Method for capacity control of electrolysis units of an electrolysis plant

Abstract

A method (100) for controlling the capacity of electrolysis units of an electrolysis plant, wherein the electrolysis plant has a control device and a plurality of electrolysis units, each of which can be selected by the control device to provide current individual hydrogen production rates when individual cell voltage values ​​are applied for the selected electrolysis units depending on a common control variable, comprises selecting a number of electrolysis units from the plurality of electrolysis units taking into account an adjustable target hydrogen production rate or an adjustable target total electrical power consumption (106);and adjusting the common control variable depending on a deviation of a current total hydrogen production rate of the number of selected electrolysis units from the adjustable target hydrogen production rate or depending on a deviation of a current total electrical power consumption of the number of selected electrolysis units from the adjustable target total electrical power consumption (110). The common control variable is a target cell voltage value common to the number of selected electrolysis units, and the number of selected electrolysis units are each operated at individual cell voltage values ​​that are continuously adjusted to the common target cell voltage value (112).

Description

[0001] The present invention generally relates to the efficient operation of electrolysis systems with a plurality of parallel, identical, or similar electrolysis units. In particular, the invention relates to an electrolysis system and a method for controlling the utilization of electrolysis units of an electrolysis system. Furthermore, the invention relates to a computer program product, a computer-readable storage medium, and a data carrier signal.

[0002] Electrolysis plants, especially large-scale electrolysis plants for the production of hydrogen on an industrial scale, typically comprise a number of electrolysis units. Such an electrolysis plant can easily comprise 100 or more electrolysis units, each with a large number of electrolysis cells in which water, in particular, is split into hydrogen and oxygen using direct current.

[0003] However, the electrolysis units of an electrolysis plant may differ from one another in terms of their power consumption, efficiency, hydrogen production rate, or other parameters. This also applies to electrolysis units of the same design but differing, for example, in their previous operating life, the degree of utilization during their previous operation, or the number of start-up and shutdown cycles during their previous operating life, and therefore, for example, have been subjected to different aging or wear processes.

[0004] In order to make optimal use of an electrolysis plant, it is therefore necessary to control which of the electrolysis units are operated at what time and how in order to achieve a desired optimization goal. An optimization can affect a multitude of different levels, which may require decisions based on very different parameters. For example, market-related parameters such as electricity prices or sales opportunities could be taken into account. The present patent application, on the other hand, relates to a technical optimization of the operation of such an electrolysis plant by distributing, for example, the utilization and wear and tear among the plurality of electrolysis units operated in parallel. This can also have an indirect impact on operating costs if it shortens the service life of the electrolysis plant orof its components is extended or their efficiency is affected while at the same time ensuring operability over the entire period.

[0005] The object of the present invention is to provide a way to operate an electrolysis system with a plurality of electrolysis units in such a way that a desired maximum or specified overall performance of the electrolysis system can be ensured over a long period of time with minimal control and regulation effort, even if the electrolysis units differ in their current performance or degree of wear. In particular, the overall performance can refer to the highest possible production rate (of hydrogen) at a given (electrical) power consumption or to a specified production rate with the lowest possible power consumption.

[0006] This object is achieved according to the invention by a method for controlling the capacity of electrolysis units of an electrolysis plant according to claim 1 and an electrolysis plant according to claim 9, as well as a computer program product according to claim 10, a computer-readable storage medium according to claim 11, and a data carrier signal according to claim 12. Preferred embodiments and further developments of the invention emerge from the dependent claims.

[0007] According to a first aspect, the invention relates to a method for controlling the capacity of electrolysis units of an electrolysis plant, wherein the electrolysis plant has a control device and a plurality of electrolysis units, each of which can be selected by the control device to provide current individual hydrogen production rates depending on a common control variable when individual cell voltage values ​​are applied for the selected electrolysis units.The method comprises selecting a number of electrolysis units from the plurality of electrolysis units taking into account an adjustable target hydrogen production rate or an adjustable target total electrical power consumption and adapting the common controlled variable depending on a deviation of a current total hydrogen production rate of the number of selected electrolysis units from the adjustable target hydrogen production rate or depending on a deviation of a current total electrical power consumption of the number of selected electrolysis units from the adjustable target total electrical power consumption.The common control variable is a common target cell voltage value for the number of selected electrolysis units, and the number of selected electrolysis units are each operated at individual cell voltage values ​​that are continuously adjusted to the common target cell voltage value.

[0008] The control device is, for example, a programmable device with a processor and a memory in which a computer program product, i.e., a computer program, is stored. The code components of the program, when loaded into the processor, enable the control device to perform steps of the described method. For this purpose, the control device has one or more interfaces via which it can receive status signals, for example, regarding individual power consumption or the currently produced hydrogen rate, directly from the electrolysis units or from measuring sensors on the electrolysis units, and can send control signals, for example, the current target cell voltage value or a switch-on or switch-off signal, to the individual electrolysis units.

[0009] A processor is a data processing unit, such as a CPU, a microprocessor, or a microcontroller.

[0010] A number of selected electrolysis units selected from the plurality of electrolysis units of the electrolysis plant is a subset of the existing electrolysis units, i.e. the plurality of electrolysis units, wherein selected electrolysis units are activated, i.e. switched on, to carry out electrolysis and produce hydrogen.

[0011] The application of a cell voltage value to an electrolysis unit describes the application of a voltage of a specific value to each electrolysis cell of the electrolysis unit, which defines an operating point of the electrolysis cell. For groups / stacks of cells, this can also be an average voltage within this stack, i.e., a cell stack voltage value, which is also referred to here as the cell voltage value. In this case, the operating state of the stack of electrolysis cells is controlled jointly; the cells within the stack are not differentiated.

[0012] An individual cell voltage value is the actual voltage value applied to a specific electrolysis unit. Individual cell voltage values ​​may (but do not have to) vary between electrolysis units, even if the electrolysis units are identical.

[0013] Current individual hydrogen production rates refer to the different current hydrogen production rates of the different selected electrolysis units. A current hydrogen production quantity per unit of time describes a production rate. The current total hydrogen production rate refers to the sum of the hydrogen quantities currently produced by all selected electrolysis units combined per unit of time.

[0014] The current total electrical power consumption of the number of selected electrolysis units refers to the total electrical power currently consumed by the selected electrolysis units to carry out the electrolysis.

[0015] The adjustable target hydrogen production rate refers to the total amount of hydrogen currently required by the electrolysis system per unit of time, based on an external setting, for example, by a user. This setting can be varied over time.

[0016] As an alternative to specifying a requested total quantity or rate of hydrogen, a target total electrical power consumption can be set. This means that the external specification does not affect the output quantity or rate of hydrogen, but rather the specification of a permissible electrical power consumption with which maximum hydrogen is to be produced in the selected electrolysis units.

[0017] To achieve the specified set hydrogen production rate or set electrical power consumption, all selected electrolysis units are adjusted using the same common control variable. This common control variable is intended to be a common target cell voltage value for the number of selected electrolysis units, and the number of selected electrolysis units is adjusted by continuously adjusting the respective associated individual cell voltage values ​​to the common target cell voltage value. In other words, the individual production rates or individual power consumption are controlled by adjusting to a common target value for the cell voltage, regardless of the status and utilization of the selected electrolysis units. The term "continuous adjustment" describes a process that is carried out continuously or at regular intervals.

[0018] A uniform cell voltage for all selected electrolysis units, which is adjusted depending on a deviation of easily measurable output values ​​from a target value, represents a suitable simple control variable for load distribution between the various selected electrolysis units, which is also easily applicable to any number of selected electrolysis units and can avoid both a complex mathematical solution approach to the optimization problem and a comprehensive ongoing real-time analysis of all current state parameters of the electrolysis units.

[0019] With the described method (and the further embodiments described below), an average increase in hydrogen production can be achieved with a fixed power consumption. Depending on the size and condition of the electrolysis plant, this increase can range from one to several percent. The required effort can be limited to modified programming of a possibly existing control device. Furthermore, the control device can also be configured to take external factors, such as current price signals for electricity or hydrogen, into account.

[0020] In a preferred embodiment of the method, a maximum number of electrolysis units is selected as the number of selected electrolysis units. In other words, the load of providing the requested target production rate or producing hydrogen according to a predetermined target electrical power consumption is distributed among the maximum possible number of the plurality of electrolysis units. This can be a maximum of all of the plurality or the maximum largest subset thereof, so that the load for each individual unit involved is minimized.

[0021] In an exemplary preferred embodiment, it is additionally taken into account that the total number of switching on and off processes of electrolysis units is reduced. This means, for example, that when selecting the maximum possible number of electrolysis units, the selection is made such that as few electrolysis units as possible have to be switched on or off, and when there is a choice between different combinations of electrolysis units, the combination is selected in which as many already switched on units as possible continue to operate. In this way, the aging of the electrolysis units, which accelerates with the number of switching on and off processes, can be reduced.

[0022] In one embodiment of the method, the step of selecting a number of electrolysis units from the plurality of electrolysis units comprises preferentially selecting an electrolysis unit with a higher efficiency over an electrolysis unit with a lower efficiency. This means that, if a choice is available (and other criteria that may need to be considered have also been taken into account), the most efficient electrolysis unit is always selected according to the method. The efficiency of an electrolysis unit is based on the efficiency that relates the actually produced and technically usable amount of hydrogen to the energy input.

[0023] In a further embodiment of the method, the step of selecting a number of electrolysis units from the plurality of electrolysis units comprises selecting an electrolysis unit based on a utilization rate during operation. Here, it is taken into account that electrolysis units achieve a higher relative efficiency at a lower utilization rate than at full load. For example, the relative efficiency can be 10% higher at a utilization rate of only 40% compared to full load operation (i.e., 100% utilization). The advantage of the higher relative efficiency outweighs the acceleration of the aging process due to a (single) additional switch-on process for each additionally activated electrolysis unit, which enables partial load operation and eliminates the need for full load operation of individual electrolysis units.

[0024] In one embodiment of the method, the step of selecting a number of electrolysis units from the plurality of electrolysis units comprises preferentially selecting an electrolysis unit with a shorter operating time over an electrolysis unit with a longer operating time. This takes into account that the aging process of an electrolysis unit continues to progress over the service life of the electrolysis unit (e.g., due to increasing corrosion) and reduces the achievable efficiency. For example, the relative efficiency of an electrolysis unit at the assumed end of its service life, which may be 10 years, for example, may be 15% lower than at the beginning of its service life.

[0025] In one embodiment of the method, several of the selected electrolysis units are switched on or off in a sequence ordered by their respective efficiencies, with an electrolysis unit with the highest associated efficiency being switched on first and / or switched off last. Preferably, the electrolysis units with the highest efficiency are switched on first and switched off last. This specification is based on the consideration that the power consumption corresponds to the cell voltage multiplied by the current density and the cell area, and that there is a monotonic relationship between cell aging and current density and cell voltage, and that there is also a close relationship between the current density and the hydrogen production rate (assuming a constant Faraday efficiency).Therefore, current density itself represents a reasonable metric of cell / stack efficiency, so that a sequence based on current density and thus efficiency is a suitable shutdown sequence.

[0026] The determined appropriate shutdown sequence, or the last electrolysis unit shut down, can then define a starting point for the subsequent startup sequence. Transient power offsets are also preferably taken into account: For example, several days after a (re)start, the required voltage may increase, e.g., by 1%, which corresponds to a change in current density of 5%. Based on this, the efficiencies and thus the startup sequence can be appropriately corrected.

[0027] In a further embodiment, the method comprises converting the adjustable target hydrogen production rate into a corresponding target current value. This offers the advantage that only one current measurement needs to be performed at the selected electrolysis units in order to determine a total value of the current power consumption. The deviation from the target current value can then be directly determined to determine how the common control variable, i.e., the common target cell voltage, should be changed. This avoids having to record the individual hydrogen production rates in order to directly determine the deviation from the target hydrogen production rate. The conversion takes into account the Faraday efficiency.

[0028] In an exemplary embodiment, the method then comprises measuring individual input currents at the selected electrolysis units and determining the deviation of the current total hydrogen production rate of the number of selected electrolysis units from the adjustable target hydrogen production rate as a deviation of a sum of the individual input currents at the selected electrolysis units from the target current value.

[0029] According to a second aspect of the invention, an electrolysis plant comprises a control device and a plurality of electrolysis units, each of which can be selected by the control device to provide current individual hydrogen production rates depending on a common controlled variable when individual cell voltage values ​​are applied for the selected electrolysis units, wherein the control device is configured to carry out a method according to the first aspect of the invention for controlling the capacity of the electrolysis units.

[0030] And according to a third aspect of the invention, a computer program product comprises code components that, when executed by a processor of a control device of an electrolysis plant according to the second aspect of the invention, configure the control device to execute steps of the method according to the first aspect of the invention. A computer program product corresponds to a computer program that comprises at least software code components to enable the execution of steps of the method.

[0031] A fourth aspect of the invention relates to a computer-readable storage medium, in particular a non-volatile computer-readable storage medium, ie a non-volatile data storage device, e.g. a CD, DVD, memory card or other non-volatile data carrier, on which a computer program product according to the third aspect of the invention is stored.

[0032] Additionally, a fifth aspect of the invention relates to a data carrier signal that transmits a computer program product according to the third aspect of the invention. A transmission medium or data carrier for transmitting a data carrier signal is, for example, a telephone cable, data cable, or a wireless connection, wherein the computer program product is represented by a data carrier signal that is transmitted via the transmission medium.

[0033] In this way, the advantages and special features of the at least partially computer-implemented method according to the invention for controlling the capacity of electrolysis units of an electrolysis plant are also implemented within the framework of a suitably configured electrolysis plant, as well as a computer program product, a computer-readable storage medium and a data carrier signal.

[0034] Properties, features, and advantages of the described invention, as well as the manner in which they are achieved, are also apparent from the detailed description and the figures. The invention will be explained in more detail below in connection with the following description of exemplary embodiments with reference to the accompanying figures. They show: Fig. 1 is a schematic representation of an example of a method for controlling the capacity of electrolysis units of an electrolysis plant according to an embodiment of the invention; Fig. 2 is a schematic representation of an example of an electrolysis plant according to an embodiment of the invention; Fig. 3 is a schematic representation of an example of a control of the cell voltages of electrolysis units for a method for controlling the capacity of electrolysis units of an electrolysis plant according to a further embodiment of the invention; and Fig. 4 a schematic representation of a diagram of an example of current-voltage characteristics of electrolysis units of an electrolysis plant.

[0035] It is understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. It is understood that the features of the various exemplary embodiments described above and below may be combined with one another unless specifically stated otherwise. Therefore, the description is not to be construed in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0036] In Fig. 1 schematically illustrates an example of a method 100 for controlling the utilization of electrolysis units of an electrolysis plant according to an embodiment of the invention. The method 100 is carried out for an electrolysis plant having a control device and a plurality of electrolysis units, each of which can be selected by the control device to provide current individual hydrogen production rates depending on a common controlled variable when individual cell voltage values ​​are applied for the selected electrolysis units. To carry out the method, the control device can comprise a processor and a memory in which a computer program product is stored, the code portions of which, when loaded into and executed by the processor, configure the control device with the processor for executing the method. This occurs in the start state 102 of the method 100.

[0037] In one step, a setpoint is recorded 104. This setpoint is adjustable, i.e., variable. The recording 104 of the setpoint relates either to the recording 104a of an adjustable setpoint hydrogen production rate or to the recording 104b of an adjustable setpoint total electrical power consumption, which either specifies a quantity of hydrogen to be produced by the electrolysis plant per unit of time or a quantity of electrical energy available per unit of time with which a maximum quantity of hydrogen is to be produced.

[0038] In a next step, the method provides for selecting 106 a number of electrolysis units from the plurality of electrolysis units, taking into account the adjustable target hydrogen production rate or the adjustable target total electrical power consumption. The selection step 106 includes selecting a maximum number of electrolysis units as the number of selected electrolysis units. Furthermore, the selection 106 is performed in such a way that the total number of electrolysis unit switching operations is reduced.Furthermore, selecting 106 a number of electrolysis units from the plurality of electrolysis units may include preferentially selecting an electrolysis unit with a higher efficiency over an electrolysis unit with a lower efficiency and / or selecting an electrolysis unit based on the degree of utilization during operation and / or preferentially selecting an electrolysis unit with a lower previous operating time over an electrolysis unit with a higher previous operating time. Furthermore, selecting 106 electrolysis units may require switching off 116 or switching on 118 several of the selected electrolysis units in an order ordered by their respective associated efficiencies, with an electrolysis unit with the highest associated efficiency being switched on first and / or switched off last.

[0039] In a next step, it is provided to determine an actual value of the state of the selected electrolysis units as a whole 108. The step of determining the actual value 108 comprises either determining a current total hydrogen production rate of the number of selected electrolysis units 108a or determining a current total electrical power consumption of the number of selected electrolysis units 108b.

[0040] In a next step, it is provided to adapt 110 the common controlled variable depending on a deviation of the actual value, which here is a sum value, from the received target value. The step of adapting 110 the common controlled variable comprises either adapting 110a the common controlled variable depending on a deviation of the current total hydrogen production rate of the number of selected electrolysis units (as actual value) from the adjustable target hydrogen production rate, or adapting 110b the common controlled variable depending on the deviation of the current total electrical power consumption of the number of selected electrolysis units (as actual value) from the adjustable target total electrical power consumption, wherein the common controlled variable is a target cell voltage value common to the number of selected electrolysis units.

[0041] In the embodiment of the method shown, it is also provided that, instead of using the adjustable target hydrogen production rate directly as a target value, this is converted 120 into an associated target current value after detection 104, so that determining the deviation of the current total hydrogen production rate of the number of selected electrolysis units from the adjustable target hydrogen production rate is simplified to measuring individual input currents at the selected electrolysis units and determining the deviation of the current total hydrogen production rate of the number of selected electrolysis units from the adjustable target hydrogen production rate as the deviation of a sum of the individual input currents at the selected electrolysis units from the target current value.

[0042] In a next step, it is planned that for the number of selected electrolysis units, each of which is operated at individual cell voltage values, the individual cell voltage values ​​are continuously adjusted to the common target cell voltage value 112.

[0043] The process continues with the determination 108 of the actual value if a check 114 of the setpoint shows that it has not changed (in Fig. 1 is marked by “-”). If checking 114 the setpoint shows that it has changed (in Fig. 1 marked by a "+"), the method continues with the step of detecting 104 the setpoint. The method ends, for example, when the control device switches off the electrolysis units.

[0044] In Fig. 2, an example of an electrolysis system according to an embodiment of the invention is schematically illustrated. The electrolysis system 200 comprises a control device 202 and a plurality of electrolysis units 204, 206, 208, 210, 212, which can each be selected by the control device 202 to provide current individual hydrogen production rates when individual cell voltage values ​​are applied for the selected electrolysis units, depending on a common control variable. In this case, the control device 202 is configured to carry out a method for controlling the utilization of electrolysis units of an electrolysis system, for example, the method described in Fig. 1. For this purpose, the control device 200 has at least one processor 214 and a memory 216 in which a computer program product is stored, the code portions of which, when loaded into the processor 214 and executed by it, set up and cause the control device 202 to execute the method for load control. In Fig. Figure 1 also shows the connection of the electrolysis units 204, 206, 208, 210, 212 to an external electrical energy source 218. This can be a public power grid. A water supply to the electrolysis units and a removal of hydrogen and oxygen are present, but are not shown for the sake of clarity.

[0045] In Fig. Figure 3 schematically illustrates an example of a control of the cell voltages of electrolysis units for a method for controlling the capacity of electrolysis units of an electrolysis plant 300 according to another embodiment of the invention. Shown are a number of selected electrolysis units 302, which were selected by the control device (not shown) of an electrolysis plant from a plurality of electrolysis units.Of the n units comprising selected electrolysis units 302, the first electrolysis unit 304, whose electrolysis cells are operated at a current cell voltage U1, the second electrolysis unit 306, whose electrolysis cells are operated at a current cell voltage U2, the third electrolysis unit 308, whose electrolysis cells are operated at a current cell voltage U3, and the nth electrolysis unit 310, whose electrolysis cells are operated at a current cell voltage Un, are shown by way of example. Each of these electrolysis units produces hydrogen, consuming an individual required current, the value of which is transmitted to a summation unit 312. This calculates the total value and outputs it 314 for further control of the power supply and makes it available as an actual value 316 of the current power consumption.For example, a production quantity or rate 318 is read in as the setpoint S, wherein it is provided that this value is fed to a conversion unit 320 (this can be part of the (not shown) control device of the electrolysis plant), where it is converted into an associated setpoint current value 322, taking into account the Faraday efficiency. Then, the deviation 324 of the actual value 316 of the current power consumption from the predetermined setpoint current value 322 is determined and fed to the controller 326. The controller 326 sets the common controlled variable Uc, i.e. a common cell voltage value 328, as a control value for all electrolysis units 304, 306, 308, 310, whereby each of the electrolysis units 304, 306, 308, 310 now controls its individual cell voltage in accordance with the deviation of its current individual cell voltage U1, U2, U3...Un from the common (target) cell voltage value Uc to be minimized.

[0046] In an alternative embodiment, it may be provided to dispense with the conversion of the target production quantity into a target current and instead to determine no electrical current measured values ​​at the electrolysis units 304, 306, 308, 310, but rather measured values ​​of the respective individual production quantities or production mass flows.

[0047] In another alternative embodiment, the target value may be the predetermined electrical power consumption rather than the amount of hydrogen to be produced. In this case, the individual power consumption of each of the electrolysis units 304, 306, 308, 310 is recorded, and the actual value 316 is the sum of the individual partial powers.

[0048] In Fig. Figure 4 shows a diagram of an example of current-voltage characteristics of electrolysis units in an electrolysis plant. The diagram shows the possible individual cell voltages U versus the current I flowing in the respective electrolysis unit. Fig. Figure 4 shows a first current-voltage characteristic curve 402 of a first electrolysis unit, a second current-voltage characteristic curve 404 of a second electrolysis unit, and a third current-voltage characteristic curve 406 of a third electrolysis unit. All three units are regulated to the same cell voltage value Uc. The areas 408, 410, 412, which are defined by the characteristic curves 402, 404, 406 until Uc is reached, represent the power of the respective units.

[0049] The operating voltage of the electrolysis cells, i.e. the cell voltage U, is inversely proportional to the efficiency of the respective electrolysis unit, whereby an approximately optimal efficiency of each electrolysis unit is achieved at minimum voltage.

[0050] The figures are not necessarily detailed or to scale and may be enlarged or reduced to provide a better overview. Therefore, the functional details disclosed herein are not to be interpreted in a limiting sense, but merely as an illustrative basis for teaching one skilled in the art how to variously employ the present invention.

[0051] It is understood that the division into various blocks shown is for illustrative purposes only, and that in other embodiments, blocks could be combined or the functionality could be divided among various other blocks. It is also understood that method steps, although described according to a certain ordered sequence, could in part be performed in a different order than that described herein. It is further understood that certain steps could be performed concurrently, that other steps could be added, or that certain steps described herein could be omitted. In other words, the present descriptions are provided for the purpose of illustrating particular embodiments and should not be construed as limiting the disclosed subject matter.

[0052] As used herein, the term "and / or," when used in a series of two or more elements, means that any of the listed elements may be used alone, or any combination of two or more of the listed elements may be used. For example, if a composition is described as containing components A, B, and / or C, the composition may contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0053] Although the invention has been illustrated in detail by the described embodiments, the invention is not limited by the disclosed examples, and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention. Therefore, the invention is not intended to be limited to individual embodiments, but only by the appended claims.

[0054] In summary, a method (100) for controlling the capacity of electrolysis units of an electrolysis plant is provided, wherein the electrolysis plant has a control device and a plurality of electrolysis units, each of which can be selected by the control device to provide current individual hydrogen production rates when individual cell voltage values ​​are applied for the selected electrolysis units depending on a common controlled variable, wherein the method comprises selecting a number of electrolysis units from the plurality of electrolysis units taking into account an adjustable target hydrogen production rate or an adjustable target total electrical power consumption (106);and adjusting the common control variable depending on a deviation of a current total hydrogen production rate of the number of selected electrolysis units from the adjustable target hydrogen production rate or depending on a deviation of a current total electrical power consumption of the number of selected electrolysis units from the adjustable target total electrical power consumption (110). The common control variable is a target cell voltage value common to the number of selected electrolysis units, and the number of selected electrolysis units are each operated at individual cell voltage values ​​that are continuously adjusted to the common target cell voltage value (112).

[0055] Additionally, an electrolysis system, a computer program product, a computer-readable storage medium and a data carrier signal are provided.

Claims

[1] Method (100) for controlling the capacity of electrolysis units of an electrolysis plant, wherein the electrolysis plant has a control device and a plurality of electrolysis units, each of which can be selected by the control device, to provide current individual hydrogen production rates when individual cell voltage values ​​are applied for the selected electrolysis units depending on a common control variable, wherein the method (100) comprises to select a number of electrolysis units from the plurality of electrolysis units taking into account an adjustable target hydrogen production rate or an adjustable target total electrical power consumption (106); and the common control variable depending on a deviation of a current total hydrogen production rate of the number of selected electrolysis units from the adjustable target hydrogen production rate or to adjust (110) depending on a deviation of a current total electrical power consumption of the number of selected electrolysis units from the adjustable target total electrical power consumption; whereby the common control variable is a common target cell voltage value for the number of selected electrolysis units and the number of selected electrolysis units are operated at individual cell voltage values, which are continuously adjusted to the common target cell voltage value (112). [2] The method according to claim 1, wherein a maximum number of electrolysis units is selected as the number of selected electrolysis units. [3] A method according to any one of the preceding claims, wherein the step of selecting a number of electrolysis units from the plurality of electrolysis units (106) comprises preferentially selecting an electrolysis unit having a higher efficiency over an electrolysis unit having a lower efficiency. [4] A method according to any one of the preceding claims, wherein the step of selecting a number of electrolysis units from the plurality of electrolysis units (106) comprises selecting an electrolysis unit based on a degree of utilization in operation. [5] The method of any preceding claim, wherein the step of selecting a number of electrolysis units from the plurality of electrolysis units (106) comprises preferentially selecting an electrolysis unit having a lower previous operating time over an electrolysis unit having a higher previous operating time. [6] Method according to one of the preceding claims, wherein switching off (116) or switching on (118) of several of the selected electrolysis units takes place in an order ordered according to the respective associated efficiencies, wherein an electrolysis unit with the highest associated efficiency is switched on first and / or switched off last. [7] Method according to one of the preceding claims, comprising converting (120) the adjustable target hydrogen production rate into an associated target current value. [8] Method according to one of the preceding claims, comprising Measuring individual input currents at the selected electrolysis units; and Determining the deviation of the current total hydrogen production rate of the number of selected electrolysis units from the adjustable target hydrogen production rate as the deviation of a sum of the individual input currents at the selected electrolysis units from the target current value. [9] Electrolysis plant (200), comprising a control device (202); and a plurality of electrolysis units (204, 206, 208, 210, 212), each of which can be selected by the control device (202), to provide current individual hydrogen production rates when individual cell voltage values ​​are applied for the selected electrolysis units, depending on a common control variable, wherein the control device (202) is configured to carry out a method (100) according to one of claims 1 to 8 for controlling the capacity of the electrolysis units. [10] A computer program product comprising code components which, when executed by a processor (214) of a control device (202) of an electrolysis plant (200) according to claim 9, configure the control device (202) to carry out steps of a method (100) according to any one of claims 1 to 8. [11] A computer-readable storage medium on which a computer program product according to claim 10 is stored. [12] A data carrier signal carrying a computer program product according to claim 10.

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