EP2724017A1

EP2724017A1 - Pumped-storage power plant

Info

Publication number: EP2724017A1
Application number: EP12729581.4A
Authority: EP
Inventors: Armin Dadgar
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-06-25
Filing date: 2012-06-21
Publication date: 2014-04-30
Also published as: WO2013000809A1; DE102011106040A1; WO2013000813A1

Abstract

The invention relates to a pumped-storage power plant, comprising at least one first reservoir (H₁, H₂), a second reservoir (H₃), a flow path (303) for a liquid, which flow path connects the at least one first reservoir (H₁, H₂) to the second reservoir (H₃) and within which a mechanically driven generator (104, 204, 304, 214, 404) of electrical energy is arranged. According to the invention, the at least one first reservoir (H₁, H₂) comprises a cavity (101, 201, 301, 401) that is closed in a pressure-tight manner and that is partially filled with liquid, the region of the at least one first reservoir (H₁, H₂) not filled with liquid is filled with a gas under pressure (P₁), wherein the pressure (P₁) is greater than a pressure (P₂) in the second reservoir (H₃), and the mechanically driven generator (104, 204, 214, 304, 404) of electrical energy is arranged in the flow path in such a way that the mechanically driven generator of electrical energy either separates the at least one first reservoir (H₁, H₂) from the second reservoir (H₃) in a pressure-tight manner, releases a flow direction from the at least one first reservoir (H₁, H₂) to the second reservoir (H₃), or releases a flow direction from the second reservoir (H₃) to the at least one first reservoir (H₁, H₂) as a pressure generator.

Description

pumped storage power plant

The invention relates to a pumped storage power plant with at least one first reservoir, with a second reservoir, with a flow path connecting the at least one first reservoir to the second reservoir, for a liquid within which a mechanically driven generator for electrical energy is arranged.

Pumped storage power plants are usually used for intermediate storage of electrical energy and take in view of the increasing importance of renewable energy sources, such as wind and sun, which produce discontinuous energy, an increasing importance to ensure a continuous power supply.

Previous concepts are often based on water, which is usually passed from a high-altitude reservoir in a lower reservoir to generate electricity and pumping in times of energy abundance water in the higher reservoir. Since suitable geological formations are limited in many regions available, further development of such storage is not easily possible. Alternatively, compressed-air underground reservoirs are shortlisted for energy storage. There is also the idea to raise a weight with water and recover the stored energy again using water turbines. Here are above all sealing and friction problems that prevent such a large scale construction. The achievable pressures by weights are also rather low. Advantage of such a design is the constant pressure, which is not possible with compressed air-based systems.

For gas storage there are several problems, such. As possible losses due to leaks of the most natural memory, large losses in the compression and relaxation of the gas and due to the relatively low energy content of compressed air, a large volume or very high pressures. In addition, under underground storage possible effects of the occurring during operation pressure changes on the rock, which in the worst case have a destruction of the memory result.

The invention has for its object to provide an energy storage, which is not dependent on large differences in height, which has a high storage capacity with relatively little space and good efficiency. According to the invention the object is achieved by a pumped storage power plant with the features mentioned in claim 1. Characterized in that the pumped storage power plant with at least a first memory, with a second memory, with a at least a first memory with the second memory connecting flow path, for a liquid, within which a mechanically driven generator for electrical energy is arranged, wherein the at least one first reservoir comprises a pressure-tightly sealed cavity which is partially filled with liquid, the non-liquid-filled region of the at least one first reservoir is filled with a gas under pressure Pi, wherein the pressure Pi is greater than a pressure P ₂ in the second memory, the mechanically driven electrical energy generator is arranged in the flow path that it pressure-tightly separates the at least one first memory of the second memory, a flow direction from the at least one first memory to the second memory releases or as a printer generator releases a flow direction from the second memory to the at least one first memory, it is advantageously possible, independently of a gradient between the at least one first memory and the second memory, to generate energy with a high degree of efficiency or, if necessary, to buffer excess energy. In the at least one first memory, the gas under the pressure Pi is enclosed in a pressure-tight manner. With the flow path released, this gas acts on the liquid which can thus flow through the mechanically driven electrical energy generator so that it can generate energy in a manner known per se. The mechanically driven generator is for example a turbine. Furthermore, this device can separate the two memory pressure-tight from each other, if neither energy to be generated nor a backfilling of the first memory takes place. In addition, this device can work as a pressure generator, namely, when excess energy to charge the at least one first memory to be used. For the purposes of the invention, the mechanically driven generator for electrical energy can also consist of several components, which then take over the individual functions required. For example, a slide, valve or the like may be provided, via which the pressure-tight separation takes place. Energy generating device and pressure generating device may also be separate units.

The basic principle of the storage power plant according to the invention with a liquid as a working medium is the utilization of a pressure difference in the absence or only slight difference in height of a system of two containers or a container and a reservoir. This pressure difference is much higher, that is at least 50% higher than achievable by the possibly existing height difference of the system. This is achieved by means of a gas pressure on a liquid, which is then given by the liquid at the same or almost the same height level.

In a preferred embodiment of the invention it is provided that in a closed container, a liquid is under high pressure, which is generated by a compressed gas. This compensates for a missing or too small height difference and thus also allows the ground-level construction of an energy storage device.

As a result, if a high pressure of several atmospheres is set or prevails, there are two significant advantages, namely a relatively small space requirement for a large amount of storage and the avoidance of large energy losses. The latter results from the compression of the gas, since the resulting heat can be introduced into the liquid and released back to the gas during the relaxation, and moreover, the expansion or compression of the gas is relatively low.

In a preferred embodiment of the invention is intended to work with other gases than air. Here are gases that are not or only slightly warm by compression and cool only slightly during expansion. So occurs z. B. when using hydrogen or helium due to the very low inversion temperature of these gases, the opposite effect, since the gas heats up during expansion. Thus, in a closed container, which has no appreciable gas losses, another gas or gas mixture used as air and energy losses are minimized by the compression of the gas. It is advantageous to take precautions in the second volume to z. B. dissolved in the water and released there released gas. This can be an additive when using water, which reduces the gas-free. This is already the case with salt water, and accordingly a salt addition or the use of seawater as a working medium can be advantageous.

For the technical realization, there are several preferred embodiments. Thus, a system of two interconnected containers can be used, between which z. B. water pumped back and forth or used for energy production and storage. The lower pressure part may also be a lake, sea. ocean, watercourse or an open basin. Also, in a not completely filled with water tank compressed air can be introduced, so the compression does not happen by pumping in water, but by the introduction of compressed air. So this is necessary at least during commissioning, if you want to come to significant operating pressures because z. B. in a configuration with 50% water and 50% gas filling only an overpressure of 1 bar would be achieved if you simply pumped the water. However, putting the half-filled system under an initial pressure of 100 bar, this corresponds to an initial height difference of 1000 m. The pressure would then reduce to about 50 bar when the water was completely drained. In this case, the gas reservoir can also be located next to the water tank and connected to this via a pipe. This would facilitate maintenance and the use of special gases, since in such a case, the water, if a separating slide between the containers is present, can be drained without pressure loss. After the maintenance, the water is simply refilled. Then it is then charged again with the pressure of the gas. For operation, a large line cross-section is preferred in order to minimize friction losses between the containers.

Due to the relatively small expansion of the gas by a factor of two, the heating and cooling of the gas during operation is relatively low.

In a further preferred embodiment of the invention is for better heat transfer to the liquid to spray them during the introduction or to initiate so that it passes in free fall and finely divided by the gas in the reservoir.

When discharging the liquid or small parts thereof can be sprayed most easily in the gas space to dissipate the heat efficiently. Here also the advantage of a liquid comes into play, since this has a relatively high heat capacity per volume and can thus prevent a strong heating or cooling of the gas during compression and expansion.

Furthermore, in a preferred embodiment, a combination of the energy storage is provided with a heat storage. Here, the liquid can be used with the use of well-insulated reservoirs to store heat energy, which can be used for cooling in summer and heating in winter. This is especially interesting near houses or industrial plants, less so when the store is near at the place of power generation, z. B. with wind power, is set up, since they are usually at a distance to possible heat consumers.

In principle, the method can be implemented in many locations and configurations. Thus, the pressure vessel can be laid both above and below ground, the pressure-poorer reservoir also and the arrangement to each other, next to, above or below each other. The pressure vessel is ideally realized as a ball or cylinder with hemispherical ends. However, it can also have any other shapes. Specifically, when installed underground in natural cavities or artificial tunnels, the supporting rock must be sealed only by a thinner outer wall.

Ideal for long-term use is a gas-tight and watertight seal of the pressure vessel. This can be done with many materials, such. B. with a film material on a supporting surface or by means of synthetic resins. The latter can z. B. with carbon fiber mats realize a pressure-resistant container, which is optionally surrounded outside with another supporting and protective material. The former solution requires a carrier, this can, for. B. a stud and / or a reinforced concrete shell and / or a metal or composite solution such as fiber-reinforced materials. But also metal containers can be used. In another possible solution, a water reservoir sealed at the bottom is provided with a traction-absorbing roof which either covers the surface or, by means of intermediate supports, absorbs the weight of the roof or the tensile forces created by an overpressure. From a safety point of view, however, at high pressures spherical or cylindrical or consisting of such elements containers, unless the pressures are not z. B. be caught in the rock or other carrier, preferable.

It is also useful for safety reasons in pressure vessels to install a safety valve at a suitable location, which allows the outflow of the gas in a safe for humans and the environment direction. This is usually an outflow vertically into the atmosphere.

The invention is useful in principle as an air-water system up to a pressure of about 830 bar. In addition, the density of the air reaches the same or higher value than water and the energy content of the storage is then comparably high, that is, the use of water is, apart from the use as a heat reservoir for the expansion and compression process unnecessary. Nevertheless, even at such high pressures, the expansion losses of the gas are significant and water as the carrier at an advantage. Since currently such large pressures can not be safely implemented, the combination of liquid-gas pressure or liquid-pressure gas is advantageous due to the higher efficiency compared to purely gas-powered storage solutions.

The invention will be explained in more detail in embodiments with reference to the accompanying drawings. Show it:

Figure 1 a an embodiment with two adjacent containers as

Storage;

Figure 1 b shows an embodiment with two containers underground;

Figure 2a shows an embodiment with superimposed arrangement;

Figure 2b shows an embodiment with each other lying arrangement;

3a shows a first embodiment as a pure gas storage supplemented by a liquid storage;

Figure 3b shows a further embodiment as a pure gas storage supplemented by a

Liquid storage and

Figure 4 shows another embodiment of the container or memory.

Figure 1 a illustrates a possible embodiment. So here two adjacent containers 101 and 102 are shown as a memory H-ι with a pressure Pi and memory H ₃ with a pressure P ₂ , which are connected to each other by means of a line (pipe) 103 and a unit 104 for power generation or pumping , In this unit 104 may also be installed a control valve, but this is also possible elsewhere in the line 103. The container 101 is closed, the container 102 is designed with an opening 105.

Figure 1 b shows an embodiment with two containers 101 and 102 underground. Figure 2a shows a possibility of superimposed arrangement. Here, the container 201 is arranged as a memory H-1 with a pressure P ₂ above the container 202 as a memory H ₃ with a pressure P ₂ , wherein over one or more elements 204 energy can be gained or stored in memory H-ι.

Another embodiment is the structure of the memories around each other, as shown in Figure 2b. Here is z. B. to a container 21 1 as memory Hi with the pressure Pi a second shell 212 as a memory H ₃ with the pressure P _{2 placed} at a greater distance and the liquid between inner and outer space via one or more elements 214 reciprocated back and forth , So here is z. For example, in a spherical shape, the inner sphere is designed with a radius of about 20 m, the outer with a radius of about 25 m, to achieve the same volume in both areas.

Analogously to FIG. 1, a reservoir H can also have two containers 301 under high pressure, which-as already explained-offer advantages with regard to maintenance work. Thus, in Figure 3a, the memory Hi with the pressure Pi as a pure gas storage supplemented by a liquid storage H ₂ with the pressure Pi, the z. B. via a line 303 and one or more energy generator or storage elements 304, the liquid can flow to another container 302 as a memory H ₃ with the pressure P ₂ or can pump.

An analogous embodiment is shown in FIG. 3b, but here with an open natural reservoir as a reservoir R ₂ with the pressure P ₂ in the form of, for example, a lake 306.

The advantage of a closed system is the prevention of contamination of the water, eg. B. by aquatic plants, branches or other occurring in natural waters objects.

In principle, both containers can in principle be closed or shaped differently, as shown in FIG. Thus, a reservoir 401 or reservoir Hi can have a high pressure Pi (eg 100 bar) and a reservoir 402 can have a low pressure P ₂ (eg 1 bar) as reservoir H ₃ . When energy is generated by the liquid via lines 403 and energy exchanger unit 404, the pressure in the container 401 drops (eg to approximately 50 bar) and rises in the container 402 (eg to approximately 2 bar). This facilitates the use of specialty gases that the minimize possible temperature change during expansion or compression. Furthermore, the gas can be separated from the liquid by an elastic membrane 405 or a balloon or balloon-like container, in order, for. For example, it is necessary to minimize the diffusion of gas into the liquid and thus pressure losses.

The reservoirs can be realized underground, above ground, in or partly in a body of water or even partly under ground.

Also suitable is a compact memory, which is continuously filled by a pump, which is fed from the power supply and continuously generates power through a generator as a buffer in case of voltage fluctuations, as well as short supply fluctuations as an energy buffer, as well as power failure in the buffer to the operation of a emergency generator. Since the pressure in the tank can remain virtually constant during normal supply from the power grid, an energy-efficient decoupling of the power grids and short-term buffering is thus easily possible. Due to the short pipelines low friction losses of the system are possible here. Only the respective efficiencies of the pumps and turbine unit are essential to the overall efficiency of the system, other factors are almost negligible.

In principle, the energy store according to the invention can be realized with all liquids and gases which have no undesired reactions with one another or with the container and generator. So you can in principle achieve a higher storage density at the same volume when using heavy liquid metals such as gallium, mercury or alloys such as Galinstan. However, these metals are expensive, sometimes toxic and currently difficult to use economically in large quantities.

The examples mentioned are only a few of a variety of design options and can usually be combined with each other. Thus, the number and type of energy producers and pumps are diverse, as well as the number of containers and reservoirs and their placement. Also, liquid and gas mixtures can be used instead of pure liquids and gases. LIST OF REFERENCE NUMBERS

101 containers

102 containers

103 line

104 unit for power generation or pumping

105 opening

201 container

202 containers

204 elements for energy production or storage

21 1 container

212 shell as memory H ₃ with pressure P ₂

214 elements for pumping

301 containers

302 containers

303 line

304 elements for energy production or storage 306 open natural storage (eg lake)

401 containers

402 containers

403 line

404 energy exchanger unit

405 elastic membrane / balloon / balloon-like container

P-i pressure

P ₂ pressure

H T memory

H ₂ memory

H ₃ storage open natural storage / reservoir

Claims

claims

Pumped storage power plant with at least one first memory (Hi, H ₂ ), with a second memory (H ₃ ), with a at least a first memory (Hi, H ₂ ) to the second memory (H ₃ ) connecting the flow path (303), for a liquid within which is arranged a mechanically driven generator (104, 204, 304, 214, 404) for electrical energy,

characterized in that

the at least one first reservoir (Hi, H ₂ ) comprises a pressure-tightly sealed cavity (101, 201, 301, 401) which is partially filled with liquid, the area of the at least one first reservoir (Hi, H ₂ ) not filled with liquid is filled with a gas under pressure (P ^, wherein the pressure (Ρ-ι) is greater than a pressure (P ₂ ) in the second memory (H ₃ ), the mechanically driven generators (104, 204, 214, 304 , 404) for electrical energy is arranged in the flow path such that it either pressure-tightly separates the at least one first reservoir (Hi, H ₂ ) from the second reservoir (H ₃ ), a flow direction from the at least one first reservoir (Hi, H ₂ ) to the second reservoir (H ₃ ) releases or as a pressure generator a flow direction from the second memory (H ₃ ) to the at least one first memory (Hi, H ₂ ) releases.

Pumped storage power plant according to claim 1,

marked by

the use of water as a liquid medium.

Pumped storage power plant according to claim 1,

marked by

the use of air as a gaseous medium.

Pumped storage power plant according to claim 1,

marked by

the use of hydrogen, helium or another gas with an inversion temperature <500 ° C as a gaseous medium.

5. pumped storage power plant according to at least one of the preceding claims, characterized by

the partial or complete realization underground.

6. pumped storage power plant according to at least one of the preceding claims,

marked by

the partial or complete realization under water.

7. pumped storage power plant according to at least one of the preceding claims,

marked by

the spatial separation of the gas from the liquid through a membrane or through a balloon-like container for the gas.

8. pumped storage power plant according to at least one of the preceding claims,

marked by

the rapid temperature compensation between liquid and gas by spraying the liquid in the gas space, the blowing of the gas into the liquid and / or through heat exchanger lines to the container walls and / or in the gas space.

9. pumped storage power plant according to at least one of the preceding claims,

marked by

the additional use as a heat storage to store surplus heat for later use.

10. pumped storage power plant according to at least one of the preceding claims,

marked by

the use as isolator, buffer and / or uninterruptible power supply between a power grid and a consumer.