Water electrolysis operation control system linked to power produced from renewable energy

Abstract

The present invention relates to a water electrolysis operation control system linked to power produced from solar energy, and, to a water electrolysis operation control system linked to solar-generated power for maximizing hydrogen production relative to renewable energy generation. The present invention comprises: a water electrolysis system (100) that is supplied with power from a solar power system and produces hydrogen; and a control unit (200) that controls an output of the water electrolysis system, wherein the control unit adjusts the output of the water electrolysis system according to the variability of the amount of solar power generation, by controlling the output of the water electrolysis system, controlling regular time intervals, controlling regular output intervals, and combining the control of the regular time intervals and the control of the regular output intervals, thus having the effect of reducing ESS capacity and increasing hydrogen production efficiency by means of a water electrolysis operation method that actively responds to the variability of renewable energy.

Description

Water electrolysis operation control system linked with renewable energy generation

[0001] The present invention relates to a water electrolysis operation control system linked with renewable energy generation power, and more specifically, to a water electrolysis operation control system linked with renewable energy generation power that maximizes hydrogen production relative to renewable energy generation.

[0002] A water electrolysis facility is a device that produces hydrogen by electrolyzing water in a stack. There are various types of water electrolysis, such as Alkaline, PEM, SOEC, and AEM, and each type differs in operating characteristics, advantages and disadvantages, and level of technological development.

[0003] Alkaline electrolysis was commercialized the longest time ago and is technically in a mature stage. However, alkaline electrolysis has the disadvantage of not being able to rapidly change the amplitude and speed of power fluctuations. This makes it difficult to actively utilize alkaline electrolysis in the recent trend of green hydrogen production, which links electrolysis facilities with renewable energy sources such as solar and wind power to reduce carbon dioxide emissions and mitigate global warming. This is because it is difficult for alkaline electrolysis to actively track the output variability of renewable energy.

[0004] Figure 1 is an example of changes in solar power generation and fixed output operation of a water electrolysis facility on a daily basis. As illustrated in Figure 1, it shows an example of changes in solar power generation and fixed output operation of a water electrolysis facility over a day. The X-axis of the graph represents time (in hourly units), the Y-axis represents solar power generation output (kW), and the red line represents the water electrolysis operation output.

[0005] This visually illustrates the difference between the variability of renewable energy generation and the fixed output operation of the electrolysis facility. Because solar power generation is inconsistent, an ESS is required to balance power when the solar power output exceeds or falls short of the electrolysis operation output. This results in additional capital expenditures (CAPEX) for the installation and operation of the ESS. In summary, Figure 1 suggests that an ESS is required when the electrolysis facility cannot keep up with the variability of renewable energy, which increases the capital expenditure of the entire system.

[0006] Hydrogen production is possible by supplying electricity generated by solar power to a water electrolysis unit, and since the operating output of the water electrolysis unit is maintained at a constant level, the amount of hydrogen produced is constant. However, in this case, depending on the difference between the solar power generated and the power input to the water electrolysis unit, it is necessary to discharge or charge the Energy Storage System (ESS).

[0007] In other words, if the water electrolysis facility cannot actively keep up with the intermittency of renewable energy generation, an energy storage device is required to compensate for this, which acts as a disadvantage that increases the capital expenditures (CAPEX) of the hydrogen production system.

[0008] [Prior Art Literature]

[0009] [Patent Literature]

[0010] Patent Document 1. Republic of Korea Registered Patent 2368675 (February 23, 2022)

[0011] The present invention aims to solve the aforementioned problems by providing a water electrolysis operation control system linked to renewable energy production power that reduces ESS capacity and increases hydrogen production efficiency through a water electrolysis operation method that actively responds to the variability of renewable energy.

[0012] To achieve the above objective, the present invention comprises a water electrolysis system (100) that produces hydrogen by receiving power from a renewable energy generation system and a control unit (200) that controls the output of the water electrolysis system, wherein the control unit controls the output of the water electrolysis system, controls a fixed time interval, controls a fixed output interval, and combines the fixed time interval control and the fixed output interval control according to the variability of the renewable energy generation amount to adjust the output of the water electrolysis system.

[0013] The water electrolysis system produces hydrogen by receiving power from a renewable energy generation system and includes an alkaline water electrolysis system and a proton exchange membrane (PEM) water electrolysis system. The control unit prioritizes increasing the output of the alkaline water electrolysis system to its maximum value when the output increases according to the variability of the renewable energy generation amount, and increases the output of the PEM water electrolysis system when the alkaline water electrolysis system reaches its maximum output.

[0014] The control unit includes an output increase adjustment module (210) that, when an output increase is required due to the variability of renewable energy generation, first increases the output of the ALK electrolysis system to the maximum level, and after the ALK electrolysis system reaches the maximum output, adjusts the output of the PEM electrolysis system to compensate for the insufficient output.

[0015] The control unit includes an output reduction adjustment module (220) that first reduces the output of the PEM electrolysis system when output is reduced according to the variability of renewable energy generation, and reduces the output of the ALK electrolysis system when the PEM electrolysis system reaches a minimum output.

[0016] The water electrolysis system includes one or more of an alkaline water electrolysis system (ALK), a proton exchange membrane (PEM) water electrolysis system, and a high-temperature water electrolysis system (solid oxide electrolysis cell, SOEC), and the control unit independently controls the increase and decrease of output according to the characteristics of each water electrolysis system based on the variability of renewable energy generation, or optimizes hydrogen production by combining them.

[0017] The control unit includes a time interval adjustment module (230) that sets the output target value of the water electrolysis system at regular time intervals and adjusts the output target value of the water electrolysis system according to the amount of solar power generated at each set time interval.

[0018] The control unit includes an output interval adjustment module (240) that sets an output target value of the water electrolysis system at a fixed output interval according to the variability of the renewable energy generation amount, and resets the output target value whenever the difference between the solar power generation output and the water electrolysis system output reaches a preset maximum range.

[0019] The control unit includes a composite adjustment module (250) that combines a constant time interval control that changes the output target value of the water electrolysis system at set time intervals and a constant output interval control that changes the output target value of the water electrolysis system whenever the difference between the renewable energy generation output and the water electrolysis system output reaches a preset maximum range, thereby enabling the water electrolysis system to respond to the variability of the renewable energy generation amount.

[0020] The water electrolysis system receives power generated from a combination of two or more renewable energy sources among solar power, wind power, and wave power, and the control unit controls the output of the water electrolysis system by considering the characteristics and variability of each power source in real time.

[0021] According to the present invention, a water electrolysis operation method that actively responds to the variability of renewable energy has the effect of reducing ESS capacity and increasing hydrogen production efficiency.

[0022] FIG. 1 is an example of a change in solar power generation amount and fixed output operation of a water electrolysis facility on a daily basis according to the prior art.

[0023] FIG. 2 is a configuration diagram of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0024] Figure 3 visually illustrates the advantages of the water electrolysis operation method of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0025] Figure 4 is a graph illustrating the time interval control of the electrolysis operation control for tracking solar power output of the electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0026] FIG. 5 is a graph illustrating the constant output interval control of the electrolysis operation control for tracking solar power output of the electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0027] FIG. 6 is a graph illustrating the combined control of electrolysis operation control for tracking solar power output of an electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0028] FIGS. 7 to 9 are graphs illustrating the difference in the required amount of energy storage device according to the time interval control and time interval setting of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0029] FIG. 10 shows a development operation logic for tracking renewable energy when Alkaline and PEM water electrolysis are combined and operated in a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0030] Figure 11 shows the logic corresponding to the case where output reduction is required in the driving logic of Figure 10.

[0031] FIG. 12 is a graph illustrating improvements to a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0032] FIG. 13 is a graph illustrating the control concept of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0033] FIG. 14 is a flowchart of the control logic of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0034] The present invention will be described in detail below with reference to the contents described in the attached drawings. However, the present invention is not limited or restricted by exemplary embodiments. Identical reference numerals in each drawing indicate components that perform substantially the same function.

[0035] The purpose and effects of the present invention may be naturally understood or become clearer through the following description, and the purpose and effects of the present invention are not limited solely to the description below. Furthermore, in describing the present invention, if it is determined that a detailed description of known technology related to the present invention may unnecessarily obscure the essence of the present invention, such detailed description will be omitted.

[0036] Hereinafter, a water electrolysis operation control system linked with renewable energy production power according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0037] FIG. 2 is a configuration diagram of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0038] As shown in FIG. 2, the water electrolysis operation control system (10) linked with renewable energy production power includes a water electrolysis system (100) and a control unit (200).

[0039] Here, since the water electrolysis operation control system linked with renewable energy production power can be linked with other renewable energy sources such as wind and wave power generation as well as solar power, in this embodiment, the renewable energy production power will be explained using a solar power generation system as an example.

[0040] In this embodiment, for ease of explanation, the description is limited to a photovoltaic power generation system; however, the present invention is not limited thereto and can be applied to various types of combined renewable energy generation. For example, it may include combinations of renewable energy such as a combination of wind and solar power, a combination of solar and wave power, etc.

[0041] Hereinafter, among renewable energy generation systems, a solar power generation system will be used as an example to describe a water electrolysis operation control system linked to renewable energy production power according to the present embodiment.

[0042] The water electrolysis system (100) is configured to produce hydrogen by receiving power from a solar power generation system.

[0043] For reference, although a solar power generation system was mentioned as an example, it is not limited thereto; hydrogen is produced by supplying power from not only solar power but also combinations of wind and wave power generation (e.g., wind + solar, solar + wave... combinations of renewable energy).

[0044] These water electrolysis systems (100) include alkaline water electrolysis systems and proton exchange membrane (PEM) water electrolysis systems. In addition, they can be applied to high-temperature water electrolysis SOECs.

[0045] A high-temperature water electrolysis SOEC (Solid Oxide Electrolysis Cell) is a water electrolysis system that operates at high temperatures. Generally, it produces hydrogen by electrolyzing water using oxide ions at an operating temperature of 600 to 1000°C. Due to its high operating temperature, the SOEC can utilize thermal energy along with electrical energy, which reduces electricity consumption and provides high energy efficiency.

[0046] SOEC is a high-temperature water electrolysis method that can produce hydrogen using electricity supplied from various renewable energy sources such as solar, wind, and wave power, and can particularly respond to variability arising from combinations with renewable energy. For example, surplus electricity from wind and solar power generation can be additionally utilized as a high-temperature heat source to maximize the efficiency of SOEC, or electricity generated from wave power generation can be combined with SOEC to compensate for seasonal variability.

[0047] The control unit (120) is configured to control the output of the water electrolysis system, and adjusts the output of the water electrolysis system by controlling the output of the water electrolysis system according to the variability of the solar power generation amount, controlling the time interval, controlling the output interval, and combining the time interval control and the output interval control.

[0048] For reference, this configuration is designed to efficiently and stably manage the output of the water electrolysis system. It plays a role in maximizing the efficiency of hydrogen production by reflecting the variability of renewable energy generation in real time.

[0049] The control unit basically performs an output control function that detects the variability of renewable energy generation in real time and sets or adjusts the target output value of the water electrolysis system accordingly. It optimizes efficiency by utilizing surplus power when output is insufficient and preventing system overload when output is excessive.

[0050] The control unit performs control at fixed time intervals. This method involves setting a target output value for the water electrolysis system at regular intervals and updating it at each set interval. This approach aims to mitigate the rapid variability of renewable energy and reduce the usage of the Energy Storage System (ESS) by gradually managing output fluctuations.

[0051] The control unit also performs constant output interval control. This is a method of adjusting the target value only when the magnitude of the output fluctuation exceeds a preset limit. Through this, system fatigue caused by frequent output changes is reduced, and system stability is maintained by changing the output target value only when necessary.

[0052] The control unit operates by combining fixed-time interval control and fixed-output interval control. This enables flexible control capable of immediately responding to rapid output changes while maintaining the regularity of time-unit control.

[0053] The control unit includes an output increase adjustment module (210). This module prioritizes increasing the output of the ALK electrolysis system when power generation increases, and increases the output of the PEM electrolysis system after reaching maximum output. This allows for the utilization of the stability of the ALK electrolysis and the fast responsiveness of the PEM electrolysis.

[0054] The control unit includes an output reduction adjustment module (220). This module operates by first reducing the output of the PEM electrolysis system when power generation decreases, and then reducing the output of the ALK electrolysis system when the PEM system reaches a minimum output. This utilizes the flexibility of the PEM system and maintains the stability of the ALK system.

[0055] The control unit includes a time interval adjustment module (230). This serves to set and update target output values ​​at regular time intervals. Through this, stable operation is possible through regular and gradual output changes.

[0056] The control unit includes an output interval adjustment module (240). This immediately resets the target value when the output fluctuation range exceeds a set range. This allows for a rapid response to sudden output fluctuations.

[0057] The control unit includes a composite adjustment module (250). This manages variability in real time by combining time interval control and output interval control. Through this, it provides optimal operation logic in complex variability situations.

[0058] The control unit operates based on real-time data. It performs real-time control by analyzing power generation data, system status information, and target output values. If power generation drops sharply, it first reduces the PEM system output and, if necessary, utilizes the ESS or adjusts the ALK system output. If solar power generation increases, it first increases the ALK system output and supplements the shortfall with the PEM system.

[0059] A control unit (200) for performing these functions includes an output increase adjustment module (210), an output decrease adjustment module (220), a time interval adjustment module (230), an output interval adjustment module (240), and a composite adjustment module (250).

[0060] The output increase adjustment module (210) increases the output of the ALK electrolysis system to the maximum value first when an output increase is required due to the variability of solar power generation, and after the ALK electrolysis system reaches the maximum output, it adjusts the output of the PEM electrolysis system to compensate for the insufficient output.

[0061] The output reduction adjustment module (220) first reduces the output of the PEM electrolysis system when reducing output according to the variability of renewable energy generation, and reduces the output of the ALK electrolysis system when the PEM electrolysis system reaches a minimum output. In this embodiment, when reducing output according to the variability of solar power generation, the output of the PEM electrolysis system is first reduced, and the output of the ALK electrolysis system is reduced when the PEM electrolysis system reaches a minimum output.

[0062] For reference, the water electrolysis system includes one or more of an Alkaline (ALK) water electrolysis system, a Proton Exchange Membrane (PEM) water electrolysis system, and a Solid Oxide Electrolysis Cell (SOEC) high-temperature water electrolysis system, and the control unit independently controls the increase or decrease in output according to the characteristics of each water electrolysis system based on the variability of renewable energy generation, or optimizes hydrogen production by combining them.

[0063] The water electrolysis system includes one or more of an Alkaline (ALK) water electrolysis system, a Proton Exchange Membrane (PEM) water electrolysis system, and a Sodium Electrolysis (SOEC) system, and optimizes hydrogen production by controlling output increase and decrease according to the characteristics of each system and the variability of renewable energy generation.

[0064] Alkaline water electrolysis systems (ALK) possess high stability and efficiency, and exhibit a relatively slow reaction rate to output fluctuations. Therefore, when renewable energy output is stable, the ALK system is operated at maximum output to serve as the fundamental basis for hydrogen production. This plays a role in enhancing the economic viability and stability of the system.

[0065] Proton Exchange Membrane (PEM) water electrolysis systems provide rapid output adjustment speeds and possess the characteristic of being able to respond immediately to variability. When renewable energy generation fluctuates rapidly, the PEM system reacts first to increase or decrease output. This enables flexible response to the intermittent nature of renewable energy.

[0066] High-temperature water electrolysis systems (SOEC) provide very high efficiency by simultaneously utilizing electrical and thermal energy at high operating temperatures. Efficient hydrogen production is possible by simultaneously utilizing surplus electricity and thermal energy from renewable sources. For example, when solar power output is surplus during the day, the SOEC is activated to produce hydrogen while minimizing electricity consumption.

[0067] Output increase and decrease are achieved through the combined operation of each water electrolysis system. When renewable energy output increases, the ALK system is increased first, and any surplus power is additionally utilized through the PEM or SOEC. When output decreases, the PEM system performs output reduction first, and the ALK system responds secondarily if necessary.

[0068] By utilizing the characteristics of each water electrolysis system to efficiently manage the variability of renewable energy, it is possible to reduce dependence on ESS (Energy Storage Systems), maximize hydrogen production, and lower the overall system operating costs. This enables the simultaneous securing of economic viability and stability in hydrogen production linked to renewable energy.

[0069] The time interval adjustment module (230) sets the output target value of the water electrolysis system at regular time intervals and adjusts the output target value of the water electrolysis system according to the amount of solar power generated at each set time interval.

[0070] The output interval adjustment module (240) sets the output target value of the water electrolysis system at a fixed output interval according to the variability of the solar power generation amount, and resets the output target value of the water electrolysis system whenever the difference between the solar power generation output and the water electrolysis system output reaches a preset maximum range.

[0071] The composite adjustment module (250) combines a constant time interval control that changes the output target value of the water electrolysis system at set time intervals and a constant output interval control that changes the output target value of the water electrolysis system whenever the difference between the renewable energy generation output and the water electrolysis system output reaches a preset maximum range, thereby enabling the water electrolysis system to respond to the variability of the renewable energy generation amount.

[0072] The control unit (200) according to the present embodiment prioritizes increasing the output of the ALK electrolysis system to a maximum value when the output increases according to the variability of the renewable energy generation amount, and increases the output of the PEM electrolysis system when the ALK electrolysis system reaches a maximum output.

[0073] The present invention is a technology that reduces CAPEX of hydrogen production facilities and maximizes hydrogen production relative to renewable energy generation by minimizing ESS capacity through the water electrolysis facility actively tracking the variability of renewable energy within the limits of the water electrolysis facility's own operating capacity.

[0074] Figure 3 visually illustrates the advantages of the water electrolysis operation method of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0075] As shown in Figure 3, among renewable energy sources, solar power output changes over time in a curved shape and reaches maximum output around noon. This graph represents the variability of actual solar power generation.

[0076] Regarding the water electrolysis operation output, the step-shaped line in Fig. 3 represents the operation output of the water electrolysis facility. The water electrolysis operation output is adjusted to actively track the solar power generation output. This means that the water electrolysis facility operates by following the variability of the solar power generation output in real time.

[0077] By actively tracking the variability of solar power output, the electrolysis facility minimizes the need for discharging and charging the ESS. As a result, the capacity of the ESS is reduced, and consequently, the initial capital expenditure (CAPEX) of the hydrogen production facility is reduced.

[0078] By operating the water electrolysis facility in accordance with the solar power output, hydrogen production can be maximized by making the most of the solar power generation.

[0079] Unlike conventional electrolysis operation methods, the electrolysis operation control system linked with renewable energy production power according to the present embodiment visually demonstrates the advantages of an electrolysis operation method that actively responds to the variability of renewable energy, as shown in FIG. 3. Through this, the main objective of the present invention is to reduce ESS capacity and increase hydrogen production efficiency.

[0080] Figure 4 is a graph illustrating the time interval control of the water electrolysis operation control for tracking the renewable energy output of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0081] Referring to Fig. 4, an example of 'fixed-time interval control' for tracking renewable energy output in a water electrolysis operation control system linked with renewable energy generation power will be explained. This graph shows the solar power output and the output of the water electrolysis facility among the renewable energy sources over time.

[0082] ① The target output of the electrolysis is changed at every electrolysis output change time (Δt) set by the operator. In the graph, Δt represents a constant time interval, and the target output (Tar) of the electrolysis equipment is changed at every interval.

[0083] ② The output target value is the PV output (Tar_t) at the corresponding time. The output target value (Tar) of the water electrolysis facility is set to match the photovoltaic (PV) output at each time interval.

[0084] ③ Before reaching the output target value, the output is changed to the Ramp Rate (RR) standard setting value (KW / s or A / s). The Ramp Rate (RR) indicates the rate at which the output changes, and the output of the water electrolysis equipment increases or decreases according to the set RR.

[0085] ④ After reaching the output target value (Tar_t1), the current output (Tar_t1) is maintained until the next output change judgment time (t_2). The output of the water electrolysis equipment is maintained until the next Δt time interval after reaching the set target value (Tar).

[0086] ⑤ Repeated control is performed after the set time interval has elapsed. When each Δt time interval has elapsed, the output target value (Tar) of the water electrolysis facility is reset to match the new PV output, and this process is repeated.

[0087] Figure 4 shows the changes in solar power generation output and water electrolysis equipment output over time, and the output of the water electrolysis equipment is controlled to generally follow the trend of changes in solar power generation. The ESS charging and discharging regions are displayed to indicate the point in time when the ESS is charged or discharged when needed.

[0088] The target value (Tar_t) for water electrolysis output is newly set at each time interval (Δt), and the output changes accordingly. This is intended to allow the water electrolysis facility to track the variability of solar power generation, thereby minimizing the use of ESS and reducing CAPEX of the hydrogen production system, while maximizing hydrogen production relative to solar power generation.

[0089] FIG. 5 is a graph illustrating the constant output interval control of the electrolysis operation control for tracking solar power output of the electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0090] With reference to Fig. 5, an example of 'constant output interval control' for tracking renewable energy output in a water electrolysis operation control system linked with renewable energy production power will be explained.

[0091] This graph aims for efficient hydrogen production by minimizing the capacity of the Energy Storage System (ESS) through adjusting the output of the water electrolysis facility in accordance with fluctuations in renewable energy generation output. The graph and key control methods are explained as follows.

[0092] ① The difference between the PV-electrolysis output set by the operator reaches the maximum range (Max dPower). During the time interval Δt, the difference between the photovoltaic power generation output and the electrolysis equipment output reaches the maximum range (Max dPower).

[0093] ② Change the output until the target output (Tar_t1) is reached based on the Ramp Rate standard setting value (kW / s or A / s). Adjust the output of the water electrolysis equipment based on the Ramp Rate (RR) standard until the set target output (Tar_t1) is reached. In the graph, the water electrolysis output increases or decreases according to RR.

[0094] ③ After reaching the target output value (Tar_t1), maintain the output if the difference between the PV and water electrolysis outputs is within the maximum range. After reaching the target output (Tar_t1), maintain the current output if the difference between the outputs is within the maximum range.

[0095] ④ The difference between the PV-water electrolysis output set by the operator reaches the maximum range (Max dPower). If the difference between the outputs reaches the maximum range again by the next time interval (t2), a new target output (Tar_t2) is set.

[0096] ⑤ Repeatedly change the output until the target output (Tar_t2) is reached using the Ramp Rate reference setting value (kW / s or A / s). Repeatedly adjust the output according to the Ramp Rate until the next target output (Tar_t2) is reached.

[0097] Figure 5 shows the changes in solar power output and water electrolysis equipment output over time. A new target output (Tar_t1, Tar_t2, ...) is set for each time interval (t1, t2, t3, ...). The ESS charging and discharging regions are displayed to indicate the point in time when the ESS is charged or discharged when needed. By adjusting the output of the water electrolysis equipment to reach the set target output (Tar_t), the amount of renewable energy generated can be utilized to the maximum extent.

[0098] FIG. 6 is a graph illustrating the composite control of water electrolysis operation control for tracking renewable energy output in a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0099] With reference to Fig. 6, an example of 'composite control' for tracking renewable energy output in a water electrolysis operation control system linked with renewable energy production power will be explained.

[0100] This 'complex control' improves tracking performance for highly variable solar output by controlling the change in electrolysis output when the difference between PV and electrolysis output exceeds a certain value during control at regular time intervals. In this process, both time and output difference limit values ​​are reflected as variables to enhance tracking performance for highly variable PV output.

[0101] In Fig. 6, PV output represents the change in photovoltaic power generation output. Constant time control represents the output of the water electrolysis facility at constant time intervals. Constant output difference control represents the output of the water electrolysis facility at constant output difference intervals.

[0102] ① A fixed time interval (Δt) elapses.

[0103] ② Set the PV output value at t_1 as the target electrolysis output value (Tar_t1).

[0104] Based on the PV output value at time t_1, the target output value (Tar_t1) of the water electrolysis facility is set.

[0105] ③ The output is changed at a pre-set Ramp Rate (kW / s or A / s) until the target output value is reached. The output of the water electrolysis equipment changes according to the set Ramp Rate until the target value (Tar_t1) is reached. This implies an increase or decrease in output.

[0106] ④ Before reaching the target value and the next time interval, the difference between the PV and water electrolysis outputs reaches the maximum range (Max dPower). After reaching the target value, the output is maintained within the maximum range (Max dPower) of the difference between the PV and water electrolysis outputs until the next time interval.

[0107] ⑤ Change the output to a preset Ramp Rate (kW / s or A / s) and Step (kW or A). The output of the water electrolysis equipment changes according to the preset Ramp Rate and Step. This process is repeated.

[0108] From t_0 to t_1, during the initial time interval, the output of the water electrolysis plant follows the increase in PV output. Each control curve shown in the figure represents an output change that rises according to the set Ramp Rate.

[0109] From t_1 to t_2, the output of the water electrolysis equipment reaches the target value (Tar_t1). The output is maintained for a certain time interval.

[0110] From t_2 to t_3, as the PV output decreases, the output of the water electrolysis facility also decreases according to the Ramp Rate.

[0111] In subsequent time intervals, this process is repeated, and at each time interval, an attempt is made to minimize the difference between the PV output and the water electrolysis output.

[0112] This complex control improves tracking of highly variable PV output by changing the electrolysis output when the difference between PV and electrolysis output exceeds a certain value, and implements more accurate control by reflecting both time and output difference limit values ​​as variables.

[0113] FIGS. 7 to 9 are graphs illustrating the difference in the required amount of energy storage device according to the time interval control and time interval setting of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0114] With reference to FIGS. 7 to 9, in a water electrolysis operation control system linked with renewable energy production power, we will explain the difference in the required amount of energy storage device (ESS) according to the time interval setting by using 'time interval control' among the water electrolysis operation control to track the renewable energy output.

[0115] The graphs in Figures 7 to 9 show the state of the water electrolysis output and the ESS by comparing three different time intervals (10 minutes, 30 minutes, and 60 minutes).

[0116] The graph in Fig. 7 shows that the electrolysis output changes at 10-minute intervals with a 10-minute interval control and a change range limited to 5 kW. The output change range is limited to 5 kW. The graph displays the solar power output of renewable energy, the electrolysis output controlled accordingly, and the actual solar power generation output, respectively.

[0117] The ESS SOC (State of Charge) in the graph of Fig. 7 represents the charging state of the ESS over time. The initial ESS SOC is approximately 150 kWh, increases to a maximum of 200 kWh, and then decreases again.

[0118] The graph in Fig. 8 shows that the electrolytic output changes at 30-minute intervals with a 30-minute interval control and a change range limited to 5kW. The output change range is limited to 5kW.

[0119] The ESS SOC (State of Charge) in the graph of Fig. 8 represents the charging state of the ESS over time. The initial ESS SOC is approximately 150 kWh, increases to a maximum of 210 kWh, and then decreases again.

[0120] The graph in Fig. 9 shows that the electrolytic output changes at 60-minute intervals with a 60-minute interval control and a change range limited to 5kW. The output change range is limited to 5kW.

[0121] The ESS SOC (State of Charge) in the third graph represents the charging state of the ESS over time. The initial ESS SOC is approximately 150 kWh, increases to a maximum of 220 kWh, and then decreases again.

[0122] In a water electrolysis operation control system linked to renewable energy generation power, when using 'fixed time interval control' during water electrolysis operation control to track renewable energy output, and in relation to the difference in the required amount of energy storage system (ESS) according to the time interval setting, if control is performed at short time intervals (10 minutes), the water electrolysis output can track the fluctuations of the renewable energy output more precisely.

[0123] At this time, as the time interval increases (30 minutes, 60 minutes), the change in water electrolysis output becomes greater, and the difference from solar power output may increase.

[0124] In addition, in short time interval control (10 minutes), the change in SOC of the ESS is relatively small and stable. In long time interval control (30 minutes, 60 minutes), the range of change in SOC of the ESS increases, and the time to reach the maximum charge state becomes longer.

[0125] In addition, the range of output change is limited to 5kW, which prevents sudden changes in output and allows for the maintenance of stable output.

[0126] Here, 10-minute interval control tracks the variability of solar power generation from renewable energy more precisely and can reduce ESS capacity by minimizing changes in the ESS SOC. 30-minute interval control tracks the variability of renewable energy generation to some extent, but the change in ESS SOC is greater compared to 10-minute interval control. 60-minute interval control tracks the variability of renewable energy generation less and has the largest change in ESS SOC. Therefore, it can be seen that 'fixed time interval control' has a significant impact on the required amount of ESS depending on the time interval setting, and that ESS capacity can be managed more efficiently as control is performed at shorter time intervals.

[0127] FIG. 10 shows a development operation logic for tracking renewable energy when Alkaline and PEM water electrolysis are combined and operated in a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0128] Since the output change characteristics of alkaline are inferior to those of PEM electrolysis, this is a technology that prioritizes increasing the ALK electrolysis output when an increase in output is required, and increases / adjusts the PEM electrolysis output only when limitations arise in increasing the ALK output.

[0129] In FIG. 10, S8-1 determines whether the current time is the control time by determining the control time. If it is the control time, proceed to the next step. If it is not the control time, maintain the output.

[0130] S8-2 is a step for calculating the required amount of change to the output target value, which calculates the output target value (Target_dp) to prepare for responding to output fluctuations.

[0131] S8-3 is a step for determining whether to increase output, and it determines whether the target output value (Target_dp) is greater than 0. If the target output value is greater than 0, it means that an increase in output is required, and the process proceeds to the next step. If the target output value is less than 0, it means that an output reduction is required, and the process proceeds to the Ramp down logic (output reduction logic, S8-4).

[0132] S8-31 is a step for determining whether the ALK is operating at maximum output, which determines whether the ALK water electrolysis has reached its maximum output (ALK_max). If the maximum output is reached, the process proceeds to the step of increasing the PEM water electrolysis output (S8-311). If the maximum output is not reached, the process proceeds to (S8-32).

[0133] S8-311 is a step that increases the output of the PEM water electrolysis.

[0134] Next, S8-312 is a step for determining whether to operate the PEM at maximum output, which determines whether the target output value (Target_dp) exceeds the maximum output (PEM_dpmax) of the PEM water electrolysis. If it exceeds it, the procedure proceeds to the step of increasing the output of the PEM water electrolysis to the maximum value (S8-3121). Otherwise, the PEM water electrolysis output is increased by the target output value (S8-3122).

[0135] S8-3121 increases the output of the PEM water electrolysis to the maximum value with PEM Ramp-up=ⓐPEM_dpmax. S8-3122 increases the output of the PEM water electrolysis to the target output value with PEM Ramp-up=ⓑTarget_dp.

[0136] If the maximum output is not reached in step S8-31, proceed to (S8-32). S8-32 is a step for determining whether the target output value > the maximum ALK output, and determines whether the target output value (Target_dp) exceeds the maximum output (ALK_dpmax) of the ALK water electrolysis.

[0137] In S8-32, if the target output value exceeds the maximum output of the ALK water electrolysis, the outputs of the ALK and PEM water electrolysis are increased simultaneously in step S8-321. Subsequently, in S8-3211, the output of the ALK water electrolysis is increased to the maximum value, and the output of the PEM water electrolysis is increased by the remaining target output value. ALK ramp-up = ⓒALK_dpmax, PEM ramp-up = Target_dp-ALK_dpmax.

[0138] In S8-32, if the target output value does not exceed the maximum output of the ALK water electrolysis, proceed to step S8-322 to increase the ALK water electrolysis output. Next, S8-3221 increases the output of the ALK water electrolysis by the target output value (Target_dp). ALK ramp-up=ⓔTarget_dp.

[0139] S8-4 is the output reduction logic (Ramp down), and if output reduction is required, it adjusts the output according to the logic.

[0140] In relation to the operation of FIG. 10, the control logic responds to the variability of renewable energy through the following steps: determine the control timing and calculate the target output value. If an increase in output is required, the ALK electrolysis is first increased to its maximum value.

[0141] Next, when the ALK electrolysis reaches maximum output, the output of the PEM electrolysis is increased. When the output of the PEM electrolysis reaches its maximum, the ALK and PEM electrolysis are combined if necessary to reach the target output value. If output reduction is required, the output is decreased according to a separate ramp-down logic. Through this control logic, fluctuations in the output of the ALK electrolysis are minimized, and the rapid responsiveness of the PEM electrolysis is utilized to effectively respond to the variability of renewable energy.

[0142] Figure 11 shows the logic corresponding to the case where output reduction is required in the driving logic of Figure 10.

[0143] If output reduction is required, reduce the PEM electrolysis output first, contrary to the increase, and when the state where PEM output adjustment is impossible is reached, adjust the ALK electrolysis output downward.

[0144] In other words, ALK water electrolysis minimizes the fluctuation range when normal output is reached, thereby enabling response to the variability of renewable energy through PEM water electrolysis and ESS.

[0145] As shown in FIG. 11, S8-1 determines whether the current time is the control time by determining the control time. If it is the control time, proceed to the next step. If it is not the control time, maintain the output.

[0146] S8-2 is a step for calculating the required amount of change to the output target value, which calculates the output target value (Target_up) to prepare for responding to output fluctuations.

[0147] S8-3 is a step for determining whether to increase output, and it determines whether the target output value (Target_up) is greater than 0. If the target output value is greater than 0, it means that an increase in output is required, and the process proceeds to the next step. If the target output value is less than 0, it means that an output reduction is required, and the process proceeds to the Ramp down logic (output reduction logic, S8-4).

[0148] S8-4 is a ramp down logic (output reduction logic, S8-4) that determines whether the PEM water electrolysis has reached the minimum output (PEM_min). As a result, if (Yes), the ALK water electrolysis output is reduced because the PEM water electrolysis has already reached the minimum output (S8-41).

[0149] Next, in S8-412, it is determined whether the target output value (Target_dp) exceeds the maximum output (ALK_dpmax) of the ALK water electrolysis. If the result is (Yes), the output of the ALK water electrolysis is reduced to the maximum value (ALK_dpmax), and the output of the PEM water electrolysis is reduced by the remaining target output value (S8-4121). ALK ramp-down = ⓐALK_dpmax.

[0150] If the result of S8-412 is (no), reduce the output of the ALK water electrolysis by the target output value (Target_dp) (S8-4122). ALK ramp-down = ⓑTarget_dp.

[0151] In step S8-4, if (no), proceed to step S8-42, and S8-42 determines whether the target output value (Target_dp) exceeds the maximum output (PEM_dpmax) of the PEM water electrolysis.

[0152] If the result of step S8-42 is (Yes), the outputs of the ALK and PEM water electrolysis are reduced simultaneously (S8-421). After S8-421, the output of the ALK water electrolysis is reduced to the maximum value, and the output of the PEM water electrolysis is reduced by the remaining target output value (S8-4211). PEM ramp-down = ⓒPEM_dpmax, ALK ramp-down = ⓓTarget_dp - PEM_dpmax

[0153] If the result of step S8-42 is (no), the output of the PEM water electrolysis is reduced by the target output value (Target_dp) (S8-422). Subsequently, in S8-4221, the output of the ALK water electrolysis is reduced by the target output value (Target_dp). PEM ramp-down = ⓔTarget_dp.

[0154] In relation to the operation of FIG. 11, the control logic responds to the variability of renewable energy through the following steps: It determines the control timing and calculates the target output value. If output reduction is required, the output of the PEM electrolysis is reduced first. When the PEM electrolysis reaches the minimum output, the output of the ALK electrolysis is reduced. If the target output value is greater than the maximum output of the PEM electrolysis and the ALK electrolysis, the outputs of the ALK electrolysis and the PEM electrolysis are reduced simultaneously. If the target output value is less than the maximum output of the PEM electrolysis, the output of the PEM electrolysis is reduced. Through this control logic, frequent output fluctuations of the ALK electrolysis can be minimized, and the rapid responsiveness of the PEM electrolysis can be utilized to effectively respond to the variability of renewable energy.

[0155] FIG. 12 is a graph illustrating improvements to a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0156] In the case of the water electrolysis operation logic described in Figures 10 and 11, when the output increases, the maximum increase in the ALK water electrolysis output is prioritized, so the control of the ALK water electrolysis output increase may occur frequently. This can be a disadvantage when considering the characteristics of the ALK water electrolysis, which cannot increase output frequently due to the operating limit that minimizes the differential pressure difference between the hydrogen side and the oxygen side. The following is a logic to improve this.

[0157] Figure 12 illustrates an example of how to respond to output fluctuations in an electrolysis system linked to a photovoltaic power generation system among renewable energy sources. The graph in Figure 12 visually displays the amount of photovoltaic power generation among renewable energy sources, the ALK (Alkaline) electrolysis output, the PEM (Proton Exchange Membrane) electrolysis output, and the total output over time.

[0158] PV output represents the amount of solar power generated over time, while ALK electrolysis output indicates the maximum output (ALK_max) and the portion where the output is maintained after reaching normal output. PEM electrolysis responds quickly to fluctuations and operates within the range of maximum output (PEM_max) and minimum output (PEM_min). Total output is (ALK + PEM electrolysis total output), representing the combined output of ALK and PEM electrolysis, and this line fluctuates in accordance with the amount of solar power generated.

[0159] In Fig. 12, the interval t0 to t1 is the ALK electrolysis output increase interval, during which the output of the ALK electrolysis is increased to a maximum value (rated output, ALK_max) as the amount of solar power generation increases. In this interval, the increase in the output of the ALK electrolysis is prioritized.

[0160] The interval t1 to t2 is the range for reaching the rated output of the ALK electrolysis, during which the ALK electrolysis reaches its rated output and is maintained without further output increase. In this range, the output fluctuation of the ALK electrolysis is minimized.

[0161] The interval t2 to t3 is a fluctuation response interval for PEM electrolysis, and fluctuations in solar power generation are mainly handled by PEM electrolysis. PEM electrolysis responds quickly to output fluctuations and maintains the output of ALK electrolysis constant.

[0162] The interval t3 to t4 is the additional response interval for ALK electrolysis after the maximum output of PEM electrolysis is reached. When the PEM electrolysis reaches its maximum output (PEM_max), if the amount of solar power generation increases further, ALK electrolysis responds additionally. The output of ALK electrolysis may increase again.

[0163] Sections t4 to t5 are PEM electrolysis output reduction sections, during which the output of the PEM electrolysis is reduced first as the amount of solar power generation decreases. The reduction of the PEM electrolysis output is carried out quickly, while the output of the ALK electrolysis is maintained.

[0164] The interval t5 to t6 is an additional response interval for ALK electrolysis after the minimum output of PEM electrolysis is reached. When the PEM electrolysis reaches its minimum output (PEM_min), if the solar power generation decreases further, the ALK electrolysis further reduces its output. The output of the ALK electrolysis can be reduced as needed.

[0165] The interval t6 to t7 is the final stabilization period, during which, when solar power generation increases again, the PEM electrolysis and ALK electrolysis cooperate to adjust the output. During this stage, the output fluctuation of the PEM electrolysis mainly occurs, while the fluctuation of the ALK electrolysis is minimized.

[0166] In other words, when output increases, the output of the ALK electrolysis is first increased to its maximum value, and the PEM electrolysis responds to additional fluctuations. When output decreases, the output of the PEM electrolysis is reduced first, and the output of the ALK electrolysis is reduced if necessary. This minimizes frequent output fluctuations of the ALK electrolysis, thereby enhancing system stability. By rapidly responding to output fluctuations of the PEM electrolysis, it is possible to effectively manage the variability of solar power generation, reduce dependence on ESS, and maximize hydrogen production efficiency.

[0167] FIG. 13 is a graph illustrating the control concept of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0168] In relation to the determination of output change of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention, the determination of output change of the water electrolysis operation control system linked with renewable energy production power is based on composite control, and in this case, the output difference is based on the difference between the PV power and the total output of the ALK / PEM water electrolysis.

[0169] At t1, at the output change judgment point ①, the output target value ② is set (Tar_t1), and as the current output ③ of the ALK electrolysis is less than or equal to ALK_max④ as needed to increase the electrolysis output, the ALK electrolysis is first increased to the target value⑤.

[0170] At t2, since Tar_t2⑥ is greater than or equal to ALK_max④, ALK is raised to maximum output⑦, and the PEM water electrolysis output is increased⑧ by the shortfallⓐ compared to the target.

[0171] At t3, since the ALK water electrolysis is already at maximum output state⑦, the PEM water electrolysis output is increased⑩ by the shortfallⓑ compared to Tar_t3⑨.

[0172] At t4, since a decrease in output is required, ALK is maintained in the Max state and the PEM water electrolysis output is reduced.

[0173] At t5, a decrease in output of ⓓ is required, but since it is necessary to respond to the minimum output of PEM water electrolysis ⑭ or less, the ALK water electrolysis output is reduced ⑮ by the additional amount of reduction required ⓕ.

[0174] At t6, the required output increase is met by PEM water electrolysis (ALK maintains output and minimizes fluctuations).

[0175] At t7, to reach Tar_t7?, it is necessary to increase the PEM water electrolysis output above the maximum output. The increase in PEM maximum output ⓘ and the additional increase required ⓙ are handled by ALK water electrolysis.

[0176] At the point of output change determination in Fig. 13, the combined control is based on the difference between the PV power and the total output of the ALK / PEM electrolysis system. This means that the system adjusts the output of the ALK and PEM electrolysis systems according to the fluctuation of the amount of solar power generated (PV power) among renewable energy.

[0177] Regarding output increase, when solar power generation increases, the output of the ALK electrolysis is prioritized to be increased to the maximum, and if an additional increase in output is required, the output of the PEM electrolysis is increased.

[0178] Regarding output reduction, when solar power generation decreases, the output of the PEM electrolytic is reduced first, and when the PEM electrolytic reaches its minimum output, the output of the ALK electrolytic is reduced to respond.

[0179] In Fig. 13, the change in output is determined by the difference between the PV power and the total output of the ALK / PEM electrolysis. Regarding the setting of target outputs (Tar_t1, Tar_t2, etc.), the output of the electrolysis system is adjusted by setting target output values ​​at each point in time. Regarding output increase and decrease, the variability of renewable energy generation is addressed through the output fluctuations of the ALK electrolysis and PEM electrolysis. Therefore, Fig. 11 illustrates a composite control method based on the difference between the PV power and the total output of the ALK / PEM electrolysis to address the variability of renewable energy generation.

[0180] The operation of each time interval in Fig. 13 is explained as follows.

[0181] The interval t0 to t1 is the ALK electrolysis output increase interval. As solar power generation increases, the current output of the ALK electrolysis is below the maximum output (ALK_max). Accordingly, the output of the ALK electrolysis is increased to the target value (Tar_t1). As a result, the increase in the output of the ALK electrolysis is prioritized. At the point of determining the output change, the output target value (Tar_t1) is set, and an increase in the electrolysis output is required. Since the current output of the ALK electrolysis is below ALK_max, the ALK electrolysis is increased to the target value first.

[0182] Next, the interval t1 to t2 is the interval for reaching the rated output of the ALK electrolysis. The output of the ALK electrolysis has reached its maximum value (ALK_max). Accordingly, the output of the PEM electrolysis is increased. As a result, the PEM electrolysis compensates for the insufficient output. Since the target output (Tar_t2) is greater than or equal to ALK_max, ALK rises to its maximum output, and the output of the PEM electrolysis increases by the amount short of the target.

[0183] The interval t2 to t3 is the interval for responding to fluctuations in the PEM electrolysis. The ALK electrolysis is already in a maximum output state, and the PEM electrolysis is responding to the fluctuations. Accordingly, the output of the PEM electrolysis is increased. As a result, the PEM electrolysis responds to additional fluctuations. Since the ALK electrolysis is already in a maximum output state, the output of the PEM electrolysis is increased by the amount that is short of the target output (Tar_t3).

[0184] Sections t3 to t4 are the sections where the PEM electrolytic is reduced first when output reduction is necessary. A drop in output is required. Accordingly, the ALK electrolytic maintains its maximum output state and reduces the output of the PEM electrolytic. As a result, the output reduction of the PEM electrolytic is achieved rapidly. Since a drop in output is required, ALK continues to maintain its maximum state and reduces the output of the PEM electrolytic.

[0185] The interval t4 to t5 is the interval for additional response by ALK electrolysis when the minimum output of PEM electrolysis is reached. The output of PEM electrolysis has reached the minimum output (PEM_min). Accordingly, when further reduction is required, the output of ALK electrolysis is reduced. As a result, ALK electrolysis responds to the additional reduction. Since further reduction is required even after PEM electrolysis has reached the minimum output, the output of ALK electrolysis is reduced.

[0186] The interval t5 to t6 is the response interval for power increase using PEM electrolysis. Power increase is required. Accordingly, the output of the PEM electrolysis is increased. As a result, the PEM electrolysis responds to variability. When a power increase is needed, the PEM electrolysis responds, while the ALK electrolysis maintains the output to minimize fluctuation.

[0187] Sections t6 to t7 are the sections where the ALK electrolysis is additionally supported after the maximum output of the PEM electrolysis is reached. The target output (Tar_t7) exceeds the maximum output (PEM_max) of the PEM electrolysis. Accordingly, the output of the PEM electrolysis is increased to its maximum value, and the ALK electrolysis supports the additional required output. As a result, the target output is achieved through the cooperation of the ALK electrolysis and the PEM electrolysis. To reach the target output (Tar_t7), it is necessary to increase the output beyond the maximum output of the PEM electrolysis, and even after the maximum output of the PEM electrolysis is increased, the ALK electrolysis supports the additional increase required.

[0188] That is, in a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention, when the output increases, the output of the ALK water electrolysis is initially increased to the maximum value, and when the ALK water electrolysis reaches the rated output, the PEM water electrolysis responds to additional fluctuations.

[0189] When reducing output, the output of the PEM electrolytic is reduced first, and when the PEM electrolytic reaches minimum output, the output of the ALK electrolytic is reduced.

[0190] Furthermore, upon final stabilization, the ALK electrolysis handles any additional fluctuations after the PEM electrolysis reaches maximum output. System stability is maintained by minimizing fluctuations in the ALK electrolysis.

[0191] FIG. 14 is a flowchart of the control logic of a water electrolysis operation control system linked with renewable energy production power according to one embodiment of the present invention.

[0192] The control concept of the water electrolysis operation control system linked with renewable energy generation power according to the present embodiment prioritizes increasing the output of the ALK water electrolysis to reach maximum output and produce hydrogen, and subsequently increases or responds to output fluctuations through PEM water electrolysis. If the load cannot be met by PEM alone, the shortfall is compensated by the ALK water electrolysis. At this time, the improvement over the control logic described in FIGS. 8 and 9 is that even if the ALK is not at maximum output, the current output is continuously maintained while additional support is provided by PEM. In this way, hydrogen production can be maximized while minimizing output fluctuations of the ALK water electrolysis.

[0193] As illustrated in FIG. 14, in the ALK priority increase & ALK_max initial arrival completion step (S1), the water electrolysis operation control system linked with solar power generation power according to the present embodiment (hereinafter referred to as the system) first increases the output of the ALK water electrolysis to a maximum value (ALK_max) and completes the initial arrival.

[0194] Next, S2 calculates the required amount of change to the target output value. In this step, the system calculates the necessary amount of output change by comparing the current solar power generation (PV power) with the target output. This value is denoted as Target_dp.

[0195] In S3, the system checks if Target_dp is greater than 0. This is a step to determine whether an output increase is required. If the result of S3 is (Yes), an output increase is required, so the process proceeds to the next step. If the result of S3 is (No), an output reduction is required, so the process switches to Ramp-down logic.

[0196] At S4, check if Target_dp > ALK_max + PEM_max. If an output increase is required, the system checks if Target_dp is greater than the sum of ALK_max and PEM_max.

[0197] If the result of S4 is (Yes), set the maximum output targets for ALK water electrolysis and PEM water electrolysis. ALK Target = ALK_max, PEM Target = PEM_max. If the result of S4 is (No), proceed to the next step.

[0198] In S5, the system checks whether Target_dp can be met by PEM water electrolysis alone. If the result of S5 is (Yes), the output target of the PEM water electrolysis is set (PEM Target = Target_dp). If the result of S5 is (No), proceed to the next step.

[0199] In S6, if output reduction is required, the system checks if Target_dp is less than the sum of ALK_min and PEM_min. If the result of S6 is (Yes), the minimum output targets for ALK water electrolysis and PEM water electrolysis are set (ALK Target = ALK_min, PEM Target = PEM_min). If the result of S6 is (No), the process proceeds to the next step.

[0200] In S7, the system checks whether the PEM electrolysis alone can meet Target_dp. If the result of S7 is (Yes), the output target for the PEM electrolysis is set (PEM Target = Target_dp). If the result of S7 is (No), targets are set for the ALK electrolysis and PEM electrolysis respectively to cover the shortfall (PEM Target = PEM_min, ALK Target = increase by the shortfall).

[0201] The control logic flowchart of Fig. 14 shows the logic for adjusting the output of the ALK and PEM water electrolysis systems according to fluctuations in renewable energy (solar power) generation.

[0202] Here, as previously mentioned, although solar power was cited as an example among renewable energy sources, combinations of renewable energy sources such as wind and wave power generation (e.g., wind + solar, solar + wave... combinations of renewable energy) are possible.

[0203] The system according to the present embodiment first increases the output of the ALK electrolysis to its maximum value and adjusts the output of the PEM electrolysis as needed. When an increase in output is required, the PEM electrolysis responds first, and the ALK electrolysis compensates for the shortfall. Conversely, when an output reduction is required, the output of the PEM electrolysis is reduced first, and when the PEM electrolysis reaches its minimum output, the output of the ALK electrolysis is reduced.

[0204] The water electrolysis operation control system linked with renewable energy production power according to the present invention is applicable to hydrogen production plants linked to renewable energy sources such as solar, wind, and wave power, as well as energy storage and supply infrastructure, and thus has industrial applicability.

Claims

1. A water electrolysis system (100) that produces hydrogen by receiving power from a renewable energy generation system and It includes a control unit (200) that controls the output of the above-mentioned water electrolysis system, and The above-described control unit is characterized by controlling the output of the electrolysis system, controlling the fixed time interval, controlling the fixed output interval, and combining the fixed time interval control and the fixed output interval control according to the variability of the renewable energy generation amount, thereby controlling the output of the electrolysis system. This describes a water electrolysis operation control system linked to renewable energy production power.

2. In Paragraph 1, The above-mentioned water electrolysis system produces hydrogen by receiving power from a renewable energy generation system and includes an alkaline water electrolysis system and a proton exchange membrane (PEM) water electrolysis system. The above-described control unit is a water electrolysis operation control system linked to a renewable energy generation system, characterized by prioritizing the increase of the output of the ALK water electrolysis system to the maximum value when the output increases according to the variability of the renewable energy generation amount, and increasing the output of the PEM water electrolysis system when the ALK water electrolysis system reaches the maximum output.

3. In Paragraph 1 or 2, The above control unit A water electrolysis operation control system linked to a renewable energy generation system, characterized by including an output increase adjustment module (210) that, when an output increase is required due to the variability of renewable energy generation, first increases the output of the ALK water electrolysis system to the maximum level, and after the ALK water electrolysis system reaches the maximum output, adjusts the output of the PEM water electrolysis system to compensate for the insufficient output.

4. In Paragraph 1, The above control unit A water electrolysis operation control system linked to a renewable energy generation system, characterized by including an output reduction adjustment module (220) that first reduces the output of the PEM water electrolysis system when reducing output according to the variability of the renewable energy generation amount, and reduces the output of the ALK water electrolysis system when the PEM water electrolysis system reaches a minimum output.

5. In any one of paragraphs 1 through 4, The above-mentioned electrolysis system comprises one or more of an alkaline electrolysis system (ALK), a proton exchange membrane (PEM) electrolysis system, and a high-temperature electrolysis system (solid oxide electrolysis cell, SOEC), and the above-mentioned control unit is characterized by independently controlling the increase and decrease in output according to the characteristics of each electrolysis system based on the variability of renewable energy generation, or by combining them to produce hydrogen, in a water electrolysis operation control system linked to a renewable energy generation system.

6. In Paragraph 1, The above control unit A water electrolysis operation control system linked to a renewable energy generation system, characterized by including a time interval adjustment module (230) that sets a target output value of the water electrolysis system at regular time intervals and adjusts the target output value of the water electrolysis system according to the amount of solar power generated at each set time interval.

7. In Paragraph 1, The above control unit A water electrolysis operation control system linked to a renewable energy generation system, characterized by including an output interval adjustment module (240) that sets an output target value of the water electrolysis system at a fixed output interval according to the variability of the renewable energy generation amount, and resets the output target value whenever the difference between the solar power generation output and the water electrolysis system output reaches a preset maximum range.

8. In Paragraph 1, The above control unit A water electrolysis operation control system linked to a renewable energy generation system, characterized by including a composite adjustment module (250) that combines a constant time interval control that changes the output target value of the water electrolysis system at set time intervals and a constant output interval control that changes the output target value of the water electrolysis system whenever the difference between the renewable energy generation output and the water electrolysis system output reaches a preset maximum range, so that the water electrolysis system responds to the variability of the renewable energy generation amount.

9. In Paragraph 1, A water electrolysis operation control system linked with renewable energy production power, characterized in that the above-described water electrolysis system receives power generated from a combination of two or more renewable energy sources among solar power generation, wind power generation, and wave power generation, and the above-described control unit controls the output of the water electrolysis system by considering the characteristics and variability of each power source in real time.

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