Distributed power systems

Abstract

To disclose an example of a distributed power supply system using hydrogen of low system dependency.SOLUTION: An EMS 11 can execute a "rising DR control mode" and a "dropping DR control mode". The "rising DR control mode" is a control mode that purchases a system power in the case where a "request for rising DR that a power consumption is increased" as a demand response is made, and there is a storage residual in a hydrogen storage device 9, and generates hydrogen in a hydrogen generation device 7. The "dropping DR control mode" is a control mode that supplies a power to be generated in a fuel cell device 5 by using hydrogen stored in the hydrogen storage device 9 in the case where the request for dropping DR that the power consumption is suppressed" as a demand response is made. Thus, the distributed power supply system can execute the "rising DR control mode" based on the "rising DR", and the "dropping DR control mode" based on the "dropping DR". Thus, the distributed power supply system can be effectively used while corresponding to the demand request.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a distributed power system using renewable energy.

Background Art

[0002] For example, Patent Document 1 describes that "a hydrogen production device that produces hydrogen using the power generated by a solar power generation device, a hydrogen storage alloy tank that stores the hydrogen, and a fuel cell that generates power using the hydrogen, and performs solar power generation output prediction from weather information to control the hydrogen production device and the fuel cell".

Prior Art Documents

Patent Documents

[0003]

Patent Document No. 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure discloses an example of a distributed power system that utilizes hydrogen with low grid dependence.

Means for Solving the Problems

[0005] The distributed power system preferably includes at least one of the following components, for example.

[0006] That is, the component is a hydrogen production device (7) that generates hydrogen using electrolysis of water, a hydrogen storage device (9) that stores the hydrogen generated by the hydrogen production device (7), a fuel cell device (5) that can generate power using an electrochemical reaction between hydrogen and oxygen, and a control unit (11) that can control the operations of the hydrogen production device (7) and the fuel cell device (5) according to demand response, and the control unit (11) that can execute an "up DR control mode" and a "down DR control mode".

[0007] The "upward DR control mode" is a control mode in which, when a "request to increase power consumption" is made as a demand response, and there is storage capacity in the hydrogen storage device (9), that is, when it is possible to store more hydrogen in the hydrogen storage device (9), grid power is purchased and hydrogen is produced in the hydrogen generator (7).

[0008] The "downward DR control mode" is a control mode in which, when a "request to reduce electricity consumption" is made as a demand response, electricity generated by the fuel cell device (5) using hydrogen stored in the hydrogen storage device (9) is supplied.

[0009] This enables the distributed power system to implement both an "upward demand response" control mode and a "downward demand response" control mode. Therefore, it becomes possible to effectively utilize the distributed power system while responding to demand.

[0010] Incidentally, the symbols in each of the parentheses above are just examples showing the correspondence with the specific configurations etc. described in the embodiments described later, and this disclosure is not limited to the specific configurations etc. indicated by the symbols in the parentheses above. [Brief explanation of the drawing]

[0011] [Figure 1] This is a diagram showing a distributed power supply system according to the first embodiment. [Figure 2] A and B are graphs showing electricity supply and demand. [Figure 3] This chart shows changes in solar power, the amount of electricity generated by fuel cell device 5, and the amount of hydrogen stored. [Modes for carrying out the invention]

[0012] The following "Embodiments of the Invention" are examples of embodiments that fall within the technical scope of this disclosure. In other words, the features defining the invention as described in the claims are not limited to the specific configurations and structures shown in the embodiments below. The distributed power system shown in this disclosure comprises at least the components that are indicated by reference numerals and described herein.

[0013] (First Embodiment) <1. Configuration of the distributed power system> As shown in Figure 1, the distributed power system 1 according to this embodiment includes at least a photovoltaic power generation device 3, a power conditioner 3A, a fuel cell device 5, a hydrogen generator 7, a hydrogen tank 9, and an energy management device (hereinafter referred to as EMS) 11.

[0014] The solar power generation device 3 is an example of a power generation device that utilizes sunlight as a renewable energy source. The power conditioner (Power Conditioning System; hereinafter abbreviated as PCS) 3A controls the power generation operation of the solar power generation device 3 and converts the generated electricity into alternating current at a predetermined voltage.

[0015] Furthermore, the PCS3A in this embodiment performs "Maximum Power Point Tracking control." Maximum Power Point Tracking control is a method of controlling the system so that the output is maximized during power generation.

[0016] The hydrogen generator 7 generates hydrogen using electricity generated by the solar power generation device 3 (hereinafter referred to as solar power). Specifically, the hydrogen generator 7 generates hydrogen by electrolyzing water into hydrogen and oxygen using solar power.

[0017] The hydrogen tank 9 is an example of a hydrogen storage device that stores hydrogen produced by the hydrogen generator 7. The fuel cell device 5 generates electricity using the electrochemical reaction between hydrogen and oxygen. Specifically, the fuel cell device 5 generates electricity using the hydrogen stored in the hydrogen tank 9 and oxygen from the air.

[0018] EMS11 is an example of a control unit that controls the operation of the distributed power system 1. Specifically, EMS11 controls the operations of at least the fuel cell device 5, the hydrogen generation device 7, the PCS 3A, and the like.

[0019] The EMS11 according to this embodiment is configured by a computer having a CPU, a ROM, a RAM, and the like. Then, when software is executed by the CPU, the following FC control and the like are realized. The software is stored in advance in a non-volatile storage unit such as a ROM.

[0020] <2. Control Operations of EMS> <2.1 FC Control> EMS11 can execute control of the fuel cell device 5 (hereinafter referred to as FC control). FC control is control using a value obtained by subtracting the power consumption on the load side (hereinafter also referred to as demand power) from the power generation amount of the solar power generation device 3 (hereinafter referred to as supply-demand difference ΔD).

[0021] Note that EMS11 grasps the power generation amount of the solar power generation device 3 by using a signal from the PCS 3A. The distributed power system 1 can supply power to the load side from at least one of the grid power, the solar power generation device 3, and the fuel cell device 5.

[0022] In FC control, any one of the first FC control, the second FC control, and the third FC control is executed. The first FC control is control executed when the supply-demand difference ΔD is a negative value, and supplies the power generated by the fuel cell device 5 to the load side.

[0023] That is, in the first FC control, power is supplied to the load side from at least the solar power generation device 3 and the fuel cell device 5. When the demand power cannot be covered by the power supplied from the solar power generation device 3 and the fuel cell device 5, grid power is also supplied.

[0024] The second FC control is a control that is executed when the supply-demand difference ΔD is less than or equal to a predetermined positive value, and is a control that stops the power generation of the fuel cell device 5 while maintaining the activity of the electrode catalyst of the fuel cell device 5.

[0025] In other words, the second FC control is executed when the power supplied by the solar power generation device 3 is sufficient to meet the power demand. If the power supplied by the solar power generation device 3 is no longer sufficient to meet the power demand, the fuel cell device 5 is started up, and power is supplied from the fuel cell device 5 as well.

[0026] The third FC control is a control that is executed when the supply-demand difference ΔD is greater than a predetermined positive value, and it is a control that stops the power generation of the fuel cell device 5 without maintaining the activity of the fuel cell device 5.

[0027] Therefore, when the third FC control is executed, even if the EMS 11 issues a start command for the fuel cell device 5, the fuel cell device 5 cannot immediately start generating power. Accordingly, the "predetermined positive value" mentioned above is a value that takes into account the time required from the start command for the fuel cell device 5 until power generation begins.

[0028] Furthermore, if the supply-demand difference ΔD is negative, the EMS11 supplies all the electricity generated by the solar power generation device 3 to the load side, and has the fuel cell device 5 supply any remaining power to the load side. If there is still a power shortage even after the fuel cell device 5 starts supplying power, grid power will also be supplied.

[0029] If the supply-demand difference ΔD is positive, the EMS 11 generates hydrogen in the hydrogen generator 7 and stores the generated hydrogen in the hydrogen tank 9. The EMS 11 continues generating and storing hydrogen until the hydrogen tank 9 reaches its maximum storage level.

[0030] <2.2 Demand Response Control (DR Control)> Demand response control is a control system based on requests (demand response) from power companies, etc. These demand responses from power companies include what are known as "upward DR" and "downward DR."

[0031] Incidentally, "upward DR" refers to a demand response that increases electricity consumption when the supply of electricity is greater than the demand. "Downward DR" refers to a demand response that reduces electricity consumption when the demand for electricity is high and there is a risk of electricity shortage.

[0032] Furthermore, the EMS11 according to this embodiment can execute an "upward DR control mode" based on "upward DR" and a "downward DR control mode" based on "downward DR" as demand response control.

[0033] <Upward DR control mode> The upward DR control mode is a control mode that is executed when a "request to increase power consumption (upward DR)" is made as a demand response. If there is storage capacity in the hydrogen tank 9, this control mode purchases grid power and generates hydrogen in the hydrogen generator 7.

[0034] In other words, when the up-DR control mode is in operation, hydrogen production is carried out using at least grid power. To put it another way, when the up-DR control mode is in operation, hydrogen production is carried out using grid power and solar power, or hydrogen production is carried out using grid power alone.

[0035] In this embodiment, the EMS11 controls the system to supply as much of the power demand as possible using solar power. Therefore, the grid power purchased is the sum of the power required by the hydrogen generator 7 and the power demanded, minus the amount of solar power (see Figure 2A).

[0036] <Down DR control mode> The downward DR control mode is a control mode that is executed when a "request to reduce power consumption (downward DR)" is made as a demand response, and it is a control that supplies electricity generated by the fuel cell device 5 using hydrogen stored in the hydrogen tank 9 to the load side.

[0037] In other words, when the down-DR control mode is executed, if solar power alone cannot meet the power demand, the fuel cell device 5 supplies power to the load side, thereby reducing the amount of grid power purchased (see Figure 2B). If the sum of solar power and the power supplied by the fuel cell device 5 is sufficient to meet the power demand, the EMS 11 does not purchase grid power.

[0038] <3. Features of the distributed power system according to this embodiment> The distributed power system 1 according to this embodiment is capable of executing an "upward DR control mode" based on "upward DR" and a "downward DR control mode" based on "downward DR". Therefore, it is possible to effectively utilize distributed power sources such as solar power generation equipment 3 while responding to demand.

[0039] In the distributed power system 1 according to this embodiment, hydrogen is generated using solar power, and this hydrogen is used to generate electricity in the fuel cell device 5. In other words, in the distributed power system 1 according to this embodiment, hydrogen generated with surplus power from the solar power generation device 3 can be used as a backup power source via the fuel cell device 5.

[0040] In the distributed power system 1, if the supply-demand difference ΔD is less than or equal to a predetermined positive value, the power generation of the fuel cell device 5 is stopped while maintaining the activity of the electrode catalyst of the fuel cell device 5 (hereinafter referred to as the standby state).

[0041] As a result, even if the solar power generation device 3 is unable to supply enough electricity to meet the demand, the fuel cell device 5 can immediately supply power to the load side because it is in a standby state.

[0042] In the distributed power system 1, if the supply-demand difference ΔD is greater than a predetermined positive value, the power generation of the fuel cell device 5 is stopped without maintaining the standby state. This reduces the power consumption required to maintain the standby state.

[0043] In the distributed power system 1, when the supply-demand difference ΔD is a negative value, all of the electricity generated by the photovoltaic power generation device 3 is supplied to the load side, thus suppressing an increase in the amount of electricity supplied to the load side from the grid power.

[0044] Furthermore, if the supply-demand difference ΔD is a positive value, the EMS 11 generates hydrogen in the hydrogen generator 7 and stores the generated hydrogen in the hydrogen tank 9, thereby enabling effective use of the surplus electricity from the solar power generation device 3.

[0045] (Second Embodiment) The EMS11 according to this embodiment controls the operation of the distributed power system 1 while forecasting the consumption of electricity demand, forecasting (planning) the amount of electricity generated and hydrogen produced (hydrogen stored) by the fuel cell device 5 based on weather data, and forecasting requests for "upward demand response" or "downward demand response" from power companies, etc.

[0046] Figure 3 is a chart showing the changes in solar power, the amount of power generated by the fuel cell device 5, and the amount of hydrogen stored when the above prediction function is executed. As shown in Figure 3, the EMS 11 changes the solar power, the amount of power generated by the fuel cell device 5, and the amount of hydrogen stored in response to "upward demand response" or "downward demand response" from the power company.

[0047] (Other embodiments) The hydrogen storage device according to the above embodiment consisted of a hydrogen tank 9 for storing compressed hydrogen. However, the disclosure is not limited thereto. That is, the disclosure may also include, for example, a hydrogen storage device having a hydrogen storage alloy, or a hydrogen tank for storing liquefied hydrogen.

[0048] Furthermore, in a configuration for storing hydrogen using a hydrogen storage alloy, it is desirable that the hydrogen storage alloy be in a detachable cartridge system, and that the hydrogen storage alloy cartridge be easily replaceable.

[0049] The hydrogen storage device according to the above embodiment was configured to store hydrogen produced by the hydrogen generator 7. However, this disclosure is not limited thereto. That is, the disclosure may also be configured to be able to fill with hydrogen produced by other hydrogen generators, for example.

[0050] In other words, if the operating time of the hydrogen generator 7 decreases due to insufficient sunlight or other reasons, the configuration may compensate for the decrease in power generation from the solar power generation device 3 by filling it with hydrogen produced by another hydrogen generator.

[0051] The EMS11 according to the above embodiment determined the amount of power generated by the photovoltaic power generation system 3 using signals from the PCS3A. However, this disclosure is not limited thereto. That is, the disclosure may, for example, predict and determine the amount of power generated by the photovoltaic power generation system 3 by considering solar radiation forecasts in addition to signals from the PCS3A.

[0052] In the embodiments described above, the heat generated by the fuel cell device 5 was not utilized. However, this disclosure is not limited thereto. That is, the disclosure may, for example, store the heat generated by the fuel cell device 5 and use that heat for other purposes.

[0053] In the embodiments described above, a solar power generation system was used as the power generation system utilizing renewable energy. However, this disclosure is not limited to this. That is, the disclosure may also use, for example, a wind power generation system or a geothermal power generation system as the power generation system utilizing renewable energy.

[0054] In the embodiment described above, all of the surplus electricity generated by the solar power generation device 3 was used to produce hydrogen. However, this disclosure is not limited to this. That is, the disclosure may also include a configuration in which, for example, a portion of the surplus electricity is stored in a battery or capacitor.

[0055] The fuel cell device 5 according to the above embodiment generated electricity using oxygen from the air. However, the disclosure is not limited thereto. That is, the disclosure may, for example, include an oxygen storage device that stores the oxygen generated when hydrogen is produced in the hydrogen generator 7, and generate electricity using the oxygen stored in the oxygen storage device.

[0056] Furthermore, this disclosure is not limited to the embodiments described above, but is sufficient to be consistent with the intent of the disclosures described in the embodiments described above. Therefore, it may be a configuration in which at least two of the embodiments described above are combined, or a configuration in which any of the illustrated components or components described with reference numerals in the embodiments described above are omitted. [Explanation of symbols]

[0057] 1… Distributed power system 3… Solar power generation equipment 3A… Power Conditioner 5… Fuel cell device 7… Hydrogen generator 9… Hydrogen tank 11…EMS

Claims

[Claim 1] Solar power generation equipment that uses sunlight as a renewable energy source, A hydrogen generation device that generates hydrogen using electricity generated by the aforementioned solar power generation device, A hydrogen storage device for storing hydrogen produced in the aforementioned hydrogen generator, A fuel cell device capable of generating electricity using the electrochemical reaction between hydrogen and oxygen, A control unit capable of controlling the operation of the hydrogen generator and the fuel cell device in response to demand, comprising a control unit capable of control using a value obtained by subtracting the power consumption on the load side (hereinafter referred to as demand power) from the amount of power generated by the solar power generation device (hereinafter referred to as supply-demand difference) (hereinafter referred to as FC control), The control unit, In the event of a "request to increase electricity consumption" in response to demand, and if there is storage capacity in the hydrogen storage device, the system will enter an "upward DR control mode" in which grid power is purchased and hydrogen is produced in the hydrogen generation device, and In response to demand, if a "request to reduce electricity consumption" is made, a "downward DR control mode" can be implemented, which supplies electricity generated by the fuel cell system using the hydrogen stored in the hydrogen storage system. Furthermore, the control unit, A first FC control in which power is supplied to the load side from at least the solar power generation device and the fuel cell device, and when the power supplied from the solar power generation device and the fuel cell device is no longer sufficient to meet the power demand, grid power is also supplied in the first FC control. A second FC control that is executed when the supply-demand difference is less than or equal to a predetermined positive value, the second FC control that stops power generation of the fuel cell device while maintaining the activity of the electrode catalyst of the fuel cell device, and A distributed power system capable of performing a third FC control, which is executed when the supply-demand difference is greater than a predetermined positive value, and which stops the power generation of the fuel cell device without maintaining the activity of the fuel cell device.

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