JP2023063851A - power supply system - Google Patents

Abstract

To provide a system capable of supplying power generated by renewable energy to power demand elements in a stable manner.SOLUTION: A power supply system has a power generation facility (10), a power distribution facility (20), a first load group (LG1) including a power demand element (50) and a first power storage facility (40), and a second load group (LG2) including a second power storage facility (60) and a water electrolysis device (70). First distribution power distributed on the basis of a distribution reference value is leveled by the first power storage facility (40) and supplied to the first load group (LG1). Second distribution power is leveled by the second power storage facility (60) and supplied to the water electrolysis device (70).SELECTED DRAWING: Figure 1

Description

Applied for the application of Article 30, Paragraph 2 of the Patent Law ・Website address http://www3. scej. org/meeting/86a/prog/keynotes. html Posting date: March 8, 2021 ・Research meeting name: The 86th Annual Meeting of the Society of Chemical Engineers, Japan Venue: Online Date: March 21, 2021

The present invention relates to power supply systems.

Conventionally, photovoltaic power generation systems are widely used. Generally, a photovoltaic power generation system is an unstable power supply affected by the amount of solar radiation. For example, there is known a technique for stabilizing power supply by combining a storage battery and a water electrolysis device with a renewable energy power generation system using photovoltaic power generation (see Patent Document 1, for example).

In the system described in Patent Document 1, the charge/discharge control of the storage battery and the operation control of the water electrolysis device are performed so as to smooth the generated power that is unstablely supplied from the renewable energy power generation system, and the surplus power is absorbed. Hydrogen is produced by a water electrolysis device that Then, the system can be stabilized by causing the smoothed generated power to flow in reverse to the power system interconnected with the system.

When the power generated on the power supply side fluctuates and the power consumed on the power demand side fluctuates, for example, a large-capacity storage battery is used to balance power supply and demand. As the power storage capacity of the storage battery is increased, the unbalanced power reception can be easily compensated for over a long period of time by charging/discharging from the storage battery. Complicated control such as prediction of power supply and power demand is required to optimize the capacity (storage capacity) of the storage battery without increasing it more than necessary.

JP 2018-085862 A

By the way, in recent years, attention has been increasing for small-scale power supply networks (microgrids) including distributed power sources (particularly, renewable energy power generation systems). Microgrids include, for example, power demand components in a local area, distributed power sources and storage facilities for storing power, and the like.

On the other hand, it is required to stably supply unstable generated power in a renewable energy power generation system to power demand elements including various loads. For example, as described above, it is possible to stabilize the power supply by increasing the power storage capacity of the power storage equipment. In this case, the cost of the power storage equipment increases as the power storage capacity increases. Realistically, there is also a strong demand to reduce the cost of the power supply system.

An object of one aspect of the present invention is, in one aspect, to provide a system capable of stably supplying power generated by renewable energy to power demand elements and facilitating downsizing of power storage equipment. Another object of one aspect of the present invention is to provide a system capable of realizing cost reduction by effectively utilizing power generated by renewable energy.

In order to solve the above problems, a power supply system according to an aspect of the present invention includes a power generation facility including a photovoltaic power generation device, a power distribution facility that distributes the power supplied from the power generation facility, the power A first group of loads electrically connected to the distribution facility, including (i) a power demand element and a first storage facility for charging and discharging power, and (ii) a second storage facility for charging and discharging power. and a second load group including a water electrolysis device that electrolyzes water to produce hydrogen, wherein the instantaneous magnitude of the supplied power is set as the power output, and the upper limit of the power output is set as peak power. , a power value that is 15% or more and 40% or less of the peak power and is greater than the maximum demand power of the power demand element is set as a distribution reference value, and the power distribution equipment controls the distribution reference in the supplied power The first distributed power that is the portion below the value is distributed to the first load group, and when the supplied power exceeds the distribution reference value, the remainder obtained by subtracting the first distributed power from the supplied power A certain second distributed power is distributed to the second load group, a difference between the first distributed power and the power demand in the power demand element is leveled by the first power storage equipment, and the second is stored in the second power storage equipment, and the leveled power from the second power storage equipment is supplied to the water electrolysis device.

ADVANTAGE OF THE INVENTION According to one aspect of the present invention, it is possible to provide a system capable of stably supplying power generated by renewable energy to power demand elements and facilitating downsizing of power storage equipment.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the outline|summary of the electric power supply system in Embodiment 1 of this invention. 4 is a graph showing an example of fluctuations in power generation output in a day corresponding to temporal fluctuations in the amount of solar radiation in a day for each of sunny weather, cloudy weather, and rainy weather. It is a graph which shows an example of the fluctuation|variation of the average amount of solar radiation for every month in a year. 4 is a graph showing an example of fluctuations in power generation output corresponding to time fluctuations in the amount of solar radiation in a day, which is obtained by averaging the amount of solar radiation for each day of a month in each month of the year. An example of daily average power generation output fluctuations for each month of the year using data that extracts only the stable portion of power that is below a certain reference value for the data that is the basis of the graph shown in FIG. It is a graph showing about. 4 is a graph showing the influence of the reference value SV on the stability factor; 1 is a block diagram showing a schematic configuration of a power supply system according to Embodiment 1 of the present invention; FIG. FIG. 10 is a graph showing an example of a change in power demand for a day, averaging the power demand in a power demanding facility for each day of a month for a month; FIG. FIG. 4 is a block diagram showing a schematic configuration of a power supply system according to Embodiment 2 of the present invention;

[Embodiment 1]
An embodiment of the present invention will be described below with reference to the drawings. The following description is for better understanding of the gist of the invention, and does not limit the invention unless otherwise specified. The configuration shown in each drawing is an example, and unless otherwise specified, the shapes, structures, positional relationships, etc. of various configurations are not limited to the examples shown in each drawing. and may have been modified as appropriate for brevity. Further, in the following description, detailed description and illustration of conventionally known configurations may be omitted, but one embodiment of the present invention can be understood by supplementing the conventionally known configurations.

In the following, in order to facilitate understanding of the power supply system according to one embodiment of the present invention, first, an overview of the power supply system and an overview of findings of the invention will be described, and then details of the power supply system will be described.

<1. System Overview>
FIG. 1 is a schematic diagram showing an overview of a power supply system 1 according to this embodiment. As shown in FIG. 1, the power supply system 1 includes a power generation facility 10, a power distribution facility 20, a first load group LG1 and a second load group LG2 electrically connected to the power distribution facility 20, have. The power supply system 1 may further include a system control device (described later) that controls the entire system. In this case, each control unit included in the power supply system 1 can communicate with the communication network NW. may be connected.

The power generation facility 10 includes a photovoltaic power generation device 11 . The solar power generation device 11 in this embodiment may be a large-scale solar power generation facility (so-called mega solar) including a plurality of solar panels 12, and has a power generation output of, for example, 10 MW (megawatt) or more. good.

The solar panel 12 is typically an array of linked modules. The power generated by the solar panel 12 may be transmitted to the power distribution facility 20 via, for example, a transmission cable.

In this specification, a group of power transmission cables connected to each of the solar panels 12 is referred to as a power transmission cable group 15 . DC power is supplied from the photovoltaic power generation device 11 to the power distribution facility 20 via the power transmission cable group 15 .

A power transmission line between the power generation facility 10 and the power distribution facility 20 is referred to as a power supply line EL0. As will be described later, the power supply system 1 according to the present embodiment has a basic configuration of mainly distributing and supplying power generated by photovoltaic power generation to the first load group LG1 and the second load group LG2. Therefore, the power supply line EL<b>0 may substantially consist of the power transmission cable group 15 . Here, "substantially" means that the power supply line EL0 may consist only of the power transmission cable group 15, or that 90% or more of the power supply line EL0 may consist of the power transmission cable group 15. means.

For example, the power generation facility 10 may include other power generation devices (wind power generation devices, etc.), and even if the power transmission cables that transmit the power generated by the other power generation devices occupy less than 10% of the power supply line EL0. good.

The power distribution facility 20 distributes power (for example, DC power) supplied from the power generation facility 10 via the power supply line EL0, and supplies power to the first load group LG1 and the second load group LG2, respectively. Details of power distribution in the power distribution facility 20 will be described later.

A first load group LG1 includes a regulator 30 , a first storage facility 40 and a power demand element 50 . Power demand element 50 includes at least one of power demand facility 51 and commercial power system 55 . In this embodiment, an example in which power demand element 50 includes both power demand facility 51 and commercial power system 55 will be described. A power transmission line between the power distribution facility 20 and the regulating device 30 is referred to as a power supply line EL1.

The adjustment device 30 distributes the power (for example, AC power) supplied from the power distribution facility 20 via the power supply line EL1, and supplies a portion of the power to the power demand element 50 so as to meet the power demand. , supplies the remaining portion to the first power storage equipment 40 . In addition, the adjustment device 30 supplies the power supplied from the first power storage equipment 40 to the power demand element 50 as necessary.

The first power storage equipment 40 is equipment capable of charging and discharging electric power, charges the electric power supplied from the adjustment device 30, and supplies electric power to the adjustment device 30 as necessary. A specific aspect of the first power storage equipment 40 is not particularly limited, and the power storage capacity of the first power storage equipment 40 is set as necessary. The setting of the power storage capacity will be described later in detail.

Power demand element 50 may include at least one power demand facility 51 . The power demanding facility 51 may be a facility of a scale that has a power demand that is relatively larger than that of households, for example, a facility of a local government, a town factory, a university, or the like. you can

In this embodiment, an example in which one power demanding facility 51 is included in the power demanding element 50 will be described for clarity of explanation. If the power demand element 50 includes a plurality of power demanding facilities 51, the power demand in the following description of this specification should be understood as the total power demand of the plurality of power demanding facilities 51.

The power demand at power demand element 50 may be substantially the power demand at power demand facility 51 . The term "substantially" as used herein means, for example, the following (i), (ii) or (iii).

(i) As in the example shown in FIG. 1, the power demanding facility 51 and the power system 55 interconnected are included in the power demand element 50, and the power demanding facility 51 and the power system 55 are normally energized. is blocked. The electric power system 55 is positioned as an emergency power supply, and when there is a problem in the power supply from the adjusting device 30 to the power demanding facility 51, power is supplied from the power system 55 to the power demanding facility 51 as necessary. ;
(ii) In the example shown in FIG. 1 , part of the power supplied from the adjusting device 30 to the power demanding element 50 is supplied as stable power to the power system 55 without being supplied to the power demanding facility 51 . In this case, the sum of the power supplied to the power demand facility 51 and the power stably supplied to the power system 55 over time becomes the power demand in the power demand element 50;
(iii) unlike the example shown in FIG.

In both cases (i) and (iii) above, the power demand of the power demanding element 50 can be said to be the same or substantially the same as the power demand of the power demanding facility 51 . The power demand of the power demanding facility 51 can be predicted using a known technique. or simulation-based method) is not particularly limited. In the case of (ii) above, the power demand of the power demand element 50 can be specified by setting the power to be supplied to the power system 55 and summing it with the power demand in the power demand facility 51 . In the following, for the sake of clarity of explanation, power loss due to power conversion, power transmission, etc. in each part of the power supply system 1 will not be considered. and power demand can be grasped.

Note that in the power supply system according to a modification of the present embodiment, all of the power supplied from the adjusting device 30 to the power demanding element 50 is supplied as stable power to the power system 55 without being supplied to the power demanding facility 51. may When the power demanding facility 51 is not supplied with power, the stable power supplied to the power system 55 is the power demand in the power demand element 50 .

Also, the stable power supplied to the power grid 55 may be set differently depending on at least one of the time of year and the time of day.

The power demanding facility 51 and the power system 55 may be interconnected via, for example, a power receiving and transforming device 511 provided in the power demanding facility 51 . The power receiving and transforming device 511 may be a device called a so-called cubicle, and a specific aspect thereof is not particularly limited.

In this embodiment, as in (i) and (iii) above, an example in which the power demand in the power demanding element 50 is substantially the power demand in the power demanding facility 51 will be described, but another aspect of the present invention Then, as in (ii) above, it is also possible to supply part of the power supplied from the adjusting device 30 to the power demand element 50 to the power system 55 . Alternatively, in another aspect of the invention, all of the power supplied from regulator 30 to power demand element 50 may be supplied to power grid 55 . For example, the power receiving and transforming device 511 may have such a power distribution function, and the power system 55 may be interconnected to the adjusting device 30 . In the power supply to the power system 55, the added value increases by stably supplying the set amount of power, and for example, the power selling price (contract price with the power company) can be set high. The steady power supplied by the conditioning device 30 of the present invention is sufficient for this.

A second load group LG2 includes a second power storage facility 60 and a water electrolysis device 70 . A power transmission line between the power distribution facility 20 and the second power storage facility 60 is referred to as a power supply line EL2.

The second power storage equipment 60 is equipment capable of charging and discharging electric power, and charges the electric power supplied from the power distribution equipment 20 via the power supply line EL2. Also, the second power storage equipment 60 supplies electric power to the water electrolysis device 70 .

Hydrogen produced by the water electrolysis device 70 is transported to, for example, the hydrogen storage unit 80 and stored in the hydrogen storage unit 80 . The hydrogen stored in the hydrogen storage unit 80 may be used or sold as appropriate depending on the application.

The specific configuration of the communication network NW is not particularly limited, and a wired communication network and a wireless communication network can be used as appropriate.

<2. Outline of knowledge of the invention>
In recent years, there has been a strong push to meet the power demand of consumers by using green power generated using renewable energy. There is also a strong demand for efficient production of hydrogen toward the realization of a hydrogen society.

The inventors of the present invention use green power to stably satisfy the power demand of the power demanding facility 51, and at the same time, to make effective use of generated power (for example, efficient production of hydrogen). Study was carried out. First, the relationship between the amount of power generated by the photovoltaic power generation device 11 and the power demand in the power demanding facility 51 was organized, and the following findings were obtained. This knowledge will be described with reference to the drawings.

FIG. 2 is a graph showing an example of variations in daily power output corresponding to variations in daily solar radiation over time for three different representative weather conditions. The horizontal axis of FIG. 2 indicates the time of day, and the vertical axis indicates the power output of the solar panel corresponding to the amount of horizontal solar radiation. FIG. 3 is a graph showing an example of variations in monthly average solar radiation during the year. The horizontal axis of FIG. 3 indicates each month in one year, and the vertical axis indicates the average amount of solar radiation for each month obtained by accumulating the amount of solar radiation on a slope facing due south with an inclination angle of 30° and averaging the amount per day.

As for the past sunshine amount data in the area where the power generation equipment 10 is installed, published data can be used.

As shown in FIGS. 2 and 3, the amount of power generated by the photovoltaic power generation device 11 can fluctuate greatly under the influence of fluctuations in the amount of solar radiation. In addition, such a specific change in the amount of solar radiation varies depending on the area to be measured.

In this specification, the instantaneous magnitude of the power supplied from the photovoltaic power generation device 11 to the power distribution facility 20 is referred to as power generation output, and the maximum power generation output in the photovoltaic power generation device 11, in other words, the upper limit of the power generation output is called peak power PG_max. The peak power PG_max is the value of the highest power output (for example, the maximum output on a sunny day in May or August) when the annual power output of the photovoltaic power generation devices 11 installed in a certain area is investigated. Although it may be, such a value generally matches the performance-wise maximum power generation output (power generation capacity) of the photovoltaic power generation device 11 . Therefore, the peak power PG_max may be the maximum power output of the photovoltaic power generation device 11 (the sum of the nominal maximum outputs of all the photovoltaic panels 12 included in the photovoltaic power generation device 11).

As shown in FIG. 2, the power output of the photovoltaic power generation device 11 has a stable portion STP1 in which the output is relatively stable regardless of the weather during the daytime, and an unstable portion in which the output fluctuates greatly depending on the weather. It is roughly divided into USP1. The photovoltaic power generation device 11 has a power output of the stable portion STP1 even on a rainy day, for example, depending on the amount of scattered solar radiation.

FIG. 4 is a graph showing an example of fluctuations in power generation output corresponding to hourly fluctuations in the amount of solar radiation in a day, which is obtained by averaging the amount of solar radiation for each day of a month in each month of the year. In FIG. 4, the horizontal axis indicates the time in a day, and the vertical axis indicates the power output of the photovoltaic power generation device 11 corresponding to the daily average amount of solar radiation. Lines PL1, PL5, PL6, PL8, and PL12 shown in FIG. 4 correspond to January, May, June, August, and December, respectively. In the example shown in FIG. 4, it is assumed that the peak power PG_max of the photovoltaic power generation device 11 is 50 MW.

As shown in FIG. 4, there is a stable portion STP2 in which the daily averaged power output for each month, averaging the effects of weather, is relatively stably output regardless of the season. The stable part STP2 has a wider range than the stable part STP1, for example the part below 40%, especially below 30% of the peak power PG_max. However, in practice, the stable portion STP2 is apparently stable, but is affected by the weather when viewed from day to day. Therefore, the power output of the photovoltaic power generation device 11, for example, in one day, may fall below the stable portion STP2.

Here, in general, the portion of the power output from photovoltaic power generation that exceeds the capacity of the power conditioner is cut (peak cut). In addition, in order to increase the amount of power generation in bad weather, intentionally constructing a system so that the power generation capacity of the solar power generation greatly exceeds the capacity of the power conditioner (so-called overloading and constructing the system). There is also

The inventors of the present invention conceived the following regarding the use of the generated power supplied from the photovoltaic power generation device 11 as an idea that has developed such a peak cut. That is, the generated power supplied from the photovoltaic power generation device 11 has a certain reference value SV as a boundary, a stable portion STP3 in which the generated output falls below the reference value SV, and an unstable portion USP3 in which the generated output exceeds the reference value SV. can be roughly divided into Instead of cutting (not using) the unstable portion, the generated power supplied from the photovoltaic power generation device 11 is distributed to the unstable portion USP3 and the stable portion STP3, and the generated power of the unstable portion USP3 is obtained. is used to produce hydrogen, and the power generated in the stable part STP3 is used to meet power demand. As a result, the generated power can be used efficiently and a stable power supply can be realized.

Setting of the reference value SV will be further described with reference to the drawings. FIG. 5 is a graph showing an example of daily average power output fluctuations in each month of the year using data obtained by extracting only the stable portion of power below a certain reference value SV from the power output for the day. is. Here, for the sake of clarity, the following will be described again. That is, the graph shown in FIG. 5 is not obtained by extracting the stable portion STP3 from the graph data (PL1, etc.) shown in FIG. 4 by simply removing the unstable portion USP3 based on the reference value SV. For the power generation output data over time for each day, which is the basis of the graph shown in FIG. Figure 5 shows the daily average results for each month.

As shown in FIG. 5, it can be seen that the peak of the daily average power generation output fluctuation is located near the reference value SV and slightly differs from month to month. Such peak fluctuations may occur, for example, due to the number of weather days in each month that the power generation output is below the reference value SV.

That is, the value of the reference value SV affects the stability of the power of the stable portion STP3. Therefore, the value of the reference value SV was changed from 100% to 0% with the value of the peak power PG_max set to 100%, and the following considerations were made.

That is, for a predetermined period (for example, one year), the integrated power amount for one day (24 hours) of the stable portion STP3 below the reference value SV of the power output from the photovoltaic power generation device 11 is calculated as stable power amount data for each day. and As a result, 365 stable electric energy data are obtained. The data of the power output from the photovoltaic power generation device 11 used to calculate such stable power amount data may be the results (actual measurement data) of actually performing a test for a predetermined period, and the photovoltaic power generation device 11 may be simulated from sunshine data in the target area.

The average value av and the variance Var are calculated by statistically processing the 365 stable electric energy data. Then, a value obtained by calculating "av"/"Var" was used as a stability coefficient, and this stability coefficient was used as an indicator of data variation. Stability factors are used for the following reasons.

That is, the average value av of, for example, 365 pieces of stable electric energy data changes according to the set reference value SV. The larger the average value av, the larger the value of the stability factor. As the reference value SV increases, the average value av increases, but converges to a certain value (peaks out). Also, the smaller the data variation (the smaller the value of Var), the larger the value of the stability coefficient. As the value of the reference value SV increases, the value of the variance Var increases. As described above, the average value av and the variance Var change according to the set reference value SV. Such changes can be evaluated comprehensively by a stability factor.

FIG. 6 is a graph showing the influence of the reference value SV on the stability factor. As a result of the above examination, as shown in FIG. At 25% or less, the stability factor became a sufficiently stable value. By setting the reference value SV to 40% or less, the stability coefficient can be set to, for example, 0.01 or more. It is assumed that the stability factor is a sufficiently stable value when the stability factor is, for example, 0.01 or more.

Also, the reference value SV is set to a value larger than the maximum power demand in the power demand element 50 . The maximum power demand may be, but is not limited to, the highest power consumption value among the results of surveying the annual power demand in the power demand element 50, for example. The maximum power demand may be obtained by adding (totaling) the stable power supplied to the power system 55 to the power demand at the power demand facility 51 . If the power demand component 50 is only the power grid 55 , the maximum power demand of the power demand component 50 may be determined based on the setting of stable power to be supplied to the power grid 55 .

Here, in the power demanding facility 51, generally, the power demand during the working period (typically daytime) on weekdays is greater than the power demand on holidays. By setting the reference value SV so that the stability coefficient is a value of 0.01 or more, most of the actual working days (for example, the number of weekdays) in one year are the actual working period (typically It is possible to stably supply power to meet the power demand during the daytime). As a result, the power storage capacity of the first power storage equipment 40 can be optimized (downsized).

Also, the lower the reference value SV, the smaller the average value av, and the larger the power distributed as the unstable portion USP3. From the viewpoint of practicality of the power supply system 1, the value of the reference value SV may be set to 15% or more. If the reference value SV is set to less than 15%, the size of the power generation facility 10 will increase with respect to the power demand of the power demand element 50 .

The power supply system 1 according to the present embodiment is configured as follows based on the knowledge described above. That is, the reference value SV is set so that the stability coefficient becomes a relatively stable value (for example, the reference value SV is set to 15% or more and 40% or less). Then, the stable portion of the power is supplied to the first load group LG1, leveled by the first power storage equipment 40 (made into a desired output pattern), and supplied to the power demand element 50. FIG. As a result, the power generated by the photovoltaic power generation device 11 can be easily and stably supplied to the first load group LG1 so as to satisfy the power demand in the first load group LG1. Then, the generated power in the unstable portion exceeding the reference value SV is supplied to the second load group LG2, leveled by the second power storage equipment 60 (made into a desired output pattern), and supplied to the water electrolysis device 70. .

In the power supply system 1, stable power can be obtained by a simple operation of distributing and using the power supplied from the power generation facility 10 based on the reference value SV (for example, 25%). The power storage capacity of the power storage equipment 40 and the like can be made compact. That is, since electric power can be stably obtained, it is possible to design the capacity of the storage battery in consideration of only fluctuations on the power demand side without considering fluctuations on the power supply side. As a result, it is possible to reduce the power storage capacity of such a storage battery.

Further, in the power supply system 1, the power generated by the photovoltaic power generation device 11 is roughly divided into a stable portion and an unstable portion, and by separating the values of these portions, the cost of the system can be reduced. Here, as a power supply system, cost is also of great significance in reality. This cost is assessed, for example, on the basis of expenses and income in operating the power supply system. Expenditure typically includes the installation cost and running cost of the power supply system. Income includes the difference between the electricity bill generated by receiving power supply from the power system 55 at the power demanding facility 51 and the electricity bill (calculated cost) reduced by the operation of the power supply system.

In one example, it is assumed that the photovoltaic power generation device 11 is used for 20 years and the expenditure and income are balanced, and the power unit price calculated by calculating the expenditure cost/total power generation amount is 8 yen/kWh. Then, the reference value SV is set to 25%, for example. In this case, depending on the power generation capacity and installation conditions (geographical conditions, topographical conditions, etc.) of the photovoltaic power generation device 11, for example, the amount of power in the stable portion corresponds to 56% of the total amount of power, It is assumed that the power consumption of the unstable part corresponds to the remaining 44% of the total power consumption. Then, in the following calculation, if the value of the unstable portion is assumed to be 1 yen/kWh, the value of the stable portion is 13.5 yen/kWh:
100% x 8 yen = 56% x (value of stable portion) + 44% x (value of unstable portion).

Thus, in the power supply system 1 , the value of the stable portion is cheaper than the electricity charges incurred by receiving power supply from the power system 55 . In addition, by leveling the unstable part with a storage battery and using it for water electrolysis, the operating rate of the water electrolysis device can be dramatically improved, and the production cost of hydrogen can be reduced.

<3. System configuration>
Hereinafter, the power supply system 1 according to this embodiment will be described in detail with reference to FIG. FIG. 7 is a block diagram showing a schematic configuration of the power supply system 1. As shown in FIG. Note that the schematic configuration of the power supply system 1 is as described above with reference to FIG. In FIG. 7, the thick solid line indicates the flow of electric power, the thin solid line indicates the flow of data, and the dashed arrow indicates the outline of the flow of communication such as control commands. In this embodiment, an example in which the maximum power demand of the power demanding facility 51 is 10 MW will be described.

As shown in FIG. 7, the power supply system 1 may have a system control device 90 in addition to the various facilities described above. The system control device 90 includes a system control section 91 , a database 92 and a communication section 93 .

The system control unit 91 centrally controls the entire power supply system 1 . Various data used for control by the system control unit 91 are stored in the database 92 . The communication unit 93 is communicably connected to each unit of the power supply system 1 via the communication network NW. The system configuration will be described below together with the description of the operation of the power supply system 1 based on the control command in the system control device 90 .

In the power supply system 1, power supplied from the power generation facility 10 via the power supply line EL0 is distributed by the power distribution facility 20 to the first load group LG1 and the second load group LG2. When the maximum power demand (maximum power demand) of the power demanding facility 51 is 10 MW, in setting the reference value SV as described above, the reference value SV needs to be 10 MW or more. Then, for example, when the reference value SV is set to 25% of the peak power PG_max of the solar panel 12, the power supply system 1 in the present embodiment also considers the power storage in the first power storage equipment 40, and the solar power generation The power generation capacity of the device 11 may be 50 MW. The reference value SV may be hereinafter referred to as a distribution reference value.

The power supply line EL0 may include a plurality of power transmission cables that transmit DC power. For example, if one power transmission cable has a rated capacity of 10 kW, DC power with a voltage of 30 to 450 kV flows through the power transmission cable. you can

The power distribution facility 20 has a converter 21 , a measuring section 22 , a distribution control section 23 , a storage section 24 and a distributor 29 . A distribution reference value 25 is stored in the storage unit 24 . As the power distribution equipment 20, an existing product (for example, a power conditioner) having a power distribution function can be appropriately applied. The power distribution facility 20 may include multiple power conditioners.

The DC power supplied from the power generation facility 10 via the power supply line EL0 is converted into AC power by the converter 21 . The converted AC power is transmitted to the distributor 29 . Converter 21 may quadrature convert the power and boost the voltage to, for example, thousands of volts (typically 6600 volts).

The measurement unit 22 measures the magnitude (for example, unit: MW) of power transmitted from the converter 21 to the distributor 29 and transmits the measured data to the distribution control unit 23 .

Distribution control unit 23 controls power distribution by distributor 29 based on data transmitted from measurement unit 22 and distribution reference value 25 . Since a known device can be used as the distributor 29, detailed description thereof is omitted.

The distribution control unit 23 uses the distributor 29 to distribute the portion of the power supplied from the power generation facility 10 that is equal to or less than the distribution reference value 25 to the first load group LG1 via the power supply line EL1 as the first distributed power. do. In addition, when the power supplied from the power generation facility 10 exceeds the distribution reference value 25, the distribution control unit 23 uses the distributor 29 to distribute the remaining power after removing the first distributed power from the power supply to the second distribution. The power is distributed to the second load group LG2 via the power supply line EL2. The first distributed power and the second distributed power respectively correspond to the stable power and the unstable power in the power generated by the photovoltaic power generation device 11 described above. In the power supply system 1 , the system control unit 91 may control power distribution by the distributor 29 instead of the distribution control unit 23 , and the distribution reference value 25 may be stored in the database 92 .

In addition, the power supply system 1 uses a plurality of power conditioners as the power distribution equipment 20, and each of the first distributed power and the second distributed power transmitted from the plurality of power conditioners is, for example, They may be merged at a power panel (not shown). In the power supply system 1 , a power supply line EL<b>1 may extend from the power panel to the adjustment device 30 , and a power supply line EL<b>2 may extend to the second power storage equipment 60 .

The first distributed power, which is AC power supplied from the power distribution facility 20 via the power supply line EL1, is further distributed to the power demand element 50 and the first power storage facility 40 by the adjustment device 30 . Adjustment device 30 includes a power supply adjustment unit 31 , an adjustment control unit 32 , a storage unit 33 and a converter 34 .

The power demand at power demand facility 51 of power demand element 50 changes over time during the day. In addition, the time-varying pattern of power demand in a day also varies depending on the season. FIG. 8 is a graph showing an example of a change in power demand for a day, which is the daily average of the power demand at the power demanding facility 51 for each day of a month.

As shown in FIG. 8, on average, in the relationship between the first distributed power and the power demand for a day, the surplus portion OVP, which is the portion where the first distributed power exceeds the power demand, and the power There is a shortfall portion SHP, which is a portion in which the first distributed power is short of the demand. In order to supply power from the adjusting device 30 to the power demanding facility 51 so as to satisfy the principle of simultaneous equality, it is preferable to grasp the power demand at the power demanding facility 51 . The power demand at the power demanding facility 51 can be predicted based on the past record of power demand. Such a pattern (daily change) of power demand of the power demanding facility 51 may be stored in the storage unit 33 .

Hereinafter, the processing of the adjustment control unit 32 will be described with an example of a day having a power reception relationship as shown in FIG. The adjustment control unit 32 adjusts the power demand element 50 so as to satisfy the power demand of the power demanding facility 51 based on the magnitude of the first distributed power supplied to the power supply adjusting unit 31 and the power demand of the power demanding facility 51 . to power the Here, the adjustment control unit 32 uses the power supply adjustment unit 31 to convert the surplus portion OVP (surplus power) into DC power by the converter 34 when there is a surplus portion OVP (surplus power) for the power demand in the first distributed power. After that, it is supplied to the first power storage equipment 40 . Further, when the first distributed electric power is insufficient for the electric power demand (when the insufficient portion SHP exists), the adjustment control unit 32 discharges the first power storage equipment 40 so as to compensate for the insufficient electric power. After the power is converted into AC power by the converter 34 , it is supplied to the power supply adjustment unit 31 . Power is then supplied to the power demand element 50 to meet the power demand.

In this way, the difference between the first distributed power and the power demand in the power demand element can be leveled by the first power storage equipment 40 . Leveling here does not mean a constant output, but means that a desired output pattern can be obtained so as to match the power demand.

The first power storage equipment 40 includes a storage battery 41 and a charge/discharge control unit 42 . Converter 34 may be included in first power storage equipment 40 , and converter 34 may be included between adjustment device 30 and first power storage equipment 40 .

The storage battery 41 may have a battery capacity of 40 MW, for example, when the power generation facility 10 has a power generation capacity of 50 MW, a distribution reference value (SV) of 25%, and a power demand of 10 MW. The battery capacity of the storage battery 41 may be determined from the viewpoint of shortening the charge/discharge cycle in order to reduce performance deterioration of the storage battery 41 . The charge/discharge control unit 42 controls charge/discharge of the storage battery 41 based on commands from the adjustment control unit 32 or the system control unit 91 .

Hypothetically, in the conventional system, in order to directly supply unstable power from the power generation facility 10 to the power demand element 50 and stably satisfy the power demand of 10 MW, the performance of the power storage facility is, for example, A battery capacity twice as large as that of the storage battery 41 may be required.

The power demand element 50 may include a number of data emitters 59 that emit data regarding the power usage of the loads included in the power demand element 50 . The data transmission device 59 may be, for example, a smart meter. The power demand in the power demanding facility 51 can be grasped based on the data transmitted from the data transmission device 59 .

Next, the second distributed power, which is AC power supplied from the power distribution equipment 20, is supplied to the second power storage equipment 60 via the power supply line EL2. Second power storage equipment 60 includes a converter 61 , a charge/discharge control unit 62 , and a storage battery unit 63 . The storage battery section 63 includes a switching mechanism 631 and two storage batteries 632 and 633 .

The converter 61 converts the second distributed power, which is AC power, into DC power, and then supplies the DC power to the storage battery unit 63 . The charge/discharge control unit 62 controls the switching mechanism 631 in the storage battery unit 63 to control charging/discharging of the storage battery 632 and the storage battery 633 . For example, the charge/discharge control unit 62 uses the switching mechanism 631 to control the storage battery unit 63 so that the storage battery 632 is charged and the storage battery 633 is discharged during a certain period. As a result, it is not necessary to excessively increase the battery capacity of the storage batteries 632 and 633, and performance deterioration of the storage batteries 632 and 633 can be suppressed.

Here, if the battery capacities of the storage batteries 632 and 633 are reduced, the scale of the water electrolysis device 70 is increased in order to properly consume the second distributed power, and as a result, the operation rate of the water electrolysis device 70 can be lowered. On the other hand, from the viewpoint of increasing the operation rate of the water electrolysis device 70, the battery capacities of the storage batteries 632 and 633 are increased. From the viewpoint of appropriately balancing the device scale of the water electrolysis device 70 and the battery capacity of the storage batteries 632 and 633, the storage batteries 632 and 633 in this embodiment may each have a battery capacity of 40 MW, for example.

Thus, in the power supply system 1 , the second distributed power is stored in the second power storage equipment 60 , and the leveled power from the second power storage equipment 60 is supplied to the water electrolysis device 70 . Leveling here means that power can be stably supplied to the water electrolysis device 70 at a constant voltage as much as possible. As a result, the operating rate of the water electrolysis device 70 can be dramatically increased.

Water electrolysis device 70 includes a hydrogen generator 71 and a controller 72 . The control unit 72 may adjust the output (operation intensity) of the hydrogen generation unit 71 according to the amount of electricity stored in the storage battery unit 63 .

Here, the magnitude of the leveled power to be supplied from the second power storage equipment 60 is determined according to the design of each device of the power supply system 1 . The magnitude of the leveled power supplied from the second power storage equipment 60 is related to the hydrogen production capacity of the hydrogen generator 71 in the water electrolysis device 70 . An anion exchange membrane (AEM) method, a polymer electrolyte membrane (PEM) method, an alkaline water electrolysis (AWE) method, and the like are known as methods of water electrolysis. When using the AEM method and the PEM method, the higher the hydrogen production capacity of the electrolytic cell, the higher the cost of the electrolytic cell (the cost per fixed hydrogen production capacity). When the AWE method is used, the cost of the electrolytic cell (the cost per fixed hydrogen production capacity) tends to decrease as the hydrogen production capacity of the electrolytic cell increases. The hydrogen generation unit 71 of the water electrolysis device 70 has an electrolytic cell of a type selected in consideration of the above tendency based on the magnitude of the leveled power supplied from the second power storage equipment 60. good.

[Embodiment 2]
Other embodiments of the invention are described below. For convenience of description, members having the same functions as those of the members described in the above embodiments are denoted by the same reference numerals, and description thereof will not be repeated.

FIG. 9 is a block diagram showing a schematic configuration of a power supply system 1A according to Embodiment 2 of the present invention.

In the power supply system 1 of Embodiment 1, the adjustment device 30 converts the DC power supplied from the power generation facility 10 into AC power and distributes it to the first load group LG1 and the second load group LG2. rice field. On the other hand, in the power supply system 1A in this embodiment, the DC power supplied from the power generation equipment 10 is first distributed. Then, the first load group LG1 is supplied with first distributed power as AC power by converting the DC power into AC power. On the other hand, the second load group LG2 is supplied with second distributed power as DC power without converting the distributed DC power.

As shown in FIG. 9, the power supply system 1A has a power distribution facility 20A and a second power storage facility 60A. The power distribution facility 20A includes a DC distributor 29A. A known device can be applied as the DC distributor 29A, and DC power is distributed by, for example, a switching mechanism.

Converter 21 converts the DC power supplied from DC distributor 29A into AC power, and then supplies first distributed power to adjustment device 30 via power supply line EL1.

The second distributed power is supplied from the DC distributor 29A to the second power storage equipment 60A via the power supply line EL2. Since the second power storage equipment 60A does not need to convert AC power into DC power, it does not need to have the converter 61 (see FIG. 7).

In general, power loss occurs in the conversion between DC power and AC power. According to the power supply system 1A of the present embodiment, the DC power supplied from the power generation facility 10 can be supplied to the second power storage facility 60A as the second distributed power without being converted. Therefore, the electric power supplied from the power generation equipment 10 can be used more efficiently.

[Additional notes]
According to the power supply system of one aspect of the present invention, the system can be introduced easily because the cost can be relatively reduced. As a result, it can contribute to the realization of a low-carbon society. Further, according to the power supply system of one aspect of the present invention, hydrogen can be produced relatively inexpensively. Therefore, it can contribute to the realization of a hydrogenated society. This will contribute to the achievement of the Sustainable Development Goals (SDGs).

The present invention is not limited to the above-described embodiments, but can be modified in various ways within the scope of the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. is also included in the technical scope of the present invention.

1, 1A power supply system 10 power generation equipment 11 solar power generation equipment 20, 20A power distribution equipment 30 regulating device 40 first power storage equipment 50 power demand element 51 power demand facilities 60, 60A second power storage equipment 70 water electrolysis device

Claims (4)

A power supply system,
a power generation facility including a photovoltaic power generation device;
a power distribution facility that distributes power supplied from the power generation facility;
A first load group electrically connected to the power distribution facility, including (i) a power demand element and a first storage facility for charging and discharging power; and (ii) a second group for charging and discharging power. a second load group including a power storage device and a water electrolysis device that electrolyzes water to produce hydrogen;
A power value that is 15% or more and 40% or less of the peak power and is greater than the maximum demand power of the power demand element, where the instantaneous magnitude of the supplied power is the power output, and the upper limit of the power output is the peak power. is set as the distribution reference value,
The power distribution equipment distributes a first distributed power that is a portion of the supplied power that is equal to or less than the distribution reference value to the first load group, and when the supplied power exceeds the distribution reference value, the supply Distributing a second distributed power, which is the remainder after removing the first distributed power from the power, to the second load group;
A difference between the first distributed power and the power demand in the power demand element is leveled by the first power storage facility, the second distributed power is stored in the second power storage facility, and the second distributed power is stored in the second power storage facility. A power supply system for supplying power leveled from the power storage equipment to the water electrolysis device. (i) when the distribution reference value is set to a certain value, data of the daily integrated power consumption of the first distributed power is acquired over a predetermined period, and a plurality of data for the number of days in the predetermined period is obtained; Based on the relationship between the stability coefficient obtained by statistically processing the integrated power amount data to calculate the average value and the variance, and dividing the average value by the variance, and (ii) the distribution reference value,
2. The power supply system according to claim 1, wherein said distribution reference value is set such that said stability factor is 0.01 or more. The power distribution equipment distributes AC power as the first distributed power to the first load group, and distributes AC power as the second distributed power to the second load group,
The first load group (i) converts the surplus power from AC power to DC power when there is surplus power for the power demand in the first distributed power, and stores the surplus power in the first power storage equipment. (ii) when the first distributed power is insufficient for the power demand, the DC power discharged from the first power storage equipment is converted to AC power so as to make up for the shortage of power; a first conversion device for converting and supplying the power demand element;
3. The power according to claim 1, wherein the second load group includes a second conversion device that converts the second distributed power from AC power to DC power and supplies the power to the second power storage equipment. supply system. The power distribution facility includes a DC distributor and a power conditioner,
When the supplied power exceeds the distribution reference value, the DC distributor distributes the DC power as the first distributed power to the power conditioner, and distributes the second distributed power to the second load group. Distributing DC power as power,
3. The power supply system according to claim 1, wherein said power conditioner converts said first distributed power from DC power to AC power and supplies said first load group with said power.

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