Hydrogen production system and hydrogen production method

Abstract

To provide a hydrogen production system capable of preventing a water electrolysis apparatus from failing even when electric power generated by renewable energy decreases abruptly.SOLUTION: A hydrogen production system 10 according to the present disclosure produces hydrogen using electric power generated by renewable energy. The hydrogen production system 10 comprises a water electrolysis apparatus 13 that electrolyzes water to produce hydrogen, an electricity storage device 12 that is chargeable by the electric power and is capable of supplying the charged electric power to the water electrolysis apparatus 13, and a control device 14 that controls the electricity storage device 12. When the electric power supplied to the water electrolysis apparatus 13 decreases at a speed exceeding a maximum rate of change of an operating power of the water electrolysis apparatus 13, the control device 14 causes the electricity storage device 12 to supply electric power to compensate for the shortage to the water electrolysis apparatus 13.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a hydrogen production system and a hydrogen production method. [Background technology]

[0002] BACKGROUND ART Conventionally, a hydrogen production system that produces hydrogen using electricity generated by renewable energy is known.

[0003] For example, Patent Document 1 discloses a hydrogen production system that produces hydrogen using power generated by solar cells. The hydrogen production system disclosed in Patent Document 1 charges a storage battery with surplus power during the day and supplies the power from the storage battery to a hydrogen production device at night. Generally, when using a storage battery to compensate for power when the output of renewable energy decreases, a large-capacity storage battery is required. Furthermore, Patent Document 1 does not mention concerns that may arise when the rate of fluctuation in power generated by renewable energy exceeds the maximum rate of fluctuation in the operating power of the water electrolysis device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-48207 Summary of the Invention [Problem to be solved by the invention]

[0005] A water electrolysis device that produces hydrogen by electrolyzing water can vary its operating power in response to the amount of power supplied. When a water electrolysis device is operated using power generated by renewable energy, a decrease in the power generated by renewable energy causes a corresponding decrease in the operating power of the water electrolysis device.

[0006] In this case, if the power generated by renewable energy decreases at a rate that exceeds the maximum fluctuation rate of the operating power of the water electrolysis device, the interlock setting of the water electrolysis device may trigger an emergency shutdown, which may unintentionally result in a loss of opportunities to produce hydrogen.Furthermore, frequent emergency shutdowns and excessive fluctuation rates may cause mechanical failures in peripheral equipment and damage to components of the water electrolysis device, which may lead to a breakdown of the water electrolysis device.

[0007] In view of the above circumstances, an object of the present disclosure is to provide a hydrogen production system and a hydrogen production method that can prevent a water electrolysis device from breaking down even when power generated by renewable energy suddenly drops. [Means for solving the problem]

[0008] That is, the present invention is as follows. [1] A hydrogen production system that produces hydrogen using electricity generated by renewable energy, a water electrolysis device that electrolyzes water to produce hydrogen; an electricity storage device that can be charged with the generated power and that can supply the stored power to the water electrolysis device; a control device that controls the power storage device; Equipped with When the generated power supplied to the water electrolysis device decreases at a rate exceeding a maximum fluctuation rate of the operating power of the water electrolysis device, the control device causes the power storage device to supply the shortfall in power to the water electrolysis device. [2] [1] The hydrogen production system according to [1], When the generated power supplied to the water electrolysis device increases at a rate that exceeds the maximum fluctuation rate of the operating power of the water electrolysis device, the control device stores the excess power in the power storage device. [3] In the hydrogen production system according to [1] or [2], The capacity of the power storage device is The power consumption is equal to or greater than 0.5 times the reference power consumption and equal to or less than 5 times the reference power consumption. The reference amount of power is calculated by the following formula (1):

number

[10] [9] The hydrogen production method according to a step of storing excess power in the power storage device when the generated power supplied to the water electrolysis device increases at a rate that exceeds the maximum fluctuation rate of the operating power of the water electrolysis device. [Effects of the Invention]

[0009] The hydrogen production system and hydrogen production method according to the present disclosure can prevent breakdown of the water electrolysis device even if the power generated by renewable energy suddenly drops. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a hydrogen production system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an example of power generated by renewable energy and operating power of a water electrolysis device. [Figure 3] FIG. 10 is a diagram for explaining a reference amount of power; [Figure 4] FIG. 10 is a diagram showing another example of power generated by renewable energy and operating power of a water electrolysis device. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0012] 1 is a schematic diagram of a hydrogen production system 10 according to one embodiment. The configuration and functions of the hydrogen production system 10 according to one embodiment will be described with reference to FIG.

[0013] The hydrogen production system 10 is a system that produces hydrogen using electricity generated by renewable energy.

[0014] As shown in FIG. 1, a hydrogen production system 10 is supplied with electric power from a power generation device 20 .

[0015] The power generation device 20 is a device that generates power using renewable energy. The power generation device 20 supplies the power generated by renewable energy to the hydrogen production system 10. The renewable energy may be, for example, solar power, wind power, hydroelectric power, geothermal power, or the like.

[0016] The hydrogen production system 10 includes a wattmeter 11, a power storage device 12, a water electrolysis device 13, and a control device 14.

[0017] The power meter 11 is a device that measures the electric power supplied from the power generation device 20 to the hydrogen production system 10. The power meter 11 transmits information on the measured electric power to the control device 14.

[0018] The power storage device 12 can be charged with power supplied from the power generation device 20 to the hydrogen production system 10. The power storage device 12 can also supply the charged power to the water electrolysis device 13. The power storage device 12 may be a power storage device of any configuration, and is configured to include at least one of a battery and a capacitor, for example. Specific examples of the power storage device 12 include batteries such as lithium ion batteries, lead acid batteries, nickel-metal hydride batteries, sodium-sulfur batteries, and redox flow batteries, and capacitors such as electric double layer capacitors and lithium ion capacitors, and the power storage device 12 may be configured by combining a plurality of these. Among these, lithium ion batteries or capacitors are particularly preferred in terms of their storage capacity and charge / discharge speed.

[0019] The water electrolysis device 13 is a device that produces hydrogen by electrolyzing water. The water electrolysis device 13 operates using power supplied from the power generation device 20. The water electrolysis device 13 may be a device of any configuration that is capable of producing hydrogen by electrolyzing water, and may be, for example, an alkaline water electrolysis device.

[0020] The water electrolysis device 13 varies its operating power in response to the power supplied. The power generation device 20 generates power using renewable energy, and therefore the amount of power generated is not constant. Therefore, the power supplied by the power generation device 20 to the water electrolysis device 13 varies over time. Therefore, the operating power of the water electrolysis device 13 also varies over time in response to the power supplied by the power generation device 20 to the water electrolysis device 13.

[0021] The control device 14 is a device that controls the power storage device 12 and the water electrolysis device 13. The control device 14 may be a dedicated computer configured to control the power storage device 12 and the water electrolysis device 13, or may be a general-purpose PC (Personal Computer).

[0022] The control device 14 is capable of communicating with the wattmeter 11, the power storage device 12, and the water electrolysis device 13 via wireless or wired communication. The control device 14 controls the various devices included in the hydrogen production system 10 and the entire hydrogen production system 10.

[0023] The control device 14 acquires information on the electric power supplied from the power generation device 20 to the hydrogen production system 10 from the power meter 11 .

[0024] (Hydrogen production system operation) The operation of the hydrogen production system 10 will be described below using an example in which the power generation device 20 generates power using sunlight. Note that using sunlight to generate power is just one example, and the hydrogen production system 10 operates in the same way even when the power generation device 20 generates power using other renewable energy sources.

[0025] FIG. 2 is a diagram showing an example of the generated power supplied by the power generation device 20 to the hydrogen production system 10 and the operating power of the water electrolysis device 13. As shown in FIG.

[0026] 2, a solid line graph 101 indicates the generated power supplied by the power generation device 20 to the hydrogen production system 10. A dashed line graph 102 indicates the operating power of the water electrolysis device 13.

[0027] 2, the power generation device 20 generates power using sunlight, so the generated power 101 is high during the day and is nearly zero at night.

[0028] The water electrolysis device 13 has a minimum operating power and a maximum operating power. The minimum operating power is the minimum power at which the water electrolysis device 13 can operate. The maximum operating power is the maximum power at which the water electrolysis device 13 can operate. In FIG. 2 , the minimum operating power is represented by Pmin, and the maximum operating power is represented by Pmax. The water electrolysis device 13 operates at an operating power between the minimum operating power and the maximum operating power.

[0029] 2, at time t1, when the generated power 101 supplied by the power generation device 20 to the hydrogen production system 10 reaches the minimum operating power Pmin, the water electrolysis device 13 starts operating. The operating power of the water electrolysis device 13 increases as the generated power 101 increases.

[0030] If power can be supplied to the hydrogen production system 10 not only from the power generation device 20 but also from a commercial power system, the water electrolysis device 13 can be operated even before time t1 by supplying power from the commercial power system to the hydrogen production system 10. Alternatively, the water electrolysis device 13 can be operated before time t1 by supplying power from the power storage device 12 to the water electrolysis device 13. In this case, for example, the water electrolysis device 13 may be operated at the minimum operating power Pmin.

[0031] When the operating power of the water electrolysis device 13 reaches the maximum operating power Pmax, the water electrolysis device 13 cannot operate at an operating power exceeding the maximum operating power Pmax, and therefore the water electrolysis device 13 operates at the maximum operating power Pmax while the supplied power exceeds the maximum operating power Pmax.

[0032] The surplus power obtained by subtracting the operating power of the water electrolysis device 13 from the generated power 101 supplied by the power generation device 20 to the hydrogen production system 10 is supplied to the power storage device 12. While there is surplus power, the power storage device 12 is charged with this surplus power.

[0033] The water electrolysis device 13 has a maximum allowable fluctuation rate for the operating power. If the power supplied to the water electrolysis device 13 decreases at a rate exceeding the maximum fluctuation rate, it may cause mechanical failure of peripheral devices and damage to components of the water electrolysis device 13. Therefore, it is conceivable to control the fluctuation rate of the operating power of the water electrolysis device 13 to impose a limit on the fluctuation rate, or to perform an emergency shutdown of the water electrolysis device 13 by setting an interlock on the water electrolysis device 13. However, frequent and repeated emergency shutdowns may lead to a breakdown of the water electrolysis device 13. Therefore, in the hydrogen production system 10 according to this embodiment, when the generated power supplied from the power generation device 20 to the water electrolysis device 13 decreases at a rate exceeding the maximum fluctuation rate, the control device 14 controls the power storage device 12 to supply the water electrolysis device 13 with power to make up for the shortage, in order to reduce the operating power of the water electrolysis device 13 at a rate equal to or lower than the maximum fluctuation rate, in order to prevent breakdown of the water electrolysis device 13.

[0034] Furthermore, if the power supplied to the water electrolysis device 13 increases at a rate exceeding the maximum fluctuation rate, this may also lead to a breakdown of the water electrolysis device 13. To prevent breakdown of the water electrolysis device 13, when the generated power supplied from the power generation device 20 to the water electrolysis device 13 increases at a rate exceeding the maximum fluctuation rate, the control device 14 can store the excess power in the power storage device 12 in order to increase the operating power of the water electrolysis device 13 at a rate equal to or lower than the maximum fluctuation rate.

[0035] 2, the operating power 102 of the water electrolysis device 13 decreases at the maximum fluctuation rate after time t2 in accordance with the decrease in the generated power 101. Here, after time t2, the generated power 101 decreases at a rate exceeding the maximum fluctuation rate, and the power in the portion indicated by region 103 is insufficient to decrease the operating power of the water electrolysis device 13 at the maximum fluctuation rate.

[0036] When it is determined from the power information obtained from the power meter 11 that the generated power 101 is decreasing at a rate exceeding the maximum fluctuation rate, the control device 14 causes the power storage device 12 to supply the shortfall of power to the water electrolysis device 13. As a result, the water electrolysis device 13 is supplied with power that enables the operating power to be decreased at the maximum fluctuation rate, so that the water electrolysis device 13 can continue to operate without an unintentional emergency shutdown and can also be prevented from breaking down.

[0037] Next, we will consider what capacity the power storage device 12 should have to be so that it can supply the water electrolysis device 13 with the shortfall in power when the power generated by the power generation device 20 and supplied to the hydrogen production system 10 suddenly drops. The capacity of the power storage device 12 is not particularly limited and can be set arbitrarily, taking into account the scale and variable speed of the water electrolysis device 13, and the scale and expected variable speed of the power generation. However, a particularly preferred embodiment will be described below.

[0038] Figure 3 is a diagram showing how the operating power 102 of the water electrolysis apparatus 13 decreases at the maximum fluctuation rate. In the example shown in Figure 3, at time t3, the operating power 102 of the water electrolysis apparatus 13 is the maximum operating power Pmax, decreases from there at the maximum fluctuation rate, and reaches the minimum operating power Pmin at time t4.

[0039] If the generated power supplied from the power generation device 20 to the water electrolysis device 13 decreases at a rate exceeding the maximum fluctuation rate, a power shortage occurs. The most severe power shortage occurs when the generated power drops from Pmax to Pmin in an instant at time t3.

[0040] In this case, the amount of power that needs to be supplied from the power storage device 12 to the water electrolysis device 13 is the amount of power shown in area 104 in Fig. 3. Hereinafter, this amount of power will also be referred to as the "reference amount of power."

[0041] The time from time t3 to time t4 is expressed by the following equation (1).

number

[0042] Therefore, the reference power amount is expressed by the following equation (2).

number

[0043] In reality, the generated power does not drop from Pmax to Pmin in an instant, so the capacity of the power storage device 12 is preferably equal to or greater than approximately 0.5 × the reference power amount. Furthermore, if the capacity of the power storage device 12 is equal to approximately 5 × the reference power amount, even if five sudden drops in generated power occur, the power storage device 12 can sufficiently supply the shortfall in power to the water electrolysis device 13. Therefore, the capacity of the power storage device 12 is preferably equal to or greater than approximately 0.5 × the reference power amount and equal to or less than approximately 5 × the reference power amount.

[0044] For example, even if the capacity of the power storage device 12 is 5× the reference power amount, this capacity is not particularly large. Therefore, the power storage device 12 is economically feasible as a small power storage device. The capacity of the power storage device 12 is determined taking into consideration the expected fluctuation speed and frequency of the generated power and the maximum fluctuation speed of the operating power of the water electrolysis device 13. For the reasons described above, the capacity of the power storage device 12 is more preferably equal to or greater than 0.8× the reference power amount and equal to or less than 3× the reference power amount.

[0045] (Power generation forecast) The control device 14 may predict fluctuations in the power generated by the power generation device 20, and if it predicts that the power generated will decrease at a rate exceeding the maximum fluctuation rate, may reduce the operating power of the water electrolysis device 13 in advance. Alternatively, the control device 14 may predict fluctuations in the power generated by the power generation device 20, and if it predicts that the power generated will increase at a rate exceeding the maximum fluctuation rate, may increase the operating power of the water electrolysis device 13 in advance.

[0046] The control device 14 may predict fluctuations in the power generation based on weather data acquired from, for example, an external server, etc. For example, if the control device 14 acquires weather data indicating that it will rain in a few hours, it can predict that the power generation of the power generation device 20 will drop sharply in a few hours.

[0047] Figure 4 shows how the control device 14 preliminarily reduces the operating power of the water electrolysis device 13. In the example shown in Figure 4, the control device 14 predicts that the generated power 101 will decrease at a rate exceeding the maximum fluctuation rate, and preliminarily reduces the operating power 102 of the water electrolysis device 13 at time t5 before the generated power 101 reaches the maximum operating power Pmax.

[0048] (Priority given to charging the storage device) The control device 14 normally supplies the power supplied from the power generation device 20 to the water electrolysis device 13 with priority to operate the water electrolysis device 13, but when the amount of charge in the power storage device 12 is equal to or less than a predetermined amount of power, the control device 14 may prioritize charging of the power storage device 12 over operation of the water electrolysis device 13.

[0049] The predetermined amount of power may be, for example, a reference amount of power. This allows the power storage device 12 to store an amount of power equal to or greater than the reference amount of power, and to supply the water electrolysis device 13 with power that makes up for the shortfall in power when the power supplied from the power generation device 20 to the water electrolysis device 13 suddenly drops.

[0050] As described above, the hydrogen production system 10 includes the water electrolysis device 13, the power storage device 12, and the control device 14. When the generated power supplied to the water electrolysis device 13 decreases at a rate that exceeds the maximum fluctuation rate of the operating power of the water electrolysis device 13, the control device 14 causes the power storage device 12 to supply the shortfall in power to the water electrolysis device 13. As a result, even if the generated power generated by renewable energy and supplied to the water electrolysis device 13 from the power generation device 20 suddenly decreases, the hydrogen production system 10 according to this embodiment can supply the shortfall in power from the power storage device 12 to the water electrolysis device 13. Therefore, the hydrogen production system 10 according to this embodiment does not perform an emergency shutdown even if the generated power from renewable energy suddenly decreases, and can also prevent the water electrolysis device 13 from breaking down.

[0051] Furthermore, when the generated power supplied to the water electrolysis device 13 increases at a rate exceeding the maximum fluctuation rate of the operating power of the water electrolysis device 13, the control device 14 of the hydrogen production system 10 may store the excess power in the power storage device 12. As a result, even if the generated power generated by renewable energy and supplied to the water electrolysis device 13 from the power generation device 20 increases suddenly, the hydrogen production system 10 according to this embodiment can store the excess power in the power storage device 12. Therefore, even if the generated power from renewable energy increases suddenly, the hydrogen production system 10 according to this embodiment does not perform an emergency shutdown, and can also prevent the water electrolysis device 13 from breaking down.

[0052] Although the above-described embodiments have been described as typical examples, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the present disclosure. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications or alterations are possible without departing from the scope of the claims. [Explanation of symbols]

[0053] 10 Hydrogen production system 11 Power meter 12. Energy storage device 13 Water electrolysis equipment 14 Control device 20 Power generating equipment

Claims

1. A hydrogen production system that produces hydrogen using electricity generated by renewable energy, a water electrolysis device that electrolyzes water to produce hydrogen; an electricity storage device that can be charged with the generated power and that can supply the stored power to the water electrolysis device; a control device that controls the power storage device; Equipped with When the generated power supplied to the water electrolysis device decreases at a rate exceeding a maximum fluctuation rate of the operating power of the water electrolysis device, the control device causes the power storage device to supply the shortfall in power to the water electrolysis device.

2. 2. The hydrogen production system according to claim 1, When the generated power supplied to the water electrolysis device increases at a rate that exceeds the maximum fluctuation rate of the operating power of the water electrolysis device, the control device stores the excess power in the power storage device.

3. 2. The hydrogen production system according to claim 1, The capacity of the power storage device is The power consumption is equal to or greater than 0.5 times the reference power consumption and equal to or less than 5 times the reference power consumption, A hydrogen production system, wherein the reference amount of power is an amount of power calculated by the following formula (1). [Equation 1]

4. 2. The hydrogen production system according to claim 1, The control device predicting fluctuations in the generated power; reducing the operating power of the water electrolysis device in advance when it is predicted that the generated power will decrease at a rate exceeding the maximum fluctuation rate; a hydrogen production system that increases the operating power of the water electrolysis device in advance when it is predicted that the generated power will increase at a rate exceeding the maximum fluctuation rate;

5. 5. The hydrogen production system according to claim 4, The control device predicts fluctuations in the generated power based on meteorological data.

6. 2. The hydrogen production system according to claim 1, When the charge amount of the power storage device is equal to or less than a predetermined amount of power, the control device prioritizes charging of the power storage device over operation of the water electrolysis device.

7. 2. The hydrogen production system according to claim 1, The hydrogen production system, wherein the power storage device includes at least one of a lithium ion battery and a capacitor.

8. 2. The hydrogen production system according to claim 1, The hydrogen production system, wherein the water electrolysis device is an alkaline water electrolysis device.

9. A hydrogen production method for producing hydrogen using electricity generated by renewable energy, comprising: producing hydrogen by electrolyzing water using a water electrolysis device; supplying power to the water electrolysis device from a power storage device to make up for the shortage when the generated power supplied to the water electrolysis device decreases at a rate exceeding a maximum fluctuation rate of the operating power of the water electrolysis device; A method for producing hydrogen, comprising:

10. 10. The hydrogen production method according to claim 9, a step of storing excess power in the power storage device when the generated power supplied to the water electrolysis device increases at a rate that exceeds the maximum fluctuation rate of the operating power of the water electrolysis device.

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