Ballast transport device assembly for gravity energy storage facility

Abstract

A ballast transport device assembly for a gravity energy storage with a power conversion system comprises a pair of two opposite vertical ribs, each fitted with a linear guide upon which a carriage moves, the carriage being equipped at each end with a vertical bogie and a ballast beam gripping system, characterised in that the vertical ribs (1) contain rest shelves (4) evenly distributed along their length and facing the adjacent vertical rib (1) to form a pair, and further, between each pair of vertical ribs (1), magnetic tracks (5) extend along their entire length, wherein each carriage (3) has at least one linear motor-generator (6) placed on the side facing the magnetic track (5) and contains a longitudinal track (7) in its lower part for moving am electrically driven ballast bogie (8), and wherein the linear motor-generator (6) is connected to an inverter with a power return function.

Description

[0001] Ballast Transport Device Assembly for Gravity Energy Storage Facility

[0002] The subject of the invention is a ballast transport device assembly for gravity energy storage facility that includes a ballast storage zone in its upper section, a ground-to-height and height-to-ground ballast block transfer system and an energy conversion system that uses the concept of kinetic energy generation to drive electrical power generation equipment that is connected to the power conversion and transmission system to be used in the public grid or directly consumed by receivers or to be stored in lithium-ion batteries. The system takes advantage of the principle that when the end customer's demand for electricity is low, the system stores energy by transporting the ballast block from low to high elevation and when the demand for electricity is high, the ballast block is lowered to the ground, and the weight of the ballast block drives the gear mechanism or flywheel during the lowering process, which in turn drives the electricity generator.

[0003] An energy storage system is known from publication W02020018329A2. The system consists of multiple ballast blocks and a crane comprising a frame, an electric motor / generator, one or more bogies capable of moving along the frame, and a cable connected to one or more bogies which are connected to the electric motor / generator. Each of the many blocks is the same size and shape or they are of different sizes. The cable is configured to connect to one or more blocks. The crane may stack one or more blocks on top of each other, moving said blocks from a lower elevation to a higher elevation in order to store an amount of electrical energy in said blocks corresponding to the gravitational potential energy of said blocks. The crane is further designed to remove one or more blocks from the stack by moving said blocks from a higher elevation to a lower elevation thanks to gravity to generate an amount of electrical energy corresponding to the amount of kinetic energy of said one or more blocks when they move from the higher elevation to the lower elevation. The crane is placed on the tower and has one or more booms extending transversely to the tower. Optionally, the booms can rotate around the tower. Two booms located on opposite sides of the tower balance each other. A motor / generator is a unit that can act as both an electric motor and an electric power generator.

[0004] The Energy Vault Resiliency Center™ is known for its ballast transport unit based on a modular frame structure in the form of a cuboid. The upper rack levels are a place for storing ballast placed on transport bogies, so that they can be moved to transfer lifts located only in the outermost perimeter of the energy storage and move along its vertical outer walls. The lifts are connected to motor / generators that can be powered from renewable energy sources.

[0005] Patent description PL243648B1 describes a ballast transport unit that forms a vertical framework of stacked modules, inside which loads suspended on lifting ropes move vertically. The lowest module of the framework houses the energy conversion unit, which is mechanically coupled to the respective ballast loads by means of a gearbox and a lifting system.

[0006] Patent description PL245013B1 describes a ballast transport unit based on two pins. On the rings of pins, main girders are mounted radially around their entire circumference, at equal intervals. Placed on each main girder there is a part of the energy conversion unit, consisting of a motor-generator, an associated gear and a flywheel. A lifting cable interacts with the flywheel. One end of the lifting cable is terminated with a suspended counterweight and on the other end there is a longitudinal carriage beam, with horizontal powered bogies at the ends, which move on two transverse carriage beams. Each transverse beam has a vertical bogie at its end, moving along linear guides. A powered horizontal bogie moves along the transverse carriage beam to capture ballast beam sockets by a pair of twist-lock pins.

[0007] A drawback of the current state of the art is that the transport of ballast utilising ropes in conjunction with a pulley system results in the generation of significant thermal energy as a direct consequence of frictional forces, leading to accelerated wear of the mechanical system components. Furthermore, existing state-of-the-art transport units impose substantial limitations on the safe operational range of ballast descent velocities. This constraint consequently leads to a reduction in both overall system efficiency and the efficiency of electrical power generation.

[0008] Additionally, the considerable length of the lifting ropes results in significant material elongation (stretching), which compromises the operational precision of the system. In comparison to a magnetic transport system, the rope-based system exhibits significantly lower operational velocity and this constraint compromises the ability of the energy storage facility to ensure full availability upon receipt of an energy dispatch signal.

[0009] The primary objective of the present invention is, therefore, to provide a ballast beam transport unit that mitigates the aforementioned deficiencies and drawbacks of the prior art. Unexpectedly, it has been determined that the replacement of the drive system — currently based on a rotary motor-generator, gears, ropes, and pulleys—with a linear motor-generator effectively overcomes the limitations inherent in the prior art.

[0010] The incorporation of magnetic elements effectively eliminates the frictional forces typically generated by the wheels within the gearbox and the pulleys. In conventional systems, this friction constitutes a significant constraint on the maximum operational velocity for both the lowering and raising of the ballast. Crucially, the inventive concept circumvents the challenges associated with wheel¬ rail dynamics. In conventional systems, these dynamics induce resonance phenomena that restrict the safe operating speed range.

[0011] In essence, the ballast transport device assembly for a gravity energy storage system with an integrated power conversion system comprises a pair of two opposing vertical ribs, each equipped with a linear guide. A carriage travels along these guides, having a vertical bogie at each end, and is furnished with a ballast beam capturing system. The unit is characterized in that the vertical ribs, within their upper section, incorporate resting shelves that are evenly distributed along their length and oriented toward the adjacent vertical rib forming the pair. Magnetic tracks are positioned between each of the two pairs of vertical ribs, extending along the entire operative length of the ribs. Each carriage incorporates at least one linear current motor-generator situated adjacent to the magnetic track. Furthermore, the lower section of the carriage contains a longitudinal track designed for the electrically-driven movement of the ballast bogie. The linear motor-generator is connected to an inverter that is configured with a power return (regenerative) function.

[0012] It is advantageous for the ballast carriage to incorporate an arm that extends laterally beyond the carriage beam toward the ballast beam. The distal end of this arm features a projection fitted with a pin that is specifically configured to mate with a corresponding socket located in the ballast beam.

[0013] In the preferred embodiment, the ballast bogie is mounted on a longitudinal track and incorporates rollers and a linear motor drive unit. Furthermore, the magnetic tread of the ballast carriage is placed along the entire length of the carriage structure.

[0014] In another preferred embodiment, the ballast bogie is mounted on a longitudinal track and incorporates rollers along with a drive mechanism configured as a rotary motor.

[0015] It is advantageous if the carriage is configured with a C-shaped cross¬ section.

[0016] The device assembly according to the present invention offers the advantage of achieving precise and flexible power generation, particularly in comparison to systems wherein the drive unit utilises a rotary motor-generator. A further advantage is that the system contributes to enhanced electrical grid stability through the simultaneous utilization of the potential energy source, the stored ballast mass.

[0017] The device assembly according to the invention exhibits high sensitivity to the dynamic requirements of the transmission grid due to the fact that, upon receipt of a dispatch signal the system can achieve a ballast lowering speed up to four times greater (e.g., 2.0 m / s for linear motors versus 0.5 m / s for a rope system) which positively impacts the effective capacity and availability of the energy storage over extended operational periods.

[0018] The device assembly according to the present invention is adaptable for use in gravity energy storage facilities having various structural configurations, including cylindrical, cubic, and other geometric designs.

[0019] The invention is described in greater detail with reference to the accompanying figures, in which:

[0020] Fig. 1 and Fig. 2 illustrate a perspective view of the ballast transport device assembly, specifically showing the upper region of the vertical ribs when the ballast units are situated in the upper storage position.

[0021] Fig. 3 illustrates a view of the ballast transport device assembly, as referenced in Fig. 1 and Fig. 2, during a period of carriage operation when one batch of ballast is located in the middle operational position.

[0022] Fig. 4 illustrates an alternative view of the ballast transport device assembly during the lowering operation of one batch of ballast.

[0023] Fig. 5 is a side elevational view of the ballast transport device assembly, consistent with the configuration shown in Fig. 1 and Fig. 2.

[0024] Fig. 6 is a front elevational view of the ballast transport device assembly, consistent with the configuration shown in Fig. 4.

[0025] Fig. 7 Is a partial top plan view of the ballast transport device assembly, consistent with the configuration shown in Fig. 1 and Fig. 2.

[0026] Fig. 8 illustrates a view of the ballast transport device assembly in the upper region of the vertical ribs, where the ballast units are in the upper storage position, further showing the ballast carriage assembly separated from the vertical ribs.

[0027] Fig. 9 illustrates the ballast transport device assembly viewed from the side of the ballast bogie.

[0028] Fig. 10 illustrates the arrangement of the ballast transport device assembly when implemented within a gravity energy storage device having a cylindrical outer shaft configuration.

[0029] Embodiment 1: The technical parameters and specifications of the primary components comprising the ballast transport assembly and operating within the gravity energy storage facility are detailed below:

[0030] Power of installed motor / generators: 10 MW.

[0031] The contact surface area between the magnet and the 320 kW linear motor¬ generator set is specified as: 10 m2.

[0032] Inverter: 10 MW - 100% utilized - the design ensures that the linear motor¬ generator can deliver energy within a significantly shorter time in both the hoisting and lowering directions, i.e., energy input and output

[0033] Charging (lifting) time for all ballast blocks 3.5 h (12,600 s)

[0034] Discharging (lowering) time all ballast blocks 3.5 h (12,600 s)

[0035] Energy Storage Capacity: 10 MW x 3.5 h = 35 MWh.

[0036] Weight of all ballast blocks: 85,627,000 kg

[0037] Absolute lifting elevation of ballast blocks: 150 m

[0038] Number of reinforced concrete ballast blocks: 1415 units

[0039] Weight of one ballast block: 60,000 kg

[0040] Dimensions of 1 ballast block: 21 x 1.5 x 0.8 m

[0041] Overall dimensions of the energy storage system:

[0042] - height 212 m

[0043] - outer cylinder diameter 76 m

[0044] - inner cylinder diameter 29 m

[0045] Given identical ballast parameters, the operational advantage of the inventive assembly over the prior art rope lifting assembly is that in the case of a rope assembly, the operational cycle time is typically not shorter than 7 hours. Conversely, the linear motor assembly substantially reduces the time required for lifting the empty carriage back to the upper position, as the empty carriage returns demonstrably faster than is possible with the rope lifting assembly.

[0046] Ballast beams are made of high-performance concrete with compressive strength from 25 to 60 MPa. The barest transport device assembly for a gravity energy storage facility with a power conversion system comprises a pair of two opposite vertical ribs (1), each provided with two opposing vertical linear guides (2) that facilitate the movement of the vertical roller bogies (3). It should be noted that only the upper portions of the vertical ribs (1) are illustrated in the provided drawing figures. Each vertical rib (1), in its upper section, is provided with resting shelves (4) that are evenly distributed along the length of the rib and are oriented facing the adjacent vertical rib (2), thereby defining a functional pair. Located between each of the two pairs of vertical ribs (2), and extending along the entire operative length corresponding to the travel of the carriage (3), are the magnetic tracks (5). Each carriage (3) is equipped, on the side facing the magnetic tracks (5), with a set of linear current motor-generators (6) with a nominal power rating of 40 kW, resulting in a total aggregate power output of 320 kW for each carriage (3). The linear motor¬ generators (6), operating in conjunction with the magnetic tracks (5), collectively constitute a part of the energy conversion unit of the gravity storage facility. The carriage beam (3) has a C-shaped cross-section and its structural configuration is defined by an upper flange, a connecting web, and a lower flange. In the lower portion of the carriage (3), located on the lower shelf, is a longitudinal track (7) that facilitates the movement of the ballast bogie (8), which is supported by rollers (18). The lateral translation of the ballast bogie (8) along the carriage beam (3) is effected by two dedicated linear motors (17) each of which is attached to the ballast bogie (8) and has a nominal power rating of 9 kW. Located on the inner side of the web (vertical element of the carriage beam 3) is the magnetic tread (9) utilized by the ballast bogie (8). A pair of ballast bogies (8) traverses along the length of each carriage beam (3). Each ballast bogie incorporates an arm (10) that extends laterally beyond the profile of the carriage beam (3). The arm (10) is configured to engage and grip the ballast beam (11) from below at a specific projection (12) that is situated on each end of the ballast beam (11). The stability of the connection between the ballast beam (11) and the ballast bogie (8) is ensured by a pin-and- socket arrangement of a pin (13) located on the top surface of the arm (10), which mates with a corresponding socket (14) situated at the bottom of the projection (12) of the ballast beam (11) and this configuration represents one embodiment of the gripping system. A single ballast beam (11) rests upon each pair of opposing resting shelves (4) located on the adjacent vertical ribs (1). After the pairs of ballast bogies (8) simultaneously engage two ballast beams (11) and move them along the carriage beam (3) to a centralized position, the carriage (3), supported by vertical roller bogies (15), descends vertically along the linear guides (2), whereby the resulting interaction between the electromagnetic field of the magnetic track (5) and the linear motor-generator (6) excites the drive-generator unit, generating electrical energy that is transmitted via an inverter to the control system for delivery to the energy storage facility or the electricity grid. The ballast beams (11) are placed directly on top of each other on the foundation slab of the energy storage facility.

[0047] Electrical energy is continuously generated along the entire travel distance of the ballast beam (11), and is subsequently fed back from the generators to the electricity grid or to the energy storage facility.

[0048] The ballast transport device assembly for a gravity energy storage facility, constructed according to the present invention, is versatile and applicable to energy storage structures regardless of the differing scale and dimensions of the ballast loads and the various forms of renewable energy supply utilised. Accordingly, the specific details depicted in the drawings and the configuration of parameters for the individual technical measures presented in this exemplary embodiment must be adapted to account for the customer's specific demands, any other operational limitations, and the unique on-site conditions of the gravity energy storage facility where the ballast transport device assembly, according to the invention, will be implemented.

[0049] The fundamental principle of storing potential energy within an energy storage facility utilising the ballast transport assembly according to the invention permits the incorporation of numerous pre-existing solutions and elements known in the prior art. This reliance on established technology has allowed for the simplification or omission of certain corresponding drawings and technical details within this description.

[0050] It is understood by a person skilled in the art that all required components are integrated with a smart management and control system essential for optimizing the operational efficiency of the transport system according to the invention. Such a system includes at least a weather station, software and controllers.

[0051] The dimensions of the ballast transport assembly, its structural components, and the technical parameters of the electrical devices and units employed are selected individually for each energy storage facility, based on specific performance requirements and the unique on-site conditions.

[0052] Embodiment 2:

[0053] The technical parameters and specifications of the primary components comprising the ballast transport assembly and operating within the gravity energy storage facility presented in embodiment 1 are detailed below:

[0054] Power of installed motor / generators: 5 MW.

[0055] Inverter: 5 MW - 100% utilized - the design ensures that the linear motor-generator can deliver energy within a significantly shorter time in both the hoisting and lowering directions, i.e., energy input and output.

[0056] Charging (lifting) time for all ballast blocks 7 h (25,200 s)

[0057] Discharging (lowering) time all ballast blocks 7 h (25,200 s)

[0058] Energy Storage Capacity: 5 MW x 7 h ~ 35 MWh.

[0059] Continued as in embodiment 1.

[0060] List of symbols:

[0061] 1. vertical rib

[0062] 2. vertical linear guide

[0063] 3. carriage

[0064] 4. resting shelf

[0065] 5. magnetic track

[0066] 6. linear motor-generator

Claims

Patent claims1. A ballast transport device assembly for a gravity energy storage with a power conversion system comprises a pair of two opposite vertical ribs, each fitted with a linear guide upon which a carriage moves, the carriage being equipped at each end with a vertical bogie and a ballast beam gripping system, characterised in that the vertical ribs (1) contain rest shelves (4) evenly distributed along their length and facing the adjacent vertical rib (1) to form a pair, and further, between each pair of vertical ribs (1), magnetic tracks (5) extend along their entire length, wherein each carriage (3) has at least one linear motor-generator (6) placed on the side facing the magnetic track (5) and contains a longitudinal track (7) in its lower part for moving am electrically driven ballast bogie (8), and wherein the linear motor-generator (6) is connected to an inverter with a power return function.

2. The ballast transport device assembly according to claim 1, characterised in that the ballast bogie (8) incorporates an arm (10) that extends beyond the carriage beam (3) toward the ballast beam (11), which features a projection (12) at its end that is provided with a pin (13) configured to mate with a corresponding socket (14) located in the ballast beam (11).

3. The ballast transport device assembly according to claim 1, characterised in that the ballast bogie (8) mounted on the longitudinal track (7) comprises rollers (16) and a linear motor (17), while a magnetic tread (9) of the ballast bogie (8) is located along the entire length of the carriage.

4. The ballast transport device assembly according to claim 1, characterised in that the ballast bogie mounted on the longitudinal track (7) comprises rollers (16) and a rotor motor.

5. The ballast transport device assembly according to claim 1, characterised in that the carriage (3) has a C-shaped cross-section.

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