CN119256157A - Storage of electrical energy in the form of underground gravitational and buoyancy energy - Google Patents

Abstract

This article describes the construction of an underground facility for storing electrical energy in the form of gravity energy and buoyancy energy. In one embodiment, the facility is set in a thixotropic fluid below the surface and contains water for maintaining positive buoyancy and a piston with a volume density greater than that of water. In another embodiment, the underground facility is configured as a buoyancy chamber arranged in a cylinder filled with water, wherein the cylinder is sealed except for an opening in the lower half of the cylinder to allow water to flow almost unimpeded from a position inside the cylinder to a position outside the cylinder. In another embodiment, the underground facility is configured as a negative buoyancy chamber.

Description

Storage of electrical energy in the form of underground gravitational and buoyancy energy

The inventor is Blaine-Lei En

Claims of priority

The present application claims priority from U.S. provisional application No. 63/344,638, filed 5/23, 2022, and U.S. non-provisional application No. 181/988,55, filed 5/18, 2023, which are incorporated herein by reference in their entirety.

Technical Field

The present disclosure relates generally to building an underground facility for storing electrical energy in the form of gravitational energy and buoyancy energy.

Background

The power generation industry sector increasingly relies on renewable energy sources such as wind energy and solar energy to generate electricity. The power generated from these sources is intermittent, so it is beneficial to increase power storage in the short, medium and long term.

Short term storage may 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 may be provided by hydraulic storage. Hydraulic storage can store large amounts of energy for long periods of time, but it is limited by geographic location.

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 an electrical grid or other source to raise and lower the mass by pumping water from the bottom of a closed container to the top or from top to bottom. This storage relies on lifting the mass to a certain height, maintaining it at a higher height, and lowering it at the required time. The energy stored by lifting the mass and the energy released by lowering the mass are the product of the mass, the height of the lift and the gravitational acceleration constant. The electrical energy stored in the form of gravitational energy may be provided in response times of minutes or hours, for example, may be cycled multiple times per 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.

There remains a need in the art for a large facility that can be adapted to be easily and inexpensively built at various sites for storing electrical energy in the form of gravitational or buoyancy energy, independent of existing configurations at the site, such as the presence of mines or the presence of terrain suitable for the formation of reservoirs.

The energy storage facility may be located underground with a sufficiently long life and/or without premature aging. Preferably, the underground facilities are designed to provide medium to large scale energy storage, on the order of tens to thousands of megawatts (MW-hr).

Or a concealed and very deep body of water may be a good location for floating facilities, where the facilities are constructed of durable materials. Preferably, the floating facility can be configured to be very large scale, as the building elements of the facility can be more easily transported from the remote offshore manufacturing facility to the site, again with storage capacities on the order of tens to thousands of megawatt hours (MW-hr).

Disclosure of Invention

A modular cylindrical structure adapted to store electrical energy in the form of gravitational or buoyancy energy, comprising a cylindrical outer wall, which may be made of steel or reinforced concrete or a composite of steel and concrete. The longitudinal axis of the cylindrical structure is in a vertical direction, closed at the bottom and comprises pipes connecting the lower and upper ends of the installation, or alternatively between the upper and lower ends of the piston and supported in a buoyancy, semi-buoyancy or fixation system. As has been proposed by others, a cylindrical structure encloses a single or segmented mass that can be moved up and down along a vertical longitudinal axis to raise or lower the mass. When the piston descends, the motor may return electrical energy to the grid or other load, for example, through a process known as regenerating the load. The piston preferably comprises 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).

The facility may be built on any land site with reasonable surface conditions or on a sea site where deep water shields the water from the grid connection. For example, the facility may be constructed as part of a power supply, for example near a farm of wind turbines or solar panels that can only generate electrical energy intermittently. A power supply that combines intermittent generation of electrical energy with storage of electrical energy in the form of gravitational energy may achieve a more uniform supply of electrical energy to the power grid and/or a higher peak electrical energy to the power grid at peak demand. The piston is configured as a solid mass with a much higher bulk density than the surrounding fluid.

Or the specific gravity of the piston may be much lower than the surrounding fluid. In this alternative case, the stored energy may resist buoyancy rise, rather than resisting downward gravity. The use of a very low density piston reduces material requirements and thus costs, which will reduce the average cost of stored energy. A low density piston can be achieved by forming the hollow chamber or chambers using a high strength material ("chamber" is a three-dimensional shape consisting of a cylinder with flattened or hemispherical ends) which has a high resistance to pressure perpendicular to its surface. Or the capsule may be a solid form of low density material that can resist hydrostatic pressure normal to its surface with very little deformation. Gravity or buoyancy structural forms may be selected based on availability or cost of field materials or geological conditions.

Drawings

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

Fig. 1 is a cross-sectional, partially cut-away view of a first embodiment of an underground utility adapted to store electrical energy in the form of gravitational energy in accordance with at least some embodiments disclosed herein.

Fig. 2 is a cutaway, partially cut view of a first embodiment of an underground utility adapted to store electrical energy in the form of gravitational energy with an onsite concrete-substituted foundation supported cylinder in accordance with at least some embodiments disclosed herein.

Fig. 3 is a plan view and cross-sectional view of a modular facility having eight (8) underground storage facilities at one location for storing electrical energy in the form of gravitational energy in accordance with at least some embodiments disclosed herein.

FIG. 4 is a detailed cross-sectional view of an underwater floating piston seal adapted to store electrical energy in the form of gravitational energy in accordance with at least some embodiments disclosed herein.

FIG. 5 is a detailed view of a piston in a raised position for periodic seal maintenance in accordance with at least some embodiments disclosed herein.

Fig. 6 is a detailed cross-sectional, partially cut-away view of a first embodiment of an underground utility adapted to store electrical energy in the form of gravitational energy using a positively buoyant compartment, in accordance with at least some embodiments disclosed herein.

Fig. 7A, 7B, and 7C illustrate cross-sectional, partially cut-away views of a negatively buoyant compartment according to at least some embodiments disclosed herein.

Fig. 8 illustrates a detailed cross-sectional, partially cut-away view of a pumping system embedded in a solid piston, in accordance with at least some embodiments disclosed herein.

Fig. 9 illustrates a detailed cross-sectional, partially cut-away view of a pumping system embedded and attached to a positive buoyancy pod, in accordance with at least some embodiments disclosed herein.

FIG. 10 is a cross-sectional view of an underwater floating installation incorporating an integral pump and piston device for storing electrical energy in the form of gravitational energy in accordance with at least some embodiments disclosed herein.

FIG. 11 is a cross-sectional view of an underwater floating facility storing electrical energy in the form of gravitational energy using a positively buoyant compartment in combination with an integral pump system in accordance with at least some embodiments disclosed herein.

Fig. 12 illustrates a detailed cross-sectional view, partial cut-away view, and detailed plan view 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 below the piston to the pump in accordance with at least some embodiments disclosed herein.

Fig. 13 is a detailed cross-sectional, partially cut-away view of a pumping system shown offset below the surface of the piston and cylinder, in accordance with at least some embodiments disclosed herein.

Fig. 14 is a detailed cross-sectional, partially cut-away view of a pumping system shown offset from a piston and cylinder at or above the surface of the earth in accordance with at least some embodiments disclosed herein.

Fig. 15 is a detailed partial cross-sectional view of a pumping system showing offset pistons and cylinders and a header system connecting multiple silos to a single pump or multiple pumps, in accordance with at least some embodiments disclosed herein.

Fig. 16 is a detailed cross-sectional, partially cut-away view of a pumping system shown positioned at the bottom of a solid piston and the bottom of a pipe caisson with a cable recovery system to accommodate piston movement according to at least some embodiments disclosed herein.

Detailed Description

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Like elements in different drawings are identified with like reference numerals. Each embodiment of the present invention will now be described in detail. These embodiments are provided to illustrate the present invention, and the present invention is not limited thereto. Indeed, various modifications and alterations will become apparent to those skilled in the art upon reading the present specification and viewing the accompanying drawings.

It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures or functions of the invention. Exemplary embodiments of components, arrangements and configurations are described below to simplify the present disclosure, however, these exemplary embodiments are provided by way of example only and are not intended to limit the scope of the present invention. Furthermore, the exemplary embodiments presented below may be combined in any way, i.e. any element of one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the present disclosure.

Fig. 1 shows an underground installation adapted to store electrical energy in the form of gravitational energy. The subterranean facility includes a deep excavated area filled with thixotropic fluid 10, which is preferably cylindrical and may include steel or reinforced concrete or composite steel-concrete pad 12 depending in part on surface and groundwater conditions. The density of the thixotropic fluid will be adjusted to accommodate the surface conditions in the vicinity of the excavation region and the buoyancy will support the gravity energy storage cylinder and associated piping without the need to provide structural support at the bottom thereof. The subterranean excavation region 12 can be built up to a depth of 5000 meters and a diameter of 50 meters, depending on the energy storage capacity desired. The roof 14 of the underground utility 16 is located on and supported by the surrounding soil.

A cylinder 16 of steel or steel bar or steel and concrete composite will be manufactured on top of the filled excavated area and gradually lowered into the thixotropic liquid. The construction technique will gradually fill the cylinder with water 18 to maintain near neutral but positive buoyancy. The piston 20 is built up 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 material having a bulk density greater than water. The highest bulk density can be achieved by adding relatively high density materials such as depleted uranium hexafluoride from relatively large amounts of waste materials found in the united states and some other countries. The higher density of material provides the opportunity to reduce the overall facility size, thus reducing the overall cost.

The outer wall of the apparatus 16 will support symmetrically arranged pipes 22, the pipes 22 connecting the water chamber at the bottom side with the pumping means 28. The plumbing system will include a submerged valve 24 and a semi-submerged pump 24 to lift water from the lower chamber to the upper chamber. The reverse flow under gravity will force the rising water back to the lower chamber and drive the regeneration pump. Power cable 26 will power the pump and water tubing, while thixotropic line 28 will provide make-up fluid to the system in the event that fluid is lost to the surface or evaporates.

Fig. 2 shows another arrangement in which a cylinder filled with water 18 is firmly supported in cast-in-place concrete plugs 44. The piston 20 is located on the structural support 46 when it is stationary in the lowermost position. This structural support arrangement provides structural support independent of the equilibrium buoyancy from the thixotropic liquid that should be beneficial, given the size of the storage facility selected and the field surface conditions.

Fig. 3 shows how multiple facilities can be built on one site limited only by the available land area and the surface conditions suitable for the excavated area and the surface support. Furthermore, the annular arrangement of the underground facilities helps to share building, operation and maintenance equipment, helping to ensure lower unit storage costs. The spacing of the subsurface facilities is three times the diameter of the excavated area, which is a conventional method of infrastructure configuration, but can be as low as twice the diameter of the excavated area if the surface conditions allow closer spacing.

Fig. 4 shows a flexible seal 32 disposed between the piston and the cylindrical wall of the piston crown. At least one but possibly up to three rows of seals should be provided as a spare. The seal is secured in the piston by an insert to resist the upward force of the water pressure on the seal and the frictional force of the outward pressure on the seal pushing against the cylinder. The seal is configured to be durable over the design life, but will provide replacement when the piston is lifted off the water surface. Several possible seal types are contemplated, such as O-rings, saddles, or more flexible petals, examples of which can be found in the industry.

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

Fig. 4 also shows an inflatable bladder 34 positioned below the seal. The bladder is inflated by the water pressure provided by the small diameter tubing 28 connected to the top of the piston 38 and the temporary pump 36, the temporary pump 36 applying water pressure to the bladder to inflate to a pressure equal to that required to support the partially submerged piston. Under the influence of the water pressure, the inflatable bladder 34 will fill the space between the piston and the cylinder to seal, unlike inflatable seals commonly used in household plumbing tasks. After the seal is in place, the piston may be lifted over the top of the cylinder for occasional maintenance or replacement of the piston seal. The ability to raise the piston seal above the water surface will be achieved by pumping water 22 into the void below the piston 20.

Fig. 5 shows the piston lifted a small distance above the surrounding cylinder sufficient to expose the seal 32 at the top of the piston 20 above the top of the cylinder. The seal may then be maintained or replaced as needed. This extreme lifting operation will only be performed regularly, since the cylinder and the container will remain in a clean state. The bottom of the piston will include guide rollers and lateral springs 40 at the bottom of the piston. These components are not maintainable and so a robust bearing is installed.

In the cycle of electrical energy storage and generation, a small amount of energy is consumed in seal friction between the piston and cylinder, friction losses of the pump motor, friction losses of the pipe inlet, pipe length and pipe outlet, and cable losses. However, by proper design of the mechanical elements, 85% or higher energy efficiency can be achieved to achieve 75% or higher round trip efficiency, consistent with what is measured in a utility scale hydroelectric storage scheme. These design factors would be the choice of low friction seals and bearings.

Fig. 6 shows an alternative to the heavy-mass configuration as a buoyancy pod configuration. The buoyancy chamber 40 is disposed within a cylinder filled with water 18, the cylinder being a sealed tube except that it is open at the lower half of the cylinder so that water flows almost unimpeded from the inside of the cylinder to the outside. When water is released or added to the top of the cylinder, buoyancy chamber 40 rises and falls. Water is added under pressure to the top of the cylinder to store energy, and water is released at the top of the cylinder through a hydraulic turbine to recover the stored energy, subtracting energy losses due to friction and mechanical losses.

Fig. 7A, 7B and 7C illustrate possible configurations of buoyancy tanks. Fig. 7A shows a stainless steel or carbon steel or aluminum cylindrical pod 40 with internal stiffeners 42 required to resist pressure differentials across the pod. The reinforced steel capsule may be configured to withstand at least half of the pressure exerted on the capsule. When the pod is on top of the water filled cylinder 18, the air pressure may be periodically increased and replenished by an air valve 44.

Fig. 7B shows an alternative arrangement of a PVC or HDPE or other plastic tank 40 filled with an aerated Polyvinylchloride (PVC) or High Density Polyethylene (HDPE) or other aerated plastic, such that the bulk density of the tank is much less than the density of the water or other fluid in the cylinder. The pod material is selected to provide as low a density as possible while maintaining sufficient strength to resist external hydrostatic pressure applied at the maximum depth of the pod. The device is provided in the form of a sea buoy of HDPE having an outer layer of rigid HDPE and an inner layer of inflated HDPE filler material.

Fig. 7C shows an alternative arrangement of a set of pipes forming a cylindrical capsule 40. The arrangement of 19 or 37 vertical tubes ensures that all tubes touch within a circle to ensure optimal lateral stability. The tubing will be gas and water tight and may be pressurized to reduce stress on the tubing. The hoop strength of the pipe may resist external hydrostatic pressure. Seals are located at the top and bottom of the cylinder with lateral restraint provided by the closure plate.

Fig. 8 shows a cross-sectional view of a pumping system mounted in a solid piston. An 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 to operate in opposite directions to reduce longitudinal axis rotation (referred to as deflection) of the pistons. Or a single pump with deflection compensation may be integrated. The power cable 50 is arranged or telescoped in a concertina fashion, or fed in and out of the cable reel for planned vertical movement of the piston. A conduit 52 is cast into the piston body to allow water to flow through the piston. When the piston is to be maintained at a selected height, the valve 54 can be remotely operated to close the flow.

Figure 9 shows a negatively buoyant pod with a pumping system mounted at the top of the pod. As above, four pumps 48 are provided and the power cables are arranged or telescoped in a concertina fashion to effect the intended 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 is to be maintained at a selected height, the valve 54 can be remotely operated to close the flow.

The proposed gravity piston solution can be adjusted to accommodate the required energy storage capacity by e.g. varying the cylindrical outer wall size, the piston height size and the piston density. For example, an excavation area having a diameter of about 20 meters and a depth of 536 meters would correspond to an energy storage capacity of 100MW-hr of gravitational energy per facility. On a larger scale, an underground storage facility with an excavation area of about 40 meters in diameter and 2634 meters deep would correspond to 10000MW-hr of energy storage capacity.

The proposed buoyancy chamber solution can also be adapted to the required energy storage capacity by e.g. varying the cylindrical outer wall dimensions, the piston height dimensions and the supporting fluid density. For example, an excavation area having a diameter of about 20 meters and a depth of 790 meters would correspond to an energy storage capacity of 100MW-hr of gravitational energy per facility. On a larger scale, an underground storage facility with an excavation area of about 38 meters in diameter and 4124 meters in depth would correspond to 10000MW-hr of energy storage capacity.

Fig. 10 shows a similar arrangement, where the floating substitution concept can be configured for similar capacity in a shaded water area. It can be installed in sea or fresh water locations, with depth and diameter limited only by water depth and actual buoyancy volume.

Fig. 11 shows a similar arrangement in which a second alternative concept of a floating positive buoyancy piston may be configured for similar capacity in a shaded water area. It can also be installed in a sea or fresh water location, with depth and diameter limited only by water depth and actual surface volume.

Fig. 12 shows a gravity piston or buoyancy pod 20 in a cylinder 16, but the cylinder has two or more vertical seal chambers 56, the vertical seal chambers 56 being arranged to guide vertical movement of the piston or pod. The guide chamber prevents the piston or the plane of the nacelle from rotating, i.e. yawing. The pilot chamber is proportioned to allow water to flow from the pump/turbine to below the piston. The chambers are open at a lower elevation to allow water to flow through. The guide chamber terminates at a height suitable for supporting the pump 24 and has a suitable water level above that height to achieve efficient pumping of water from above and below the piston. In addition, the bottom of the piston is backfilled with coarse gravel 70, the coarse gravel 70 providing water permeable support for the piston if the piston is at its lowest elevation.

Fig. 13 shows a gravity piston or buoyancy pod fitted with a guide chamber (as shown in fig. 12) in the cylinder. The upper water and guide chambers 56 are hydraulically connected to external piping 58 at a level below the surface of the exterior of the silo. The combined pump/turbine embeds a height suitable to support the pump and has a suitable water level above that height to achieve efficient pumping of water from above and below the piston.

Fig. 14 shows a cylinder with the guide chamber shown in fig. 12, but for ease of operational access, the pump is disposed at or above the surface. The water level in the cylinder is raised to a height suitable for supporting the pump and has a suitable water level above the height to achieve efficient pumping of water from above and below the piston. This requires a closed top of the cylinder 60 and a raised riser 62. The closed top of the cylinder is removable to occasionally raise the piston to complete the aforementioned seal maintenance.

Fig. 15 shows a plurality of silo energy storage facilities, wherein several silos 64 are grouped adjacent a common pump and turbine facility 66 for electricity consumption and generation. By sharing the utility, the overall economy, redundancy, and responsiveness of the energy storage facility may be improved. By opening or closing the valve 68 to each silo, the combined pump/turbine facility can be operated at different but staged flow rates.

Figure 16 shows a positively buoyant tank with a pumping system mounted at the bottom of the tank consisting of a relatively high bulk density set of pipes with integral sealed top and bottom. A pump 70 is provided and power cables are arranged in a rolled or telescoping fashion 72 for the intended vertical movement of the piston. There are one or more vertical pipes 74 in the compartment to allow water to flow through the compartment. When the piston is to be maintained at a selected height, the valve 76 can be remotely operated to close the flow. In the case where the pump is located at the lower end of the piston, the water level 76 may be lowered to a level slightly above the upper level of the piston, thereby maximizing the effective use of the overall facility height. A similar arrangement may be configured with a solid piston instead of a set of tubes. As described above, a similar arrangement of inflatable bladders below the top seal may be included to occasionally lift to access and maintain the seal.

The proposed gravity piston solution can be adjusted to accommodate the required energy storage capacity by e.g. varying the cylindrical outer wall size, the piston height size and the piston density.

The description of the 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 embodiments. The terminology used herein is for the purpose of best explaining the principles of the embodiments, practical applications, or technical improvements to the technology found in the market, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

When introducing elements of the present disclosure or the embodiments thereof, the articles "a/an" and "the" are intended to mean that there are one or more of the elements. Similarly, the adjective "another" when used to introduce elements is intended to mean one or more of the elements. The terms "comprising" and "having" are intended to be inclusive and so that there may be additional elements other than the listed elements.

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

Claims (44)

1. A system adapted to store electrical energy in the form of gravitational energy, the system comprising:

An excavation region disposed below the earth's surface, the excavation region being surrounded by a fluid;

A pad surrounding the excavation region;

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 houses water for maintaining positive buoyancy and a piston having a bulk density greater than that of the water;

A pipe means connecting the cylindrical facility with a pumping facility disposed above the surface;

a top cover disposed above the ground surface and covering a first side of the cylindrical facility;

A power cable disposed above the ground surface, and

A water pipe and a thixotropic pipe disposed above the surface and configured to supply fluid to the system.

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

6. The system of claim 1, wherein the excavation region is up to about 50 meters in diameter.

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

8. The system of claim 1, further comprising:

a chock disposed below the second side of the cylindrical facility.

9. The system of claim 8, further comprising:

and a structural support member disposed between the second side of the cylindrical facility and the chock.

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

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

12. The system of claim 1, wherein the number of 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 disposed between the piston and a wall of a cylindrical facility at the 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 disposed below the one or more flexible seals.

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

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

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

20. The system of claim 1, wherein an 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 polyurethane coatings, fusion-bonded epoxy or powder coatings, and thin film epoxy or powder coatings.

22. The system of claim 1, wherein the conduit means comprises a set of vertical conduits located in an inner wall of the cylindrical facility, and

Wherein the set of vertical tubes places a deflection constraint on the piston.

23. The system of claim 22, further comprising:

One or more flexible seals disposed between the piston and a wall of a cylindrical facility at the top of the piston, wherein the one or more flexible seals are continuous and shaped around a non-cylindrical shape comprising the set of vertical tubes.

24. The system of claim 1, wherein the plumbing is supported in a top 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 region disposed below the earth's surface, the excavation region being surrounded by a fluid;

A pad surrounding the excavation region;

a buoyancy chamber disposed in the water-filled cylinder, wherein the cylinder is sealed with an opening portion in a lower half of the cylinder so that water flows almost unimpeded from a position inside the cylinder to a position outside the cylinder;

A pipe device connecting the cylinder and a pumping facility disposed above the surface;

A power cable disposed above the ground surface, and

A water pipe and a thixotropic pipe disposed above the surface and configured to supply fluid to the system.

26. The system of claim 25, wherein the buoyancy tanks rise and fall as water is released or added to the top of the cylinder.

27. The system of claim 25, further comprising:

A pressure resistant top cap and riser that cover the cylinder and are 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 tanks are formed from a vertical pipe arrangement.

30. The system of claim 29, wherein the vertical pipe 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 region disposed below the earth's surface, the excavation region being surrounded by a fluid;

A pad surrounding the excavation region;

A negative buoyancy chamber;

a pumping system mounted on top of the negatively buoyant compartment;

a plurality of pumps above the surface and configured to interact with a power cable above the surface to move the piston vertically, and

A conduit valve that is remotely actuated to close flow when the piston is held at a given height.

32. The system of claim 31, wherein the buoyancy tanks are formed from an array of vertical pipes, and wherein the vertical pipes 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 number of the plurality of pumps is four.

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

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

37. The system of claim 35, wherein the plurality of silos are arranged with energy storage facilities sharing pump/turbines and plant auxiliary facilities.

38. The system of claim 37, wherein the system further comprises:

valve options that allow for stepped energy storage and power generation operation of the facility from low power to very high power operation.

39. The system of claim 35, wherein the system further comprises:

A gravel pack at the bottom of the silo, the gravel pack having the ability to support the weight of the piston or pod in case the piston or pod is lowered to the lowest possible height.

40. The system of claim 39, wherein a plumbing device into the gravel pack applies water pressure under the piston or pod that causes it to be lifted to store energy.

41. The system of claim 1, wherein the piston comprises a set of negatively buoyant conduits in the form of cylinders or other polygons or variable pipe diameters that can be filled with soil, rock or even depleted uranium hexafluoride for optimal efficiency to achieve higher packing densities.

42. The system of claim 41, wherein the single or multiple conduits deliver 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 effect vertical movement to a total depth of the facility of ¹/₂.

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