforced concrete, and composite steel-concrete.

5. The system of claim 1, wherein the excavation zone has a depth of up to about 5000 meters.

6. The system of claim 1, wherein the excavation area has a diameter of up to about 50 meters.

7. The system of claim 1, wherein the plumbing arrangement comprises a valve and a pump disposed below the surface of the earth, and wherein the plumbing arrangement is configured to lift water from the lower chamber to the upper chamber.

8. The system of claim 1, further comprising: A plug is disposed below the second side of the cylindrical facility.

9. The system according to claim 8, further comprising: A structural support member is disposed between the second side of the cylindrical facility and the plug.

10. The system of claim 9, wherein the piston is located on the structural support member when the piston is at rest in a lowermost position.

11. The system of claim 8, wherein the plug comprises a concrete material.

12. The system of claim 1, wherein the number of the cylindrical facilities is more than one, such that a first cylindrical facility is spaced a distance from a second cylindrical facility.

13. The system of claim 1, further comprising: One or more flexible seals are provided between the piston and the wall of the cylindrical arrangement on top of the piston.

14. The system of claim 13, wherein the one or more flexible seals are arranged in at least three rows.

15. The system of claim 13, wherein the one or more flexible seals are secured in the piston by an insert.

16. The system of claim 13, further comprising: An inflatable bladder is disposed beneath the one or more flexible seals.

17. The system of claim 16, wherein the inflatable bladder is configured to inflate under water pressure, the water pressure being provided by a conduit connected to the top of the piston and a temporary pump, the temporary pump applying water pressure to the inflatable bladder to inflate to a pressure equal to the pressure required to support the partially submerged piston.

18. The system of claim 17, wherein under the action of the water pressure, the inflatable bladder is configured to fill the space between the piston and the cylindrical facility to seal.

19. The system of claim 18, wherein the piston can be raised to a position above the top of the cylindrical facility with the seal in place to allow maintenance or replacement of the piston seal.

20. The system of claim 1, wherein the interior of the cylindrical facility is lined with a coating material.

21. The system of claim 20, wherein the coating material is selected from the group consisting of a polyurethane coating, a fusion bonded epoxy or powder coating, and a thin film epoxy or powder coating.

22. The system of claim 1, wherein the ducting means comprises a set of vertical ducts located in the inner wall of the cylindrical facility, and The set of vertical pipes constrains the piston from deflection.

23. The system of claim 22, further comprising: One or more flexible seals are disposed between the piston and a wall of a cylindrical facility on top of the piston, wherein the one or more flexible seals are continuous and formed around a non-cylindrical shape including the set of vertical conduits.

24. The system of claim 1, wherein the conduit arrangement is supported in an overhead position and is sufficiently submerged to operate the pumping facility.

25. A system adapted to store electrical energy in the form of gravitational energy, the system comprising: an excavation area disposed below the surface of the earth, the excavation area being surrounded by a fluid; a liner surrounding said excavated area; a buoyancy chamber disposed in a water-filled cylinder, wherein the cylinder is sealed with an opening portion in a lower half of the cylinder to allow water to flow virtually unimpeded from a location inside the cylinder to a location outside the cylinder; Pipe means connecting the cylinder to the pumping facilities located above the ground surface; Power supply cables located above ground level; and A water pipe and a thixotropic pipe are disposed above the ground surface and are configured to supply fluid to the system.

26. The system of claim 25, wherein the buoyancy chamber rises and falls as water is released or added to the top of the cylinder.

27. The system of claim 25, further comprising: A pressure-resistant top cover and riser covering the cylinder and configured to provide the water pressure required for optimal pump operation.

28. The system of claim 25, wherein the buoyancy chamber is made of a material selected from the group consisting of stainless steel, carbon steel, aluminum, polyvinyl chloride (PVC), and high-density polyethylene (HDPE).

29. The system of claim 25, wherein the buoyancy chamber is formed by an arrangement of vertical tubes.

30. The system of claim 29, wherein the vertical conduit is gas-tight, water-tight, and pressurized.

31. A system adapted to store electrical energy in the form of gravitational energy, the system comprising: an excavation area disposed below the surface of the earth, the excavation area being surrounded by a fluid; a liner surrounding said excavated area; Negative buoyancy tank; a pumping system mounted on top of the negative buoyancy tank; a plurality of pumps located above the surface and configured to interact with a power cable located above the surface to move the piston vertically; and A pipeline valve is remotely actuated to shut off flow when the piston is maintained at a given height.

32. The system of claim 31 , wherein the buoyancy compartment is formed by an arrangement of vertical tubes, and wherein the vertical tubes are gas-tight, water-tight and pressurized.

33. The system of claim 32, wherein a set of vertical pipes are located in the buoyancy chamber to allow water to flow through the buoyancy chamber.

34. The system of claim 31 , wherein the plurality of pumps number four.

35. The system of claim 31 , wherein the plurality of pumps are located outside of the silo and connected to the internal piping.

36. The system of claim 35, wherein the guide and the internal conduit extend to the surface, and wherein the plurality of pumps or turbines are located above the surface.

37. The system of claim 35, wherein a plurality of silos are arranged as an energy storage facility with a common pump / turbine and plant utilities.

38. The system of claim 37, wherein the system further comprises: Valve options that allow facilities to operate in stepped energy storage and generation from low to very high power.

39. The system of claim 35, wherein the system further comprises: A gravel cushion at the bottom of the silo having the ability to support the gravity weight of the piston or chamber to prevent the piston or chamber from being lowered to the lowest possible height.

40. The system of claim 39 wherein a conduit into the gravel pad applies water pressure beneath the piston or chamber causing it to be lifted to store energy.

41. The system of claim 1, wherein the piston comprises a set of negatively buoyant tubes in cylindrical or other polygonal forms or of variable diameter to achieve higher packing density, which negatively buoyant tubes can be filled with soil, rock or even depleted uranium hexafluoride to achieve optimal efficiency.

42. The system of claim 41, wherein the single or multiple conduits transport fluid from above the piston to below the piston with a pump and turbine located at the bottom of the piston.

43. The system of claim 42, wherein the power cord is fed from a roller above the facility to achieve a total depth of the facility. 1 / 2 vertical movement.

44. The system of claim 42, wherein the liquid level is at atmospheric pressure and near the surface.

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