Device assembly comprising at least two electrolysis devices and power source

Abstract

The invention relates to a plant assembly (100) comprising at least two electrolysis plants (1A, 1B), a power source (3) and a central power supply line (5), the central power supply line (5) being connected to the secondary side of a transformer (7) into which power from the power source (3) can be fed on the primary side. The transformer (7) is designed on the basis of an operating frequency higher than the grid frequency of the utility grid so as to form a higher frequency AC grid to which the electrolysis device (1A, 1B) is connected via a central supply line (1A, 1B).

Description

Technical Field

[0001] The invention relates to an apparatus complex comprising at least two electrolysis apparatuses and a power supply. The invention also relates to a use. Background Art

[0002] An electrolysis device is a device that uses electric current to convert substances (electrolysis). Depending on the electrochemical electrolysis process, there are also many types of electrolysis devices, such as electrolysis devices for electrolyzing water.

[0003] Nowadays, hydrogen is produced from water, for example, by means of proton exchange membrane (PEM) electrolysis, anion exchange membrane or alkaline electrolysis. Electrolysis plants use electrical energy to produce hydrogen and oxygen from supplied water. The process takes place in an electrolysis stack consisting of a plurality of electrolysis cells. In the electrolysis stack, which is under direct current voltage (DC voltage), water is introduced as a reactant, wherein, after passing through the electrolysis cells, a gas consisting of water and gas bubbles (O 2 or H 2 ) consists of two fluid flows.

[0004] The idea is to use the excess energy of renewable energy sources to produce valuable substances during periods of high sunshine and high winds, i.e. when solar or wind power generation is above average. One valuable substance can be hydrogen produced by water electrolysis plants in particular. Based on hydrogen, for example, so-called renewable energy gas - also called EE gas - can be produced. EE gas is a combustible gas obtained using electrical energy from renewable energy sources.

[0005] Hydrogen is a particularly environmentally friendly and sustainable energy carrier. It has the unique potential to realize energy systems, transport and large parts of the chemical sector without CO2 emissions. But in order to achieve this, hydrogen cannot come from fossil energy sources, but must be produced from renewable energy sources. At least nowadays, more and more electricity produced from renewable energy sources is fed into the public grid. Therefore, if the electrolysis plant is operated with electricity from the public grid, it can produce green hydrogen in a corresponding proportion depending on the power mix.

[0006] In electrolysis carried out on an industrial scale, direct current is mainly supplied via rectifiers that are connected to the grid. During the rectification of the AC voltage on the grid side, harmonics may be generated due to the way the rectifiers work, which can put stress on the AC grid and / or the DC grid.

[0007] EP 3 723 254 A1 discloses such an electrolysis device, which is connected to a public power grid and is accordingly powered by the mains. For this purpose, the electrolysis device has a circuit structure comprising four coil mechanisms and four rectifiers. The first coil of the coil mechanism is respectively connected to the DC voltage side of one of the rectifiers. The circuit structure also includes two transformers, which respectively have a primary winding and two secondary windings. The primary winding of the transformer is connected to a power grid, such as a medium voltage grid or a high voltage grid. In this way, although the iron content in the first coil is reduced, the desired DC current smoothing or suppression of harmonics can still be achieved.

[0008] One of the sources of renewable energy is the increasing use of wind power. In particular, large amounts of electricity can be achieved by so-called offshore wind power plants close to the coast. However, the challenge is that there are still large distances to be covered to the load. Therefore, the energy should be delivered to the load with as few losses as possible. Hydrogen is very suitable as a transport medium and energy carrier. For example, it can be transported in gaseous form via pipelines. The positive aspect here is that the hydrogen-carrying pipeline can also fulfil the function of an energy storage device, since the internal pressure can be varied within a certain range.

[0009] Based on these considerations, it is of particular economic interest to produce hydrogen directly at the energy source, i.e. to be self-sufficient and independent of the public grid. For this purpose, it is proposed to install the electrolysis plant on an offshore platform in the maritime sector directly on or near the offshore wind power plant and to supply it with the generated electricity.

[0010] For inland areas, it is also proposed to directly produce hydrogen using electricity from onshore wind power plants or photovoltaic power plants, at least partially by directly connecting to and feeding into an electrolysis plant. In all these applications, the electrolysis plant is part of a so-called island grid. The electrolysis current is therefore not obtained from the public grid, but is directly provided by the wind power plant or PV plant and fed into the electrolysis cell of the electrolysis plant. The electrical energy generated by the wind power plant or PV plant may also be temporarily stored in batteries, for example. Compared with the above-mentioned grid-connected operation, this brings special challenges and problems in the electrical connection and interconnection of the electrolysis plant with the corresponding EE power plant (whether a wind power plant or a photovoltaic power plant), in particular in order to ensure safe and especially trouble-free operation of the electrolysis plant in a plant complex directly connected to the EE power plant.

[0011] Whether in grid-connected operation or in island operation, technical solutions are highly desirable for the reliable and at the same time cost-effective electrical connection of one or more electrolysis plants to the corresponding power generator. This is particularly true when, in increasingly larger and more complex electrolysis plants or electrolysis systems, a large number of electrolysis cells must be supplied with power simultaneously and correspondingly connected to an external power source. This poses particular problems with regard to the cost-effective transmission of power from the corresponding power source to the electrolysis plants, which in these combined plants are partially connected together in a complex plant complex. Summary of the invention

[0012] It is therefore the object of the present invention to provide a plant complex in which an electrical connection of an electrolysis plant to a power supply is achieved in a manner that is as reliable and cost-effective as possible.

[0013] According to the invention, this object is achieved by a plant complex comprising at least two electrolysis plants, a power supply and a central power supply line, wherein the central power supply line is connected to the secondary side of a transformer into which current from the power supply can be fed on the primary side, wherein the transformer is designed based on an operating frequency that is higher than the grid frequency of the public grid, thereby forming a higher-frequency AC grid, to which the electrolysis plants are connected via the central power supply line, and wherein the power supply has a wind energy plant as an electric power generator, to which a frequency converter is connected, the output of which is designed based on the operating frequency, wherein the output is connected to the primary side of the higher-frequency transformer, wherein the transformer is installed in a nacelle of the wind energy plant.

[0014] The present invention is based on the following problem recognition: when different external power sources are sometimes combined with the electrolysis equipment to form an equipment complex, connection problems and problems of efficient power transmission arise. This applies not only to island operation, but also to grid-connected operation when the electrolysis equipment is connected to the public power grid. Depending on the distance between the electrolyzer of the electrolysis equipment to be supplied with direct current and the corresponding power supply, power transmission at low voltage leads to very high material costs, such as the material cost of the electrical conductors used to limit transmission losses as much as possible. Especially in the case of large spatial distances, for example, if the generator in the wind power generation equipment is located in a nacelle at a high altitude, and the electrolysis equipment is arranged on the ground near the wind tower or further away. Only this simple example will easily use hundreds of meters of cables to power the electrolysis equipment and connect it to the power supply. Only the line distance and the corresponding material use lead to a large part of the cost for the connection and power supply of the electrolysis equipment. In addition, there are the costs of electrical facilities for connecting and transmitting electricity.

[0015] As a known solution, it is proposed on an industrial scale, for example, to reduce the power losses by reducing the current and increasing the voltage. In order to increase the transmission voltage, transformers are usually used. These transformers require an alternating voltage system, i.e. an AC power grid, which is designed for the current frequencies of 50 Hz to 60 Hz in grid operation. In fact, by selecting a higher transmission voltage, the transmission losses caused by the connecting lines and the power supply lines can be reduced. However, this design also has disadvantages, since the transformers are correspondingly large, heavy and expensive.

[0016] In order to solve the connection and transmission problems in the equipment complex with multiple electrolysis equipment as low-cost and efficient as possible, the present invention proposes to connect via a higher frequency AC power grid set for this purpose. The required transmission power is led from the power supply to the electrolysis equipment via the higher frequency AC power grid, thereby providing the electrolysis current. The operating frequency of the higher frequency AC power grid is specially selected to be higher than the power grid frequency, and for this purpose, the transformer is designed based on an operating frequency of 50Hz to 60Hz of the power grid frequency higher than the public power grid. The power supply feeds electricity into the central power supply line through the HF transformer. The electrolysis equipment in the equipment complex is all connected to the central power supply line and draws electricity for the electrolysis process from the higher frequency AC intermediate circuit. If necessary, multiple HF transformers designed based on the same operating frequency higher than the power grid frequency can be set in the AC intermediate circuit and connected to the central power supply line accordingly.

[0017] This allows a very advantageous higher-frequency connection of any number of electrolysis plants to the power supply via a central power supply line, wherein the central power supply line acts as an AC bus line in the plant complex. In addition to the low-loss transmittability of the power, the advantage is that the size of the transformer can be selected to be smaller, since the size or the installation space of the transformer decreases approximately linearly with the operating frequency. In this way, compared with conventional connections and designs based on the available grid frequency, in particular material costs for lines and transformers can be saved, but also installation space for accommodating the transformer can be saved. Thus, the transformer can be placed, for example, near the power supply or structurally integrated into the plant complex in some other way.

[0018] The power supply has a wind power generation device as an electric power generator, a frequency converter is connected to the wind power generation device, an output terminal of the frequency converter is designed based on the operating frequency, wherein the output terminal is connected to the primary side of the transformer.

[0019] In this way, the electrolysis plant and the wind power plant are connected or switched on and powered via a higher-frequency AC grid in the plant complex, wherein island grid operation is advantageously possible. If the plant complex is operated in an island grid, it is not connected to the public grid. The grid frequency of the public grid of 50 Hz to 60 Hz is therefore irrelevant to the design and operation of the electrical components in the AC grid, for example to the necessary conversion, transmission or rectification. This allows greater flexibility in the design and selection of components, in particular in the selection of the operating frequency in the AC intermediate circuit on the central supply line designed as an AC bus.

[0020] The invention also proposes integrating a higher-frequency transformer in the nacelle of the wind energy plant, which brings about, among other things, numerous cost advantages in terms of construction and operating advantages for the plant complex.

[0021] Due to this design and the specified higher operating frequency, the weight and size of the required transformer can be advantageously reduced. This reduces the use of materials, in particular the use of iron and copper, which also means that less installation space is required. Due to the reduced weight, it becomes much easier to install the high-frequency transformer in the nacelle of the wind power plant and it can be carried out within the limited installation space in the nacelle. At the same time, this arrangement makes the transformer well protected in the nacelle and can advantageously be installed in the nacelle together with the frequency converter. In addition, a DC isolation is provided by the transformer and the higher-frequency AC intermediate circuit, which is very advantageous for the electrolysis process, which in particular avoids or reduces possible stray currents in the process technology equipment part of the electrolysis plant.

[0022] The concept with a higher-frequency central supply line is easily scalable and very flexible with regard to the number of electrolysis plants supplied by the higher-frequency AC grid and the type of power supply. The higher-frequency AC grid is independent of or independent of the possible type of generation of the power fed into the central supply line. Thus, the plant complex can be designed for island grid operation but can also be connected to the public grid. Advantageous combinations are also possible and can come from various power sources, for example from wind power, photovoltaics or hydropower.

[0023] In a particularly preferred embodiment of the plant complex, the electrolysis plants are connected in parallel to one another, wherein the electrolysis plants are connected to a central power supply line via corresponding connecting lines.

[0024] This makes use of the advantages of the AC bus principle with a central power supply line, which enables and provides individual connection lines for the electrolysis plants. In the plant complex, the higher-frequency AC power supply network can be flexibly expanded if necessary and can be expanded to include additional electrolysis plants by adjusting the feed-in power of the power supply.

[0025] In a preferred design, a connecting transformer designed based on the operating frequency is connected to the connecting line. Therefore, when the connecting line is connected to the central power supply line, the AC power grid expands the connection possibilities and is designed to operate at the operating frequency, so that AC power can be transmitted from the higher frequency central power supply line to the connecting line via the connecting transformer at the operating frequency. This power can be used for other purposes of electrolysis in the electrolysis equipment connected via the connecting line. Depending on the application and the number of connecting lines and electrolysis equipment to be powered, a corresponding number of higher frequency connecting transformers can be set. For example, a corresponding connecting transformer is usually set in each connecting line to output power from the AC power grid to the corresponding connecting line. The design of the connecting transformer can be flexibly adapted individually to the required power extraction in the corresponding connecting line.

[0026] In a further preferred embodiment, a rectifier is provided in the connecting line, which rectifier is connected to the secondary side of the connecting transformer.

[0027] Advantageously, any number of higher-frequency connecting transformers can be arranged in the constructed higher-frequency AC grid. The connecting transformer can be fed into each rectifier or into a plurality of rectifiers, thereby supplying power to the electrolysis device. The secondary side is designed accordingly for a variety of connection possibilities. The rectifier converts the higher-frequency alternating current input from the AC grid on the input side into direct current, so that the electrolytic direct current can be supplied to the electrolyzer of the electrolysis device via connecting lines on the output side. In terms of circuit technology, the rectifier can also be regarded as part of the electrolysis device and integrated into the electrolysis device, wherein the rectifier is connected to the AC grid on the AC side via a connecting transformer.

[0028] Preferably, the electrolysis cell is connected to a rectifier in the plant complex. Thus, it is achieved that the electrolysis cells in the electrolysis plant are supplied with direct current at the desired voltage level. The electrolysis plant can also include a plurality of electrolysis cells, each of which has one electrolysis module or a plurality of electrolysis modules.

[0029] Preferably, the power supply comprises a photovoltaic power generation device as an electric power generator, an inverter is connected to the photovoltaic power generation device, an output end of the inverter is designed based on an operating frequency, wherein the output end is connected to the primary side of a transformer designed based on an operating frequency higher than a grid frequency of a public grid.

[0030] With this design, an advantageous connection or switching of the electrolysis device is achieved in the device complex via a higher frequency AC grid, and the power obtained from the photovoltaic power generation device is additionally used to power it. Island grid operation based on photovoltaic power generation is also possible. From a similar point of view, according to the advantages of the above-mentioned connection of the electrolysis device with the wind power generation device, operation independent of the public grid frequency is carried out in the island grid, which can achieve particularly high design flexibility and self-sufficient application possibilities away from the public grid. Therefore, the grid frequency of the public grid of 50Hz to 60Hz has nothing to do with the design and operation of the electrical components in the AC grid, and it is irrelevant to the need to convert the PV direct current into an alternating current with an operating frequency, which is fed into the central power supply line for transmission or rectification. In connection with photovoltaic power generation, an inverter can be used to generate an alternating current based on the operating frequency directly on the output side, which can be directly fed into the central power supply line. Therefore, compared with connecting the wind power generation device of AC power generation to the generator, the converter, that is, the combination of the rectifier and the inverter is omitted. An inverter of corresponding design is sufficient.

[0031] In another preferred design scheme, the power supply includes a hydroelectric power generation device as an electric power generator, which has a generator whose output frequency is designed based on an operating frequency, wherein the generator is connected to the primary side of a transformer designed based on an operating frequency higher than a grid frequency of a public grid.

[0032] In hydroelectric power plants, generators are advantageously used which already output a correspondingly higher frequency than the grid frequency directly at the output, i.e. the generators of the hydroelectric power plants are designed based on the operating frequency of the AC intermediate circuit. Compared with wind power plants, the DC intermediate circuit is thus omitted, which is necessary for the frequency conversion due to the interconnection of the rectifier and the inverter. When connected to a hydroelectric power plant, additional cost advantages can be achieved due to this lower complexity and the lower number of components, where island grid operation is also possible. The output frequency of the generator is obtained by the number of poles and the rotational speed. Therefore, the generators of hydroelectric power plants are particularly suitable for higher frequency connection and precise frequency input into the AC grid, because they can - at least within certain structural limitations - be well adapted to the requirements in the application case.

[0033] In a preferred embodiment, the power supply comprises a public power grid, wherein a frequency converter is provided, the output of which is designed based on the operating frequency and connected to a central power supply line. In the plant complex, the power supply can also be formed or fed by a combination of different power generators (e.g. wind power plants, photovoltaic power plants or hydroelectric power plants).

[0034] Therefore, the equipment complex is advantageously designed and arranged to be connected to the public grid as required. Therefore, both grid operation and island operation are possible. If it is to be connected to the public grid, it is feasible and also preferred to design the frequency converter as a central frequency converter with corresponding performance, such as a central conversion station, in order to save components and provide a central connection point for drawing power from the grid. This can be achieved, for example, in such a way that a rectifier and an inverter are arranged in a combined circuit arrangement so that at the grid connection point, the grid frequency is first rectified by the rectifier and then converted into a higher frequency operating frequency of the AC intermediate circuit. This central connection to the public grid via a central frequency converter can be achieved, for example, particularly easily at the grid connection point of a wind power generation device or a wind farm.

[0035] In a preferred design, the transformer is designed as a high-frequency transformer, which is designed based on an operating frequency greater than 80 Hz. Therefore, current with the operating frequency can be fed into the AC grid on the central power supply line.

[0036] Preferably, the plant complex has a higher-frequency AC power system designed for an operating frequency of 80 Hz to 1000 Hz, in particular 200 Hz to 500 Hz. The transformers are each correspondingly designed to feed alternating current at the operating frequency into the central power supply line.

[0037] When selecting the operating frequency and designing the components for the AC grid, care must be taken to select as the operating frequency a frequency which should not be too high for efficient and low-loss transmission. Otherwise, the capacitive losses along the central supply line would increase too much. The optimum frequency as the operating frequency therefore depends on the line length and the line capacity of the central supply line and can be adjusted accordingly. Preferably, the plant complex is technically most promising for implementation in island grid applications with generally limited distances and line distances of a maximum of several hundred meters (typically in the range of 50 m to 150 m). Thus, island grid operation independent of the public grid can be implemented in the plant complex and electrolysis can be carried out directly using electricity exclusively from renewable sources to form green hydrogen.

[0038] Another particularly preferred aspect relates to the use of a higher-frequency AC grid in the described plant complex, wherein a plurality of electrolysis plants are connected to a central power supply line and wherein the higher-frequency alternating current is fed into the central power supply line via a transformer installed in a nacelle of the wind energy plant.

[0039] In this application, a higher frequency AC power is provided by a transformer having an operating frequency higher than the grid frequency. The transformer is supplied with power on the primary side via a frequency converter from an AC generator of a wind energy plant as a power source.

[0040] Due to this design and the specified higher operating frequency, the weight and size of the required transformer can be advantageously reduced. This reduces the use of materials, in particular iron and copper, which also means that less installation space is required. Due to the reduced weight, this makes it much easier to install the high-frequency transformer in the nacelle of the wind power plant and can be carried out within the limited installation space in the nacelle. In addition, a DC isolation is provided by the transformer and the higher-frequency AC intermediate circuit, which is very advantageous for the electrolysis process, which in particular avoids or reduces possible stray currents in the process technology equipment parts of the electrolysis plant.

[0041] Advantages and advantageous embodiments of the device complex according to the invention are to be regarded as advantages and advantageous embodiments of the corresponding use, and vice versa.

[0042] Further advantages, features and details of the invention are apparent from the following description of preferred exemplary embodiments with reference to the drawings. The features and feature combinations mentioned above in the description of the drawings and the features and feature combinations mentioned below in the description of the drawings and / or shown individually in the individual drawings can be used not only in the respectively indicated combination but also in other combinations or alone without departing from the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Embodiments of the present invention are explained in more detail with reference to the accompanying drawings. Here, schematically and greatly simplified are:

[0044] Figure 1 A device complex is shown which is connected to a wind energy generating device at a higher frequency;

[0045] Figure 2 A system complex is shown which is connected to a photovoltaic power generation system at a higher frequency.

[0046] In the drawings, the same reference numerals have the same meaning. DETAILED DESCRIPTION

[0047] Figure 1 The device complex 100 according to the invention is shown. The device complex 100 comprises an electrolysis system 1 having two electrolysis devices 1A, 1B and a power source 3 connected to the electrolysis system 1. The power source 3 has a wind energy plant 19 as an electric power generator, which serves as a renewable energy plant (EE plant) and a source of green electricity. The electrolysis system 1 is supplied with electrolysis current via a central power supply line 5.

[0048] Here, each of the electrolysis devices 1A, 1B of the electrolysis system 1 is connected to the central power supply line 5 via respective connecting lines 9A, 9B at power supply connections 27A, 27B, so that the electrolysis devices 1A, 1B are connected in parallel. Here, the electrolysis device 1A has at least one electrolysis cell 15A, and the electrolysis device 1B has at least one electrolysis cell 15B. The electrolysis cells 15A, 15B can be optionally designed as PEM electrolysis cells, AEM electrolysis cells (AEM: Anion-Exchange-Membran, anion exchange membrane) or alkaline electrolysis cells, wherein combinations are also possible.

[0049] On one side of the power source 3, downstream of the wind power generation device 19, on the output side of the generator of the wind power generation device 19, a frequency converter 17A is connected. The frequency converter 17A has a rectifier 25 and an inverter 23 connected downstream of the rectifier 25. Therefore, the alternating current generated by the generator of the wind power generation device 19 can be converted into an alternating current with a frequency higher than the grid frequency, and the higher frequency alternating current can be fed into the central power supply line 5. In order to receive the fed-in power, a transformer 7 is provided in the central power supply line 5, and the power generated in the wind power generation device 19 can be fed or input into the transformer on the primary side via the inverter 23. The central power supply line 5 is connected to the secondary side of the transformer 7. The operating frequencies of the transformer 7 and the inverter 23 are designed and coordinated with each other based on a frequency higher than the grid frequency of the public grid, thereby ensuring the ideal input and transmission of the higher frequency alternating current. For this purpose, the transformer 7 is designed as a high-frequency transformer (HF transformer) and is designed, for example, based on an operating frequency greater than 80 Hz, for example, between 200 Hz and 500 Hz. By means of this interconnection, a higher-frequency AC grid or an AC intermediate circuit is formed and provided with a central supply line 5. The central supply line 5 is very advantageously used as a central AC bus line, via which a higher-frequency connection of the electrolysis system 1 can be realized. The transformer 7 is arranged together with the generator and the frequency converter 17A in the nacelle of the wind energy plant 19 and is structurally integrated into the nacelle.

[0050] In order to connect and power the electrolysis devices 1A, 1B in coordination with the operating frequency, a connecting transformer 11A is connected to the connecting line 9A, and a connecting transformer 11B is connected to the connecting line 9B accordingly. The primary side, i.e. the input side, of the connecting transformer 11A is connected to the central power supply line 5 via a power supply connection 27A, and similarly, the primary side of the connecting transformer 11B is connected to the central power supply line 5 via a power supply connection 27B. On the secondary side, the connecting transformers 11A, 11B are connected to the corresponding rectifiers 13A, 13B, so that the corresponding direct current is provided for the electrolysis in the electrolysis cells 15A, 15B. During the operation of the plant complex 100, a higher-frequency AC grid is provided on the central power supply line 5 and is used to supply electrolysis current to the electrolysis devices 1A, 1B connected in parallel to the central power supply line 5. By using a higher-frequency transformer 7, a higher-frequency alternating current can be provided and fed into the central power supply line 5. In this case, the plant complex can be flexibly designed or expanded, for example by connecting additional electrolysis devices 1A, 1B. The system complex 100 can advantageously be used to implement an island grid operation that is independent of the grid.

[0051] However, on the side of the power source 3, alternatively or additionally, a connection to the public grid is also possible. Figure 1 As indicated by dashed lines in the figure, a power connection 27C is provided in the central power supply line 5. A frequency converter 17B comprising an inverter 23 and a rectifier 25 connected downstream of the inverter ensures that the alternating current output from the public power grid 29 at the grid frequency is converted to a higher operating frequency. Therefore, if necessary, the power from the public power grid 29 can also be fed into the central power supply line 27C in a frequency-matched manner and provided for electrolysis purposes in the electrolysis system 1. It has been shown here that it is advantageous that, for example, by providing a connection to the public power grid 29, for example, replacement needs are met, for example when the wind energy generation device 23 does not generate electricity due to maintenance or only generates electricity to a very limited extent or during dark periods, so that a backup solution is available to ensure the most continuous power supply to the electrolysis devices 1A, 1B for hydrogen production and their smooth operation. Sometimes, even in the case of insufficient AC power supply on the central power supply line 5, one or more electrolysis devices 15A, 15B can be operated at partial load or disconnected from the AC grid. Finally, excess electrical energy that cannot be drawn by the electrolyzers 15A, 15B can be fed into the public grid 29 via the grid connection 27C. In pure island grid operation, replacement requirements cannot usually be taken into account due to the lack of an available connection to the public grid 29.

[0052] The concept of a higher frequency AC grid provided via the central power supply line 5 is adopted, and thus a higher frequency AC intermediate circuit is provided in the plant complex 100, by which an advantageous DC decoupling is also achieved. On the primary side, the inverter 23 is connected to the transformer 7. On the secondary side, the corresponding rectifiers 13A, 13B are connected to the transformer 7 in the connecting lines 9A, 9B. The electrolysis current is supplied to the electrolysis cells 15A, 15B with direct current via the rectifiers 13A, 13B. The DC isolation of the electrolysis plants 1A, 1B is carried out via the respective connecting transformers 11A, 11B in the corresponding connecting lines 9A, 9B, which reduces the stray currents that are disadvantageous in the electrolysis process technology.

[0053] In another embodiment of the device complex 100 according to the invention, Figure 2 An alternative power source 3 is shown for supplying direct current to the electrolysis system 1. Here, the power source 3 has a photovoltaic power plant 21 with a large number of PV modules (not shown in detail). The photovoltaic power plant 21 can be designed, for example, as a large-scale and powerful open-air plant—preferably in sunny areas—so that PV power with an electrical power of 10 MW and more is available for electrolysis. On one side of the electrolysis system 1, a direct current is supplied to the electrolysis system 1 using a photovoltaic power plant 21. Figure 1 The electrical connection and power supply of the completely similar plant concepts and corresponding plant components, ie the electrolysis plants 1A, 1B, takes place via a central power supply line 5. To achieve this, the electrolysis plant 1A is connected to the power supply connection 27A and the electrolysis plant 1B is correspondingly connected to the power supply connection 27B.

[0054] In order to achieve a desired and advantageous AC voltage level for feeding into the central power supply line 5 with respect to the photovoltaic power generation system 21, Figure 2 In the example of FIG. 2 , an inverter 23 is connected to the DC output of the photovoltaic power generation device 21. The inverter 23 is designed based on the operating frequency and provides a higher frequency AC voltage at the output. The power of the photovoltaic power generation device 21 is coupled via a transformer 7 and fed into the central power supply line 5. In order to transmit power and draw power from the electrolysis system 1, the electrolysis devices 1A, 1B are connected to the central power supply line 5 via corresponding connecting lines 9A, 9B, as described in more detail above. Advantageous DC decoupling is also achieved by connecting transformers 11A, 11B. In PV applications, it is also possible to use Figure 1 A similar design as described in feeds grid power from the public grid 23 into the central power supply line 5. It is also possible to feed power from the photovoltaic power generation device 21 into the public grid 23 via the central power supply line 5.

[0055] The invention proposes a plant complex 100, with which electricity, in particular from a renewable energy source 3, can be fed into an electrolysis system 1 having a plurality of electrolysis plants 1A, 1B, so that 100% green hydrogen can be produced in the electrolysis cells 15A, 15B. This is done very advantageously in the described plant complex 100, which comprises at least two electrolysis plants 1A, 1B, an energy source 3 and a central power supply line 5, which is designed as a central AC bus line and provides alternating current with an operating frequency higher than the grid frequency of the public grid. Thus, a higher-frequency AC grid is provided and used in the plant complex 100, wherein a plurality of electrolysis plants 1A, 1B are connected to the central power supply line 5 and operated, wherein the higher-frequency alternating current is fed into the central power supply line 5. Alternatively, in the simplest application case in particular, only one electrolysis plant 1A, 1B can also be electrically connected to the central power supply line 5 in the application of the plant complex 100 and can be supplied with electrolysis current accordingly and operated. Thus, if necessary, the system or plant complex 100 can be modularly expanded or reduced and can be flexibly adapted to a corresponding number of electrolysis plants 1A, 1B. The central power supply line 5 forming the central AC grid can be designed according to the AC grid power or the power drawn by the electrolysis plants 1A, 1B to be supplied. The number of electrolysis plants 1A, 1B is in principle unlimited and depends on the feed power into the central AC grid and the power drawn by the electrolysis plants 1A, 1B.

Claims

1. A plant complex (100), comprising at least two electrolysis plants (1A, 1B), a power source (3) and a central power supply line (5), wherein: The central power supply line (5) is connected to the secondary side of a transformer (7), and the power from the power source (3) can be fed into the transformer on the primary side, wherein the transformer (7) is designed based on an operating frequency higher than the grid frequency of the public grid, thereby forming a higher frequency AC grid, the electrolysis equipment (1A, 1B) is connected to the AC grid via the central power supply line (5), and wherein the power source (3) has a wind power generation device (19) as a power generator, and a frequency converter (17A) is connected to the wind power generation device, the output end of the frequency converter is designed based on the operating frequency, wherein the output end is connected to the primary side of the higher frequency transformer (7), wherein the transformer (7) is installed in the nacelle of the wind power generation device (19).

2. The device complex (100) according to claim 1, wherein: The electrolysis devices (1A, 1B) are connected in parallel with one another, wherein the electrolysis devices (1A, 1B) are connected to the central power supply line (5) via corresponding connecting lines (9A, 9B).

3. The device complex (100) according to claim 2, wherein: A connection transformer (11A, 11B) is connected to the connection line (9A, 9B), and the connection transformer is designed based on the operating frequency.

4. The device complex (100) according to claim 3, wherein: A rectifier (13A, 13B) is provided in the connecting line (9A, 9B), and the rectifier is connected to the secondary side of the connecting transformer (11A, 11B).

5. The device complex (100) according to claim 4, wherein: The electrolytic cells (15A, 15B) are connected to the rectifiers (13A, 13B).

6. The device complex (100) according to any one of the preceding claims, wherein: The power supply (3) includes a photovoltaic power generation device (21) as an electric power generator, an inverter (23) is connected to the photovoltaic power generation device (21), the output end of the inverter is designed based on the operating frequency, wherein the output end is connected to the primary side of a transformer (7) designed based on an operating frequency higher than a grid frequency of the public grid.

7. The device complex (100) according to any one of the preceding claims, wherein: The power source (3) comprises a hydroelectric power generation device as an electric power generator, the hydroelectric power generation device having a generator whose output frequency is designed based on the operating frequency, wherein the generator is connected to the primary side of a transformer (7) designed based on an operating frequency higher than a grid frequency of the public grid.

8. The device complex (100) according to any one of the preceding claims, wherein: The power source (3) includes the public power grid, wherein a frequency converter (17B) is provided, the output end of which is designed based on the operating frequency and connected to the central power supply line (5).

9. The device complex (100) according to any one of the preceding claims, wherein: The transformer (7) is designed as an HF transformer, which is particularly designed for an operating frequency of more than 80 Hz.

10. The plant complex (100) according to any one of the preceding claims, comprising a higher-frequency AC power grid designed for an operating frequency of 80 Hz to 1000 Hz, in particular 200 Hz to 500 Hz.

11. Use of a higher frequency AC power grid in a plant complex (100) according to any one of the preceding claims, wherein: A plurality of electrolysis devices (1A, 1B) are connected to a central power supply line (5), wherein a higher frequency alternating current is fed into the central power supply line (5).

12. The use according to claim 11, wherein A transformer (7) installed in a nacelle of a wind power generation device (19) provides alternating current with a higher frequency at an operating frequency higher than a grid frequency.

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