EA044162B1 - COMBINED GRAVITY-HYDRAULIC ELECTRIC ENERGY STORAGE SYSTEM - Google Patents

Description

A combined gravity-hydraulic electrical energy storage system is designed primarily for electrical grid operation, used to store large/significant amounts of energy during periods of time when the grid has excess electrical energy production, in order to power it during peak demand periods. The system provides energy storage with zero environmental cost and risk during operation and is made from material that is 100% recyclable at the end of the product's life. Initial environmental costs (eg CO2 emissions) are low and no materials with high environmental risks are used. The system can act as a buffer for any green energy production system to store and provide 100% customer-profiled operation of the electrical grid.

Energy Storage Systems, a solution for optimizing the operation of electrical networks connected to intermittent renewable sources of various energy storage systems, AGIR Bulletin, Supplement 1/2015, mentions several energy storage technologies, including the so-called Hydroelectric System (PHS). It consists of a hydraulic pumping station that stores energy by pumping wastewater from a basin located at the outlet of the turbines (the lower reservoir where it is collected during the operation of the hydroelectric power station) to an upper basin (the upper reservoir), for periods or time intervals in which the system produces excess electricity. Such pumped hydro plants require a smaller wastewater collection basin and use reversible turbine generator units, typically reversible turbines derived from Francis or Kaplan turbines, to be as efficient as possible, but with the disadvantage of very large volumes of water. The environmental costs of such technologies are extremely high due to the severe impacts on landscapes and rivers.

The website http://www.gravitypower.net/technology-gravity-power-energy-storage/ presents a gravity power module (GPM-Gravity Power Module), which contains a very large piston that is placed in a deep well or shaft filled with water , the piston is provided with sliding gaskets to prevent leakage around it, and a vertical return pipe located outside the piston connecting the bottom of the piston to a reversible type Francis turbine connected to an electrical machine located at ground level. The piston is made of reinforced stone or concrete. The well is filled with water once at the beginning of operations and then capped, after this initial filling no additional water is required. When electricity is produced by lowering the piston, it causes water from the storage well to rise through the return pipe and, through a turbine, drive the electrical machine into generator mode. When it is necessary to store energy, the electric machine is controlled in the mode of a motor powered by the network, and rotates the same turbine (reversible) in pump mode to lower the water to the return pipe at the base of the well, raising the piston. The GPM module is presented only at the idea level, and the use of reversible technology (reversible turbine/generator group) has the disadvantage that the limited pressure (20-30 bar) has low efficiency and requires large volumes of water per MWh.

From the patent literature we know the invention CN 204061053 (U), entitled Hydropower system for wind energy storage, published on 12/31/2014. The system according to the invention contains a primary vertical well, a second deeper vertical well located in the offshore zone, a hydroelectric generation module (turbine generator group) located in the lower part of the first vertical well, and a group of pumps located in the lower part of the second vertical well. Seawater is pumped into the first vertical well in the hydroelectric generation module, which supplies excess electricity through an underground line. After this, the water is carried through a pipe at the base of the second vertical well, from where it is pumped to the ground surface, into the pool, by a group of pumps driven by an external wind turbine. In this way, the pool water stores wind energy as potential energy and can then be used to generate electricity.

Also known is the invention DE10 2011012261 (A1), published on 08/30/2012 under the title Electric energy storage device for the power plant of a storage tank, which recovers the potential energy generated by emptying the tank into the surrounding waters using pumping devices under the influence of electrical energy during the filling of the tank ( Werner RAU). The device has a tank filled with water over ballast material (eg gravel, concrete), the tank is located on the seabed. The tank is connected to outside air through a pipe or hose with the possibility of uncompressed air exchange and the formation of an air chamber above the water when the tank is emptied. Through the inlet valve, a reversible turbine connected to an electric motor/generator, water is either drawn into the reservoir from the outside or pumped back into the surrounding water from the inside. The potential energy generated when the tank is emptied into the surrounding waters by hydraulic or pneumatic pumping devices under the influence of electrical energy is recovered when the tank is filled. The water flow is adjusted so that the power of the reversible turbine and electric motor/generator is adapted to the requirements of the electrical network.

The invention uses reversible technology (reversible turbogenerator group), which has low efficiency.

In addition, the invention US 2012/0049673 published on 03/01/2012 entitled Generator system for a water tank (Myung Hoe KOO) is also known. The invention provides a generator system comprising a water tank in the form of a cylinder having an upper opening and a lower opening; a dividing wall disposed vertically in the water tank, dividing the water tank into a first vertical column and a second vertical column, which are connected near the bottom opening of the water tank. Each of the cylindrical plates is positioned and configured to move a piston through a respective vertical column of the water tank, said cylindrical plates being connected by a pulley through a cable, and each having a plurality of one-sided openings to allow water to flow only downwards. An electric motor powered by the solar panel drives a pulley to alternately lift the first cylindrical plate or the second cylindrical plate; a turbine generator is located at the lower opening of the water tank and to generate electricity using the flow of water generated by the falling cylindrical plates, a return pipe is provided having a lower end located at the lower opening of the water tank and an upper end open to the upper opening of the water tank for return water from the turbine generator to the water reservoir.

The efficiency of the turbine is reduced by the column of water in the return pipe.

The technical problems solved by the invention are to reduce the volume of water required per MWh stored in a gravity-hydraulic electrical energy storage system - hence high energy storage density per volume built.

The combined gravity-hydraulic electrical energy storage system of the invention comprises a large heavy piston, weighted/loaded with blocks of high volumetric mass material, mounted symmetrically on the surface of the piston for uniform mass distribution, designed to store potential gravitational energy by lifting it vertically within a cylinder of reinforced concrete walls and a high-quality steel inner coating filled with water, the piston being guided on the vertical wall of the cylinder by means of guides and equipped, in the center, with an annular hole, while in the axis of the cylinder there is a high-pressure channel passing through the piston and conducting water under pressure from the base of the cylinder to electric power generation system using impulse turbines, the outlet channel being sealed at the top and deaerated, the water used in the electric power generation cycle being discharged back into the cylinder, above the piston, through the return channel at atmospheric pressure, and for the energy absorption and storage cycle from the electrical network, also contains a system of high pressure and variable flow pumps that receives water above the piston, through the return channel, and introduces it through a pressure channel below the piston, causing it to rise, thus accumulating energy.

Compared with the prior art, the gravity-hydraulic combined cycle electricity storage system according to the invention has the following advantages:

has zero environmental costs and zero environmental risk during operation. The system is closed, so there is no exchange of substances with the environment, and the fluid inside (water) is neutral to the environment in the event of a leak. If turbines or pumps fail, oil does not release into free flowing water as in standard PHS systems. The design competes with an extremely low average cost per MWh, maintained with an extremely low carbon footprint of materials and equipment put into operation. At the end of the plant's life cycle, all materials inside are 100% recyclable;

Reduced amount of water per MWh stored is required, water is used in a completely closed cycle;

The system has separate equipment for input and output, so it can be sized fluctuatingly to accommodate full load during off-peak hours (2 to 6 hours or when green energy is available in abundance) and offload during peak hours (6 to 18 hours when little or no green energy); - network operation is 100% profiled in any sense of operation - input or output of electrical energy - suitable for 100% of the projected use of uncontrolled green energy (i.e. wind, solar, waves, etc.);

allows you to continuously change power generation from 0 to 100% of the installed output power, being able to fully profile consumers on the small/medium distribution network;

allows continuous absorption of electricity from 0 to 100% of the installed power consumption, with the ability to fully profile production at low/medium uncontrolled power generation capacity;

- 2 044162 allows an unlimited theoretical number of loading and unloading cycles only with the cost of mechanical/electrical maintenance of the equipment;

allows long-term energy storage, without storage losses, theoretically unlimited;

allows you to install such units near network substations due to the small footprint and the absence of special geophysical requests;

allows the installation of such units in densely populated (urban) areas, since the footprint is extremely small and the construction is completely underground, allowing the reuse of surface land for other purposes plus zero impact on the area.

An embodiment of the invention is shown below with reference to FIG. 1-6, in this case:

fig. 1 is a schematic diagram of a combined gravity-hydraulic electrical energy storage system according to the invention;

fig. 2 - detail of the design of the cylinder wall/cylindrical pool;

fig. 3 - detail of the pressure channel design;

fig. 4 - structural detail of a heavy piston;

fig. 5a is a schematic representation of a detail of a concrete cylinder wall;

fig. 5b is a schematic illustration of a precast concrete cylinder segment;

fig. 6 - design of the cylinder cuff.

The combined gravity-hydraulic electrical energy storage system in accordance with the present invention operates in a cycle of energy absorption and storage, during periods or time intervals in which the electrical network to which it is connected produces excess electricity, or when the operator of the module decides to store energy, and in the power generation cycle for the grid, during periods of peak demand or when the module operator decides to extract energy. The system can also be used for long-term or short-term storage of uncontrolled renewable energy (wind and/or solar) for use during peak demand periods. The system can also be configured to provide a small to medium network with 100% customer profiled power regardless of power generation fluctuations (right sized/adequately sized).

In fig. 1 shows a combined gravity-hydraulic cycle electric energy storage system, which consists of a right-hand cylinder 10 with reinforced concrete walls and a high-quality steel internal lining to withstand high pressures, having a high-pressure channel/pipe 20 in the axis, a movable large heavy piston 30 is located in the cylinder, designed to accumulation of potential gravitational energy during its vertical rise inside the cylinder 10, which is filled with water under and above the piston. The piston 30 is provided with an annular hole in the center to allow a high pressure passage 20 to pass through the piston 30, said high pressure passage 20 having at least one elbow at an upper end. In the energy absorption and storage cycle, water above the piston 30 is pumped under pressure by the power input system 60 through the high pressure passage 20 below the piston, causing it to rise, thereby storing potential gravitational energy, and in the electric power generation cycle, water under pressure from the base of the cylinder 10 is supplied through the high pressure channel 20 into the power generation system 50, simultaneously with the lowering of the piston 30 using its gravitational potential energy. The pressure in the high pressure passage is constant regardless of the position of the piston 30, so the power systems of the input 60 and output 70 are easy to design. The water processed in the power generation cycle is discharged back into the cylinder 10, above the piston 30, at atmospheric pressure through a return channel 25, made at the upper level of the cylinder 10's water filling, and built below the freezing depth characteristic of the geographical area in which the pool is built. . Thus, the water in cylinder 10 is used in a closed loop, compensated only by losses from evaporation during system operation and protected from freezing.

Cylinder 10 is a large right-hand cylindrical basin with a diameter and height of tens of meters, depending on the required storage volume. It is built below ground level in the manner described below. The cylinder 10 has walls made of precast concrete in the form of a prestressed cylindrical shell/hollow segments 12 (an example of such a concrete segment is shown in Fig. 5b), said concrete segment is then prestressed with steel strands, said cylinder 10 is provided with a cylindrical collar 70 on top (shown). in Fig. 6), and in the lower part - a dome 40 of the reverse position. The inside of the cylinder 10 is covered with a high-quality steel coating 11. The cylinder 10 is filled with water, the piston 30 is located inside the water volume. The piston 10 is loaded with weights 31 made of blocks of high bulk material, fixed symmetrically on the surface of the piston 30. Above the piston 30 there is water up to the top level of the said cylinder, in line with the top of the return channel 25. Weights 31 are fixed symmetrically on the surface of the piston , are placed during installation, simultaneously in pairs in diametrically opposite positions within the framework of uniform mass distribution.

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Axially in the cylinder 10 there is a high pressure passage 20 which conducts pressurized water into a power generation system 50 composed of impulse turbines, for example of the Pelton type. The high-pressure channel 20, in the lower part, is equipped with an inlet-outlet 29 for water, through which, depending on the operating cycle, water is supplied or extracted from under the piston. The high pressure channel 20 is sealed at the top and deaerated. The water processed in the power generation system 50 is discharged back into the cylinder 10 through the return channel 25, the channel is under atmospheric pressure. In order to introduce energy from outside, the input system 60 includes a high pressure and variable flow pump system that takes water from the return channel 25 (above the piston 30) and introduces it into the high pressure channel 20, pumped below the piston 30, so it lifts it and accumulates potential energy. The two water circuits are completely separated. The high pressure circuit begins at the base of the cylinder and ends at the turbine access valves (which open only during the power generation cycle) and at the high pressure pump outlet guide valves (which open only during the energy absorption and storage cycle).

Water is an incompressible fluid and therefore an ideal agent for transferring potential energy. Energy is stored within the system through the vertical position of the piston 30. The cylinder 10 is filled with water below and above the piston, the pressure in the high pressure channel 29 will be constant regardless of the vertical position of the piston 30. To use a small amount of water, it is necessary that the total weight of the piston 30 (including weights) 31) was tall; the higher the total weight of the piston 30, the higher the hydrostatic pressure, therefore the greater the amount of energy stored in the system per cubic meter of water.

In an example embodiment of the invention, the cylinder 10 is constructed below ground level with a depth h of the order of tens of meters/between 20-100 m and a diameter D between 10 and 75 m. The cylinder is made of pre-stressed precast concrete segments 12 connected and then stressed by steel conductors 15, covered inside with high-quality steel coating 11. In Fig. 2 shows a detail of the cylinder wall 10. The inner surface of the vertical cylinder wall has a high quality steel coating 11, the coating segments must be factory fabricated, then installed, welded and straightened in place, allowing the piston 30 to easily slide and take pressure in the horizontal shear areas from the joint between the precast concrete segments 12. The high-quality steel covering works in combination with prestressed segments, which also, after being stressed by steel conductors, absorb the circumferential stress in the cylinder 10. A waterproofing 19 is applied to the outer surface of the vertical wall of the cylinder, which also serves to allow expansion and contraction in the soil during construction and operation.

To ensure system integrity at high operating pressures at the lowest possible construction cost, prestressed precast concrete segments 12 are manufactured in a controlled manner at the manufacturing plant, prestressed before casting, and provided, in the portion that will be outside the cylinder 10, with holes through which high-quality steel conductors 15. These will then be stressed in place, after installation, to the hoop stress required for balancing, with the additional resistance of a high quality steel covering 11 equivalent to the hydrostatic pressure obtained from the weight load 31 of the piston 30, so that the concrete in the wall will only work compressed regardless of piston position for maximum efficiency. In this case, prestressed precast concrete segments 12 are provided at the edges, from the manufacturer, with some access points to some connecting elements 72 for assembly between them, as well as with clearance required for core tension devices - core openings. In an embodiment of the invention, said core holes are in the form of internal toroidal parallel channels/holes along the length of the concrete segments 12.

The assembly design of prefabricated blocks is shown in Fig. 5a. Prefabricated elements - prestressed precast concrete segments 12 are installed in place by means of removable screw and nut type connecting elements 72. The prefabricated elements 12 will be installed alternately (staggered vertically) so that the holes for the cores continue as disclosed in FIG. 5a, however, continuous connecting lines are avoided. On piston 30, the hydrostatic pressure below it is very high (200-500 bar) and that above it is low (0-10 bar), resulting in a constant/significant circular shear force. To accommodate this, prestressed precast concrete segments 12 are assembled one at a time precisely to avoid continuous connection lines and therefore reduce connection resistance requirements (and, indirectly, cost). To prevent deformation of the high quality steel covering 11, after the high quality steel conductors 15 are installed and tensioned, the access points to the connecting members 72 and the tensile members of the conductors 15 and the connections between the members will be sealed in place with high density concrete.

In fig. 6, which shows the proposed design of the platform on the surface of the earth (around the top of the future cylinder 10), the foundation 71 is made in the form of a round ring, the size of which

- 4 044162 corresponds to the geomorphological characteristics of the area, the dimensions of the cylinder 10 and the proposed future weight of the piston 30, including the weights 31. A dense reinforced concrete slab 70 will be built on site above the foundation 71, which continues downward with a cylindrical neck having the same proposed diameter as the cylinder 10, and which also contains the connecting elements 72 necessary for securing/installing the prestressed concrete segments 12. Construction will be carried out by digging down in stages, depending on the size of the designed prestressed precast concrete segments 12, so as to allow easy access from the bottom of the excavation , to install the prefabricated elements 12, install the cores 15, install the high quality steel cover 11. After reaching the design minimum (lower) installation level, the lower inverse dome 40 will be provided with steel reinforcement and concrete poured into the mold on site, with the provision of some locking projections 41 connected with steel fittings of the lower return dome and with a high-pressure channel 20 for inlet-outlet 29 for water, and between the fixing eyes 41 there are spaces for water circulation. The locking lugs are intended to discharge the upward force applied by the high pressure duct 20 to the reinforcement of the lower inverted dome 40. The inverted dome is designed to provide the foundation required to anchor the high pressure duct using the dead weight of the system, further reducing construction costs.

The high-pressure duct 20 is made of high-quality steel (for example, but not excluding other suitable options, steel 1.5423 in accordance with EN 10027-2), having a diameter D from 1 to 10 m and produced in the production plant in sections of length from 3 to 12 m in depending on site access restrictions and cost analysis. Steel segments are fabricated and surfaces adjusted to better than 1mm tolerances and are provided with coupling flanges at the ends to ensure minimal tearing when exposed to the piston water seal rings/isolating gasket 33. The connection detail is shown in Fig. 3, where the upper section 21 is assembled by a precision tongue and groove connection 26 with the lower section 22, the locking catch being provided within the high pressure channel by means of suitable flanges 27 and removable connecting elements 25, for example, such as a screw and nut. At the junction between the sections, the flange is provided with holes, preferably semi-toroidal, corresponding to some rubber gaskets 24, preferably toroidal.

In fig. 4 shows the design of the heavy piston 30. The piston is made of steel, manufactured in a factory, and installed on site. The piston 30 can be made, for example, from segments of sheet steel, shaped like a circular sector with a tip cut out in the center, assembled to obtain the design shape. This piston 30 is subjected to only a uniformly distributed static load, being essentially just a separating membrane between two areas of differential pressure. Therefore, to avoid piston deformation, a support grid made of steel T-profiles is sufficient. The piston 30 is provided with roller guides 35 that act as piston guides within the cylinder to ensure the desired horizontal position of the piston as it moves up and down. Guides are manufactured on a case-by-case basis in quantities and sizes tailored to each installation. In the proposed design shown in FIG. 4, the roller guides 35 are in the shape of right triangles of steel profile mounted on the top surface of the piston 30. The piston 30 is mounted/attached to blocks of high bulk material (31), manufactured in a factory and insulated from contact with water to prevent degradation over time. . Blocks 31 will be loaded onto and off the piston (during installation and possible maintenance operations) so as to avoid imbalance of the piston 30 to minimize the resistance required by the guides 35.

On the lower surface of the piston 30, at the outer lower edge towards the steel cover of the cylinder, as shown in FIG. 4, a monolithic steel guide 36 will be provided, designed to relieve the pressure gradient on the annular hydraulic insulating gasket 32 relative to the steel coating 11 of the cylinder 10. Also in the central part, where the piston 30 moves along the high pressure channel 20, a monolithic steel guide 37 will be provided, designed to release the pressure gradient onto the annular waterproofing gasket 33 to the outer wall of the high-pressure channel 20.

The electrical energy input (absorption) system 60 is different from the electrical energy generation (production) system 50. This allows the use of optimized and highly efficient electrical and hydraulic equipment. Electrical energy production is carried out by impulse turbines, such as Pelton turbines, which ensure low water consumption, so the system can increase the amount of energy stored per cubic meter of water. The system may also be unbalanced in size in the sense that it allows completely different input levels compared to output levels (for example, full load during off-peak hours and unloading during peak hours).

The power generation system 50 may include one or more Pelton turbines coupled to power generators. The power generation system 50 may be a classic Pelto system

- 5 044162 on with flow control, therefore changing the continuous production of electricity from 0 to 100% of the installed power through linear control of the intake valves in the turbines. The energy input (absorption) system 60 contains several high pressure pumps in order to be able to absorb a controlled amount of energy and achieve high efficiency, while the set of pumps contains only one or two with variable flow, the rest with fixed flow and pressure, which is cheaper , more efficient and less maintenance-intensive. The design of the power input system 60 maximizes power transfer efficiency by using fixed power synchronous motors for fixed power stages and variable power motors for linear variable amounts.

To continuously absorb electricity in a controlled manner, for example in the case of a wind farm, the electrical energy absorption system (input system) (60) is equipped with several constant pressure and constant flow pumps attached to electric motors with a fixed rated power and without control elements, they are low cost, low maintenance and high efficiency. For continuous regulation in the range of 0-100%, one or two pumps with constant pressure but variable flow will be used with connected electric motors equipped with the power control system used. These variable systems will have unit capacity compared to 150% fixed systems to allow the controller to continuously adjust energy absorption regardless of the direction and rate of change of power required for absorption.

Since the present invention has also been described with reference to a preferred embodiment, it is understood that various alternatives, modifications and variations thereof will be apparent to those skilled in the art. Accordingly, all such alternatives, modifications and variations are intended to be included within the scope and scope of the technical solution as defined in the appended claims.

Claims (9)

1. A combined gravity-hydraulic electrical energy storage system comprising a heavy piston (30) housed in a cylinder-shaped reservoir (10) filled with water, the piston being provided with sliding gaskets to prevent leakage around it, and a vertical return pipe connecting the flow of water from the lower part of the tank with a turbine connected to an electrical machine located at ground level, characterized in that the piston (30) is weighted with blocks of material of high volumetric mass density (31), fixed symmetrically on the surface of the piston for uniform distribution of mass, designed to accumulate potential gravitational energy during its vertical rise inside the specified cylinder (10) with reinforced concrete walls and an internal surface covered with a steel coating (11), and the piston (30) is guided on the wall of the cylinder (10) by means of roller guides (35) and is equipped with an annular hole in the center , in the cylinder axis there is a high-pressure channel (20), the specified piston (30) is equipped with insulating gaskets (32, 33) both in relation to the specified steel coating (11) of the cylinder (10), and in relation to the specified high-pressure channel (20) passing through the center of the piston (30) and conducting pressurized water from the base of the cylinder to the power generation system (50) using pulsed water turbines, the high pressure channel (20) is sealed at the top and also deaerated, with the water used in the power generation process of the system (50) for generating electricity, is discharged back into the cylinder (10), above the piston (30) through the return channel (25) at atmospheric pressure, and for the cycle of input and storage of electrical energy from the electrical network, also contains an electrical energy input system (60) , containing high-pressure pumps with a fixed and variable flow, taking water from above the piston (30), through the return channel (25), and supplying it to the high-pressure channel (20), under the piston (30), causing the piston (30) to rise. 2. Electricity storage system according to claim 1, in which the cylinder (10) is a large cylindrical basin of the order of meters or tens of meters, depending on the required storage volume, built below ground level, having a wall made by connecting precast concrete segments, in in the form of cylindrical segments (12) of the shell, equipped with holes for the conductors, and the concrete segments (12) are installed in place by means of removable connecting elements (72) followed by tension with several steel conductors (15), the cylinder (10) is equipped on top with a dense steel-reinforced concrete slab (70), which continues downward with a cylindrical collar having the same diameter as the cylinder (10), and which rests on a foundation (71), and in the lower part with a reverse dome (40), the cylinder wall being lined from the inside with a high-quality steel coating (11), formed from cylindrical segments of the coating, allowing easy sliding of the piston (30), and on the outside - waterproofing (19), designed to accommodate expansion and contraction in the soil during operation, as well as protect the structure from water from the soil. - 6 044162 3. Electricity storage system according to claim 2, in which the cylinder (10) is provided with locking projections (41) for the pressure channel (20), which also form an outlet (29) for water, and spaces for circulation are provided between the projections (41) water. 4. The electrical energy storage system of claim 1, wherein the piston (30) is made of steel, factory machined and field mounted, has top surface mounted blocks (31) factory machined and insulated from contact with water, and roller guides (35), designed to ensure its horizontal position, while on the lower surface of the piston (30), at its edge, a monolithic steel guide (36) is provided, relieving pressure on the annular waterproofing gasket (32) along a gradient relative to the steel coating (11) of the cylinder (10), and in the central part, where the piston (30) crosses the pressure channel (20), monolithic steel guides (37) are provided to ensure pressure relief along the gradient to another annular waterproofing gasket (33) relative to the outer wall of the channel (20) pressure. 5. Electricity storage system according to claim 1, in which the high-pressure channel (20) is a cylindrical pipe with at least one elbow at the upper end, made of high-quality steel in sections (21, 22) and equipped at the ends with connecting flanges ( 27) to ensure minimal rupture under the influence of the annular water seals (33) of the piston, and the upper section (21) is assembled by a precision tongue and groove connection (26) with the lower section (22), and the locking grip is made inside the high pressure channel by means of corresponding flanges ( 27) and removable connecting elements (25), at the junction between the sections, the flange being provided with holes corresponding to some rubber gaskets (24). 6. Electricity storage system according to claim 1, in which the piston (30) is equipped with a monolithic steel guide (36) configured to relieve pressure on the annular waterproofing gasket (32) along a gradient relative to the steel coating (11) of the cylinder (10). 7. Electricity storage system according to claim 1, in which the piston (30) is equipped with a monolithic steel guide (37) configured to relieve pressure on the annular waterproofing gasket (33) along a gradient relative to the outer wall of the high-pressure channel (20). 8. An electrical energy storage system according to claim 1, wherein the electrical energy input system (60) with an amount of adjustable input power in the range of 0-100% is equipped with a plurality of constant pressure and constant flow pumps driven by electric motors with a fixed rated power and without regulation power/speed, and for continuous adjustment in the range of 0-100% uses one or more constant pressure but variable flow pumps driven by electric motors with power/speed control. 9. An electrical energy storage system as claimed in claim 1, wherein the electrical energy generation system (50) with a variable output power volume in the range of 0-100% comprises one or more Pelton turbines coupled to electrical generators, each of which has a flow control in the range of 0 -100%.