Gravity-based energy accumulation plant
Patent Information
- Application Number
- PCT/ES2026/070144
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-25
- Filing Date
- 2026-03-25
- Publication Date
- 2026-10-01
Smart Images
Figure ES2026070144_01102026_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] Qualification
[0003] gravity energy storage plant
[0004] Field of invention
[0005] The present invention belongs to the technical field of renewable energies, and more specifically to the management, transport, and storage of renewable energy that has already been generated but not consumed when there is a generation surplus, for later use when there is high energy demand. The present invention specifically relates to a high-altitude energy storage system, specifically a gravity-fed energy storage plant, in which surplus renewable energy lifts water, which is then stored in an upper reservoir until it is needed for release. The water is then transformed into electrical energy by towers with hollow columns containing magnets. The movement of transformer modules inside these hollow columns generates electrical energy by electromagnetic induction.
[0006] Background of the invention
[0007] Currently, due to the boom in renewable energies, primarily solar and wind power, there are instances of overgeneration when energy demand is lower than energy generation. In these cases, energy storage systems are needed to store this excess energy and use it later when demand requires it, or when energy generation is limited and insufficient.
[0008] Currently, there are various energy storage technologies, such as capacitors and supercapacitors, which store energy in electric fields and provide rapid charging and discharging, although their capacity is limited. The batteries used in these systems convert energy by storing it as chemical energy during charging and releasing it as electricity during discharge, which leads to inefficiencies and significant energy losses.
[0009] Furthermore, hydrogen can also be used to store excess energy. Water electrolysis separates water into oxygen and hydrogen using electricity, via an electrolyzer. Therefore, when excess energy is produced, electrolysis harnesses the surplus to produce hydrogen, which is then stored for later use as a raw material in fuel production during periods of low energy generation or high demand.
[0010] Alternatively, energy can be stored as hydroelectric power, either through high-altitude storage or gravity-fed systems, using reservoirs or elevated water storage tanks. During periods of high power generation, excess electricity is used to pump water from a lower level or reservoir to a higher level or reservoir, transforming this excess energy into potential energy stored as water at a higher elevation. Subsequently, during periods of low power generation or high demand, the stored water is released, flowing down to a lower level through turbines that convert it into electricity. These high-altitude hydroelectric power storage methods can be used both on land with reservoirs and at sea, for storing offshore wind energy.
[0011] Currently, and related to the concept of high-altitude or gravity-fed energy storage, there are other storage systems that, in this case, do not use hydroelectric power. Some are already being implemented, while others are still under development. These systems primarily utilize surplus renewable energy, mainly wind and solar, to lift heavy weights, typically concrete blocks, to a height. These blocks are stored at height, storing the excess energy as potential energy. When energy generation is low or demand increases, the concrete blocks are released, and their descent triggers generators, producing electricity. These systems have the drawbacks of requiring large structures and significant heights, as well as substantial resources for managing and handling the heavy weight of the concrete blocks.Therefore, an efficient and lightweight high-altitude storage system is desirable that can store surplus energy at height and generate electricity during periods of low generation or high demand, avoiding the drawbacks of existing state-of-the-art systems.
[0012] Description of the invention
[0013] The present invention overcomes the drawbacks of the prior art by means of a gravity-fed energy storage plant, which has a lower and an upper water storage tank, separated by a certain height. This height provides the potential energy, or the storage by height, or gravity. In other words, the present invention is based on the concept of storage by height or gravity, but it does not use large weighted blocks, as is already the case in the prior art; instead, it uses the concepts of hydraulic storage and electromagnetic induction.
[0014] Thus, the plant's storage capacity depends on the volume of water contained in these tanks. The lower tank is filled with water, which can be either saltwater or freshwater, depending on the location and its abundance. However, due to the plant's design, the amount of water circulating between the two tanks remains constant, except for the water that evaporates under normal operating conditions. If the plant is installed in desert areas, water can be transported to the tanks.
[0015] The plant has water lift pipes connecting the lower and upper reservoirs, transferring water from the lower to the upper reservoir via electric pumps connected to both the lower reservoir and the lift pipes. These electric pumps are powered by electricity generated from surplus energy produced by various means, which is intended to be stored for later use when demand increases. This surplus energy can come primarily from renewable sources, such as wind or solar power, but can also come from surplus thermoelectric energy generated by burning fossil fuels. In addition, the storage plant has vertical power transformer towers positioned between the lower and upper reservoirs, and these transformer towers are connected to both reservoirs.These towers will be responsible for providing the electrical energy converted from the surplus energy accumulated at height in the set of reservoirs.
[0016] Each power transformer tower has two adjacent, hollow vertical columns with upper and lower ends. The inner walls of these hollow columns are lined with permanent magnets. Each tower also has a transformer module inside one of the hollow columns. This module moves along the inside of the column and includes a water tank and locking mechanisms. The outer walls of the transformer module are lined with coils. Additionally, each tower has a pulley located at the top, between the two hollow columns, at the height of the upper ends of the hollow columns. This pulley connects the two transformer modules using conventional means, such as a drag cable or other suitable method.This pulley allows the alternating linear movement of both transformer modules along the hollow columns between their upper and lower ends, depending on the weight of the modules. In other words, according to the pulley's operation, depending on the weight of each transformer module at any given time, and specifically the difference in weight between them, while one module moves down along the hollow column in which it is mounted, from the upper to the lower end, the other moves up the adjacent hollow column, from the lower to the upper end—that is, in the opposite direction. Thanks to this linear movement of the transformer modules along the inside of the hollow columns, the coils generate electrical energy by electromagnetic induction through the relative linear movement between the coils and the permanent magnets.Thus, each tower formed by two hollow columns becomes a generation unit.
[0017] To achieve the weight difference between the transformer modules connected to the pulley that will provide their displacement along the inside of the hollow columns, the plant has loading means, with their corresponding valves, gates or any opening system, which are arranged in the upper tank, which supply water from said upper tank to the water container of the transformer modules when they are at the upper end of the hollow columns, and unloading means, with their corresponding valves or discharge gates, arranged in the lower tank, which discharge water to said lower tank from the water container of the transformer modules when they are at the lower end of the hollow columns.
[0018] The locking mechanisms for the transformer modules prevent their movement during the water supply from the loading system. These mechanisms prevent the transformer module from descending the column as soon as it begins receiving water from the upper tank, which would prevent its water container from filling to the desired level. This level determines the transformer module's movement speed.
[0019] These loading and unloading means are connected to a control and regulation system and are synchronized with each other to achieve efficient movement of the transformer modules and electricity generation adapted to the needs of each moment.
[0020] In this configuration, the two transformer modules in each tower weigh exactly the same when empty, or when filled with the same amount of water and stationary. Therefore, in these circumstances, the weight of both is neutralized on the pulley. When water is added to one of them (the one at the top), the weight becomes unbalanced, and this transformer module begins to descend, pulling down the transformer module that was at the bottom of the other hollow column, whose container was empty. As the modules ascend and descend, the magnetic fields generated between the walls of the columns and the coils of the modules are excited, generating electrical energy through electromagnetic induction.
[0021] The speed of the transformer modules' movement can be regulated, either accelerating or decelerating, by adjusting the water level in each module. If the module's tank is filled to 100% capacity, the movement speed (one module ascending and the other descending) will be at its maximum. Conversely, if the water level decreases, the movement speed will slow down. This allows for regulating the speed of the modules' movement and, consequently, regulating the generation of electrical energy. Since the loading and unloading systems are connected to a control and regulation system and synchronized with each other, the process can be adjusted so that, for example, the programmed water load at the upper end is ready before the empty transformer module arrives, allowing the loading to be completed in just a few seconds. The same applies to the water discharge to the lower tank.Charging and unloading can be synchronized so that each cycle is completed in the shortest possible time. Since several towers or units are generating simultaneously, they can be programmed or synchronized so that neither the charging nor the unloading of all of them coincides at the same time, or conversely, so that all charging and unloading occur simultaneously, depending on the energy generation needs. Therefore, this system achieves simple and efficient speed regulation that does not require gears, reduction gearboxes, etc.
[0022] Thus, the energy conversion system can be considered similar to that of a direct-drive generator with permanent magnets. However, a key difference adapted to the present configuration is that the conventional circular motion of electromagnetic induction is replaced by the linear motion—in this case, vertical motion—of the transformer modules inside the hollow columns. Therefore, in the present invention, the hollow column is the stator, and in this case, the stator carries the permanent magnets, while the moving transformer module is the rotor, which in this case carries the coils, contrary to the arrangement of the elements in a conventional electromagnetic generator.
[0023] Because the plant is made up of many towers, each with two vertical columns, a robust structure is achieved that supports the upper tank, so large capacity tanks can be used, and therefore high storage capacity plants can be achieved.
[0024] The permanent magnets of hollow columns can be made of different materials, although preferably they will be ferrite magnets, which is a very abundant material on earth and which, moreover, is easily obtained. Alternatively, any other type of magnets can be used, such as neodymium, rare earth or others.
[0025] According to different specific embodiments of the invention, the hollow columns can be cylindrical or square in cross-section, which simplifies their manufacture, although they can also have any other type of cross-section to adapt to different required configurations or structural shapes. It should be noted that, correspondingly, to facilitate and optimize electromagnetic induction and eliminate friction, the transformer modules will preferably have the same cross-section as the hollow columns through which they circulate.
[0026] Depending on the specific implementation, transformer modules may include power inverters, power converters, power stabilizers, or any combination thereof, depending on the intended use of the generated or converted energy and its required processing. Alternatively, the energy can be fed into a transformer substation, where it is regulated using appropriate components (inverters, converters, stabilizers, etc.).
[0027] In particular, among other possibilities, the means of locking the transformer module to block the loading means during water supply can be formed by movable tabs that hook onto the inner surface of the hollow columns preventing the displacement of the transformer module, and by floating buoys arranged in the water container, connected to the movable tabs, which unhook these movable tabs from the hollow columns once the water has reached a certain level in the water container, allowing the transformer module to descend through the hollow column.
[0028] Alternatively, the locking means may consist of movable tabs that engage with the inner surface of the hollow columns, preventing the transformer module from moving, and electronic means connected to the movable tabs and the control and regulation system, configured to actuate, engage, and disengage the movable tabs from the hollow columns as required. According to a particular embodiment of the invention, the transformer modules have a plurality of bearings arranged on their outer surface that contact the inner surface of the hollow columns, facilitating and smoothing the movement of the transformer modules along the hollow columns, preventing friction and damage to the system and structures.
[0029] Preferably, the storage plant may have progressive braking means to gradually slow down the transformer modules as they descend through the hollow columns before reaching the bottom, thus avoiding a possible impact if the module descends at high speed, which could cause damage, breakage or malfunctions in the system.
[0030] Brief description of the drawings
[0031] Next, to facilitate understanding of the invention, by way of illustration but not limitation, an embodiment of the invention will be described which refers to a series of figures.
[0032] Figure 1 schematically represents an embodiment of a gravity energy storage plant, the subject of the present invention, showing its essential elements.
[0033] Figure 2 schematically shows in a frontal longitudinal section the detail of two transformer towers of an accumulator plant of the present invention, with their essential elements.
[0034] Figure 3 is a cross-sectional plan view of a hollow column of a transformer tower of the present invention, showing the generation module inside.
[0035] Figure 4 is a partial schematic front longitudinal section view showing a particular embodiment of a transformer module inside a hollow column, showing some of its elements. These figures refer to a set of elements which are:
[0036] 1. storage plant
[0037] 2. lower tank
[0038] 3. upper tank
[0039] 4. Water lifting pipes
[0040] 5. Electric pumps
[0041] 6. Power transformation towers
[0042] 7. Water loading methods
[0043] 8. Water discharge methods
[0044] 9. Hollow columns of the transformer towers
[0045] 10. Permanent manes of hollow columns
[0046] 11. Transformer modules of the transformer towers
[0047] 12. Transformer module coils
[0048] 13. Air gap between permanent magnets and coils
[0049] 14. Water container of the transformer module
[0050] 15. Transformer module transmission system
[0051] 16. Pulleys of the transformer towers
[0052] 17. pulley drive cable
[0053] 18. upper end of hollow columns
[0054] 19. Lower end of the transformer towers
[0055] 20. Bearings of transformer modules
[0056] 21. Braking springs
[0057] Detailed description of the invention
[0058] The object of the invention is a gravity energy storage plant 1.
[0059] As can be seen in the figures, the storage plant 1 has two water tanks, a lower tank 2 and an upper tank 3, separated by a certain height, which is what provides the potential energy to the whole, or the storage of energy at height, or by gravity.
[0060] The storage plant 1 has water lift pipes 4 that connect the lower tank 2 and the upper tank 3, and transfer water from the lower tank 2 to the upper tank 3 by means of electric pumps 5 connected to the lower tank 2 and the lift pipes 4, as shown in Figure 1. The electric pumps 5 are powered by electricity generated from surplus energy, which is precisely what is to be stored. This surplus energy can come from any source, renewable energy sources such as wind or solar, or it can also come from surplus thermoelectric energy generated by the combustion of fossil fuels.
[0061] In addition, storage plant 1 has vertical energy transformation towers 6 located between the lower tank 2 and the upper tank 3, connected to both tanks by means of water loading means 7 and unloading means 8. The transformation towers 6 are responsible for supplying, when energy demand increases, the converted energy from the surplus energy stored at height.
[0062] As can be seen in detail in Figure 2, each transformer tower 6 has two vertical hollow columns 9 with an upper end 18 and a lower end 19, and are adjacent, i.e., side by side. The inner walls of both hollow columns 9 are lined with permanent magnets 10. Each tower 6 also has a transformer module 11 arranged inside each of the hollow columns 9, which can be moved along the interior of said hollow columns 9. The transformer module 11 includes a water tank 14, a transmission system 15 for the generated energy, and locking means. The outer walls of the transformer module 11 are lined with coils 12. Additionally, each tower 6 has a pulley 16, located at the top of it, i.e., at the height of the upper ends 18 of the hollow columns 9, between them.This pulley 16 connects both transformer modules 11 by conventional means, such as a drag cable 17. The pulley 16 allows the alternating linear displacement of both transformer modules 11 along the hollow columns 9 between their upper ends 18 and their lower ends 19, depending on the weight of said transformer modules 11. That is, according to the operation of the pulley 16, depending on the weight at any given moment of each of the transformer modules 11, and specifically on the difference in weight between them, while one goes down along the hollow column 9 in which it is located from the upper end 18 to the lower end 19, the other will go up in the adjacent hollow column 9, from the lower end 19 to the upper end 18.This linear displacement of the transformer modules 11 along the interior of the hollow columns 9 causes the coils to generate energy by electromagnetic induction, due to the relative linear displacement between the coils 12 and the permanent magnets 10. Since these are robust structures, the air gap 13 can be minimized. According to different specific embodiments, the permanent magnets 10 of the hollow columns 9 can be made of different materials, although ferrite magnets are preferred.
[0063] To achieve the weight difference between the transformer modules 11 that will cause their displacement along the interior of the hollow columns 11, the plant 1 has loading means 7, with their corresponding discharge valves or gates, arranged in the upper tank 3, which supply water from said upper tank 3 to the water container 14 of the transformer modules 11 when they are at the upper end 18 of the hollow columns 9, and discharge means 8, with their corresponding discharge valves or gates, arranged in the lower tank 2, which discharge water to said lower tank 2 from the water container 14 of the transformer modules 11 when they are at the lower end 19 of the hollow columns 9.
[0064] The locking means of the transformer modules block the movement of said transformer modules 11 during the supply of water from the loading means 7. These locking means will prevent the transformer module 11 from starting to descend through the hollow column 9 as soon as it begins to receive water from the upper tank 3, which would prevent its water container 14 from filling to the desired level, which is what determines the displacement speed of the transformer module 11.
[0065] The loading means 7 and the unloading means 8 are connected to a control and regulation system and are synchronized with each other to achieve efficient movement of the transformer modules 11 and energy generation adapted to the needs of each moment. In Figure 2, a front longitudinal section shows two transformer towers 6, each with two hollow columns 9, in two different positions.In the snapshot, in tower 6 on the left, the transformer module 11 of the hollow column 9 on the left can be seen at the upper end 18, having received water from the upper reservoir 3 by means of the loading means 7, so it will descend along the hollow column 9 to its lower end 19, while the transformer module 11 of the hollow column 9 on the right has discharged water from its water container 14 by means of the discharge means 8 to the lower reservoir 2, so it will ascend along the hollow column 9 to its upper end 18.In contrast, in the snapshot of tower 6 on the right, the transformer module 11 of the hollow column 9 on the right can be seen at the lower end 19, which has just come down, before discharging water into the lower tank 2 through the discharge means 8, while the transformer module 11 of the hollow column 9 on the left has just come up, and has not yet been charged with water from the upper tank 3 through the charging means 7.
[0066] According to different specific embodiments of the invention, the hollow columns 9 can be cylindrical or square in cross-section, which simplifies their manufacture, although they can also have any other type of cross-section to adapt to different required configurations or shapes in the structures. It should be noted that to facilitate and optimize electromagnetic induction, the transformer modules 11 will preferably have the same cross-section as the hollow columns 9 through which they circulate. Figure 3 is a cross-sectional plan view showing a square-section hollow column 9 of a transformer tower 6 of the present invention, with the square-section generating module 11 inside.
[0067] According to different embodiments, the transformer modules 11 of the transformer towers 6 may include current inverters, or current converters or current stabilizers, or any combination of the above.
[0068] In particular, the locking means of the transformer module 11, which lock it during the supply of water from the loading means 7, may consist of movable tabs that engage on the inner surface of the hollow columns 9, in such a way as to prevent the displacement of the transformer module 11, and of floating buoys arranged in the water container 14, connected to the movable tabs, which disengage these movable tabs from the hollow columns 9 once the water has reached a certain level in the water container 14, allowing the descent of the transformer module 11 through the hollow column 9.Alternatively, the locking means may consist of movable tabs that engage on the inner surface of the hollow columns 9, preventing the displacement of the transformer module 11, and may also include electronic means connected to the movable tabs and to the control and regulation system, configured to actuate, and engage and disengage the movable tabs from the hollow columns 9, as required.
[0069] According to a particular embodiment of the invention, shown schematically in Figure 4, the transformer modules 11 may have a plurality of bearings 20 arranged on their outer surface, which contact the inner surface of the hollow columns 9, facilitating and smoothing the movement of said transformer modules 9 along the hollow columns 9.
[0070] Preferably, the storage plant 1 may be equipped with progressive braking means to gradually slow the transformer modules 11 as they descend inside the hollow columns 9 before reaching the lower end 19, thus preventing a possible impact if the transformer module 11 descends at high speed, which could cause damage, breakage, or malfunctions in the system. Figure 4 schematically shows a possible embodiment of these progressive braking means, which has braking springs 21 arranged on the inner surface of the hollow columns 9. These braking springs 21 can be positioned at different heights on the hollow columns 9 and will gradually slow the transformer modules 11 as they move inside them.
Claims
CLAIMS 1. Gravity energy storage plant, comprising: a lower tank (2) and an upper tank (3) separated by a certain height and configured to store water, water lifting conduits (4) connecting the lower tank (2) and the upper tank (3), configured to transfer water from the lower tank (2) to the upper tank (3) by means of electric pumps (5) connected to the lower tank (2) and the lifting conduits (4), powered by an excess of energy to be stored, characterized in that it comprises a plurality of vertical energy transformation towers (6) arranged between and connected to both tanks (2,3), each energy transformation tower (6) comprising two adjacent vertical hollow columns (9) with an upper end (18) and a lower end (19), whose inner walls are lined with permanent magnets (10), a transformer module (11) arranged inside each of the hollow columns (9) and movable along them, whose outer walls are lined with coils (12) and comprises a water container (14) and locking means, and a pulley (16) connecting both transformer modules (11) allowing the alternating linear displacement of both along the hollow columns (9) between their upper end (18) and their lower end (19), depending on the weight of said transformer modules (11), so that the coils (12) generate electrical energy by electromagnetic induction through the relative linear displacement between the coils (12) and the permanent magnets (10), understanding the plant loading means (7) that supply water from the upper reservoir (3) to the water container (14) of the transformer modules (11) when they are at the upper end (18), the locking means of the transformer modules (11) being configured to block the displacement of said transformer modules (11) during the supply of water by the loading means (7), and discharge means (8) that discharge water to the lower tank (4) from the water container (14) of the transformer modules (11) when they are at the lower end (19), varying the weight of the transformer modules (11), the loading means (7) and the discharge means (8) being connected to a control and regulation system.
2. Gravity energy storage plant, according to claim 1, wherein the permanent magnets (10) of the hollow columns (9) are made of ferrite.
3. Gravity energy storage plant, according to any of the preceding claims, wherein the hollow columns (9) are cylindrical.
4. Gravity energy storage plant, according to any of claims 1 to 2, wherein the hollow columns (9) have a square cross-section.
5. Gravity energy storage plant, according to any of the preceding claims, wherein the transformer modules (11) comprise current inverters.
6. Gravity energy storage plant, according to any of the preceding claims, wherein the transformer modules (11) comprise current converters.
7. Gravity energy storage plant, according to any of the preceding claims, wherein the transformer modules (11) comprise stabilizers.
8. Gravity energy storage plant, according to any of the preceding claims, wherein the locking means for the transformer module (11) comprise movable tabs configured to hook onto the inner surface of the hollow columns (9), and Floating buoys arranged in the water container (14), connected to said movable tabs, and configured to disengage the movable tabs from the hollow columns (9) once the water has reached a predetermined level in said water container (14).
9. Gravity energy storage plant, according to any of claims 1 to 7, wherein the locking means for the transformer module (11) comprise movable tabs configured to hook onto the inner surface of the hollow columns (9), and electronic means connected to the movable tabs and to the control and regulation system, configured to actuate the movable tabs and to engage and disengage them from the hollow columns (9).
10. Gravity energy storage plant, according to any of the preceding claims, wherein the transformer modules (11) comprise a plurality of bearings arranged on their outer surface that contact the inner surface of the hollow columns (9).
11. Gravity energy storage plant, according to any of the preceding claims, comprising progressive braking means configured to progressively brake the transformer modules (11) as they descend through the hollow columns (9) before reaching the lower end (19).
12. Gravity energy storage plant, according to claim 11, wherein the progressive braking means comprise braking springs (21) arranged on the inner surface of the hollow columns (9).