GRAVITY-BASED ENERGY STORAGE SYSTEM IN UNUSED QUARRIES AND MINES

Abstract

A gravity energy storage system in unexploited quarries and mines that uses the walls of the unexploited quarry or mine as part of its structure, comprising a plurality of elevator-generators (1, 2 and 3), blocks (7), and guides (4, 5, 6 and 12), the elevator-generators (1, 2, 3) being configured to lift the blocks (7) for storage in the guides (4, 5, 6 and 12) in order to accumulate potential energy from the blocks (7) during off-peak consumption periods; The elevator-generators (1, 2, 3) are configured to generate energy from the kinetic energy produced during the descent of the blocks (7) stored on the guides (4, 5, 6, and 12) in order to generate electrical energy during peak consumption periods, the guides (4, 5, 6, 12) being configured to guide the blocks (7) towards the elevator-generators (1, 2, 3) during said peak consumption periods.

Description

GRAVITY-DRIVEN ENERGY STORAGE SYSTEM IN QUARRIES AND MINES WITHOUT EXPLOITATION Technology sector The present invention relates to the accumulation of electrical energy primarily from renewable energy sources. This invention solves the problems existing in current gravity systems, primarily the high investment required for construction, to make it a form of electrical grid accumulation as efficient as, or even more efficient than, other existing systems. It is well known that one of the main problems of the electrical grid is balancing electricity generation with consumption. With thermal power plants that use fossil fuels, this is not difficult, and this is how the grid is usually balanced: by increasing generation by burning more gas, fuel oil, or coal. Due to global commitments to reduce CO2 emissions caused by these technologies, a transition is taking place towards renewable energies, mainly wind and solar, which generate energy when there is wind or when there is sun respectively, making it impossible to balance demand and generation. To solve this, energy storage systems are needed. These come in various types: lithium batteries or other types, water pumping stations, flywheels, compressed air tanks, thermal storage systems, and gravity storage systems. Recent studies have significantly penalized gravity accumulators due to the need to construct large structures and the resulting high investment. This can be clearly seen in the following graph (source: BloombergNEF). However, that same graph shows that in projects where investment is contained, gravity storage technology is competitive with any of the other systems. Existing gravity storage systems require large infrastructures for their implementation, such as the construction of large buildings to support the weights when they accumulate potential energy. This can be seen in the following patents: WO2022006584 WO2023114001 WO2023239264 These structures, in addition to having a huge visual impact and therefore posing a challenge to their implementation due to environmental damage, require enormous investments for their construction. Additionally, the weights needed for the accumulation of potential energy require transport from their origin to the place where this structure is being built, with the consequent cost and increase in CO2 emissions, something that this type of accumulators aims to avoid. Object of the invention The present invention aims to take advantage of the cavities created by humans in mining operations and quarries to install renewable electrical energy gravity accumulators in these locations, restoring the original state of the natural space. It so happens that these quarries or mining operations have: 1. Significant difference in elevation to be able to accumulate potential energy and generate kinetic energy. 2. Walls where the entire complex can be structurally braced, greatly reducing its construction costs, making them part of the structural responsibility of the system. 3. Terraces where elements with high potential energy can be accumulated. 4. Material to be able to perform the weights that have to be lifted to accumulate energy and lowered to produce it. 5. High or medium voltage lines that were used during the operation, which would now serve to deliver electricity and be able to evacuate it. 6. Proximity to industrial or population centers, which means that transmission does not have many losses. 7. Deterioration of the natural space where they were carried out, where frequently that unsightly hollow mars the landscape and can be a risk to people and animals. These circumstances make them perfect locations for the system that is the subject of this patent, which is specifically designed to take advantage of all these features and transform them into benefits. The system consists of a series of elevator-generators that raise and lower blocks or aggregates made from quarry or mine material. Each elevator-generator has a motor-generator that operates in different modes depending on whether it is to consume or generate electricity for the grid. The blocks would be placed on trolleys that would allow them to be stacked and moved along radial and concentric rails, either by a motor or actuator, or by gravity. Aggregates could be stored in silos and transported by wagons, conveyor belts, or other existing transport systems. The open or closed-loop rail configuration allows for maximum utilization of the quarry or mine volume and enables the parallel operation of multiple elevator-generators to meet peak demand or generation needs. Similarly, a series of silos can be implemented for aggregates. To recover the natural space, it is planned that the system can be provided with a cover, preferably using recyclable materials such as wind turbine blades, on which soil and vegetation would be placed. Description of the figures To aid in a better understanding of the functionality of the invention, illustrative drawings, which are not limiting, are attached to the description. Figure 1 shows a mountain where a cavity has been made to exploit an already abandoned quarry. Figure 2 is a perspective view of the proposed gravity-fed power generation system. Figure 3 is a plan view of the proposed power generation system. Figure 4 is an elevation view of the proposed generation system. Figure 5 is an elevation view showing the block stacking system. Figure 6 is an elevation view of the block locking system Figure 7 is an elevation view of the system for moving and accumulating blocks on the intermediate floors. Figure 8 is a plan view of the block accumulation system in concentric or transverse lanes. Figure 9 shows a plan view of a chain of aggregate silos with their respective aggregate lifting and lowering systems to accumulate or generate electrical energy. Figure 10 shows section AA shown in the plan view of Figure 9, where you can see what a possible elevation of a chain of aggregate silos would look like with their respective systems for raising and lowering the aggregates to accumulate or generate electrical energy. Figure 11 shows a perspective view of the application of the accumulation system to an open-pit mine. Figure 12 shows a perspective view of the mountain once it has been restored and covered with vegetation. Detailed description of the invention Humans have been quarrying and open-pit mining since the dawn of civilization, usually near population centers. Figure 1 shows a mountain with a quarry carved into it. Figure 2 shows the perspective view of the preferred but not restrictive embodiment of a gravitational accumulation system that is the subject of this patent, implemented in the cavity of a mountain where the roof has been omitted to visualize the system. Figure 3 shows the different elements required to raise and lower the blocks (7) from one level to another. The purpose is to raise them to increase their potential energy when energy storage is needed, or to lower them when energy is generated from the kinetic energy produced during their descent. To achieve this, the system includes elevator-generators of varying heights (1) and heights (2) (3). Slightly inclined guides (4) allow the blocks to move by gravity for storage and positioning, while steeper inclined guides (5) enable the blocks to generate energy during their movement. The system can also include guides (6) and (12) at different levels and configurations to store a greater number of blocks at different heights, thus increasing the amount of energy stored. The system would operate as follows: during off-peak periods of electricity demand on the grid, the elevator-generators (1, 2, and 3) would be used to raise the blocks. Initially, the highest level would be raised, and as it fills, the other levels would be filled using the guide rails (6). During peak electricity demand periods on the grid, the blocks would be lowered, and it is during this descent that the elevator-generators would produce electricity for the grid. The descent could be done with one or more elevators, block by block or stacked (see Fig. 5), depending on the magnitude of the peak grid demand. It is precisely the proposed configuration of inclined rails that, thanks to this slight incline, allows the next blocks to be prepared for descent in the following elevator-generator cycle.Additionally, the fact that the blocks can be stacked makes it an exceptionally versatile system for responding to consumption demand quickly and efficiently. Figure 5 shows how the blocks (7) have a base (8) and a top (9) that allows them to be stacked. Figure 6 shows that the base can incorporate wheels (8) to facilitate the movement of the blocks (7). It also shows that they can incorporate an interlocking system (10) consisting of two latches (10.1 and 10.2) that can be activated remotely, so that the blocks (7) can be moved together if desired. Figure 7 shows how blocks (7) could be extracted from intermediate levels of the elevator-generators for storage. This would be accomplished using an actuator (11) that moves the train of blocks (7) up the guide (6), leaving them in a position to be lowered if energy demand requires it. Figure 8 shows guides (12) perpendicular to guides (4) and (6), which allow for greater utilization of the block (7) storage at the different levels. Figures 9 and 10 detail a possible embodiment of the invention using aggregates instead of blocks (7). In this case, and in the case of blocks (7), a closed-loop silo arrangement (16) can be used where the elevator-generators (1) move the aggregates or blocks (7) up or down to increase or generate stored energy, respectively. Each elevator-generator draws power from the silo above it on its left when generating electricity from stored potential energy and from the silo below it on its right when consuming electricity and accumulating potential energy. These elevator-generators could be conveyor belts or wagon trains. This arrangement allows, in the event of a peak demand on the grid, the generation of large amounts of energy at once by activating all the generators.The base of the silos (16) would have an inclined base (5a) that favors the aggregate going towards the generator by its own gravity, just as it occurred in the guides (5) for the realization with blocks (7). Figure 11 shows a possible configuration of the energy storage system in an open-pit mine, where the terraces (13) present in this type of mining operation would be used to accumulate the blocks (7). Although not shown in the figure, it is also planned to cover the system with a layer that will allow the surrounding area to be restored to its original state through vegetation. Figure 12 shows a possible implementation of the environmental regeneration roof (14). This drawing considers the possibility of using scrap wind turbine blades (15) as a structural element of the roof. This would both restore the original appearance of the hillside and give a use to a waste product that is difficult and costly to dispose of.

Claims

1. A gravity energy storage system in unexploited quarries and mines that uses the walls of the unexploited quarry or mine as part of its structure, comprising a plurality of elevator-generators (1, 2 and 3), blocks (7), and guides (4, 5, 6 and 12), the elevator-generators (1, 2, 3) being configured to lift the blocks (7) for storage in the guides (4, 5, 6 and 12) in order to accumulate potential energy from the blocks (7) during off-peak consumption periods; The elevator-generators (1, 2, 3) are configured to generate energy from the kinetic energy produced during the descent of the blocks (7) stored in the guides (4, 5, 6 and 12) in order to generate electrical energy during peak consumption periods, the guides (4, 5, 6, 12) being configured to guide the blocks (7) towards the elevator-generators (1, 2, 3) during said peak consumption periods. 2.An energy storage system according to claim 1, wherein the guides (4, 5, 6, 12) comprise an incline that allows the blocks to be moved by gravity for storage and lowered by the elevator-generators (1, 2, 3).

3. An energy storage system according to claim 2, wherein the blocks (7) are in the form of silos (16) that accumulate an aggregate, the guide for storing and transporting said aggregate being an inclined base (5a) of said silos (16).

4. An energy storage system according to the preceding claim, wherein the blocks (7) are transported by elevator-generators (1) that are conveyor belts or a train of wagons.

5. An energy storage system according to any one of the preceding claims, wherein the blocks (7) or the silos (16) comprise aggregates of material extracted from the quarry or mine itself. 6.Energy storage system according to any one of the preceding claims, wherein the blocks (7) are configured to be stacked and formed into trains.

7. Energy storage system according to the preceding claim, wherein the blocks (7) comprise a base (8) and a top portion (9) that allow for stacking.

8. Energy storage system according to claim 1, wherein the elevator-generators are configured to lower stacked blocks (7).

9. Energy storage system according to any one of the preceding claims, comprising a cover (14) configured to cover the cavity of the quarry or mine workings. 10.An energy storage system according to any one of the preceding claims, comprising actuators (11) configured to extract the blocks (7) from the elevator-generator (1, 2, 3) and push the block train (7) to the top of the guides (4 and 6), leaving them in a position to be lowered if energy demand so requires.

11. An energy storage system according to the preceding claims, wherein the cover (14) comprises scrapable wind turbine blades (15) as a structural element.

12. An energy storage system according to claim 1 or 2, comprising a closed-loop arrangement, wherein each elevator-generator is supplied from an upper silo (16) to its left when generating electrical energy from stored potential energy, and is supplied from a lower silo (16) to its right to consume electrical energy and store potential energy.