Method for controlling the capacity utilisation of electrolysis units of an electrolysis system

Abstract

The invention relates to a method (100) for controlling the capacity utilisation of electrolysis units of an electrolysis system, wherein the electrolysis system has a control device and a plurality of electrolysis units, each of which can be selected by the control device; comprising providing current individual hydrogen production rates when there are cell voltage values individual to the selected electrolysis units depending on a common controlled variable, selecting (106) a number of electrolysis units from the plurality of electrolysis units taking into account a settable target hydrogen production rate or a settable target total electrical power consumption; and adapting (110) the common controlled variable depending on a deviation of a current total hydrogen production rate of the number of selected electrolysis units from the settable 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 settable target total electrical power consumption. The common controlled variable is a target cell voltage value common to the number of selected electrolysis units, and the number of selected electrolysis units are operated at respective individual cell voltage values which are continuously adjusted to the common target cell voltage value (112).

Description

[0001] Description

[0002] Method for capacity control of electrolysis units of an electrolysis plant

[0003] The present invention generally relates to the efficient operation of electrolysis systems having a plurality of parallel-operated, 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.

[0004] 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 may well have 100 or more electrolysis units, each with a multitude of electrolysis cells in which, using direct current, water is split into hydrogen and oxygen.

[0005] However, the electrolysis units within an electrolysis plant may differ from one another in 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 previous operation, or the number of switch-on and switch-off cycles during previous operating life, and therefore, for example, have been subjected to different aging or wear processes.

[0006] 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. Optimization can affect a variety 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, concerns 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 and at the same time their operational capability is ensured over the entire period.

[0007] The object of the present invention is to provide a way of operating an electrolysis system with a plurality of electrolysis units in such a way that, with minimal control and regulation effort, a desired maximum or predetermined overall performance of the electrolysis system can be ensured even over a long period of time, even if the electrolysis units differ in their current performance or degree of wear. In particular, the overall performance can relate to the highest possible production rate (of hydrogen) at a given (electrical) power consumption or to a predetermined production rate with the lowest possible power consumption.

[0008] This object is achieved according to the invention by a method for controlling the capacity of electrolysis units in 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. According to a first aspect, the invention relates to a method for controlling the capacity of electrolysis units in an electrolysis plant, the electrolysis plant having a control device and a plurality of electrolysis units which can each 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.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.

[0009] 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 which, when loaded into the processor, enable the control device to carry out 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 relating to the individual power consumption or the currently produced hydrogen rate, from the electrolysis units directly 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.

[0010] A processor is a data processing unit, such as a CPU, a microprocessor, or a microcontroller.

[0011] 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.

[0012] The application of a cell voltage value to an electrolysis unit describes the application of a voltage of a specific voltage 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.

[0013] An individual cell voltage value is the actual voltage value present at a specific one of the selected electrolysis units. Individual cell voltage values ​​may (but do not have to) differ between electrolysis units, even if the electrolysis units are of the same design.

[0014] 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 together per unit of time.

[0015] 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.

[0016] 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. The setting can be varied over time.

[0017] 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 a maximum amount of hydrogen is to be produced in the selected electrolysis units.

[0018] In order to achieve the specified set hydrogen production rate or set electrical power consumption, all of the selected electrolysis units are adjusted using the same common control variable. This common control variable is intended to be a target cell voltage value that is common to 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 time intervals.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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 the method provides that, if a choice is possible (and if other criteria that may need to be taken into account have also been taken into account), the most efficient electrolysis unit is always selected. The efficiency of an electrolysis unit is used here as the ratio of the actually produced and technically usable amount of hydrogen to the energy input.

[0024] 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. This takes 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 makes full load operation of individual electrolysis units unnecessary.

[0025] 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 previous operating time over an electrolysis unit with a longer previous operating time. This takes into account that the aging process of an electrolysis unit progresses 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.

[0026] In one embodiment of the method, several of the selected electrolysis units are switched on or off in a sequence ordered according to 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 hence efficiency is a suitable shutdown sequence.

[0027] The determined suitable shutdown sequence or the last electrolysis unit switched off can then define a starting point for a subsequent switch-on sequence.

[0028] Preferably, transient power offsets are also 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 start-up sequence can be appropriately corrected.

[0029] 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 carried out at the selected electrolysis units in order to determine a total value of the current power consumption. The deviation of this total from the target current value can then be directly determined in order to then determine how the common controlled 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.

[0030] 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.

[0031] 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 when individual cell voltage values ​​are applied for the selected electrolysis units depending on a common control variable, wherein the control device is designed to carry out a method according to the first aspect of the invention for controlling the capacity of the electrolysis units.

[0032] And according to a third aspect of the invention, a computer program product comprises code components which, 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 carry out steps of the method according to the first aspect of the invention. A computer program product corresponds to a computer program which comprises at least software code components to enable the execution of steps of the method.

[0033] A fourth aspect of the invention relates to a computer-readable storage medium, in particular a non-volatile computer-readable storage medium, i.e. 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.

[0034] 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.

[0035] 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.

[0036] 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 is explained in more detail below in connection with the following description of exemplary embodiments with reference to the accompanying figures. They show:

[0037] 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;

[0038] Fig. 2 is a schematic representation of an example of an electrolysis plant according to an embodiment of the invention;

[0039] 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

[0040] Fig. 4 is a schematic representation of a diagram of an example of current-voltage characteristics of electrolysis units of an electrolysis plant. It is understood that other embodiments may be used 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. The description is therefore not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0041] Fig. 1 schematically shows an example of a method 100 for controlling the capacity of electrolysis units in an electrolysis plant according to one embodiment of the invention. The method 100 is carried out for an electrolysis plant which has a control device and a plurality of electrolysis units which can each 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. In order 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 the processor and executed by it, configure the control device with the processor for carrying out the method. This takes place in the start state 102 of the method 100.

[0042] In one step, a setpoint is recorded 104. This setpoint is adjustable, i.e., changeable. The recording 104 of the setpoint concerns either the recording 104a of an adjustable setpoint hydrogen production rate or the recording 104b of an adjustable setpoint total electrical power consumption, whereby either an amount of hydrogen to be produced by the electrolysis plant per unit of time or an amount of electrical energy available per unit of time is specified, with which a maximum amount of hydrogen is to be produced.

[0043] 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 such that the total number of switching operations of electrolysis units is reduced.Furthermore, selecting 106 a number of electrolysis units from the plurality of electrolysis units may comprise 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 shorter previous operating time over an electrolysis unit with a longer 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 the respective associated efficiencies, wherein an electrolysis unit with the highest associated efficiency is switched on first and / or switched off last.

[0044] 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 . In a next step, it is provided to adapt the common controlled variable depending on a deviation of the actual value, which is a sum value here, from the received target value 110 .The step of adjusting 110 the common control variable comprises either adjusting 110a the common control variable depending on a deviation of the current total hydrogen production rate of the number of selected electrolysis units (as the actual value) from the adjustable target hydrogen production rate, or adjusting 110b the common control variable depending on the deviation of the current total electrical power consumption of the number of selected electrolysis units (as the actual value) from the adjustable target total electrical power consumption, wherein the common control variable is a target cell voltage value common to the number of selected electrolysis units.

[0045] In the embodiment of the method shown, it is also provided that, instead of using the adjustable target hydrogen production rate directly as the 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.

[0046] In a next step, it is intended that for the number of selected electrolysis units, which are each operated at individual cell voltage values, the individual cell voltage values ​​are continuously adjusted to the common target cell voltage value 112 .

[0047] The method continues with the determination 108 of the actual value if a check 114 of the setpoint shows that it has not changed (indicated by in Fig. 1). If the check 114 of the setpoint shows that it has changed (indicated by "+" in Fig. 1), 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.

[0048] Fig. 2 shows a schematic illustration of an example of an electrolysis plant according to an embodiment of the invention. The electrolysis plant 200 has 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 controlled variable. The control device 202 is configured to carry out a method for controlling the utilization of electrolysis units of an electrolysis plant, for example the method 100 shown in Fig. 1, in order to control the utilization of the electrolysis units 204, 206, 208, 210, 212.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 the latter, set up and cause the control device 202 to carry out the method for capacity control. Fig. 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 supply of water to the electrolysis units and a discharge of hydrogen and oxygen are present, but are not shown for the sake of clarity.

[0049] Fig. 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 system 300 according to a further 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 system from a plurality of electrolysis units.Of the n units comprising a number of selected electrolysis units 302, the first electrolysis unit 304, whose electrolysis cells are operated at a current cell voltage Ul, 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, each 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 target value 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 target 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 target 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 Ul, U2, U3...Un from the common (setpoint) cell voltage value Uc to be minimized.

[0050] 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.

[0051] In a further alternative embodiment, the target value may be the specified 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, and 310 is recorded, and the actual value 316 is the sum of the individual partial powers.

[0052] Fig. 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. 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.

[0053] The operating voltage of the electrolysis cells, i.e. the

[0054] 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.

[0055] 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 utilize the present invention in various ways.

[0056] 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 between various other blocks. It is also understood that method steps, although described according to a certain ordered sequence, could in part be carried out in a different order than that described here. It is further understood that certain steps could be performed concurrently, that other steps could be added, or that certain steps described here 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.

[0057] The term "and / or" as used herein, when used in a series of two or more elements, means that any one 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.

[0058] 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.

[0059] 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 which can each 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 to adapt 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 ​​which are continuously adjusted to the common target cell voltage value (112). In addition, an electrolysis system, a computer program product, a computer-readable storage medium and a data carrier signal are provided.;

Claims

Patent 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 controlled variable, wherein the method (100) comprises selecting (106) 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 to adapt 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 ); wherein 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 ​​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. The 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. The 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 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 with a lower previous operating time over an electrolysis unit with 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 a corresponding 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 depending on a common controlled variable when individual cell voltage values ​​are applied for the selected electrolysis units, 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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