Pumped-storage power plant

Abstract

A pumped-storage power plant is proposed with a cycling volume consisting of an upper volume (V1) which provides a water reservoir and a lower volume (V2) which is arranged at a lower level than the upper volume. A flow connection (1) opens at its upper end into the upper volume and at its lower end into the lower volume. Constituent parts of the flow connection (1) are - a feed pump or pump turbine for transporting water from the lower volume to the upper volume, - a turbine for power supply which is arranged at or close to the lower level and can be flowed through by water which flows through the flow connection from the upper to the lower volume. In order to provide a pumped-storage power plant which is suitable even for those regions, in which there is no possibility, on account of climatic or regional geographic conditions or on account of regulations and requirements for nature conservation, to utilize already existing bodies of water or to convert existing areas to create artificial bodies of water, and the storage medium water is not consumed, it is proposed by way of the invention that: the upper volume (V1) is a cavity which is enclosed by a storage tube (3) and into which the upper end of the flow connection (1) opens, - and the lower volume (V2) is a cavity which is enclosed by a storage tube (3) and into which the lower end of the flow connection (1) opens, and that the storage tube (3) has a slope (β) with respect to the horizontal which falls or rises towards the flow connection (1) depending on the situation.

Description

[0001] Pumped storage power plant

[0002] The invention relates to a pumped storage power plant with a pendulum volume consisting of an upper volume providing a water reservoir and a lower volume, wherein the lower volume is arranged at a lower level than the upper volume, with a flow connection which opens at its upper end into the upper volume and at its lower end into the lower volume, wherein components of the flow connection are a feed pump or pump turbine for transporting water from the lower to the upper volume, a turbine which is arranged at or near the lower level and through which water can flow, which flows through the flow connection from the upper to the lower volume.

[0003] Pumped-storage power plants are energy storage systems consisting of several devices or components that interact to store energy, recover stored energy, or transform stored energy into other forms or energy carriers. Water typically serves as the storage medium.

[0004] In particular, the invention relates to a storage system for accommodating a pendulum volume with high storage capacities, said system resulting from the generation of energy via the storage medium water and for this purpose consisting of devices which are capable both of accommodating water for energy storage and of releasing this storage volume with energy generation by means of a turbine in order to use this storage medium for the renewed storage of potential energy.

[0005] Among other well-known examples are pumped-storage power plants with underground caverns. The caverns, which must be large enough to accommodate the oscillating volume, are naturally occurring cavities, e.g., caves formed in rock layers, such as those found primarily in certain Alpine regions and suitable for storing large quantities of water. However, in the vast majority of regions, comparable natural conditions for such pumped-storage power plants are lacking, which is why artificial caverns for storing oscillating volumes using excavation technology have so far been the alternative. Cavern power plants are therefore the exception, not the rule. The most common type of construction uses a storage system with an upper and a lower body of open water, usually a natural or artificial reservoir.An early technical example is the Kochel storage power plant in the Federal Republic of Germany, in which the oscillating volume is distributed between a natural lake as the upper volume and a lower natural lake, which is also connected to a flowing water body, as the lower volume.

[0006] However, even this common construction type is not suitable for all regions. This applies, for example, to low-precipitation regions with few or only a small amount of water-bearing bodies, or to high-temperature regions with high evaporation and correspondingly high natural water losses, or to regions with arid conditions without flowing water or natural surface waters.

[0007] Not only due to climatic conditions, but also due to regional geographical, geological and / or physical conditions or due to nature conservation regulations and requirements, in many regions there is no possibility of using existing bodies of water or converting existing areas for the creation of artificial reservoirs, especially when high storage capacities are required.

[0008] The invention is therefore based on the object of providing a pumped storage power plant which is also suitable for such regions and has a pendulum volume consisting of at least one upper and / or at least one lower volume, which can store energy in large quantities.

[0009] To solve this problem, a pumped storage power plant with the features specified in patent claim 1 is proposed. The remaining patent claims specify preferred, but not mandatory, embodiments.

[0010] The invention is based on the idea that at least one of the volumes that together provide the pendulum volume is a cavity enclosed by a man-made tube. This storage tube can preferably be constructed using a technique commonly used, for example, in the construction of tunnels for transportation purposes. Therefore, tunneling technology is used due to standardization and structural advantages. The pumped-storage power plant according to the invention has the advantage of being able to store large amounts of energy, which can be made available quickly and at any time.Due to the small space requirement, only minimal interventions in the landscape and urban structures are required for its construction, so that it can be positioned even in urban regions, requires only a small amount of space and is therefore environmentally friendly. However, in contrast to battery storage systems, it is less dependent on critical raw materials and the consumption of the storage medium "water" is negligible depending on the design.

[0011] Preferably, the cavity enclosed by the storage tube is itself divided into individual storage segments. The flow connection, which connects the upper and lower volumes, opens into the cavity. For improved filling and emptying, the storage tube has a downward slope relative to the horizontal, sloping toward the flow connection.

[0012] In exceptional cases, an increasing inclination of the storage tube relative to the horizontal is also possible.

[0013] Such a pumped-storage power plant is also suitable in environments and situations where conventional pumped-storage power plants are not feasible or not practical. This applies, for example, to low-precipitation regions with few bodies of water or with only a small amount of water, or to regions with high temperatures and high water evaporation, resulting in high natural water losses from open bodies of water. It is also suitable in regions where, due to geographical, geological and / or physical conditions or due to strict nature conservation regulations and requirements, it has previously not been possible to use existing bodies of water or to convert existing areas to create artificial bodies of water and / or to generate high nominal outputs via large storage volumes.

[0014] Particularly preferred embodiments of the pumped storage power plant according to the invention are specified in the subclaims.

[0015] The advantage of this is that the storage tube enclosing the cavity, if constructed using the tunneling technique, has a consistent cross-section along its length and can be maintained at a specified incline. The incline of the storage tube relative to the horizontal should ideally be between a minimum of 0.5 mm per 1000 mm of length and up to 2 mm per 1000 mm of length. This allows for overall standardization, particularly for a circular cross-section with an inner wall enclosing the cavity. The diameter of this wall should ideally be between 10 and 12 meters, since according to current cost-benefit estimates, the shield diameter of the tunnel boring machine when using the tunneling technique should be between 12 m and 14 m, although 14 m is optimal.

[0016] It is highly advantageous if the entire cavity enclosed by the storage tube is divided into individual storage segments by partition walls. This results in several storage chambers being arranged in series within the storage tube, one behind the other. These storage chambers together form the volume of the storage tube. In the longitudinal direction of the storage tube, each individual cavity or storage segment is delimited by a front and a rear transverse wall. The transverse walls thus form partition walls that separate the successive cavities and thus the storage segments from one another.

[0017] However, the transverse wall, which defines a non-floodable cavity at least 20 m long at the inlet or access to the storage tube, is reinforced compared to the transverse walls behind it. This first partition wall at the access to the storage tube thus represents a flooding barrier, preventing external flooding in the event of a malfunction and also serving as a protective device against violent attacks.

[0018] With regard to the special use as a water storage tank, the storage tube should have a multi-wall construction and comprise an outer wall and an inner wall, with the inner wall lining the water reservoir of the individual storage segments and forming a pressure chamber in the low-pressure area.

[0019] The outer wall is so stable that it can withstand both tectonic and rock pressure. It is formed from segments, which are implemented using the tunneling technique.

[0020] The single- or multi-layered inner wall provides stability against water pressure and tectonic events. It must be mechanically and chemically stable and is therefore formed from a stabilizing inner wall and an inner layer acting as a "protected layer." Each layer contains different, yet corrosion-free, reinforcement material to cope with the frequently changing wet-dry conditions caused by the filling or emptying of the storage tubes. The inner layer consists of a special cement / mortar mixture and contains corrosion-free, electrically conductive reinforcement material that completely lines the storage space, thus forming a Faraday cage. Overvoltages can be dissipated via special devices.

[0021] It can be advantageous to add filler material and / or building material additives, preferably carbon and / or glass fiber components, to the inner layer or, if this is omitted, to the stabilizing inner wall in a concentration that, depending on the layer thickness and configuration, has a positive effect on both the mechanical strength of the inner layer and its water-chemical resistance. If the inner layer is omitted, these additives and / or building elements can also be added to the stabilizing inner wall, although in both cases, material tests related to the on-site conditions are required. This applies to both the water-chemical conditions and the mechanical effects of sediments in the water storage medium on the building fabric.

[0022] It may be advantageous if a lining is applied to the inner layer, or if such a lining is omitted, to the stabilizing inner wall, which prevents material losses due to fluid and / or mechanical forces, especially during the filling process of the storage tubes.

[0023] The single- or multi-layer inner wall not only covers the outer wall on the inside. If the storage tube as a whole is divided into individual segments by partition walls, the materials of which the inner wall is made also extend to both sides of this dividing wall, so that each segment forms its own pressure chamber.

[0024] If the storage pipe as a whole is divided into individual segments by partition walls, devices are introduced into or attached to the outer wall, which is preferably formed by segments, or into the segments, which are suitable, on the one hand, for fixing the main body of the partition wall to the outer wall via specific connecting elements, and, on the other hand, allow a better connection of the outer wall to the inner wall.

[0025] It is highly advantageous if the cavity enclosed by the entire storage tube is further subdivided by dividing the entire tube into the aforementioned individual storage segments. For this purpose, several cavities are arranged one behind the other in the storage tube, forming a row. These cavities together form the volume of the storage tube. In the longitudinal direction of the storage tube, each cavity is bounded by a front and a rear transverse wall. The transverse walls represent partitions, separating the successive cavities and thus storage segments.

[0026] Preferably, the transverse walls have a multi-layer structure, are passable via passages when the storage segments are empty and can be closed by means of locking devices before the filling process.

[0027] If, as is preferred, the tube is constructed with multiple walls, consisting of an outer wall and at least one inner wall lining the water reservoir, the material of the inner wall should extend into the transverse wall, forming its multi-layer structure. This ensures that the beneficial effects of the material of the single- or multi-layer inner wall also benefit the transverse wall.

[0028] Due to the segmentation of the entire pipe into individual cavities or storage segments, it is advantageous if the flow connection which connects the two volumes of the pumped storage power plant and usually forms the downpipe is provided with a flow branch after entering the pipe, regardless of whether it is the storage pipe located above a usable head or the storage pipe located below it.

[0029] At the flow branch, which is preferably located in a non-floodable first cavity at the inlet of the storage tube, individual fill pipes branch off, which can also serve as discharge pipes, with a separate fill or discharge pipe leading into each floodable cavity of the tube and opening or ending therein. Another advantage is that the respective fill or discharge pipe, which supplies a downstream storage segment, extends closed and thus, as it were, "in transit" through the cavities arranged upstream of this storage segment, and only has openings for filling or emptying this storage segment in the respective storage segment in which it ends. The respective fill or discharge pipe can therefore form a spatial unit with this storage segment.

[0030] If several storage tubes need to be supplied, it can be advantageous for the main branch of the flow connection to split outside the storage tubes. The flow connection reaches the respective non-flooded antechambers or cavities of the storage tubes via partial branches and has a further flow branch there to supply the individual storage segments via fill pipes, which also serve as discharge pipes. This flow branching and thus the inflow and outflow to and from the individual cavities can be individually regulated via a pipe distribution system, for which IT-supported closure and / or control devices are available. The closure and / or control devices are preferably located in a protected location in the antechamber, i.e. in the first segment of the tube, which lies before the first transverse wall and thus before the first floodable cavity.

[0031] The filling and emptying pipes should each be provided with a shut-off valve between the flow branch and the inlet into the first flooded cavity, by means of which the individual filling and emptying pipe can also be switched on and off individually, preferably under processor control.

[0032] All filling and draining pipes run along the bottom of the storage tube, which is preferably circular in cross-section, and thus at the lowest point, preferably at the base of a segment of the storage tube. However, they should not directly touch the bottom, which can be achieved, for example, by using brackets supported on the bottom.

[0033] The opening of each filling and emptying pipe into the respective cavity which it fills or empties should not be a single opening, but should consist of a plurality of openings, the openings being distributed over the longitudinal section of the filling and emptying pipe arranged between the front and rear transverse walls of the cavity in question.

[0034] In particular, based on numerical calculations, the size, configuration, and design of the orifices should correspond to the calculated pressure drop along the respective filling or emptying pipe, for example, by increasing the size and / or number of orifices toward the end of the filling or emptying pipe, so that the water pressure at the end of the filling or emptying pipe converges toward zero. If necessary, specific devices made of special materials such as alloys can be inserted into the orifices of the filling or emptying pipes or screwed to them, allowing replacement in the event of wear, or allowing the configuration, size, and design to be changed.

[0035] Due to the high flow forces when the storage medium "water" flows in or out, the outlet openings should only be located on the upper fifth of the circumferential segment of the respective filling or draining pipe. The filling or draining pipe should therefore be closed and have no outlets on its lower circumferential segment. The water inflow and outflow into and from the filling or draining pipes can be controlled via a hydraulic distance control system, which extends along the filling pipe individually and / or in combination. Its fluid-mechanically designed protective devices reduce fluid forces and thus mechanical impacts on the building structure.

[0036] To facilitate faster emptying of the respective cavity, the filling or emptying pipe ending in it should be designed to be closable at its axial end by means of a closure device, e.g., a valve. This valve should be actuated by a processor so that the axial end is closed during the filling process and open during the emptying process.

[0037] The filling and drain pipes extend in a predominantly parallel alignment along the base of the storage wall. Preferably, the filling and drain pipe runs directly above the apex of the base, while the remaining filling and drain pipes run on either side. Preferably, the filling and drain pipe running along the base is the one whose opening is located and ends in this cavity.

[0038] Although all fill and drain pipes extend along the bottom of a storage segment, they should not touch it, nor should they touch each other. This can be achieved, for example, by using fill pipe supports mounted on a separate fixture adapted to the radius of a storage tube, or by using suitable spacers that keep the fill and drain pipes spaced apart.

[0039] To avert static loads on the partition walls and prevent damage to the filling and drain pipes due to temperature-related length changes, it is advantageous to install longitudinally deformable, longitudinally movable compensating elements (compensators) of the same cross-section, and to flange these together with the respective filling or drain pipe to the separate pipe fixed or concreted into the partition wall. The filling and drain pipes therefore contain compensators at specific intervals to compensate for material expansion. This applies particularly to the filling and drain pipes that run through a storage segment, but also to the filling and drain pipe that ends in a storage segment.

[0040] To ensure that the storage tube is continuous over its entire length from the flooding barrier, which is essential for the internal construction of the storage tubes into storage segments, as well as for the subsequent execution of inspection or repair work in the storage segments, the cross walls or partition walls from the flooding barrier have a watertight opening that can be closed off by a pre-closure device (bulkhead). This means that the storage tube is continuous up to the last cross wall or partition wall when emptied. If there is another non-flooded cavity behind this last partition wall, e.g. for technical reasons, with a flooding barrier at its end, the last partition wall of the storage tube is also continuous up to the rear flooding barrier. If the storage tube, e.g.ends with the breakthrough through a mountain top, it is advantageous that there is generally a continuous flooding barrier at the end of the storage tube with a non-flooded cavity in front of it.

[0041] The openings or passages in the transverse wall should be large enough to allow vehicles to pass through when the bulkhead is open. For structural reasons, they should be as circular as possible and flattened at the base. Therefore, the openings should each have a diameter of at least 3.5 meters.

[0042] Preferably, wide grates, easily accessible by vehicles, extend to the flattened opening of each partition wall, i.e., above the filling or emptying pipes running underneath, and end there. Preferably, sections of the grates below which the outlet openings of the filling or emptying pipes are located can also be designed as a grid, which is fluidically designed to reduce both fluid and mechanical forces during the filling process.

[0043] To ensure functionality, operation, and for monitoring purposes, each transverse or partition wall should have a walk-in chamber in its upper quarter, which is watertight and pressure-resistant relative to the storage segment located below or above. Access to the chamber leads from outside the storage tube. Both the storage segment of a storage tube located below and above a partition wall are accessible via the chamber via an emergency access or emergency exit, but are usually locked. Portholes, which are always closed, allow visual contact with the neighboring storage segments via the chamber, even when the storage segments are full.

[0044] The chamber thus serves both to ensure safety standards and to house control and regulation technology, as well as to position functional equipment to ensure the operational sequence of the storage system. For example, supply and ventilation pipes, which are required for pressure equalization during the filling or emptying process of a storage segment and also function as a surge tank, are preferably led from the chamber via the access. The supply and ventilation pipes therefore open into the storage space of a storage segment at the non-flooded area of ​​a partition wall. This is because the inclination of the storage pipe to the horizontal creates a space at the upper partition wall of a storage segment that is not filled with water. This is because filling is stopped when the fill level reaches the inner diameter of the lower partition wall of a storage segment.

[0045] The drawings, which are explained in more detail below, illustrate an embodiment of the invention. They show:

[0046] Fig. 1a - Fig. 1d: schematic representations of four different types of pumped storage power plants;

[0047] Fig. 2: a partial length of the storage tube in a longitudinal section;

[0048] Fig. 3: a cross-section through the storage tube according to the section plane III - III of Fig. 2;

[0049] Fig. 4: a cross-section through the storage tube according to the section plane IV - IV of Fig. 2

[0050] Fig. 5: a longitudinal section in the area of ​​a partition wall according to the section plane V -

[0051] V of Fig. 4;

[0052] Fig. 6: a longitudinal section in the area of ​​a partition wall according to section plane VI

[0053] - VI of Fig. 4;

[0054] Fig. 7: a section on a partial circumference of the storage tube.

[0055] Fig. 1a to Fig. 1d show four basic embodiments of a pumped storage power plant using a pendulum volume, consisting of at least one upper volume V1 providing a water reservoir and at least one lower volume V2, wherein the lower volume V2 is arranged at a lower level than the upper volume V1.

[0056] In the illustrated embodiments, it is advantageous to use Francis pump turbines, which are suitable both for power generation and as vertical reversible Francis pump turbines for pumped storage, i.e., as feed pumps. However, within the scope of the invention, the functions of power generation on the one hand and feed pumping on the other can also be performed by different units.

[0057] For low heads of less than 60 m, Kaplan turbines are suitable. They can be used as a feed pump for pumped storage and, if required, for energy generation, both in the low-pressure range. Francis turbines, as well as Kaplan turbines, can also be used as pump turbines and thus as feed pumps. In the high-pressure range, this is the case with (vertical) reversible Francis pump turbines and, with Kaplan turbines, by adjusting the runner blades. In the first embodiment according to Fig. 1a, storage tubes 3, which form the lower volume V2 of the pendulum volume, are located below an open body of water 7, which here forms the upper volume V1 of the pendulum volume. The open body of water 7 is, for example, a natural lake or an artificial reservoir. The potential energy in the form of flowing water reaches, if necessary.by means of a pressure tunnel 1e via a flow connection 1, which is a downpipe 1a over most of its length, from the body of water 7 down to the Francis turbine 2a, in order to then secure the pendulum volume in the storage tubes 3 as volume V2.

[0058] A surge tank 1c is located in front of the downpipes 1a to absorb pressure surges caused by closure elements 11 of pressure pipelines or pressure tunnels 1e. After energy generation, this oscillating volume is transported via a bypass line 1d into the storage tube 3, provided the water pressure in the suction hose of the Francis turbine 2a after energy generation is sufficient. If the residual pressure in the suction hose of the Francis turbine 2a is insufficient, low-pressure turbines 2b of the Kaplan turbine design, which can also operate as pump turbines, can take over or support the filling of the storage tubes 3, for which purpose the bypass line 1d is usually bypassed. An appropriately dimensioned receiving watercourse 1b, which serves as a surge chamber and simultaneously as a surge tank 1c, can compensate for fluctuations in the water inflow and outflow between the Francis turbine 2a and the Kaplan turbine 2b.When the pendulum volume is emptied from the storage tube 3, additional energy can be generated via the low-pressure turbine 2b, while simultaneously regulating the water flow to the Francis pump turbines 2a in order to store this pendulum volume as potential energy in the body of water 7, i.e., in the upper volume V1. In this embodiment, closure and / or control devices 11 are used with IT support to optimize the efficiency of the pumped-storage power plant.

[0059] In the second embodiment according to Fig. 1b, the storage tubes 3 form the upper volume V1. A body of water 7, which can be a natural lake, an artificial reservoir, or a flowing watercourse, forms the lower volume V2. The potential energy is stored in the storage tubes 3 of the upper volume V1 via the downpipes 1a, preferably via Francis pump turbines 2a.

[0060] If the water pressure of the Francis pump turbines 2a is insufficient to fill the storage tubes 3 in the upper volume V1, low-pressure turbines 2b support the filling process, for which the bypass line 1d is bypassed. A receiving channel 1b, which serves as a surge chamber and simultaneously as a surge chamber 1c, can compensate for fluctuations in the water inflow and outflow between the Francis pump turbine 2a and the low-pressure turbine 2b. When the storage tubes 3 and thus the upper volume V1 are emptied, additional energy can be generated via the low-pressure turbine 2b before the storage medium water reaches the downpipes 1a via the receiving channel 1b. The turbines 2a and 2b can also regulate the water inflow and outflow to or from the storage tubes 3. In this embodiment, closure and / or control elements 11 are IT-supported to optimize the efficiency of the pumped storage power plant.

[0061] The third embodiment according to Fig. 1c is a combination of Fig. 1a and Fig. 1b. Here, first storage tubes 3 are located at a level above a body of water 7, which can be a natural lake or an artificial storage lake / reservoir or a flowing water body, and thus form an upper volume V1 with respect to the body of water 7. Second storage tubes 3 are located at a level below the lake or artificial storage lake / reservoir and thus form a lower volume V2 with respect to the lake or reservoir. The flow connections 1 connecting these three levels, in the form of downpipes 1a, supply the potential energy from the storage tubes 3 to the power plant located on the lake or storage lake / reservoir. In addition, potential energy from the lake or storage lake / reservoir is generated via the further downpipes 1a for the power plant located below the level of the lake or storage lake / reservoir.Before pumped storage into the lake or reservoir / reservoir from the storage pipes 3 located below with volume V2, energy can be generated via the low-pressure turbine 2b when the storage pipes 3 are emptied, and at the same time, the water flow to the pump turbines 2a can be controlled during the pumping process. Fluctuations in the inflow or outflow to the turbines 2a and 2b can be compensated via a receiving watercourse 1b, which serves as a surge chamber and surge chamber 1c and is located between the turbines 2a and 2b, respectively. If the water pressure in the suction pipe of the turbines 2a is sufficient after energy generation to maintain the oscillating volume in the storage pipes 3 with volume V2, the low-pressure turbines 2b can be bypassed by a bypass line 1d.

[0062] Even when emptying those storage pipes 3 located above the body of water 7, additional energy can be generated via low-pressure turbines 2b, while simultaneously regulating the water inflow to the flow connection 1 in the form of the downpipes 1a. This requires a receiving channel 1b, which acts as a surge chamber to compensate for fluctuations in the water inflow or outflow to the turbines 2a or 2b and simultaneously serves as a surge chamber 1c, located upstream of the downpipes 1a. If the water pressure for pumped storage from the Francis pump turbines 2a is sufficient to fill the storage pipes 3 located at the level above the lake / reservoir with volume V1, the low-pressure turbine 2b can be bypassed via the bypass line 1d during pumped storage. Otherwise, the low-pressure turbine 2b can assist in filling the storage tubes 3 or take over the filling.In this embodiment, closure and / or control elements 11 are IT-supported to optimize the efficiency of the pumped storage power plant.

[0063] In the fourth embodiment according to Fig. 1d, the storage tubes 3 form the upper volume V1 at a usable head, while further storage tubes 3 form the lower volume V2, so that open bodies of water are not required. The flow connections 1 in the form of downpipes 1a supply the potential energy for the power plant 2a located below a usable head from the storage tubes 3 arranged at a higher level. The oscillating volume is secured by the storage tube 3 located at or near the power plant 2a via the volume V2. To generate energy and to support the filling or emptying processes, low-pressure turbines 2b can be used, as already described for Figs. 1a - 1c. For this purpose, appropriately dimensioned receiving waters 1b are required if necessary to compensate for fluctuations in the water inflow and outflow; these also serve as surge chambers and surge tanks 1c.The low-pressure turbines 2b can assist in filling the storage tubes to volumes V1 and V2 if, on the one hand, the water pressure of the Francis pump turbines 2a is insufficient to pump water into the higher-lying storage tubes 3 with volume V1, and, on the other hand, if the water pressure in the suction hose of the Francis turbines 2a is too low after energy generation to secure the volume in the lower-lying storage tubes 3 with volume V2. It is advantageous that the pumping power of the Francis pump turbines 2a is sufficient to eliminate the need for support via low-pressure turbines 2b to fill the storage tubes 3 or volume V1. As described in the embodiments in Fig. 1a to Fig. 1c, additional energy can be generated via the low-pressure turbines 2d when the storage tubes 3 or volumes V1 and / or V2 are emptied.

[0064] Overall, the result, particularly in the embodiment shown in Fig. 1d, is a closed storage system, which is why the storage medium "water" is hardly consumed. Chlorination, for example, is advantageous in this case to prevent possible contamination of the storage medium "water" in arid regions with high subsurface temperatures. The embodiment shown in Fig. 1d, in particular, enables multi-stage cascade solutions with high energy generation efficiency. In this embodiment, IT-supported closure and / or control devices 11 also contribute to optimizing the efficiency of the pumped-storage power plant.

[0065] In all embodiments of Figures 1a - 1d, additional surge chambers 1c can be dispensed with for the individual storage segments of the storage tubes, since the supply and exhaust pipes 20 of the storage segments 4 of the storage tube 3, described below, simultaneously function as surge chambers. This effect is supported by a residual space in the individual storage segments 4 that is not filled with water.

[0066] The pumped storage power plant designs shown in Figures 1b - 1d eliminate the need for reservoirs on mountaintops, which would, among other things, require significant natural areas and entail environmental impacts and / or potentially impair the operation of a pumped storage power plant. Unlike above-ground reservoirs, particularly those on mountaintops, underground storage in regions with subzero temperatures does not experience icing. Another advantage is that pumped storage power plants with underground storage spaces are feasible in both arid and urban areas. As with open volumes, or rather, reservoirs, the risk of flooding is minimized by the special design of the storage tubes 3 with flood barriers, even in the event of violent attacks.The flooding barrier is located directly at the access to each storage tube 3 in front of a non-floodable cavity of at least 20 m in length and thus in front of a first partition wall of a first storage segment 4 of the storage tube 3. Depending on the situation, if the storage tube 3 emerges from the ground on the opposite side, a flooding barrier is also located there, possibly after an additional cavity.

[0067] In a further variant of the embodiments of the pumped storage power plant according to the invention shown in Fig. 1a - Fig. 1d, for geographical, geological and / or physical reasons, the case may arise that the volume V1 and / or V2 must be stored in a storage tube 3, starting from the inflow of the water to be stored, with a decreasing angle of inclination ß relative to the horizontal. This results in a different constellation in which low-pressure turbines 2b for filling or assisting in filling the storage tubes 3 for the volume V2 could be omitted. This is possible when emptying the volume V2 if a favorable suction hose configuration of the Francis turbines or Francis pump turbines 2a is present, which allows the volume V2 to be sucked in from the storage tube 3 and at the same time ensures that the water thread does not break off.An advantage of the pumped storage power plant's specifications is that, for example, with a gradient of a storage pipe 3 of 1 mm to 1000 mm, a total storage pipe length of 5 km, and a zero fill level at the inlet of a storage pipe 3, with the same fill level of opposite storage segments 3, the water column or fill level at the end of the storage pipe 3 is approximately 5 m, thus enabling the storage medium "water" to be drawn in via the Francis turbine 2a. In contrast, low-pressure turbines 2b are required to empty the volume V1 if the pressure tunnel 1e is omitted.For these reasons, it may be advantageous if the upper storage tubes 3 for storing potential energy via the volume V1, starting from the inflow of the water to be stored, have an increasing angle of inclination ß relative to the horizontal, whereas the lower storage tubes 3 for storing the pendulum volume via the volume V2, also starting from the inflow of the water to be stored, have a decreasing angle of inclination ß relative to the horizontal.

[0068] At a decreasing angle of inclination ß to the horizontal, the supply to the storage segments 4 via the filling and draining pipes 9a - 9e occurs in reverse, since the filling and draining pipe 9e is located at the lowest point of the storage tube 3. Therefore, the filling and draining pipes 9a - 9e are designed in reverse. At the end of the storage tube 3, there is therefore an additional cavity 5 with a flooding barrier, which may house a pipe distribution system.

[0069] It is advantageous in the embodiments of Fig. 1b that flowing waters 7 can be used, whereby the storage volume V2 forms the flowing water 7. However, the use of flowing waters with regard to the pendulum volume is dependent on the flow of the flowing waters 7 in m 3per second in the worst case scenario, which affects both the withdrawal for pumped storage and the discharge of the pendulum volume into the river 7. Regarding the withdrawal of water from rivers, specific receiving waters are required that eliminate sediment, organic substances, and animal life. However, it is advantageous that the waters 7 experience oxygen enrichment when a pendulum volume is discharged into the rivers.

[0070] The illustrated embodiments of pumped storage power plants in Fig. 1a - Fig. 1d require a special specification of turbines, in particular Francis turbines 2a, and if possible, preferably vertical reversible Francis pump turbines 2a. To ensure the pendulum volume in the lower volume V2, the residual pressure in the suction hose of a Francis turbine 2a or a Francis pump turbine 2a should still be high enough after energy generation to fill the volume V2 without causing the flow to break. This can be achieved by the suction hose of the Francis turbine 2a or the Francis pump turbine 2a having a specific configuration based on numerical methods and / or by the special design of the impeller shape of the Francis turbine 2a or the Francis pump turbine 2a helping to generate this residual pressure in the suction hose.

[0071] Fig. 2 shows a longitudinal section through one of the storage tubes 3 of the pumped-storage power plant. Within the scope of the invention, the storage tube 3 can, generally without changes to its basic design, accommodate either the upper volume 1 or the lower volume V2. Furthermore, it is possible for the storage tube 3 to accommodate only a portion of the total volume V1 or V2, for example, by installing several storage tubes 3 in parallel or, due to geological, physical, and / or geographical constraints, in a non-parallel arrangement in order to jointly provide the required volume V1 and / or V2.

[0072] The storage tube 3 has a circular, constant cross-section and is formed by a tunnel tube. If tunneling technology is used for its construction, according to current cost-benefit criteria, the shield diameter of the tunnel boring machine should be at least 12 m, but preferably 14 m, which, minus the storage wall 8, corresponds to an inner diameter of a storage chamber of at least 10 m to almost 12 m. Unlike a conventional traffic tunnel, the tunnel tube, or storage tube 3, is segmented longitudinally into individual cavities, each of which forms an independently floodable storage segment 4. The exception to this is an approximately 20 m long cavity located between the flooding barrier and the lowest dividing wall of the first storage segment 4, which is not flooded.This also applies to a cavity which may be located at the end of a storage pipe 3 if it emerges from the subsoil, or which may be necessary at the end of a storage pipe 3 if the angle of inclination ß to the horizontal decreases, starting from the inflow to the storage pipe 3.

[0073] The segmentation of a storage tube 3 into successive storage segments 4 is achieved by transverse walls forming partition walls 6. Each storage segment 4 is therefore delimited by its front transverse wall 6 and its rear transverse wall 6, each forming a separate storage space.

[0074] The transverse or partition walls 6 have such longitudinal distances that each cavity or each storage segment 4 has a volume of preferably above 100,000 m 3This would result in a clear length of approximately 1000 m for each storage segment 4, since, based on cost-benefit considerations, the shield diameter of the tunnel boring machine used in the construction of the storage tube should be above 12 m, and 14 m is optimal.

[0075] The construction of the storage tube 3 can be carried out using construction techniques known from tunnel construction and / or mining. If the tunneling technique is preferably used, the outer wall 25 of the storage wall 8 of the storage tube 3 is formed from segments 26, which is known from the construction of traffic tunnels. Preferably, the construction of a storage tube 3 is driven underground from a suitable starting point, specifically over a length corresponding to the desired storage volume V1 and / or V2. Construction of the storage tube 3 with a complete breakthrough through a mountain top is also possible and economically advantageous because this results in structural advantages.

[0076] To ensure the operational capability of the pumped storage power plant, for example, in the event of maintenance work, at least two storage tubes 3 will be required in practice. If these are designed as tunnel tubes using state-of-the-art tunneling technology, which allows for very high storage volumes, a shield diameter of the tunnel boring machine of 14 m is optimal based on current cost-benefit estimates.

[0077] For the use of tunnel boring machines, tunnel lengths of more than 3 km are still considered economical, which is why the storage tubes 3 should preferably have this minimum length. On the other hand, the storage tube length is limited, due to increasing flow resistances in the filling and emptying tubes 9a - 9e, which are described in more detail below. Against this background, the construction of not just one but several storage tubes per volume V1 or V2 is advantageous, either in parallel or, if necessary, in a non-parallel orientation.

[0078] The entire storage tube 3, starting from the inflow of the water to be stored, has an angle of inclination ß relative to the horizontal, which is between 0.5 mm per 1000 mm and 2 mm per 1000 mm, and which should preferably be 1 mm per 1000 mm of the length of the storage tube 3. The inclination means that, firstly, the water can leave the storage tubes 3 without energy expenditure due to gravity, supported by the hydrostatic pressure due to the fill level in the storage segments 3, and secondly, the energy required to fill the storage tubes 3 is as low as possible, and thirdly, a minimum volume of space not filled with water is always present in each storage segment 4. This sub-space not filled with water serves to expand the water during temperature changes, absorbs delays in the system control, and also pressure fluctuations in the storage segments 4 when filling or emptying the storage tube 3. This particularly applies to the filling process.Because of the angle of inclination ß to the horizontal, which should be constant during tunnel excavation and thus also over the entire length of the storage tube 3 created in this way, an area not wetted by water results in the upper region of the dividing walls 6 due to the aforementioned specifications, and this is because filling is stopped as soon as the filling level in the storage segment 4 has reached the inner diameter of the transverse wall 6 arranged below of the relevant storage segment 4. This, together with the clear length per storage segment 4 of over 1000 m, proves to be advantageous for the desired high filling capacities, so that the water pressure remains as low as possible when the water escapes from the filling pipes 9a - 9e into the storage spaces, and thus also the fluid and mechanical forces.

[0079] The storage tube 3 is explained below for an embodiment with five storage segments 4 arranged in series and separated from each other by partition walls 6. However, this is only to be understood as an example, since the number of storage segments 4 can naturally be greater or less than five depending on the length of the storage tube 3, but should be at least three storage segments due to the aforementioned specifications.

[0080] Fig. 3 shows a cross-section through a storage segment 4 in plane III-III of Fig. 2. Since the storage tube 3 in question has a total of five storage segments 4, the number of filling or emptying pipes 9a-9e must also be preferably five, or in the case of longer storage tubes 3, a multiple of five. This is because each storage segment 4 has its own filling pipe 9a-9e, which simultaneously serves as an emptying pipe 9a-9e. Therefore, each filling or emptying pipe 9b-9e, which supplies a subsequent storage segment 4 and previously runs through one or more storage segments 4 in transit, already bends in the preceding storage segment 4 in front of the transverse wall 6 to the apex base in order to enter the next storage segment 4 as a filling or emptying pipe 9b-9e via the apex base, which it fills or empties. The pipes are made of metal and have a special external and, if necessary,an internal coating adapted to the local water-chemical conditions in order to reduce susceptibility to corrosion.

[0081] The filling and drain pipes 9a-9e are loosely mounted in brackets 10a, which, for fixation and weight distribution, are firmly anchored to fixing brackets 10b, which rest on the bottom of the storage wall 8 and are fixed longitudinally by spacers (not shown). The filling and drain pipes 9a-9e themselves have no contact with the bottom of the storage wall 8, so they remain permeable to flow, reducing the settling of dirt particles.

[0082] The filling and drain pipes 9a-9e can expand or contract longitudinally due to temperature fluctuations. To compensate for their temperature-related length variation, compensating elements or expansion joints 21 are located in the area of ​​the partition wall 6, where the water inflow and outflow of the filling and drain pipes 9a-9e each transits via separate, but identically sized pipes fixed or concreted into the partition wall. The expansion joints 21 are typically flexible corrugated pipes. The expansion joints 21 are connected to a filling or drain pipe 9a-9e of the same cross-section, which is flanged to a pipe of the same sized, firmly anchored or concreted into the base body 6a of a partition wall 6, which fills or empties the respective storage segment 4.

[0083] The flow connection 1, which connects the two volumes V1 and V2 and forms the downpipe 1a over most of its length, ends after passing through a flooding barrier in a first cavity of the storage tube 3, which, however, is not flooded. This cavity is preferably a first longitudinal section of the storage tube 3, which is located behind the flooding barrier and still in front of the dividing wall 6 behind which the first storage segment 4 is located. The flow connection 1 has a flow branch at this end and preferably within the non-floodable first cavity, at which the individual filling and emptying pipes 9a - 9e branch off from the main branch of the flow connection 1, which fill or empty the respective storage segments 4 individually.

[0084] If a pumped storage system consists of several storage tubes 3, the first flow branch, which supplies the respective storage tubes 3, is located outside the storage tubes 3, if necessary. The second flow branch, which then supplies the individual storage segments 4 of a storage tube 3 via the respective filling or emptying pipes 9a - 9e, is thus located in the respective cavity.

[0085] Starting from the flow branch in the cavity 3a, a separate filling or emptying pipe 9a - 9e leads into each of the five storage segments 4, which fills or empties this storage segment 4, but ends therein. The other filling or emptying pipes 9b - 9e pass through this first storage segment 4 in a closed manner and thus, as it were, in transit, as shown in Fig. 2 and in the sectional planes III - III and iV - IV of Fig. 3 and Fig. 4. The pipe ending in a storage segment 4 has openings 12a for the water outlet or for the water inlet into the storage segment 4 over its entire length. On the other hand, there is an inlet at its end, which can correspond to the pipe diameter except for the pipe diameter and is closed when filled.

[0086] The filling and emptying pipes 9a-9e run parallel along the base of the storage wall 8. The filling and emptying pipe 9a-9e that fills or empties a storage segment 4 and terminates therein runs directly above the apex base of the base. The remaining filling and emptying pipes run parallel to the apex base on both sides.

[0087] The flow branch in the non-floodable first cavity has a separate shut-off valve for each filling or emptying pipe 9a - 9e as a closure and / or as a control element 11, via which each filling or emptying pipe 9a - 9e can be individually switched on or off or the flow can be regulated, which is preferably done using a central system control.

[0088] The filling or emptying pipe 9a-9e that fills or empties a storage segment 4 and ends in this storage segment 4 at least 10 m in front of the upper partition wall 6 does not have a single opening for the water outlet or water inlet into a storage segment 4, but is composed of a plurality of outlet openings 12a (Fig. 2). The outlet openings 12a extend over the entire length of the filling or emptying pipe located between the front and rear partition walls 6 of a storage segment 4 and are arranged in a distributed manner.

[0089] For fluidic reasons, the orifices 12a (Fig. 2) are located only in the upper fifth of the circumference of a filling or emptying pipe 9a - 9e. For fluidic reasons, it is also intended that the size of the orifices 12a increases toward the pipe end. In this context, the distances between the orifices 12a toward the pipe end are dimensioned according to numerical calculations so that the water pressure at the end of a filling or emptying pipe 9a - 9e converges towards zero.

[0090] The outlet openings 12a are therefore those that do not generate a jet flow, but are upward-directed outlet openings, the shape and configuration of which are designed according to numerical calculations and fluid dynamic experience as well as depending on the local water pressure in the filling or emptying pipe so that the fluid forces are minimized when filling a storage segment 4. The positioning, configuration and size of the outlet openings 12a are therefore determined using numerical methods, whereby, among other things, the inflow or outflow quantity in m 3 / sec and the pipe length are parameters.

[0091] In order to avoid wear on the outlet openings 12a, which is accelerated by sediment in the storage medium "water", the outlet openings can be provided with inserts which are inserted into openings in the filling or emptying pipes 9a - 9e (not shown), preferably by screwing, and are therefore replaceable. It is advantageous that these can be made of low-wear and corrosion-resistant metal, preferably a suitable alloy. This option also allows corrections to be made to the outlet openings in order to control the water flow to the turbines, thereby optimising their characteristics. To regulate the water flow or water flow to or from the filling or emptying pipesSpecifically configured closure devices 13 for the outlet openings, either individually or in combination, are located along a filling pipe and above the outlet openings 12a to prevent fluid and mechanical forces from entering the storage segment 4. These can control both the emptying and filling of a storage segment 4 via hydraulic devices 13a. Due to their specific fluid-mechanical configuration, these simultaneously reduce the fluid forces during the filling process and thus have a significant influence on reducing mechanical stress on the building structure, which is caused in particular by sediment in the storage medium "water". This is due to the requirement that the filling or emptying of a storage segment 4 must take place via the outlet openings 12a in order to enable rapid filling of a storage segment 4.On the other hand, a defined water supply is required in order to maintain the optimum characteristic curves of turbines 2a and, if applicable, 2b.

[0092] In the axial direction of the filling or emptying pipes 9a - 9e, however, a flow leak is not desired. Instead, it is provided that each filling or emptying pipe 9a - 9e can be closed at its pipe end by means of a closure element 11. The closure element 11, the control of which is also part of the central system control, is generally only opened to support the emptying of a storage segment 4 in order to accelerate the water outflow on the one hand, and to additionally regulate the outflow rate on the other. However, due to possible disruptions, the pipe end with the closure element 11 should be at least 10 m away from the upper dividing wall 6 of a storage segment 4. This is advantageous so that the respective filling or emptying pipe 9b - 9e, which fills or empties the next storage segment 4 after the first storage segment 4, can be fed to the following storage segment 4 via the apex base of this storage segment 4.

[0093] A further closure member 11 is located immediately after the entry of each filling or emptying pipe 9a-9e into the storage segment 4 it supplies. This closure member 11 is preferably opened only to empty the remaining volume in the storage segment 4 and for cleaning purposes.

[0094] Overall, the entire process of inflow and outflow from or to the individual filling and discharge pipes 9a-9e is centrally controlled using IT, specifically using IT-supported crisis and safety management in the event of operational disruptions. The application of centrally IT-supported control and regulation technology regarding the water inflow and outflow to the high-pressure and low-pressure turbines 2a and 2b, respectively, enables optimization of the efficiency of the pumped storage system according to the invention, so that, depending on the turbine type and its design, the optimum characteristic curves of these turbines can be maintained. This includes the efficiency, power, and torque characteristics, as well as the shell diagrams for optimal design under different turbine operating conditions, both for energy generation and pumped storage.

[0095] Each partition 6 has a closable opening 17 as a passage from one storage segment 4 to the other. The opening 17 is located as axially as possible and preferably centrally in each partition 6, also in the flooding barrier as access to the storage tube 3 or the cavity. The openings 17 are round in configuration, but flattened at their base and are located at a corresponding distance above the filling and emptying pipes 9a - 9e concreted into the partition 6. The opening 17 can be closed by a bulkhead 22, which provides a watertight seal on both sides of the storage segment 4 located below and above a partition 6. The opening 17 is of such a size that, with the bulkhead 22 open, vehicles can drive through it and should have a width of approximately 3 m each at its flattened base. The opening 17 should, as shown in the drawing in Fig.4, should therefore be as round as possible and have a diameter of preferably up to 4 m.

[0096] The opening or passage 17, which is sealed watertight on both sides by a bulkhead 22 for safety reasons to adjacent storage segments 4, has a configuration based on static calculations to absorb the water pressure, and therefore also a curvature toward the respective storage segment 4. To open, the bulkhead 22 can be pivoted about pivoting hinges. This can preferably be done upwards using hydraulic devices, or to one side if necessary.

[0097] Grates 15, which can be accessed by small transport vehicles, extend from the access of a storage tube 4 from the flooding barrier in the longitudinal direction through each cavity or through each storage segment 4 of the storage tube 3 up to the level of the flattened portion of the opening 17, and end there. The grates 15 thus pass through each storage segment 4 of a storage tube 3, including the cavity, so that correspondingly large vehicles can reach all storage segments 4 via the flooding barrier. The grates 15 are thus located above the filling or emptying pipes 9a-9e and are preferably attached via brackets 16 to the fixing brackets 10b of the filling or emptying pipes 9a-9e. Due to the arrangement of the grates 15, they can have a grid in sections, preferably in the area of ​​the outlet openings 12, which is fluidically designed to reduce fluid and mechanical forces during the filling process.

[0098] As shown in Fig. 4 and Fig. 6 from section VI-VI of Fig. 4, a walk-in chamber 18 is arranged in the base body 6a of the partition wall 6, preferably at the level of the upper quarter of the partition wall 6, the clear width of which should be at least 1.2 m. An access 19 leads into the chamber 18 from outside the storage tube 3 and preferably from above.

[0099] From chamber 18, adjacent storage segments 4 are accessible via watertight, lockable emergency access and exits 19a. This is required by safety standards, and it also allows for inspections and minor repairs in the storage segments 4 without major effort. Chamber 18 also houses the supply and ventilation pipes 20, as well as measurement, control, and monitoring equipment.

[0100] Through the chamber 18, watertight portholes provide visual contact both into the storage segment 4 below and above a partition wall 6 (not shown), allowing a direct view into adjacent storage segments 4 of a partition wall 6. The portholes are usually made of glass and are always closed, so that at the maximum achievable water level of the respective storage segment 4, visual contact into the storage segments 4 is maintained both above and below the waterline. The following example illustrates this: Even with the storage segment 4 fully filled, due to a gradient angle ß of preferably 1 mm per 1000 mm, a clear internal diameter of a storage segment 4 of approximately 12 m and a storage volume of more than 100,000 m 3a residual space not completely filled with water, since filling is stopped as soon as the fill level reaches the height of the front, i.e., the lower, transverse wall 6 of the same storage segment 4. The height above the maximum water level at the rear, i.e., the higher, transverse wall 6 is then approximately 0.9 m.

[0101] Fig. 6 also shows the structure of the storage wall 8 and the partition wall 6, both of which are also shown in detail in Fig. 7 described below. With a target shield diameter of the tunnel boring machine of 14 meters, up to ten segments 26 per wall circumference are required, which is why segments 26(2), 26(3), 26(9) and 26(10) are shown in Fig. 6.

[0102] Fig. 7 shows how the storage wall 8 of the storage pipe 3 can be stabilized to withstand rock pressure and tectonic events 32. It also ensures that the individual storage segments 4 can absorb the water pressure 33. This also applies to pressure differences that may arise when filling or emptying the individual storage segments 4. On the other hand, through coordinated, simultaneous filling or emptying of adjacent storage segments 4, the water pressure 33, as far as the dividing walls 6 are concerned, can be almost equalized when the fill levels of adjacent storage segments 4 differ, which relieves the load on the dividing walls 6.

[0103] When designing the storage wall 8 according to Fig. 7, it must also be ensured that the fluid forces generated when filling the storage segments 4 do not have any negative impacts on the building structure. This also applies to the storage wall that comes into contact with the stored water, with regard to water-chemical causes as well as fluid-mechanical effects on concrete, which could lead to substantial material loss.

[0104] These fluid forces arise due to the requirement for the pumped-storage system to quickly fill all storage segments 4 of each storage tube 3 so that stored potential energy can be quickly made available again. On the other hand, the volume V2 should be stored immediately after energy generation as a reciprocating volume, which leads to the opposite challenges. Since water as a storage medium usually contains sediment, this leads to mechanical stress on the structure, including on the turbines used for energy generation.

[0105] According to Fig. 7, the storage wall 8 consists of at least one outer wall 25 and at least one inner wall 25a. Their dimensions are based, among other things, on calculations based on local geological and tectonic conditions as well as static requirements.

[0106] The outer wall 25 is primarily a concrete wall. This is typically reinforced with structural steel and is preferably formed from the segments 26 used in tunnel construction using the tunneling technique. The outer wall is compacted and stabilized toward the rock 28 or the external medium by a concrete filling 27. If the storage tube 3 is constructed using the tunneling technique, the outer wall 25 corresponds to the thickness of the segments 26.

[0107] The inner wall 25a is multi-walled, consisting of a stabilizing inner wall 29 of at least 25 cm thickness, based on a tunnel boring machine shield diameter of 14 m, which is optimal according to cost-benefit criteria, and an inner layer 30 applied thereon, the thickness of which can be in the cm or mm range. The inner layer 30, which comes into contact with the water, consists of a mortar adapted to the respective water chemistry. Its composition can be adjusted to the pH value of the stored water in order to avoid or at least reduce material losses due to water chemistry. For static reasons, it is advantageous if the inner wall 25a with the stabilizing inner wall 29, like the inner layer 30, also extends to the dividing walls 6 of a storage segment 4.

[0108] If the inner layer 30 is designed as a protected layer to counteract both mechanical and water-chemical influences, additives to the filler material, which is preferably a special cement mixture / special mortar mixture, are required, as has already proven successful in the construction industry. On the other hand, it can prove advantageous if structural elements, preferably carbon structural elements and / or glass fiber structural elements, are added to the filler material in a concentration that has a positive effect on the mechanical strength of the inner layer 30. Depending on their special configuration and / or coating, these can contribute to a better bond with the filler material. These structural elements should be dimensioned such that they are preferably up to 1 mm thick and their length is just below the layer thickness of the inner layer 30.Optimization of the resistance of the inner layer 30 against water-chemical and / or mechanical stresses is achieved by investigating the existing on-site conditions and adapting these conditions, on the one hand by the type and concentration of the aggregates to the filling material of the inner layer 30, and on the other hand by the configuration and concentration of the building elements to the special cement mixture / special mortar mixture.

[0109] Given the frequent wet / dry conditions of the storage tubes 3 during filling or emptying of the storage segments 4, it is advantageous to incorporate corrosion-free reinforcement material into the stabilizing inner wall 29 and the inner layer 30 applied thereto, as well as into the partition walls 6, or rather, their base body 6a. The use of conventional structural steel would result in increased corrosion. Fiberglass, for example, is a suitable reinforcement material for this purpose, as fiberglass has more favorable properties than structural steel and is also more resistant to chemical or electrochemical influences.

[0110] Instead of fiberglass reinforcement, it is advantageous to incorporate a corrosion-free grid 31 into the inner layer 30. This grid is conductive and can dissipate leakage currents, while also exhibiting high material resistance and good properties as a reinforcement material. If an inner layer 30 is omitted, it is therefore advantageous to incorporate such a grid 31 in addition to the fiberglass reinforcement into the stabilizing inner wall 30. Carbon grids 31, which have proven themselves in the construction industry, are suitable as reinforcement material. This allows ion currents in the building material as well as electrostatic fields, such as overvoltages and lightning strikes, to be dissipated simultaneously, provided the grids are interconnected via devices (not shown) that enable these voltages to be dissipated. This creates a Faraday cage that surrounds each storage segment 4, since the carbon grids 31 are connected to one another via connecting elements.

[0111] The individual layers of the walls of the storage segments 4 can be connected to one another and stabilized via connecting elements, particularly with regard to the stabilizing inner wall 29 to the outer wall 25, which increases the stability of the structure. This is preferably done using means and / or devices that are corrosion-resistant. For this purpose, devices and / or structural features are located in the segments 26 of the outer wall 25, into which, on the one hand, connecting elements are introduced and / or applied to better connect the wall structure and stabilize the inner wall. On the other hand, these connecting elements serve to fix the base bodies 6a of the partition walls 6 to the outer wall 25. It can also be advantageous if the segments 26 are roughened on the concave side after their implementation in order to better connect the stabilizing inner wall 29 to the outer wall.

[0112] Due to the high stresses encountered during the filling process, the inner layer 30 of the storage wall 8, which comes into contact with the water, is susceptible to fluid and mechanical forces, especially when sediments are present in the water. It is therefore advisable to additionally line the storage segments 4, for which purpose hard and wear-resistant materials, e.g., certain metals, are suitable. For this purpose, the inner wall is lined with metal plates 14 of low thickness, preferably 1-2 mm, and as wide as possible. These linings should be corrosion-resistant, preferably extending to and covering the lower half-radius of the storage tube 3, but resting loosely there.

[0113] The metal plates 14 are secured together on both sides by two folds, which preferably extend over the entire half-radius of a storage segment and overlap each other by locking in the folds. It is advantageous if this lining also extends to the partition walls 6 at the same height.

[0114] If the entire inner wall 25 or the inner layer 30 is severely affected by high loads, particularly due to sediment during the filling process, it may be advantageous to line the storage segments 4 completely with metal plates 14 so that these rest in one piece over the entire radius on the inner wall 25a or on the inner layer 30 applied thereto. At their radial ends, the metal plates 14 should overlap to absorb the expansion of the material. In the axial direction of the storage tube 4, these metal plates 14 should be fixed to one another by folds of the type mentioned. The thickness of the metal plates should be at least 1 mm, and their width should be selected so that the metal plates 14 are still easy to process.

[0115] To prevent the metal plates 14 from sagging into the storage spaces, they are secured by devices, preferably made of corrosion-resistant materials (not shown), which allows material costs to be saved by using thinner plates. For example, the metal plates 14 are pressed against the wall by devices that extend circularly over the entire radius of a storage segment 4 and are tensioned by strong internal tube compression springs. The metal plates 14 therefore have folds for the purpose of, on the one hand, connecting the metal plates 14 to one another to prevent lateral slippage and, on the other hand, securing the devices that press the metal plates against the inner wall 25a. Pipes that press the metal plates 14 against the storage wall can be used for this purpose.

[0116] Reference symbol Flow connection a Downpipe b Outfall / surge chamber with surge tank function c Surge tank d Bypass line e Pressure tunnel, pressure line a High-pressure turbine, Francis turbine or vertical reversible Francis pump turbine b Low-pressure turbine, Kaplan turbine Storage tube Cavity, storage segment Cross wall, partition wall a Main body of the cross wall Water body Storage wall a Filling or emptying pipe (storage segment 1) b Filling or emptying pipe (storage segment 2) c Filling or emptying pipe (storage segment 3) d Filling or emptying pipe (storage segment 4) e Filling or emptying pipe (storage segment 5) 0a Bracket 0b Fixing bracket 1 Closure and / or control element (e.g. flat, ball or ring gate valve, throttle valve) 2a Outlet openings 4 Lining, metal plate 5 Driveable grate 6 Bracket 7 Opening (Passage) 8 Chamber 9 Access 9a Emergency access or emergency exit 0 Ventilation pipe 1 Compensator (compensating element) 2 Bulkhead 25 Outer wall

[0117] 25a interior wall

[0118] 26 segments

[0119] 27 Concrete filling

[0120] 28 rocks

[0121] 29 stabilizing inner wall

[0122] 30 inner layer (protected layer)

[0123] 31 Carbon Grid

[0124] 32 Rock pressure, tectonic pressure

[0125] 33 Water pressure

[0126] V1 upper volume

[0127] V2 lower volume ß inclination, inclination angle

Claims

Claims 1. A pumped-storage power plant with a reciprocating volume consisting of an upper volume (V1) providing a water reservoir and / or a lower volume (V2), wherein the lower volume (V2) is arranged at a lower level than the upper volume (V1), with a flow connection (1) which opens into the upper volume at its upper end and into the lower volume at its lower end, wherein components of the flow connection (1) are a feed pump or pump turbine for transporting water from the lower volume (V2) to the upper volume (V1), a turbine for power generation which is arranged at or near the lower level and through which water can flow, which flows through the flow connection (1) from the upper to the lower volume, characterized in that the upper volume (V1) is a cavity enclosed by a storage tube (3) into which the upper end of the flow connection (1) opens,and / or the lower volume (V2) is a cavity enclosed by a storage tube (3) into which the lower end of the flow connection (1) opens, and that the storage tube (3) has a downward or, depending on the case, an upward inclination (ß) relative to the horizontal towards the flow connection (1). 2 Pumped storage power plant according to claim 1, characterized in that the storage tube (3) has a cross-section that remains constant over its length. 3 Pumped storage power plant according to claim 1 or 2, characterized in that the inclination (ß) of the storage tube (3) is between 0.5 mm per 1000 mm and 2 mm per 1000 mm. 4 Pumped storage power plant according to one of claims 1 - 3, characterized in that the storage tube (3) is of circular cross-section with an inner wall (25a) enclosing the cavity, the diameter of which is between 10 and 12 meters. 5 Pumped storage power plant according to one of the preceding claims, characterized in that the storage tube (3) is constructed with multiple walls and comprises an outer wall (25) composed of individual tubbing elements (26) and at least one inner wall (25a) which lines a water reservoir.

6. Pumped storage power plant according to claim 5, characterized in that the outer wall (25) is of such stability that it withstands tectonic pressure and rock pressure, and that the inner wall (25a) is designed to stabilize it against water pressure and tectonic events. 7 Pumped storage power plant according to one of the preceding claims, characterized in that in the storage tube (3) several cavities (4) are arranged one behind the other and forming a row, which together form the volume (V1 or V2), each cavity (4) being delimited by a front and a rear transverse wall (6).

8. Pumped storage power plant according to claim 7, characterized in that the flow connection (1) is provided with a flow branch at which individual filling and emptying pipes (9a - 9e) branch off, and in that a separate filling and emptying pipe (9a - 9e) leads into each cavity (4), wherein the filling and emptying pipe extends in a closed state and in transit through the cavities (4) arranged in front of the respective cavity (4) and has an opening only in the respective cavity (4) and ends there. Pumped storage power plant according to claim 8, characterized in that the flow branch is arranged in a longitudinal section of the storage tube (3) which is located at the beginning of the tube before the first floodable cavity (4). 10 Pumped storage power plant according to claim 8 or 9, characterized in that the filling and emptying pipes (9a - 9e) between the flow branch and the inlet into the first cavity (4) are each provided with a shut-off valve, by means of which the individual filling and emptying pipe (9a - 9e) can be individually switched on and off and the flow can be controlled. 11 Pumped storage power plant according to one of claims 8 - 10, characterized in that the inlet is composed of a plurality of outlet openings (12a), and that the outlet openings (12a) are arranged distributed over the longitudinal section of the filling or emptying pipe (9a - 9e) arranged between the front and the rear transverse wall (6) of the cavity (4).

12. Pumped storage power plant according to claim 11, characterized in that the outlet openings (12a) are located only on the upper circumferential segment of the filling or emptying pipe (9a - 9e).

13. Pumped storage power plant according to claim 11, characterized in that the size of the orifices (12a) increases towards the pipe end and / or the distances between the orifices (12a) decrease towards the pipe end.

14. Pumped storage power plant according to one of claims 8 - 13, characterized in that the filling or emptying pipe (9a - 9e) is closed at its axial pipe end or is designed to be closable by means of a closing and regulating element (11).

15. Pumped storage power plant according to one of claims 8 - 14, characterized in that the filling and emptying pipes (9a - 9e) are arranged in a predominantly parallel alignment along the bottom of the storage tube (3), wherein one of the filling and emptying pipes (9a - 9e) runs directly above the apex base of the bottom, and the remaining filling and emptying pipes run on both sides.

16. Pumped storage power plant according to claim 15, characterized in that in each cavity (4) the filling and emptying pipe (9a - 9e) running directly above the apex base of the soil is the one whose mouth is located in this cavity (4) and ends there.

17. Pumped storage power plant according to one of claims 8 - 16, characterized in that the filling and emptying pipes (9a - 9e) extend along the ground without touching it and without touching each other.

18. Pumped storage power plant according to one of claims 8 - 17, characterized in that the transverse wall (6) is provided with one or more fixed openings by means of concrete-in pipes, wherein the filling or emptying pipe (9a - 9e) is fixed to the transverse wall (6) via compensators which connect the opening to a filling or emptying pipe (9a - 9e), and the compensators are designed to be deformable in the longitudinal direction and are deformable in a longitudinally movable manner.

19. Pumped storage power plant according to claim 18, characterized in that each transverse wall (6) has a closable opening (17) through a bulkhead (22), which opening is preferably located axially above the filling or emptying pipes (9a - 9e) in the transverse wall.

20. Pumped storage power plant according to one of claims 7 - 19, characterized in that a walk-in chamber (18) is arranged in the upper quarter of the transverse walls (6), and that an access (19) leads from outside the storage tube (3) into the chamber (18).

21. Pumped storage power plant according to claim 20, characterized in that the transverse wall (6) is provided with inspection openings which connect the chamber (18) with the adjacent cavity (4).

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