Power supply system using renewable energy and method thereof

Abstract

To provide a power supply system and method capable of efficiently and stably supplying the amount of power generated using renewable energy to a power system using a storage battery.SOLUTION: A power supply system 1 includes first power storage units 5, 6 that charge and discharge power generated by a solar power generator 18 and a wind power generator 19 that use renewable energy, second storage units 7, 8 that charge and discharge in the opposite manner to the first storage units 5, 6, a control device 2 that controls the charging and discharging of the storage units, and a calculation device 3 that predicts the amount of power generated during a prediction period in a power generation facility. The control device 2 charges either the first or second storage units 5-8 with the amount of power actually generated by the power generation facility during the prediction period, and discharges the predicted amount of power generation predicted using the calculation device 3 from the other of the first or second storage units 5-8 to a power system 25 during the prediction period.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power supply system and method for efficiently and stably supplying power using renewable energy. [Background technology]

[0002] Even in areas such as remote islands where electricity is supplied by a standalone system using internal combustion power generation facilities, electricity supplies using renewable energy sources such as solar power generation and wind power generation are being introduced. However, power generation using renewable energy sources is subject to frequent fluctuations in output due to weather and shutdowns, forcing the use of internal combustion power generation equipment to adjust output, increasing the burden on operations. To address these issues, for example, Patent Document 1 discloses an invention entitled "Power generation system utilizing storage batteries and renewable energy, and its operating method." According to this power generation system, two storage batteries are placed between the power generation facility and the power grid, one for charging from the power generation facility and the other for discharging to the power grid, and the storage batteries are switched between charging and discharging, with the timing of this switching being determined by comparing the total amount of charging and the total amount of discharging. Furthermore, Patent Document 2 discloses an invention entitled "Independent Power Supply System and Control Method Thereof," which has a first storage battery and a second storage battery provided between a renewable energy source and a load, one of which performs only the storage function and the other only the power supply function, and which is equipped with a control unit that controls the execution entity to alternate over time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-113034 [Patent Document 2] Patent Publication No. 2021-5978 Summary of the Invention [Problem to be solved by the invention]

[0004] The invention disclosed in Patent Document 1 describes, as an example, that when switching between 12 hours of charging and 12 hours of discharging in a day, the time when the amount of energy stored through 12 hours of charging matches the amount of energy supplied through 12 hours of discharging is set as the appropriate time (T) for switching. However, while this works well under ideal conditions (Figure 4), when the wind speed is weak (Figure 5), strong (Figure 6), or when demand is high (Figure 7), or even when there is no wind (Figure 8), if the supply situation of renewable energy required for power generation changes, the storage battery may be switched at time T even if the battery is not fully charged, or switching may not be possible even if charging is completed before time T, resulting in the suppression of wind power generation, which creates the problem of not necessarily being able to utilize power generation from renewable energy efficiently or stably. In addition, the invention disclosed in Patent Document 2 also specifies that the timing of switching the executor over time is either when the discharging battery reaches its discharge limit or when the charging battery reaches its upper charge limit. However, in such cases, if the switching occurs due to the battery reaching its discharge limit, the battery being substituted may not be sufficiently charged, and if the switching occurs due to the battery reaching its upper charge limit, the discharging battery may not be sufficiently discharged. Therefore, as with the invention disclosed in Patent Document 1, there is a problem in that power generation from renewable energy cannot necessarily be utilized efficiently or stably. The present invention has been made in response to such conventional circumstances, and aims to provide a power supply system and method that can efficiently and stably supply the amount of electricity generated using renewable energy to a power grid using a storage battery. [Means for solving the problem]

[0005] In order to achieve the above object, a first invention is a power supply system comprising a first energy storage unit that charges and discharges electricity generated by a power generation facility that uses renewable energy; a second energy storage unit that charges and discharges electricity in the opposite direction to the first energy storage unit; a control device that controls the charging and discharging of the first and second energy storage units; and a calculation device that predicts the amount of electricity to be generated by the power generation facility during a predetermined period, wherein the control device charges either the first or second energy storage unit with the amount of electricity actually generated by the power generation facility during the period, and discharges the predicted amount of electricity predicted using the calculation device from the other of the first or second energy storage unit to a power grid during the period. In this application, renewable energy means energy that can be steadily or repeatedly supplied by natural forces, including solar power, wind power, wave power, tidal power, etc. Furthermore, "conversely charging and discharging" means that the second power storage unit charges when the first power storage unit is discharging, and discharges when the first power storage unit is charging.

[0006] The second invention is a power supply system according to the first invention, characterized in that the calculation device adds the difference between the amount of power actually generated by the power generation facility during the period and the predicted amount of power to the predicted amount of power for the next period, which predicts the amount of power to be generated by the power generation facility after the period, and corrects the difference between the actual amount of power generated during the period and the predicted amount of power discharged to the power grid during the period with the discharge for the next period.

[0007] A third invention is a power supply system according to the first invention, characterized in that the power grid comprises an internal combustion power generation facility and an adjustment storage unit that charges and discharges only between the power grid, and the control device controls the first and second storage units as well as the charging and discharging of the adjustment storage unit and the amount of power generated by the internal combustion power generation facility, and further controls the adjustment storage unit to discharge power to the power grid when the amount of power demand in the power grid is greater than the sum of the discharged predicted amount of power and the amount of power generated by the internal combustion power generation facility, and controls the adjustment storage unit to charge power from the power grid when the amount of power demand is less than the sum. In this application, internal combustion power generation facilities refer to diesel power generation facilities, thermal power generation facilities, and hydroelectric power generation facilities.

[0008] A fourth invention is an electric power supply system according to the first invention, wherein the electric power system includes an internal combustion power generation facility and an adjustment storage unit that charges and discharges only between the electric power system and the control device controls the first and second storage units as well as the charging and discharging of the adjustment storage unit and the amount of electric power generated by the internal combustion power generation facility, and further, when the amount of electric power demand in the electric power system is greater than the sum of the predicted amount of electric power discharged and the amount of electric power generated by the internal combustion power generation facility, increases the amount of electric power generated by the internal combustion power generation facility, and when the amount of electric power demand is less than the sum, charges the adjustment storage unit from the electric power system.

[0009] A fifth invention is a power supply system according to the third or fourth invention, characterized in that the storage capacity of the adjustment storage unit is the amount of power that can be generated for at least one day by a generator with the maximum single-unit generating capacity of the internal combustion power generation equipment on the power grid.

[0010] A sixth invention is an electric power supply method, which uses a first energy storage unit that charges and discharges electric power generated by a power generation facility that uses renewable energy, and a second energy storage unit that charges and discharges electric power in the opposite manner to the first energy storage unit, and discharges the electric power to a power grid, the method comprising: calculating a predicted amount of electric power to be generated by the power generation facility during a predetermined period; charging either the first or second energy storage unit with the amount of electric power actually generated by the power generation facility during the period; and controlling the other of the first or second energy storage unit to discharge the predicted amount of electric power to the power grid during the period.

[0011] A seventh invention is a power supply method according to the sixth invention, characterized in that the difference between the amount of power actually generated by the power generation facility during the period and the predicted amount of power is added to the predicted amount of power for a next period that predicts the amount of power to be generated by the power generation facility after the period, and the difference between the actual amount of power generated during the period and the predicted amount of power discharged to the power grid during the period is controlled to be corrected by the discharge in the next period.

[0012] An eighth invention is the power supply method of the sixth invention, characterized in that, in addition to the first and second power storage units, an internal combustion power generation facility and an adjustment power storage unit that charges and discharges only between the internal combustion power generation facility and the power grid are used, and when the amount of power demand in the power grid is greater than the sum of the discharged predicted amount of power and the amount of power generated by the internal combustion power generation facility, control is performed so that the adjustment power storage unit is discharged to the power grid, and when the amount of power demand is less than the sum, the adjustment power storage unit is charged from the power grid.

[0013] A ninth invention is the power supply method of the sixth invention, characterized in that, in addition to the first and second power storage units, an internal combustion power generation facility and an adjustment power storage unit that charges and discharges only between the internal combustion power generation facility and the power grid are used, and when the amount of power demand in the power grid is greater than the sum of the predicted amount of power discharged and the amount of power generated by the internal combustion power generation facility, the amount of power generated by the internal combustion power generation facility is increased, and when the amount of power demand is less than the sum, the adjustment power storage unit is controlled to be charged from the power grid.

[0014] A tenth aspect of the present invention is a power supply method according to the eighth or ninth aspect of the present invention, characterized in that the storage capacity of the adjustment storage unit is the amount of power that can be generated for at least one day by a generator with the maximum single-unit generating capacity of the internal combustion power generation equipment on the power grid. [Effects of the Invention]

[0015] In the power supply system according to the first aspect of the present invention, a calculation device is used to predict the amount of power to be generated by the power generation facility during a predetermined period, and a control device charges either the first or second power storage unit with the amount of power actually generated by the power generation facility during the period, and discharges the predicted amount of power predicted using the calculation device from the other of the first or second power storage unit to the power grid during the period, so that the amount of power actually generated and charged approximates the amount of power discharged to the power grid, making it possible to maintain a constant amount of power stored in the first and second power storage units as a whole after the predetermined period has elapsed. Therefore, even if charging and discharging are repeatedly performed during the predetermined period, there is little chance that the balance between the amounts of stored power in the first and second power storage units will be lost during the period, and the risk of having to switch between charging and discharging between the power storage units due to only one of the power storage units is reduced, so that by alternately using these power storage units, it is possible to efficiently and stably provide the amount of power generated using renewable energy to the power grid.

[0016] In the power supply system according to the second aspect of the present invention, the calculation device adds the difference between the amount of power actually generated by the power generation equipment during the previous period and the predicted amount of power to the predicted amount of power for the next period, which predicts the amount of power to be generated by the power generation equipment after the previous period, and corrects the difference between the actual amount of power generated during the previous period and the predicted amount of power discharged to the power grid during the previous period by the discharge in the next period.Therefore, the difference between the amount of power actually generated and charged during the previous period and the amount of power discharged based on the predicted amount of power can be corrected in the next period, and at the end of the next period, the amount of power actually generated and charged up to the previous period and the amount of power discharged can be made equal. In other words, compared to the effect of the first invention, there is a lower possibility that the balance of the stored power amounts in the first and second storage units will be disrupted during operation, and it is possible to further reduce the risk of having to switch between charging and discharging between the storage units due to a problem in only one of the storage units. Therefore, compared to the effect of the first invention, by alternately using these power storage units, it is possible to more efficiently and stably provide the amount of electricity generated using renewable energy to the power grid.

[0017] In the power supply system according to the third aspect of the invention, the control device controls the adjustment power storage unit to discharge power to the power grid when the amount of power demand in the power grid is greater than the sum of the predicted discharged amount of power and the amount of power generated by the internal combustion power generation facility, and controls the adjustment power storage unit to charge power from the power grid when the amount of power demand is less than that sum, thereby making it possible for the adjustment power storage unit to follow the load for the amount of power demand. Therefore, in addition to the effect of the first aspect of the invention, there is no need to follow the load for the amount of power from the first power storage unit and the second power storage unit, and a more stable supply is possible.

[0018] In the power supply system according to the fourth aspect of the invention, the control device increases the amount of power generated by the internal combustion power generation facility when the amount of power demand in the power grid is greater than the sum of the predicted amount of power discharged and the amount of power generated by the internal combustion power generation facility, and controls the adjustment power storage unit to charge from the power grid when the amount of power demand is less than the sum, thereby making it possible for the internal combustion power generation facility to follow the load for the amount of power demand. Therefore, in addition to the effect of the first aspect of the invention, there is no need to follow the load for the amount of power from the first power storage unit and the second power storage unit, and a more stable supply is possible.

[0019] In the power supply system of the fifth invention, in the third or fourth invention, the storage capacity of the adjustment storage unit is the amount of electricity that can be generated for at least one day by a generator with the maximum single-unit generating capacity of the internal combustion power generation equipment on the power grid. Therefore, even if a single failure occurs in the generator of the internal combustion power generation equipment, it is not necessary to stop operation of the power supply system for one day, and one day's grace period can be guaranteed for the equipment to be restored. Therefore, in addition to the effects of the third or fourth invention, it is possible to supply electricity more stably.

[0020] The sixth invention is an embodiment of the first invention as a method invention, and its effects are similar to those of the first invention.

[0021] The seventh invention is the second invention as a method invention, and its effects are similar to those of the second invention.

[0022] The eighth invention is the third invention as a method invention, and its effects are the same as those of the third invention.

[0023] The ninth invention is the fourth invention as a method invention, and its effects are similar to those of the fourth invention.

[0024] The tenth invention is the fifth invention as a method invention, and its effects are the same as those of the fifth invention. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a system configuration diagram of a power supply system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a conceptual diagram illustrating a database configuration of the power supply system according to the embodiment of the present invention. [Figure 3] 3 is a first flowchart of a power supply method executed by the power supply system according to the embodiment of the present invention. FIG. [Figure 4] FIG. 5 is a second flowchart of the power supply method executed by the power supply system according to the embodiment of the present invention. [Figure 5] FIG. 2 is a conceptual diagram showing the relationship between the amount of power generated by renewable energy and the amount of discharge by a discharge unit. [Figure 6] FIG. 6 is a third flowchart of the power supply method executed by the power supply system according to the embodiment of the present invention. [Figure 7] 1 is a conceptual diagram showing operation during normal operation of a power supply system according to an embodiment of the present invention. [Figure 8] 1 is a conceptual diagram showing operation of a power supply system according to an embodiment of the present invention during load-following power generation by an internal combustion power generation facility. FIG. [Figure 9] 10 is a modified portion of the third flowchart of the power supply method executed by the power supply system according to the embodiment of the present invention. [Figure 10] FIG. 10 is a conceptual diagram showing operation during direct power transmission operation as a modified example of operation during normal operation of the power supply system according to the embodiment of the present invention. [Figure 11] FIG. 4 is a fourth flowchart of the power supply method executed by the power supply system according to the embodiment of the present invention. [Figure 12] 1 is a conceptual diagram showing operation during load-following power generation by an adjustment power storage unit of a power supply system according to an embodiment of the present invention. FIG. [Figure 13] FIG. 5 is a fifth flowchart of the power supply method executed by the power supply system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, a power supply system according to an embodiment of the present invention will be described with reference to FIGS. 1 to 13. FIG. FIG. 1 is a system configuration diagram of a power supply system according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram showing the configuration of a database of the power supply system. In Figure 1, the power supply system 1 is shown in the area surrounded by a two-dot chain line and is mainly composed of first storage units 5 and 6, second storage units 7 and 8, an adjustment storage unit 13, a control device 2, a calculation device 3, and a database 4. The first power storage units 5, 6 and the second power storage units 7, 8 charge and discharge electricity generated by renewable energy. Specifically, for example, electricity generated by a solar power generator 18 and a wind power generator 19 is converted by a power conditioner 20 for the solar power generator and a power conditioner 21 for the wind power generator, respectively, and then the electricity is charged by turning on the charge switches 9a-12a and turning off the discharge switches 9b-12b, and conversely, the electricity is discharged by turning off the charge switches 9a-12a and turning on the discharge switches 9b-12b. The first power storage units 5, 6 and the second power storage units 7, 8 are each provided in two systems, one of the first power storage units 5, 6 and the second power storage units 7, 8 functions as a charging unit, and the other functions as a discharging unit, with the functions of the charging unit and the discharging unit being alternated.

[0027] The electricity discharged by the first energy storage units 5, 6 and the second energy storage units 7, 8 is supplied to the power grid 25 via the battery power conditioner 29 and the step-up transformer 30, and is distributed to general consumers 26 together with electricity generated by internal combustion power generation facilities such as the diesel generator 23 a and the hydroelectric generator 23 b and supplied to the power grid 25. Furthermore, basically, the first power storage units 5, 6 and the second power storage units 7, 8 are each operated as only one system, and the other system is used to respond to unforeseen circumstances such as a single failure of a power storage unit, but two systems may be operated in the event that the supply of power from sources other than renewable energy, i.e., power from the internal combustion power generation facility, drops significantly or an accident occurs in power system 25. In this embodiment, the first power storage unit 5 shown by the solid line is operated as a charging unit, and the second power storage unit 7 is operated as a discharging unit, in a single system, as will be described. The first power storage unit 6 and the second power storage unit 8 shown by the dashed line are in a standby state with charging switches 10a, 12a and discharging switches 10b, 12b turned off, respectively.

[0028] Next, the adjustment power storage unit 13 will be described. The adjustment power storage unit 13 is not charged directly from a power generation facility using renewable energy such as a solar power generator 18 or a wind power generator 19, but is charged from the power grid 25 via a step-down transformer 32 and a power conditioner for storage battery 31 by turning on the charge switch 14a and turning off the discharge switch 14b. In addition, when discharging, the charge switch 14a is turned off and the discharge switch 14b is turned on, and power is supplied to the power grid 25 via a power conditioner for storage battery 29 and a step-up transformer 30. In other words, the adjustment power storage unit 13 charges and discharges only between itself and the power grid 25. The control device 2 controls the amount of power charged and discharged to the first energy storage units 5, 6, the second energy storage units 7, 8 and the adjustment energy storage unit 13 by transmitting on / off signals to the charge switches 9a-12a via a control signal line 15a, to the discharge switches 9b-12b via a control signal line 15b, to the charge switch 14a via a control signal line 16a and to the discharge switch 14b via a control signal line 16b, respectively, to turn the switches on and off (close / open).

[0029] The control device 2 also acquires data on the amount of power generated from the solar power generator 18 and the wind power generator 19 via the data signal line 22 as needed, and stores the data in a readable manner in the database 4 as actual solar power generation amount data 36 and actual wind power generation amount data 39 (see FIG. 2), respectively. The control device 2 also acquires data on the amount of power generated from the diesel generator 23a and the hydroelectric generator 23b via the data signal line 24a. Therefore, if an event such as a malfunction or breakdown occurs in the diesel generator 23a or the hydroelectric generator 23b, the control device 2 can determine that an event has occurred based on a decrease in the data on the amount of power generated. The control device 2 can also transmit a control signal via a control signal line 24b to control the amount of power generated by the diesel generator 23a and the hydroelectric generator 23b. The control device 2 also acquires data on the amount of power demand from general consumers 26 via a data signal line 27. Furthermore, the control device 2 acquires data regarding the SOC value (State of Charge: charging rate) from the first storage units 5, 6 and the second storage units 7, 8 via a data signal line 17, and also acquires data regarding the SOC value from the adjustment storage unit 13 via a data signal line 28.

[0030] Next, the database 4 will be described. As shown in Fig. 2, the database 4 readably stores sunrise / sunset data 33, a photovoltaic power generation amount prediction function 34, sunshine condition data 35, actual photovoltaic power generation amount data 36, ​​wind power generation amount prediction function 37, wind condition data 38, and actual wind power generation amount data 39. The sunrise / sunset data 33 is data related to sunrise and sunset on any one day of the year, and is read by the calculation device 3 and input to the photovoltaic power generation amount prediction function 34 when calculating the photovoltaic power generation amount prediction value. The solar power generation prediction function 34 is a function for predicting the amount of solar power generation using sunshine condition data 35 such as sunshine intensity, sunshine duration, and weather. The sunshine condition data 35 is data that is input so as to be readable at any time via an input device (not shown) using a weather observation system or the like. The solar power generation actual data 36 is time-series data on the amount of power generated by the solar generator 18. The wind power generation prediction function 37 is a function for predicting the amount of wind power generated using wind condition data 38 such as wind direction, wind blowing time, and wind speed. The wind condition data 38 is data that is input so as to be readable at any time via an input device (not shown) using a meteorological observation system or the like. The actual wind power generation data 39 is time-series data on the amount of power generated by the wind turbine generator 19. The photovoltaic power generation amount prediction function 34 and the wind power generation amount prediction function 37 are expressed by regression curves based on the actual values ​​of the power generation amounts of the photovoltaic power generator 18 and the wind power generator 19, respectively.

[0031] Next, the arithmetic unit 3 will be described. The arithmetic unit 3 and other components will be described together with a description of the steps of the power supply method according to the present invention, with reference to FIGS. Figure 3 is a first flowchart of a power supply method executed by a power supply system according to an embodiment of the present invention. This diagram shows the steps of the power supply method, and explaining the functions of the components of the power supply system 1 with reference to this diagram and other flowcharts is equivalent to explaining an embodiment of the power supply method. Also, dashed lines indicate the components of the power supply system 1 that are related to that step, and the reference numerals indicate the components shown in Figures 1 and 2. Note that these components include not only the components of the power supply system 1 but also the components of peripheral devices. In the power supply system 1, first, in step S1, the arithmetic device 3 having a clocking function reads out the sunrise / sunset data 33 from the database 4 and determines whether the current time is after sunrise and before sunset. If the current time is within that time range, the process proceeds to step S2, where the arithmetic device 3 reads from the database 4 a solar power generation amount prediction function 34 expressed by a regression curve or the like based on the actual amount of power generated by the solar power generator 18, and inputs the sunshine condition data 35 read from the database 4 to calculate a predicted value of the solar power generation amount of the solar power generator 18 for a period (hereinafter referred to as the prediction period) arbitrarily determined in advance for predicting the amount of power generation, which in this embodiment is a period up to 10 minutes into the future. Note that if the current time is not within that time range in step S1, the process returns to step S1. The prediction period may be determined as a period desirable for operation, and a short prediction period is considered to result in a close relationship between the actual and predicted amounts of power generation, although frequent control of the entire power supply system 1 is required. The opposite is considered to be true for a long prediction period.

[0032] In step S3, the calculation device 3 transmits the calculated predicted value of the amount of solar power generation to the control device 2, the control device 2 sets the predicted value of the amount of solar power generation as the discharge output value of the second power storage unit 7 (discharge unit), the control device 2 transmits an ON control signal to the discharge switch 11b via the control signal line 15b, and the second power storage unit 7 discharges the discharge output value to the power grid 25. From this step S3, the process proceeds to not only step S4 but also to symbol A shown in Fig. 6, but the steps from that transition destination will be described later, and first step S4 will be described. In step S4, after the prediction period has elapsed, that is, after 10 minutes have elapsed, the calculation device 3 reads and acquires from the database 4 the actual photovoltaic power generation amount data 36 of the power generated during those 10 minutes. In step S5, the calculation device 3 compares the predicted solar power generation amount for that 10-minute period with the solar power generation amount actual data 36 to determine whether there is a difference. If there is a difference, the calculation device 3 reflects the difference in the solar power generation amount prediction function 34 when calculating the predicted solar power generation amount for the next prediction period in step S6. This eliminates the difference between the predicted solar power generation amount for the previous prediction period and the solar power generation amount actual data 36 for the next prediction period, and the process returns to step S1. If there is no difference in step S5, the process returns to step S1. When determining whether there is a "difference" in step S5, an appropriate numerical range may be set in advance as a standard depending on the length of the prediction period, such as determining that there is a difference if the difference exceeds ±5 kWh. By setting a numerical range, it is possible to prevent the calculation device 3 from always proceeding to step S6 based on a strict judgment, which may improve the efficiency and accuracy of the entire system by reducing the processing time of the calculation device 3.

[0033] Next, the steps of the power supply method and the functions of the arithmetic unit 3 and other components of the power supply system 1 will be described with reference to Fig. 4. Fig. 4 is a second flowchart of the power supply method executed by the power supply system according to the embodiment of the present invention. Although the steps begin with step S7, this is executed independently of the first flowchart in Fig. 3. 4, in the power supply system 1, first in step S7, the calculation device 3 reads out wind power generation result data 39 from the database 4 and determines whether the wind power generator 19 generated power before the prediction period, that is, 10 minutes ago in this embodiment. If power was being generated, the process proceeds to step S8, where ... using a regression curve or the like based on the actual power generation result of the wind power generator 19. The calculation device 3 then inputs the current wind condition data 38 read out from the database 4 into this function, and calculates the predicted wind power generation value of the wind power generator 19 for the prediction period up to 10 minutes from now. If it is determined in step S7 that the wind power generator 19 has not generated power before the prediction period, the process proceeds to step S9, where the calculation device 3 reads and inputs sample wind conditions that have a certain degree of certainty based on the current wind condition data 38 and statistics, etc., from the database 4 into the wind power generation prediction function 37 in the same manner as in step S8, thereby calculating the predicted wind power generation value of the wind power generator 19 for the prediction period.

[0034] After steps S8 and S9 are executed, the process proceeds to step S10, where the calculation device 3 transmits the calculated predicted wind power generation amount value to the control device 2, the control device 2 sets the predicted wind power generation amount value as the discharge output value of the second power storage unit 7 (discharge unit), the control device 2 transmits an ON control signal to the discharge switch 11b via the control signal line 15b, and the second power storage unit 7 outputs the discharge output value to the power grid 25. From step S10, the process proceeds to not only step S11 but also to symbol B shown in Fig. 6, but the steps from that transition destination will be described later, and step S11 will be described first. In step 11, after the prediction period has elapsed, that is, after 10 minutes have elapsed, the calculation device 3 reads and acquires from the database 4 the wind power generation amount record data 39 of the power generated during those 10 minutes. In step S12, the calculation device 3 compares the predicted wind power generation amount for those 10 minutes with the wind power generation amount actual data 39 to determine whether there is a difference. If it is determined that there is a difference, in step S13, the difference is reflected in the wind power generation amount prediction function 37 when calculating the wind power generation amount predicted value for the next prediction period, and the difference between the wind power generation amount predicted value for the previous prediction period and the wind power generation amount actual data 39 is eliminated for the next prediction period, and the process returns to step S7. If it is determined that there is no difference in step S12, the process returns directly to step S7. When determining whether there is a "difference" in step S13, an appropriate numerical range may be set in advance as a criterion similar to that in step S5, and the same effect can be expected.

[0035] The relationship between the predicted solar power generation amount for each prediction period obtained by executing steps S1-6 and S7-13 and the solar power generation amount actual data 36 will be described with reference to Fig. 5. Fig. 5 is a conceptual diagram showing the relationship between the combined amount of power generation by the solar power generator and the amount of power generation by the wind power generator, i.e., the amount of power generation by renewable energy and the amount of discharge by the discharge unit. 5, renewable energy power generation amount line 40, indicated by a two-dot chain line, shows the change over time in the power generation amount that is the sum of the power generation amount by photovoltaic power generator 18 and the power generation amount by wind power generator 19, and discharge unit discharge amount line 41, indicated by a solid line, shows the change over time in the amount of power discharged by second power storage unit 7. As described with reference to FIGS. 3 and 4, since the difference between the predicted photovoltaic power generation amount value and actual photovoltaic power generation amount data 36 and the difference between the predicted wind power generation amount value and actual wind power generation amount data 39 that occurred in the previous prediction period are included in photovoltaic power generation amount prediction function 34 and wind power generation amount prediction function 37, respectively, the difference across multiple prediction periods decreases, and the power generation amount by renewable energy that is the sum of the predicted photovoltaic power generation amount value and the predicted wind power generation amount value and the sum of photovoltaic power generation amount actual data 36 and wind power generation amount actual data 39 generally coincide. That is, the amount of power generated by renewable energy roughly matches the amount of power discharged by the second power storage unit 7. In this embodiment, both solar power and wind power are shown as renewable energy, but either one of them may be used alone, or other renewable energy may be adopted or combined.

[0036] Next, how to supply power in response to the power demand of general consumers 26 will be described with reference to Fig. 6. Fig. 6 is a third flowchart of the power supply method executed by the power supply system according to the embodiment of the present invention. In this diagram, the process starts from step S14, but this is executed independently from the first flow diagram in Fig. 3 and the second flow diagram in Fig. 4. However, there may be cases where the two flow diagrams branch off or merge. 6, in step S14, the control device 2 of the power supply system 1 acquires the SOC value data of the first power storage units 5 and 6 and the second power storage units 7 and 8 via the data signal line 17, and the SOC value data of the adjustment power storage unit 13 via the data signal line 28. Step S14 includes a merging step indicated by reference symbol E, which will be described later, and step S15 will be described first. Here, the steps indicated by reference symbols A and B are the steps in which the control device 2 acquires the predicted photovoltaic power generation amount value in step S3 and the predicted wind power generation amount value in step S10, and therefore, following these steps, in step S15 the control device 2 determines whether an event such as a malfunction or failure has occurred in the internal combustion power generation equipment. As already explained, this determination is made by the control device 2 acquiring data on the amount of power generated from the diesel generator 23a and the hydroelectric generator 23b, and it is possible to determine from this data whether or not a malfunction has occurred. From this step S15, the process proceeds to step S16 as well as to symbol C shown in Figure 11, but the steps from that point on will be described later, and step S16 will be described first.

[0037] If there is no event such as a malfunction in step S15, the process proceeds to step S16. In step S16, the control device 2 compares the total value of the predicted solar power generation amount and the predicted wind power generation amount for the prediction period with the SOC value of the second power storage unit 7 to determine whether charging is required when discharging from the discharge unit, which in this embodiment corresponds to the second power storage unit 7. Since the SOC value ranges from 0% (fully discharged state) to 100% (fully charged state), it is preferable to set the SOC value required for charging in advance taking into consideration the specifications of the power storage unit, the charge / discharge record, or the degree of deterioration, and the control device 2 makes a judgment based on that value. From this step S16, in addition to step S17, the process also proceeds to symbol D1 shown in Fig. 13, but the steps from that transition destination will be described later, and step S17 will be described first. If it is determined that charging is not necessary, the process proceeds to step S17, in which the control device 2 commands the second power storage unit 7 to discharge. Specifically, the control device 2 causes discharge by transmitting a control signal via the control signal line 15b to turn on the discharge switch 11b, which is currently in the off state. Note that this step S17 may be joined from another flow diagram, which will be described later, and the adjustment power storage unit 13 may be operating at that time. In this case, the adjustment power storage unit 13 is stopped in this step S17. Also, step S17 includes a joining step indicated by the symbol F, which will be described later; first, step S18 will be described. In step S18, the control device 2 acquires data on the amount of demanded power from the general consumers 26 via the data signal line 27, and determines whether the sum of the amount of discharge by the second power storage unit 7 acquired via the data signal line 17 and the amount of power generated by internal combustion power generation facilities such as the diesel generator 23a and the hydroelectric generator 23b acquired via the data signal line 24a is greater than the amount of demanded power. Note that, in the present embodiment, the amount of demanded power from the general consumers 26 is illustrated in FIG. 1 as being acquired by the control device 2 directly via the data signal line 27, but if demand in the power grid 25 is monitored by a demand monitoring system or the like, the control device 2 may acquire data on the amount of demanded power from the demand monitoring system or the like.

[0038] Here, with reference to FIG. 7 as well, an explanation will be given of how the power supply system 1 is operated to deal with the difference between the sum of the amount of discharge from the second power storage unit 7 and the amount of power generated by internal combustion power generation facilities such as the diesel generator 23a and the hydroelectric generator 23b, and the amount of power demanded by general consumers 26. FIG. 7 is a conceptual diagram showing the operation of a power supply system according to an embodiment of the present invention during normal operation. The horizontal axis of FIG. 7 represents the passage of time, and the vertical axis represents the demanded power amount, discharged power amount, and power generation amount. In FIG. 7, the solid line represents the discharge unit discharge amount line 41, the dashed-dotted line represents the supplied power amount line 42 obtained by adding the internal combustion power generation amount 45 to the discharge unit discharge amount line 41, and the dashed line represents the demanded power amount line 43. The discharge unit discharge amount line 41 is based on the discharge unit discharge amount 44a obtained by the predicted solar power generation amount and the predicted wind power generation amount. However, as described above, since the discharge unit discharge amount line 41 reflects the difference between the actual measured value of the power generation amount by the solar power generator 18 or the wind power generator 19 for each prediction period, the sum of the total for the prediction period generally matches the actual measured value. Furthermore, according to the power supply system 1 of this embodiment, it is possible to operate the internal combustion power generation facility as a base load power source, so that the amount of internal combustion power generation 45 is kept roughly constant, but it is preferable to control the amount of power demand indicated by the demand power amount line 43 and the amount of power indicated by the supply power amount line 42 so that they roughly match.

[0039] Next, steps S19 and S20 will be described with reference to FIGS. If the sum of the discharge unit discharge amount 44a from the second power storage unit 7 and the internal combustion power generation amount 45 is greater than the demand power amount line 43, that is, in the area hatched with diagonal lines sloping upward to the right in Figure 7, the process proceeds to step S19, and the control device 2 keeps the discharge switch 14b off and turns on the charge switch 14a via the control signal line 16a to charge the surplus power from the power grid 25 to the adjustment power storage unit 13 via the step-down transformer 32 and the power conditioner for the storage battery 31. By charging the adjustment power storage unit 13 in this way, the internal combustion power generation equipment can be operated for base load operation, and the discharge unit discharge amount 44a can discharge the same amount of power as the actual values ​​of the power generation amounts of the photovoltaic power generator 18 and the wind power generator 19. Furthermore, operation that follows up on load fluctuations by general consumers 26 is also possible. Therefore, there is no need to suppress the power generation of the photovoltaic power generator 18 or the wind power generator 19, and it is possible to efficiently and stably supply the amount of power generated by renewable energy to the power grid 25, thereby suppressing frequency fluctuations in the power grid 25 and stabilizing the grid. When the execution of step S19 is completed, the process returns to step S14.

[0040] On the other hand, if the sum of the discharge unit discharge amount 44a and the internal combustion power generation amount 45 is less than the demand energy line 43, that is, in the area hatched with diagonal lines slanting downward to the right in Fig. 7, the process proceeds to step S20, and the control device 2 either discharges the excess energy demand from the adjustment energy storage unit 13 by turning on the discharge switch 14b via the control signal line 16b while keeping the charge switch 14a off to perform load following operation, or sends a control signal to the internal combustion power generation equipment, such as the diesel generator 23a or the hydroelectric generator 23b, via the control signal line 24b to increase the amount of power generation to make up for the excess energy demand. When the sum of the amounts of power generation is greater than the amount of power demand, the adjustment energy storage unit 13 is charged, so discharge from the adjustment energy storage unit 13 is basically selected. However, if the charge rate of the adjustment energy storage unit 13 is low or if some kind of malfunction occurs, it is desirable to increase the amount of power generation by the internal combustion power generation equipment. In the case of step S20, it is also possible to efficiently and stably supply the amount of electricity generated by renewable energy to power grid 25, and it is also possible to increase the amount of electricity generated by the internal combustion power generation equipment, so that frequency fluctuations in power grid 25 can be suppressed and system stability can be achieved.

[0041] Such a case will be explained further with reference to FIG. Figure 8 is a conceptual diagram showing operation of a power supply system according to an embodiment of the present invention during load-following power generation by an internal combustion power generation facility. The horizontal and vertical axes in Figure 8 are the same as those in Figure 7. Elements already explained in Figure 7 are given the same reference numerals, and their explanation will be omitted. In Figure 8, when it is found that the storage rate of the adjustment storage unit 13 is decreasing while the internal combustion power generation equipment is being operated as a baseload power source, the control device 2 issues a command to the internal combustion power generation equipment, such as the diesel generator 23a and the hydroelectric generator 23b, to perform load following operation, as shown by symbol M, to change the internal combustion power generation amount 45 to the load following power generation amount 50a or the load following power generation amount 50b. By doing so, the amount of discharge by the adjustment storage unit 13 decreases when the demand power line 43 increases, as in the case of the load following power generation amount 50a, and it is also possible to charge the adjustment storage unit 13 when the demand power line 43 falls below the supply power line 42, as in the case of the load following power generation amount 50b (step S19). The original storage capacity of adjustment power storage unit 13 is determined depending on the scale of the entire power supply system 1, the renewable energy power generation facility, and the internal combustion power generation facility, but as will be explained with reference to Fig. 12, assuming a single failure of the generator with the maximum single-unit generating capacity in the internal combustion power generation facility, it is desirable for the storage capacity to be sufficient to cover the amount of power generated in one day by the generator with that maximum single-unit generating capacity. By doing so, it is possible to assume a single failure of the generator with the maximum single-unit generating capacity and the repair period until recovery, which can ensure the stability of power system 25. Furthermore, if the sum of the power generation amounts is the same as the power demand amount, the excess power demand amount becomes 0, so there is no discharge by the adjustment power storage unit 13 and no increase in the power generation amount by the internal combustion power generation facility. Furthermore, when the execution of step S20 is completed, the process returns to step S14.

[0042] Next, with reference to Figures 9 and 10, an operation of a renewable energy power generation facility such as a solar power generator 18 or a wind power generator 19 when good sunshine and wind conditions continue will be described as a modified example of this embodiment. Figure 9 shows a modified portion of steps S17 to S20 of the third flowchart (Figure 6) of the power supply method executed by the power supply system according to the embodiment of the present invention. Also, Figure 10 is a conceptual diagram showing operation during direct power transmission operation as a modified example of operation during normal operation of the power supply system according to the embodiment of the present invention. Elements already described in Figures 6 and 7 are assigned the same reference numerals, and their description will be omitted. 9 , in the modified example, first, in step S17a, the control device 2 determines whether the amount of discharge from the discharge unit, i.e., the second power storage unit 7, is greater than the amount of power generated by the internal combustion power generation facilities, such as the diesel generator 23a and the hydroelectric generator 23b. If not, the process merges from step S17a to step S18 in FIG. 6, but if greater, the process proceeds to the next step S17b. In step S17b, the control device 2 turns off the discharge switch 11b via the control signal line 15b, thereby stopping the discharge from the second power storage unit 7, and performs control so that the amounts of power generated by the solar generator 18 and the wind power generator 19 are all transmitted directly to the power grid 25 via the solar generator power conditioner 20 and the wind power generator power conditioner 21, respectively, and further via the storage battery power conditioner 29 and the step-up transformer 30. Then, in step S18a, the control device 2 determines whether the sum of the amount of power generated by renewable energy power generation facilities such as the solar power generator 18 and the wind power generator 19 obtained via the data signal line 22 and the amount of power generated by internal combustion power generation facilities such as the diesel power generator 23a and the hydroelectric power generator 23b obtained via the data signal line 24a is greater than the amount of demanded power obtained via the data signal line 27.

[0043] Figure 10 shows the relationship between the amount of power demand and the amount of power generated and discharged during this type of operation. The horizontal and vertical axes in Fig. 10 are the same as those in Fig. 7, but unlike Fig. 7, a renewable energy power generation amount line 40 based on renewable energy power generation amount 44b is shown instead of discharge unit discharge amount line 41 based on discharge unit discharge amount 44a. The vertical and horizontal axes are the same as those in Fig. 7 and Fig. 8. This is because, in step S17a, it was determined that the discharge amount from the discharge unit exceeds the power generation amount by the internal combustion power generation equipment, and therefore the discharge amount 44a of the discharge unit is being supplied stably, that is, there are many actual values ​​of the power generation amount by the solar power generator 18 and the wind power generator 19, and a stable and large power generation amount is being obtained, and therefore, in the modified example, it was determined that it would be more efficient to discharge directly from the solar power generator 18 or the wind power generator 19 rather than discharging via the second storage unit 7. Therefore, in Figure 10, renewable energy power generation amount 44b, which indicates the actual value of power generation by solar power generator 18 and wind power generator 19, is shown instead of discharge unit discharge amount 44a, which is set by the sum of the predicted solar power generation amount and the predicted wind power generation amount for each prediction period, and therefore renewable energy power generation amount line 40 changes over time regardless of the prediction period, compared to discharge unit discharge amount line 41 in Figure 7. The operation regarding the difference between the demand power line 43 and the supply power line 42, which is the sum of the renewable energy power generation amount 44b and the internal combustion power generation amount 45, is the same as the operation regarding the difference between the discharge amount from the second energy storage unit 7 and the sum of the power generation amount by the internal combustion power generation facility, as described using Figure 7. That is, if the control device 2 determines in step S18a that the sum of the renewable energy power generation amount 44b and the internal combustion power generation amount 45 is greater than the demanded power amount, that is, in the area hatched with diagonal lines slanting upward to the right in Fig. 10, the process proceeds to step S19a, where the control device 2 keeps the discharge switch 14b off and turns on the charge switch 14a via the control signal line 16a to charge the surplus power from the power grid 25 to the adjustment power storage unit 13 via the step-down transformer 32 and the power conditioner for the storage battery 31. When the execution of step S19a is completed, the process merges with step S14 in Fig. 6.

[0044] On the other hand, if it is determined that the sum of the power generation amounts is not greater than the power demand amount, as in the embodiment, that is, in the area hatched with diagonal lines slanting downward to the right in FIG. 10, the process proceeds to step S20a, and the control device 2 either discharges the excess power demand amount from the adjustment power storage unit 13 by turning on the discharge switch 14b via the control signal line 16b while keeping the charge switch 14a off, in order to perform load following operation, or sends a control signal to the internal combustion power generation equipment such as the diesel generator 23a or the hydroelectric generator 23b via the control signal line 24b to increase the power generation amount so as to make up for the excess power demand amount. Therefore, it becomes possible to efficiently and stably supply the amount of power generated by renewable energy to the power grid 25, thereby suppressing frequency fluctuations in the power grid 25 and stabilizing the grid. When the execution of step S20a is completed, the process merges with step S14 in FIG. Having finished the explanation of the modified example, next, with reference to Figs. 11 and 12, the operation when an event such as a malfunction in power generation occurs in the internal combustion power generation facility will be explained.

[0045] FIG. 11 is a fourth flowchart of the power supply method executed by the power supply system according to the embodiment of the present invention. In Fig. 11, the symbol C indicates the diversion from step S15 in Fig. 6. When an event such as a malfunction occurs in the internal combustion power generation equipment, in step S21, the control device 2 acquires data relating to the amount of power generated from the diesel generator 23a and the hydroelectric generator 23b via the data signal line 24a, and based on the sum of the amounts of power generated, increases the base outputs of the diesel generator 23a and the hydroelectric generator 23b so as to compensate for the amount of power generation lost due to the malfunction. Then, in step S22, similar to step S16, the control device 2 determines whether charging is necessary or not by comparing the sum of the predicted photovoltaic power generation amount and the predicted wind power generation amount for the prediction period with the SOC value of the second power storage unit 7 when the second power storage unit 7 is discharged. From step S22, the process proceeds to step S23 as well as to symbol D2 shown in Fig. 13, but the steps from that transition destination will be described later and step S23 will be described first. If it is determined that charging is not necessary, the process proceeds to step S23, where the control device 2 commands discharging by the second power storage unit 7. Specifically, the control device 2 transmits a control signal via the control signal line 15b to switch the discharge switch 11b, which is currently in the OFF state, to the ON state, thereby causing discharging. Step S23 includes a merging process indicated by the symbol G, which will be described later. First, step S24 will be described. In step S24, similar to step S18, the control device 2 acquires data regarding the demanded amount of electricity via the data signal line 27, and determines whether the sum of the amount of discharge by the second storage unit 7 obtained via the data signal line 17 and the amount of electricity generated by the internal combustion power generation equipment obtained via the data signal line 24a is greater than the demanded amount of electricity.

[0046] Here, with reference to FIG. 12 as well, an explanation will be given of how the power supply system 1 is operated to deal with the difference between the sum of the amount of discharge from the second power storage unit 7 and the amount of power generated by internal combustion power generation facilities such as the diesel generator 23a and the hydroelectric generator 23b, and the amount of power demanded by general consumers 26. FIG. 12 is a conceptual diagram showing operation of the power supply system according to the embodiment of the present invention during load-following power generation by the adjustment storage unit. The horizontal axis of FIG. 12 represents the passage of time, and the vertical axis represents the demand power amount, discharge amount, and power generation amount. In FIG. 12, the solid line represents the discharge unit discharge amount line 41, the dashed-dotted line represents the supply power amount line 42 obtained by adding the internal combustion power generation amount 45 to the discharge unit discharge amount line 41, and the dashed line represents the demand power amount line 43. The discharge unit discharge amount line 41 is based on the discharge unit discharge amount 44a obtained by the predicted solar power generation amount and the predicted wind power generation amount. However, as described above, since the discharge unit discharge amount line 41 reflects the difference between the actual measured value of the power generation amount by the solar power generator 18 or the wind power generator 19 for each prediction period, the discharge unit discharge amount line 41 generally matches the actual measured value throughout the prediction period. However, if an event such as a malfunction occurs in an internal combustion power generation facility such as the diesel generator 23a or the hydroelectric generator 23b at timing 46 indicated by an arrow in Fig. 12, the amount of internal combustion power generation 45 will drop suddenly, causing frequency fluctuations in the power grid 25 and potentially destabilizing the system. For example, in the worst case scenario, if a generator having the maximum single-unit generating capacity 47 in the internal combustion power generation facility experiences a single failure and stops, the generating capacity 48 excluding the maximum single unit will be insufficient, and an auxiliary discharge amount 49 will be required to compensate for the maximum single-unit generating capacity 47. In such a case, the process proceeds to step S26, in which the control device 2 activates the adjustment power storage unit 13 to compensate as the auxiliary discharge amount 49. Specifically, the control device 2 keeps the charging switch 14a off and turns on the discharge switch 14b via the control signal line 16b to discharge the auxiliary discharge amount 49. Therefore, it is desirable that the storage capacity of the adjustment storage unit 13 be such that it can cover the amount of electricity generated in one day by a generator with the maximum single-unit generating capacity 47 in the internal combustion power generation facility, assuming a single failure of the generator with the maximum single-unit generating capacity 47. By providing the adjustment power storage unit 13 with such a storage capacity, even if a single failure occurs in the generator with the maximum single-unit power generation capacity, it is possible to operate the adjustment power storage unit 13 and stably supply power to the power grid 25. Note that it is preferable to determine the storage capacity of the adjustment power storage unit 13 with a certain degree of likelihood based on the normal SOC value. This state is assumed in the process from reference C in FIG.

[0047] 11, if an event such as a malfunction occurs at timing 46 and supply power line 42 based on discharge unit discharge amount 44a from second power storage unit 7, auxiliary discharge amount 49, and power generation capacity 48 excluding the largest single unit of the internal combustion power generation equipment is greater than demand power line 43, control device 2 transmits a control signal via control signal line 16b to reduce auxiliary discharge amount 49 from adjustment power storage unit 13 so as not to exceed demand power line 43. Specifically, a plurality of discharge switches 14b are provided, and control signals are transmitted to switch some of them from on to off. By controlling the adjustment power storage unit 13 in this way, even if a malfunction event occurs, the discharge unit discharge amount 44a can discharge the same amount of power as the actual values ​​of the power generation amounts of the photovoltaic power generator 18 and the wind power generator 19. Furthermore, by controlling the adjustment power storage unit 13, it is also possible to operate it in accordance with load fluctuations by the general consumers 26. Therefore, it is not necessary to suppress the power generation of the photovoltaic power generator 18 or the wind power generator 19, and it is possible to efficiently and stably supply the amount of power generated by renewable energy to the power grid 25, thereby suppressing frequency fluctuations in the power grid 25 and stabilizing the grid. When the execution of step S25 is completed, the process returns to symbol E in FIG. 6.

[0048] On the other hand, even if the adjustment power storage unit 13 is started to compensate for the maximum single-unit power generation capacity 47 and the auxiliary discharge amount 49 is discharged, fluctuations may cause the demand power line 43 to exceed the supply power line 42. In such a case, the process proceeds to step S26, and the control device 2 transmits a control signal to the discharge switch 14b of the adjustment power storage unit 13 via the control signal line 16a, thereby controlling the discharge to further compensate for the shortage of demand power. Specifically, the control is performed to increase the number of the multiple discharge switches 14b that are turned on. When the execution of step S26 is completed, the process returns to symbol E in FIG. 6.

[0049] Next, operation when charging of the second power storage unit 7 is required will be described with reference to Fig. 13. Fig. 13 is a fifth flowchart of the power supply method executed by the power supply system according to the embodiment of the present invention, in which symbol D1 indicates the branch from step S16 in Fig. 6 and symbol D2 indicates the branch from step S22 in Fig. 11. In FIG. 13, in step S27, control device 2 acquires data on the SOC value of first power storage unit 5 from data signal line 17 to determine whether the SOC value (charging rate) of the charging unit, i.e., first power storage unit 5, is 90% or higher. If the SOC value of the first storage unit 5 is 90% or more, the process proceeds to step S28, and the control device 2 determines whether or not there is a fluctuation in the system during the shutdown operation by comparing the discharge amount of the second storage unit 7, which is a discharge unit, with the amount of power supplied to general consumers 26 in the entire power system 25, and if it determines that there is no fluctuation, the process proceeds to step S30. In step S30, the control device 2 stops the second power storage unit 7 and issues a command to switch the first power storage unit 5 from a charge unit to a discharge unit. Specifically, the control device 2 turns off the discharge switch 11b of the second power storage unit 7 via the control signal line 15b, turns off the charge switch 9a of the first power storage unit 5 via the control signal line 15a, turns on the discharge switch 9b of the first power storage unit 5 via the control signal line 15b, and turns on the charge switch 9a of the second power storage unit 7 via the control signal line 15a. When execution of step S30 is completed, the process returns to F in FIG. 6 if the process flow starts from D1, or returns to G in FIG. 11 if the process flow starts from D2. Next, if the SOC value of the charging unit is lower than 90% in step S27, or if the control device 2 determines in step S28 that system fluctuation will occur during the stopping operation of the discharging unit, the process proceeds to step S29. In step S29, the control device 2 controls the discharge unit to be switched to the adjustment power storage unit 13 without stopping the discharge unit, and to discharge the adjustment power storage unit 13. Therefore, it is possible to supply a stable amount of power without causing system fluctuation in the power system 25.

[0050] Next, in step S31, the control device 2 acquires data regarding the amount of demanded electricity via the data signal line 27, and determines whether the sum of the amount of discharge by the adjustment storage unit 13 obtained via the data signal line 28 and the amount of electricity generated by the internal combustion power generation equipment obtained via the data signal line 24a is greater than the amount of demanded electricity. Therefore, if the amount is greater than the demand, the process proceeds to step S32, where the control device 2 transmits a control signal via the control signal line 16b to reduce the number of on-state discharge switches 14b, thereby reducing the amount of discharge by the adjustment power storage unit 13 and controlling it so that it does not exceed the demand power line 43. If the amount is less than the demand, the process proceeds to step S33, where the control device 2 transmits a control signal via the control signal line 16b to increase the number of on-state discharge switches 14b, thereby controlling it so that the amount of discharge by the adjustment power storage unit 13 increases. When the execution of steps S32 and S33 is completed, the process returns to symbol E in FIG.

[0051] As described above, according to the power supply system 1 and power supply method of this embodiment, the calculation device 3 is used to predict the amount of power to be generated in a renewable energy power generation facility during a prediction period, and the control device 2 charges either the first energy storage units 5, 6 or the second energy storage units 7, 8 with the amount of power actually generated during the prediction period, and discharges the predicted amount of power predicted using the calculation device 3 from the other of the first energy storage units 5, 6 or the second energy storage units 7, 8 to the power grid 25 during the prediction period.As a result, the amount of power actually generated and charged and the amount of power discharged to the power grid 25 approximate each other, and it is possible to maintain a constant amount of power stored in the first energy storage units 5, 6 and the second energy storage units 7, 8 as a whole after the lapse of a predetermined prediction period. Therefore, even if charging and discharging are repeatedly performed during the prediction period, there is little possibility that the balance of the amount of stored power in the first storage units 5, 6 and the second storage units 7, 8 will be disrupted along the way, and the risk of having to switch between charging and discharging between the storage units due to a problem in only one of the storage units is reduced.Therefore, by alternately using these storage units, it is possible to efficiently and stably provide the amount of power generated using renewable energy to the power grid 25.

[0052] Furthermore, the control device 2 adds the difference between the actual value of the amount of electricity actually generated by the renewable energy power generation equipment during the prediction period and the predicted solar power generation amount or the predicted wind power generation amount as a correction value to the solar power generation amount prediction function 34 or the wind power generation amount prediction function 37, and reflects this in the predicted power generation value for the period predicting the amount of electricity to be generated by those power generation equipment after the prediction period.The difference between the actual amount of electricity generated during the previous prediction period and the predicted amount of electricity discharged to the power grid 25 during the previous prediction period is corrected for the discharge in the next period.Therefore, the difference between the amount of electricity actually generated and charged during the previous prediction period and the amount of electricity discharged based on the predicted amount of electricity can be corrected in the next prediction period, and it is possible to make the amount of electricity actually generated and charged up to the previous prediction period the same as the amount of electricity discharged at the end of the next prediction period. Therefore, there is less possibility that the balance of the amount of stored power in the first storage units 5, 6 and the second storage units 7, 8 will be disrupted during operation, and the risk of having to switch between charging and discharging between the storage units due to a problem in only one of the storage units can be reduced, making it possible to provide the amount of power generated using renewable energy to the power grid 25 more efficiently and stably.

[0053] Furthermore, when the amount of power demanded by general consumers 26 in power system 25 is greater than the sum of the amount of power discharged from the discharge unit and the amount of power generated by the internal combustion power generation facility, control device 2 controls so that adjustment power storage unit 13 discharges power to power system 25, and when the amount of power demanded is less than the sum, control device 2 controls so that adjustment power storage unit 13 is charged from power system 25, thereby making it possible to load follow the amount of power demand using adjustment power storage unit 13. Also, instead of adjustment power storage unit 13, load following is also possible with power generation by internal combustion power generation facility such as diesel generator 23a or hydroelectric generator 23b. Therefore, when discharging from first power storage units 5, 6 or second power storage units 7, 8, there is no need to load follow the amount of power demand, and it is possible to more efficiently and stably supply the amount of power generated by renewable energy. [Industrial Applicability]

[0054] As described above, the present invention can be used as a power supply system and a power supply method for efficiently and stably supplying renewable energy. [Explanation of symbols]

[0055] REFERENCE SIGNS LIST 1...power supply system 2...control device 3...arithmetic device 4...database 5,6...first power storage unit 7,8...second power storage unit 9a-12a...charging switch 9b-12b...discharging switch 13...regulating power storage unit 14a...charging switch 14b...discharging switch 15a,15b...control signal line 16a,16b...control signal line 17...data signal line 18...solar generator 19...wind power generator 20...power conditioner for solar generator 21...power conditioner for wind power generator 22...data signal line 23a...diesel generator 23b...hydroelectric generator 24a...data signal line 24b...control signal line 25...power system 26...general consumer 27...data signal line 28...data signal line 29...power conditioner for storage battery 30...step-up transformer 31...Power conditioner for storage battery 32...Step-down transformer 33...Sunrise / sunset data 34...Solar power generation forecast function 35...Sunshine condition data 36...Actual solar power generation data 37...Wind power generation forecast function 38...Wind condition data 39...Actual wind power generation data 40...Renewable energy power generation line 41...Discharge unit discharge amount line 42...Supply power amount line 43...Demand power amount line 44a...Discharge unit discharge amount 44b...Renewable energy power generation amount 45...Internal combustion power generation amount 46...Timing 47...Maximum single unit power generation capacity 48...Power generation capacity excluding maximum single unit 49...Auxiliary discharge amount 50a...Load following power generation amount 50b...Load following power generation amount

Claims

1. a control device that controls the charging and discharging of the first and second energy storage units; and a calculation device that predicts an amount of energy to be generated by the power generation facility during a predetermined period, wherein the control device charges one of the first or second energy storage unit with an amount of energy actually generated by the power generation facility during the period, and discharges the other of the first or second energy storage unit to an electric power grid during the period with the predicted amount of energy predicted using the calculation device.

2. 2. The power supply system according to claim 1, wherein the arithmetic device adds a difference between the amount of power actually generated by the power generation facility during the period and the predicted amount of power to a predicted amount of power for a next period that predicts the amount of power to be generated by the power generation facility after the period, and corrects the difference between the actual amount of power generated during the period and the predicted amount of power discharged to the power grid during the period by the discharge in the next period.

3. 2. The power supply system according to claim 1, wherein the power system includes an internal combustion power generation facility and an adjustment power storage unit that charges and discharges only between the power system and the internal combustion power generation facility, and the control device controls the charging and discharging of the adjustment power storage unit and the amount of power generated by the internal combustion power generation facility in addition to the first and second power storage units, and further controls the adjustment power storage unit to discharge power to the power system when an amount of power demand in the power system is greater than the sum of the discharged predicted amount of power and the amount of power generated by the internal combustion power generation facility, and controls the adjustment power storage unit to charge power from the power system when the amount of power demand is less than the sum.

4. 2. The power supply system according to claim 1, wherein the power system includes an internal combustion power generation facility and an adjustment power storage unit that charges and discharges only between the power system and the internal combustion power generation facility, and the control device controls the charging and discharging of the adjustment power storage unit and the amount of power generated by the internal combustion power generation facility in addition to the first and second power storage units, and further controls the control device to increase the amount of power generated by the internal combustion power generation facility when the amount of power demand in the power system is greater than the sum of the discharged predicted amount of power and the amount of power generated by the internal combustion power generation facility, and to charge the adjustment power storage unit from the power system when the amount of power demand is less than the sum.

5. 5. The power supply system according to claim 3, wherein the storage capacity of the adjustment storage unit is an amount of power that can be generated for at least one day by a generator with a maximum single-unit generating capacity of the internal combustion power generation equipment on the power grid.

6. A power supply method for discharging power generated by a power generation facility that uses renewable energy to a power grid using a first power storage unit that charges and discharges the power, and a second power storage unit that charges and discharges the power in the opposite manner to the first power storage unit, comprising: calculating a predicted amount of power to be generated by the power generation facility for a predetermined period of time; a control to charge one of the first and second power storage units with an amount of power actually generated by the power generation facility during the period, and to discharge the predicted amount of power from the other of the first and second power storage units to the power grid during the period.

7. 7. The power supply method according to claim 6, further comprising: adding a difference between the amount of power actually generated by the power generation facility during the period and the predicted amount of power to a predicted amount of power for a next period that predicts the amount of power to be generated by the power generation facility after the period; and performing control so that the difference between the actual amount of power generated during the period and the predicted amount of power discharged to the power grid during the period is corrected by the discharge in the next period.

8. 7. The power supply method according to claim 6, further comprising the steps of: using, in addition to the first and second power storage units, an internal combustion power generation facility and an adjustment power storage unit that charges and discharges only between the internal combustion power generation facility and the power grid; and controlling so that, when an amount of power demand in the power grid is greater than a sum of the discharged predicted amount of power and an amount of power generated by the internal combustion power generation facility, the adjustment power storage unit is discharged to the power grid; and, when the amount of power demand is less than the sum, the adjustment power storage unit is charged from the power grid.

9. 7. The power supply method according to claim 6, further comprising: using, in addition to the first and second power storage units, an internal combustion power generation facility and an adjustment power storage unit that charges and discharges only between the internal combustion power generation facility and the power grid; and controlling to increase the amount of power generated by the internal combustion power generation facility when an amount of power demand in the power grid is greater than the sum of the discharged predicted amount of power and the amount of power generated by the internal combustion power generation facility, and to charge the adjustment power storage unit from the power grid when the amount of power demand is less than the sum.

10. 10. The power supply method according to claim 8 or claim 9, wherein the storage capacity of the adjustment storage unit is an amount of power that can be generated for at least one day by a generator with a maximum single-unit generating capacity of the internal combustion power generation equipment on the power grid.

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