Charging and discharging plan creation system

Abstract

To provide a charging and discharging plan creation system capable of effectively increasing revenue from selling electricity.SOLUTION: A charging and discharging plan creation system 100 that creates a charging and discharging plan for a storage battery 31 capable of charging and discharging power generated by a solar power generation unit 21 includes: an acquisition unit that acquires a predicted value of an electricity market price on a bidding target date and the day after the bidding target date in the electricity market (step S11); and a plan creation unit that creates a charging and discharging plan on the bidding target date so as to charge the storage battery 31 in a low price range where the predicted value of the electricity market price is low on the bidding target date and discharge the storage battery 31 in a high price range where the predicted value of the electricity market price is higher than in the low price range on the bidding target date, in which the plan creation unit determines the discharge amount from the storage battery 31 on the bidding target date based on a comparison of the predicted value of the electricity market price on the bidding target date and the predicted value of the power market price on the day after the bidding target date (steps S15 and S16).SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a technique of a charge-discharge plan creation system for creating a charge-discharge plan of a storage battery.

Background Art

[0002] As described in Patent Document 1, in the conventional charge-discharge control of a storage battery, the operation of the storage battery is performed such that the generated power of a solar power generation device is charged into the storage battery during a time period when the electricity market price is low in a day, and the power is discharged from the storage battery during a time period when the electricity market price is high in a day. By such an operation of the storage battery, an increase in power selling profit is attempted.

[0003] However, in the comparison of the electricity market prices in a day, the trend of the electricity market prices after the next day cannot be reflected. Specifically, when the electricity market price of the next day is higher than the electricity market price of the current day, the power selling profit increases if more power is discharged from the storage battery on the next day. However, when the generated power of the solar power generation device is small on the next day, there is a problem that the amount of power discharged from the storage battery becomes small despite the high electricity market price, and the power selling profit cannot be sufficiently obtained.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of the above circumstances, and the problem to be solved is to provide a charge-discharge plan creation system capable of effectively increasing the power selling profit.

Means for Solving the Problems

[0006] The problem to be solved by the present invention is as described above. Next, means for solving this problem will be described.

[0007] That is, in claim 1, a charge / discharge plan creation system that creates a charge / discharge plan for a rechargeable battery with the electric power generated by a power generation unit capable of generating power using natural energy, the system comprising: an acquisition unit that acquires predicted values of electricity market prices on the bidding target date and on a predetermined date after the day following the bidding target date; and a plan creation unit that creates the charge / discharge plan for the bidding target date such that the battery is charged in a low price band where the predicted value of the electricity market price is low during the bidding target date, and the battery is discharged in a high price band where the predicted value of the electricity market price is higher than the low price band during the bidding target date. The plan creation unit determines the discharge amount from the battery on the bidding target date based on a comparison between the predicted value of the electricity market price on the bidding target date and the predicted value of the electricity market price on the predetermined date.

[0008] In claim 2, the acquisition unit acquires predicted values of the power generation amount of the power generation unit on the bidding target date and on the predetermined date, and the plan creation unit sets the discharge amount from the battery on the bidding target date to the discharge amount at which a predetermined remaining amount remains in the battery when it is predicted that the power generation amount of the power generation unit on the predetermined date is less than the capacity of the battery and it is predicted that the electricity market price in the high price band on the predetermined date is higher than the electricity market price in the high price band on the bidding target date.

[0009] In claim 3, when the predicted value of the electricity market price in the high price band on the predetermined day is higher than the predicted value of the electricity market price in the high price band on the bidding target day by a certain value or more, the planning unit predicts that the electricity market price in the high price band on the predetermined day is higher than the electricity market price in the high price band on the bidding target day; when the predicted value of the electricity market price in the high price band on the predetermined day is not higher than the predicted value of the electricity market price in the high price band on the bidding target day by a certain value or more, the planning unit predicts that the electricity market price in the high price band on the predetermined day is not higher than the electricity market price in the high price band on the bidding target day.

[0010] In claim 4, the planning unit sets the predetermined remaining amount to a value obtained by subtracting the power generation amount of the power generation unit on the predetermined day from the capacity of the storage battery.

[0011] In claim 5, the acquisition unit predicts the electricity market price based on at least any one of weather information, electricity charge performance, power generation amount and demand amount performance, power plant operation information, or exchange rate.

Advantages of the Invention

[0012] As an effect of the present invention, the following effects are achieved.

[0013] In claim 1, the electricity sales revenue can be effectively increased.

[0014] In claim 2, the electricity sales revenue can be more effectively increased.

[0015] In claim 3, it is possible to suppress a decrease in the electricity sales revenue due to prediction deviation.

[0016] In claim 4, the electricity sales revenue can be more effectively increased.

[0017] In claim 5, the electricity market price can be accurately predicted.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0019] Hereinafter, the charge-discharge planning system 100 according to an embodiment of the present invention will be described.

[0020] The charge-discharge planning system according to an embodiment of the present invention creates a charge-discharge plan (hereinafter referred to as "charge-discharge plan") for the storage battery 31 of the power selling system 1 shown in FIG. 1. Hereinafter, first, the configuration of the power selling system 1 will be described with reference to FIG. 1.

[0021] The power selling system 1 shown in FIG. 1 generates electricity using sunlight and sells the generated electricity. In the present embodiment, the power selling system 1 is one in which a storage station is provided adjacent to a solar power generation station. The users of the power selling system 1 and the charge-discharge planning system 100 are, for example, power generation companies. The power selling system 1 mainly includes a power generation system 20, a power storage system 30, and a control device 40.

[0022] The power generation system 20 is capable of generating electricity using sunlight. The power generation system 20 includes a solar power generation unit 21 and a power conditioner 22.

[0023] The solar power generation unit 21 is a device that generates electricity using sunlight. The solar power generation unit 21 is composed of a solar cell panel or the like. The solar power generation unit 21 is installed in a sunny place such as on the roof of a building. The solar power generation unit 21 is connected to the power conditioner 22 described later.

[0024] The power conditioner 22 is a power conditioner that can appropriately convert power. The power conditioner 22 is connected to the solar power generation unit 21 as described above.

[0025] The power storage system 30 is capable of charging and discharging electricity. The power storage system 30 includes a storage battery 31 and a power conditioner 32.

[0026] The storage battery 31 is capable of charging and discharging electricity. The storage battery 31 is composed of, for example, a lithium-ion battery or the like. The storage battery 31 is connected to the power conditioner 32 described later.

[0027] The power conditioner 32 is a power conditioner that can appropriately convert power. The power conditioner 32 is connected to the storage battery 31 as described above. Also, the power conditioner 32 is arranged closer to the utility power source S than the power conditioner 22.

[0028] The control device 40 controls the operation mode of the power storage system 30. The control device 40 is connected to the power conditioner 32 of the power storage system 30.

[0029] The control device 40 can control the storage battery 31 via the power conditioner 32. More specifically, the control device 40 controls the charging and discharging of the storage battery 31 via the power conditioner 32 based on a pre-created charging and discharging plan. The charging and discharging plan is created by the charging and discharging plan creation system 100.

[0030] In the power selling system 1 configured as described above, the electric power generated by the solar power generation unit 21 is first charged into the storage battery 31, and the surplus electric power is sold back to the grid power supply S by reverse power flow. Also, the power selling system 1 can sell the electric power discharged from the storage battery 31 back to the grid power supply S by reverse power flow. Further, the power selling system 1 can purchase electric power from the grid power supply S and charge the storage battery 31. The trading of electric power is carried out in the wholesale power market.

[0031] Here, the main wholesale power market is the one-day-ahead market (spot market). The one-day-ahead market is a market where electricity trading is conducted on the day before the bidding target day (the day of actual supply and demand). In the one-day-ahead market, trading is carried out for 48 products (48 frames) obtained by dividing one day into 30-minute units.

[0032] Generally, the electricity market price in the wholesale power market is relatively low during late night and daytime hours when demand is low, and relatively high during early morning (around 6 - 8 o'clock) and evening (around 16 - 20 o'clock) hours when demand is high. Therefore, by charging the storage battery 31 during late night and daytime hours when the electricity market price is relatively low, and discharging the storage battery 31 during early morning and evening hours when the electricity market price is relatively high, it is possible to increase the power selling profit (profit from power selling).

[0033] In order to increase the power selling profit obtained by such charging and discharging of the storage battery 31, the charge / discharge plan creation system 100 creates a charge / discharge plan for the storage battery 31. As shown in FIG. 2, the charge / discharge plan creation system 100 includes an information acquisition unit 110 and a calculation unit 120.

[0034] The information acquisition unit 110 acquires various types of information. The information acquisition unit 110 can acquire information for predicting the power generation amount by the solar power generation unit 21 and information for predicting the electricity market price via a network such as the Internet.

[0035] The calculation unit 120 performs various calculations. Based on the information acquired by the information acquisition unit 110, the calculation unit 120 can predict the amount of power generated by the solar power generation unit 21 (hereinafter referred to as "solar power generation amount") and the power market unit price. Further, the calculation unit 120 can create a charge / discharge plan based on the predicted value of the solar power generation amount and the predicted value of the power market unit price. The calculation unit 120 creates a charge / discharge plan such that the battery 31 is charged in the low-price band where the power market price is low during the day and the battery 31 is discharged in the high-price band where the power market price is high during the day.

[0036] The calculation unit 120 creates a charge / discharge plan by executing the plan creation control shown in FIG. 3. Hereinafter, the method for creating the charge / discharge plan will be described using the flowchart shown in FIG. 3. The plan creation control shown in FIG. 3 is executed once a day. Note that the bidding in the wholesale power market (one-day-ahead market) is performed based on the charge / discharge plan created by executing the plan creation control shown in FIG. 3. The plan creation control shown in FIG. 3 needs to be performed by 10:00 am on the day of the one-day-ahead market bidding. For example, it is executed at 21:00 on the day before the day when the one-day-ahead market bidding is performed.

[0037] Hereinafter, the day when the one-day-ahead market bidding is performed (the day after the day when the charge / discharge plan is created) will be referred to as the "current day", the bidding target day (that is, the day after the day when the one-day-ahead market bidding is performed) will be referred to as "one day ahead", the day after the bidding target day will be referred to as "two days ahead", and the day after the day after the bidding target day will be referred to as "three days ahead".

[0038] Figure 4(b) is a graph showing an example of the transition of the solar power generation amount, the electricity market price, and the remaining battery level in the conventional case. Figure 4(b) is a graph showing an example of the transition of the solar power generation amount, the electricity market price, and the remaining battery level in the charge / discharge plan creation system 100 according to the present embodiment. Note that the solar power generation amount, the electricity market price, and the remaining battery level shown in FIGS. 4(a) and 4(b) are predicted values. In the example shown in FIG. 4(b), January 4th is the "current day" on which the bidding is conducted, January 5th is the "one day ahead" which is the target day for bidding, January 6th is the "two days ahead" which is the day after the target day for bidding, January 7th is the "three days ahead" which is the day after the day after the target day for bidding, and the plan creation control is executed at 21:00 on January 3rd.

[0039] In step S11, the calculation unit 120 predicts the solar power generation amount up to two days ahead. The calculation unit 120 predicts the solar power generation amount up to two days ahead (one day ahead and two days ahead) based on the weather information and the solar radiation forecast up to two days ahead (one day ahead and two days ahead) acquired via the information acquisition unit 110, and the data of the past solar power generation amount, etc. As shown in FIG. 4(b), on the planned day of January 3rd, the calculation unit 120 predicts the solar power generation amounts on January 5th and January 6th. Note that in FIG. 4(b), the predicted values of the solar power generation amount for each day obtained by executing the plan creation control shown in FIG. 3 once a day are shown.

[0040] After performing the process of step S11, the calculation unit 120 proceeds to step S12.

[0041] In step S12, the calculation unit 120 predicts the electricity market price from one day ahead (more specifically, from one day ahead to early morning of two days ahead). The calculation unit 120 predicts the electricity market price from one day ahead to early morning of two days ahead based on the weather information (El Niño, La Niña, heavy snow information, etc.), the actual performance of the electricity bill, the actual performance of the solar power generation amount and the demand amount, the operation information of the power plant, the exchange rate, etc., and the data of the past electricity market price, etc. The prediction result of the electricity market price is acquired for each frame (48 frames a day) divided into 30-minute units. As shown in FIG. 4(b), on the planned day of January 3rd, the calculation unit 120 predicts the electricity market price from January 5th to early morning of January 6th.

[0042] After the arithmetic unit 120 performs the process of step S12, it proceeds to step S13. Hereinafter, for the sake of simplicity of explanation, the predicted value of the solar power generation amount may be simply referred to as the "solar power generation amount", and the predicted value of the electricity market unit price may be simply referred to as the "electricity market unit price".

[0043] In step S13, the arithmetic unit 120 determines whether the predicted value of the solar power generation amount two days ahead obtained in step S11 exceeds the battery capacity (solar power generation amount two days ahead > battery capacity). Here, the "battery capacity" means the chargeable amount (maximum capacity) of the storage battery 31. As shown in FIG. 4(b), on the planned day of January 3, the arithmetic unit 120 determines whether the solar power generation amount on January 6 > the battery capacity.

[0044] If the arithmetic unit 120 determines that the solar power generation amount two days ahead > the battery capacity (YES in step S13), it proceeds to step S19. On the other hand, if the arithmetic unit 120 determines that the solar power generation amount two days ahead > the battery capacity is not satisfied (NO in step S13), it proceeds to step S14.

[0045] Note that the case where the solar power generation amount two days ahead > the battery capacity (YES in step S13) means that it is predicted that the storage battery 31 can be fully charged by the solar power generation amount two days ahead. On the other hand, the case where the solar power generation amount two days ahead > the battery capacity is not satisfied (NO in step S13) means that it is predicted that the storage battery 31 cannot be fully charged only by the solar power generation amount two days ahead. For example, when the weather two days ahead is not excellent, there is a possibility that the storage battery 31 cannot be fully charged only by the solar power generation amount two days ahead.

[0046] In step S14, the arithmetic unit 120 obtains the prediction result of the electricity market price two days ahead (more specifically, from two days ahead to early morning three days ahead). The arithmetic unit 120 obtains the prediction result of the electricity market price from two days ahead to early morning three days ahead based on weather information (El Niño, La Niña, heavy snow information, etc.), past electricity bill records, past records of solar power generation and demand, operation information of power plants, exchange rates, and past electricity market price data, etc. The prediction result of the electricity market price is obtained for each frame (48 frames per day) divided into 30-minute units. As shown in Fig. 4(b), on the planned day of January 3, the arithmetic unit 120 predicts the electricity market price from January 6 to early morning of January 7.

[0047] After performing the process of step S14, the arithmetic unit 120 proceeds to step S15.

[0048] In step S15, the arithmetic unit 120 determines whether the predicted value of the electricity market price two days ahead (from two days ahead to early morning three days ahead) predicted in step S14 exceeds the predicted value of the electricity market price one day ahead (from one day ahead to early morning two days ahead) predicted in step S12 (electricity market price two days ahead > electricity market price one day ahead). More specifically, the arithmetic unit 120 determines whether the predicted value of the highest electricity market price among the frames (30 minutes) from two days ahead to early morning three days ahead exceeds the predicted value of the highest electricity market price among the frames (30 minutes) from one day ahead to early morning two days ahead. When it takes a plurality of frames (30 minutes) to discharge from the storage battery 31, the arithmetic unit 120 may make the determination by comparing the total value or average value, etc. of the electricity market prices of the frames required for discharge among the frames with a high electricity market unit price.

[0049] If the arithmetic unit 120 determines that the electricity market price two days ahead > the electricity market price one day ahead (in step S15, "YES"), it proceeds to step S16. On the other hand, if the arithmetic unit 120 determines that the electricity market price two days ahead > the electricity market price one day ahead is not true (in step S15, "NO"), it proceeds to step S19.

[0050] Note that when the electricity market price two days ahead > the electricity market price one day ahead (YES in step S15), it means that even if the discharge amount from the storage battery 31 one day ahead (from one day ahead to early morning two days ahead) is reduced, selling electricity profit will increase more if the discharge amount from the storage battery 31 two days ahead (from two days ahead to early morning three days ahead) is increased.

[0051] In step S16, the calculation unit 120 determines the discharge amount from the storage battery 31 one day ahead (more specifically, from the night one day ahead to early morning two days ahead). In this process, the calculation unit 120 does not discharge all the remaining charge in the storage battery 31 from the night one day ahead to early morning two days ahead, but discharges a part of the power charged in the storage battery 31 so that a predetermined remaining amount remains in the storage battery 31. More specifically, the calculation unit 120 sets the discharge amount from the storage battery 31 from the night one day ahead to early morning two days ahead so that the remaining charge amount in the storage battery 31 after discharge is "battery capacity - solar power generation amount two days ahead" (that is, the value obtained by subtracting the "solar power generation amount two days ahead" from the "battery capacity"). That is, when the maximum value of the remaining charge amount in the storage battery 31 on one day ahead (the remaining charge amount immediately before discharge) is 100% of the battery capacity, the calculation unit 120 sets the discharge amount from the storage battery 31 from the night one day ahead to early morning two days ahead to the same amount as the solar power generation amount two days ahead.

[0052] For example, in the example shown in FIG. 4, assuming that the solar power generation amount two days ahead (January 6) is 70% of the battery capacity, the discharge amount from the storage battery 31 from the night one day ahead (January 5) to early morning two days ahead (January 6) is set so that the remaining charge amount in the storage battery 31 after discharge is 30%. That is, when the maximum value of the remaining charge amount in the storage battery 31 on one day ahead (January 5) (the remaining charge amount immediately before discharge) is 100% of the battery capacity, the discharge amount from the storage battery 31 from the night one day ahead (January 5) to early morning two days ahead (January 6) is set to 70% of the battery capacity (that is, the amount corresponding to the solar power generation amount two days ahead (January 6)).

[0053] Also, if the combined solar power generation amount for the day after tomorrow and the day after the day after tomorrow is still less than the battery capacity (100% of the battery capacity), then on the day after tomorrow, the battery 31 will not be discharged, and all the power charged in the battery 31 will be carried over (set aside) for the day after the day after tomorrow.

[0054] After performing the process of step S16, the arithmetic unit 120 proceeds to step S17.

[0055] In step S17, the arithmetic unit 120 determines the discharge amount from the battery 31 for the day after the day after tomorrow (more specifically, from the night of the day after the day after tomorrow to the early morning of the third day). Specifically, the arithmetic unit 120 sets the amount obtained by adding "the solar power generation amount for the day after the day after tomorrow + the carry - over amount from the day after tomorrow" (that is, the solar power generation amount for the day after the day after tomorrow plus the carry - over amount (the remaining amount after discharging from the battery 31 on the day after tomorrow)) as the discharge amount from the battery 31 at night on the day after the day after tomorrow.

[0056] After performing the process of step S17, the arithmetic unit 120 proceeds to step S18.

[0057] In step S18, the arithmetic unit 120 creates charge - discharge plans for the day after tomorrow and the day after the day after tomorrow. Specifically, the arithmetic unit 120 creates charge - discharge plans for the day after tomorrow and the day after the day after tomorrow based on the discharge amount from the battery 31 from the night of the day after tomorrow to the early morning of the third day determined in step S16 and the discharge amount from the battery 31 at night on the day after the day after tomorrow determined in step S17, etc. More specifically, the arithmetic unit 120 allocates the discharge amount determined in step S16 to the discharge times from the battery 31 in order from the time zones with high electricity market unit prices during the period from the night of the day after tomorrow to the early morning of the third day. Also, the arithmetic unit 120 allocates the discharge amount determined in step S17 to the discharge times from the battery 31 in order from the time zones with high electricity market unit prices during the period from the night of the day after the day after tomorrow to the early morning of the fourth day.

[0058] After performing the process of step S18, the arithmetic unit 120 ends the plan creation control shown in FIG. 3.

[0059] On the other hand, in step S19, the arithmetic unit 120 creates a charge / discharge plan to discharge all of the remaining charge in the storage battery 31 from the night of the day after tomorrow to the early morning of the day after that. Specifically, the arithmetic unit 120 allocates the discharge time from the storage battery 31 in order from the time zone with the highest electricity market unit price between the night of the day after tomorrow and the early morning of the day after that.

[0060] For example, when the electricity market unit price at night the day after tomorrow is higher than the electricity market unit price in the early morning the day after that, the arithmetic unit 120 creates a charge / discharge plan to discharge all of the remaining charge in the storage battery 31 at night the day after tomorrow. On the other hand, when the electricity market unit price in the early morning the day after that is higher than the electricity market unit price at night the day after tomorrow, the arithmetic unit 120 creates a charge / discharge plan to discharge all of the remaining charge in the storage battery 31 in the early morning the day after that. Also, when the time zone with the highest electricity market unit price is divided between the night of the day after tomorrow and the early morning of the day after that, it may be discharged from the storage battery 31 separately for the night of the day after tomorrow and the early morning of the day after that. In this way, in step S19, in order to maximize the selling electricity profit, a charge / discharge plan is created to discharge all of the remaining charge in the storage battery 31 in the high price band with a high electricity market unit price (in order from the time zone with the highest electricity market unit price).

[0061] After performing the process of step S19, the arithmetic unit 120 ends the plan creation control shown in FIG. 3. The charge / discharge plan created by the plan creation control shown in FIG. 3 can be reflected in the bidding in the electricity market.

[0062] As described above, in the charge / discharge plan creation system 100 according to the present embodiment, the battery 31 is preferentially discharged on days when the electricity market unit price is high. In particular, when it is predicted that the solar power generation amount will be small even though the day after the bidding target day is a day with a high electricity market unit price, by carrying over a part of the power charged in the battery 31 on the bidding target day to the day after the bidding target day, the electricity sales profit can be expanded. In the example shown in FIG. 4(b), instead of discharging all of the power charged in the battery 31 at night on January 5 as in the prior art shown in FIG. 4(a), a part of the power charged in the battery 31 at night on January 5 is discharged, and the remaining power is carried over to January 6. As a result, in the high price band on January 6 where the electricity market unit price is higher than on January 5, it is possible to discharge the power of 100% of the battery capacity charged in the battery 31.

[0063] As described above, the charge / discharge plan creation system 100 according to the present embodiment is a charge / discharge plan creation system 100 that creates a charge / discharge plan for a rechargeable battery 31 using the power generated by a solar power generation unit 21 (a power generation unit capable of generating power using natural energy), an information acquisition unit 110 and an arithmetic unit 120 (acquisition unit) that acquire predicted values of electricity market prices on the bidding target day of the electricity market and the day after the bidding target day (a predetermined day after the day after the bidding target day) (step S11), an arithmetic unit 120 (plan creation unit) that creates the charge / discharge plan for the bidding target day so as to charge the battery 31 in a low price band where the predicted value of the electricity market price is low among the bidding target days and discharge the battery 31 in a high price band where the predicted value of the electricity market price is higher than the low price band, and includes the arithmetic unit 120 (plan creation unit) determines the discharge amount from the battery 31 on the bidding target day based on a comparison between the predicted value of the electricity market price on the bidding target day and the predicted value of the electricity market price on the day after the bidding target day (steps S15 and S16).

[0064] With such a configuration, the revenue from selling electricity can be effectively increased. Specifically, by determining the discharge amount from the storage battery 31 on the bid target date in consideration of the predicted value of the electricity market price on the day after the bid target date, for example, when it is predicted that the electricity market price on the day after the bid target date is higher than that on the bid target date, the discharge amount from the storage battery 31 on the bid target date can be set to an amount that can ensure the discharge amount from the storage battery 31 on the day after the bid target date.

[0065] Also, the information acquisition unit 110 and the calculation unit 120 (acquisition unit) acquire the predicted values of the power generation amounts of the solar power generation unit 21 on the bid target date and the day after the bid target date, The calculation unit 120 (plan creation unit) If it is predicted that the power generation amount of the solar power generation unit 21 on the day after the bid target date is less than the capacity of the storage battery 31 (NO in step S13), and it is predicted that the electricity market price in the high-price band on the day after the bid target date is higher than the electricity market price in the high-price band on the bid target date (YES in step S15), the discharge amount from the storage battery on the bid target date is set to the discharge amount that leaves a predetermined remaining amount in the storage battery (step S16).

[0066] With such a configuration, the revenue from selling electricity can be more effectively increased. Specifically, by carrying over a part of the power charged in the storage battery 31 on the bid target date to the day after the bid target date, the discharge amount from the storage battery 31 in the time zone with a higher electricity market unit price can be increased, and thus the revenue from selling electricity can be more effectively increased.

[0067] Also, the calculation unit 120 (plan creation unit) sets the predetermined remaining amount to a value obtained by subtracting the power generation amount of the solar power generation unit 21 on the day after the bid target date from the capacity of the storage battery 31 (step S16).

[0068] With such a configuration, the revenue from selling electricity can be more effectively increased. Specifically, since the storage battery 31 can be fully charged on the day after the bidding target date, the amount of power discharged from the storage battery 31 can be increased during a time period when the electricity market unit price is higher, and thus the electricity sales revenue can be more effectively increased.

[0069] Also, the calculation unit 120 (acquisition unit) predicts the electricity market price based on at least any one of weather information, past electricity charges, past power generation amounts and demand amounts, operation information of power generation plants, or exchange rates (steps S12 and S14).

[0070] With such a configuration, the electricity market price can be accurately predicted.

[0071] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above configuration, and various modifications are possible within the scope of the invention described in the claims.

[0072] For example, in this embodiment, the solar power generation amount and the electricity market price up to the day after the bidding target date (2 days ahead) are predicted, and based on the prediction results, if necessary, a part of the power charged to the storage battery 31 on the bidding target date (1 day ahead) is carried over to the day after the bidding target date (2 days ahead). However, the solar power generation amount and the electricity market price up to several days (3 days or more ahead) after the day after the bidding target date may be predicted, and based on the prediction results, the day to carry over the power may be determined.

[0073] Also, in this embodiment, the configuration has the solar power generation unit 21 as the power generation unit, but instead of the solar power generation unit 21, it may have other power supply sources (for example, a hydroelectric power generation unit or a wind power generation unit that generates electricity using natural energy other than sunlight, etc.).

[0074] In addition, although this embodiment does not assume that the electric power generated by the solar power generation unit 21 is used in the power selling system 1, the power selling system 1 may use the electric power generated by the solar power generation unit 21 within the system. In this case, in step S11, the calculation unit 120 reads "solar power generation amount" as "sellable amount" and performs processing. Here, the sellable amount is calculated by "(solar power generation amount - demand amount)" (that is, subtracting the "electric power demand amount within the power selling system 1" from the "solar power generation amount").

[0075] In addition, in this embodiment, the calculation unit 120 predicts the solar power generation amount and the electricity market price. However, those that predict the solar power generation amount and the electricity market price outside the charge and discharge plan creation system 100 may be used for creating the charge and discharge plan. That is, the information acquisition unit 110 may acquire the predicted values of the solar power generation amount and the electricity market price from the outside.

[0076] In addition, in this embodiment, when the electricity market price on the day after the bidding target day (2 days ahead) is higher than the electricity market price on the bidding target day (1 day ahead) and the solar power generation amount on the day after the bidding target day (2 days ahead) is less than the battery capacity, a part of the electric power charged in the storage battery 31 on the bidding target day (1 day ahead) is carried over to the day after the bidding target day (2 days ahead). However, if the storage battery 31 cannot be fully charged on the day after the bidding target day (2 days ahead) even so, the storage battery 31 may be charged with the electric power from the grid power source S in the low price band.

[0077] In addition, in this embodiment, the control device 40 is configured to be provided outside the power storage system 30. However, it may be configured to be provided inside the power storage system 30, such as being incorporated inside the storage battery 31, and its configuration is not limited.

[0078] In addition, in this embodiment, the charge and discharge plan creation system 100 is configured to be provided outside the control device 40. However, it may be configured to be provided inside the control device 40, and its configuration is not limited.

[0079] Also, in the present embodiment, in step S15, it is determined whether the electricity market price two days ahead is > the electricity market price one day ahead. When the determination in step S15 is YES, a part of the electricity charged to the storage battery 31 on the bidding target day (one day ahead) is carried over to the day after the bidding target day (two days ahead). However, the determination in step S15 may be made as in step S15a shown in FIG. 5.

[0080] Specifically, when the difference between the predicted value of the electricity market price on the day after the bidding target day and the predicted value of the electricity market price on the bidding target day is equal to or greater than a certain value X, it is determined that the electricity market price on the day after the bidding target day is higher than the electricity market price on the bidding target day (YES in step S15a). When the difference between the predicted value of the electricity market price on the day after the bidding target day and the predicted value of the electricity market price on the bidding target day is less than the certain value X, it may be determined that the electricity market price on the day after the bidding target day is not higher than the electricity market price on the bidding target day (NO in step S15a).

[0081] Thereby, due to prediction deviation, it is possible to suppress the situation where, although the electricity market price on the bidding target day is actually higher than that on the day after the bidding target day, a part of the electricity charged to the storage battery 31 on the bidding target day is carried over to the day after the bidding target day.

[0082] As described above, the arithmetic unit 120 (planning unit) When the predicted value of the electricity market price in the high price band on the day after the bidding target day is higher than the predicted value of the electricity market price in the high price band on the bidding target day by a certain value or more (YES in step S15a shown in FIG. 5), it is predicted that the electricity market price in the high price band on the day after the bidding target day is higher than the electricity market price in the high price band on the bidding target day. When the predicted value of the electricity market price in the high price band on the day after the bidding target day is not higher than the predicted value of the electricity market price in the high price band on the bidding target day by a certain value or more (NO in step S15a shown in FIG. 5), it is predicted that the electricity market price in the high price band on the day after the bidding target day is not higher than the electricity market price in the high price band on the bidding target day.

[0083] With such a configuration, it is possible to suppress a decrease in power selling profit due to a prediction deviation.

Explanation of Signs

[0084] 21 Photovoltaic power generation unit 31 Storage battery 100 Charge / discharge plan creation system 110 Information acquisition unit 120 Calculation unit

Claims

1. A charge / discharge planning system that creates a charge / discharge plan for a rechargeable battery with the electric power generated by a power generation unit capable of generating power using natural energy, an acquisition unit that acquires predicted values of power market prices on the bidding target date and on predetermined days after the day following the bidding target date, a planning unit that creates the charge / discharge plan for the bidding target date such that the battery is charged in a low price range where the predicted value of the power market price on the bidding target date is low, and the battery is discharged in a high price range where the predicted value of the power market price on the bidding target date is higher than the low price range, comprising: wherein the planning unit determines the discharge amount from the battery on the bidding target date based on a comparison between the predicted value of the power market price on the bidding target date and the predicted value of the power market price on the predetermined day, a charge / discharge planning system.

2. wherein the acquisition unit acquires predicted values of the power generation amount of the power generation unit on the bidding target date and on the predetermined day, wherein the planning unit when it is predicted that the power generation amount of the power generation unit on the predetermined day is less than the capacity of the battery and it is predicted that the power market price in the high price range on the predetermined day is higher than the power market price in the high price range on the bidding target date, sets the discharge amount from the battery on the bidding target date to a discharge amount that leaves a predetermined remaining amount in the battery, the charge / discharge planning system according to Claim 1.

3. wherein the planning unit when the predicted value of the power market price in the high price range on the predetermined day is higher than the predicted value of the power market price in the high price range on the bidding target date by a certain value or more, predicts that the power market price in the high price range on the predetermined day is higher than the power market price in the high price range on the bidding target date, when the predicted value of the power market price in the high price range on the predetermined day is not higher than the predicted value of the power market price in the high price range on the bidding target date by a certain value or more, predicts that the power market price in the high price range on the predetermined day is not higher than the power market price in the high price range on the bidding target date, the charge / discharge planning system according to Claim 2.

4. wherein the planning unit sets the predetermined remaining amount to a value obtained by subtracting the power generation amount of the power generation unit on the predetermined day from the capacity of the battery. The charge / discharge plan creation system according to claim 2 or claim 3.

5. The acquisition unit predicts the electricity market price based on at least any one of weather information, electricity charge performance, power generation amount and demand amount performance, power plant operation information, or exchange rate. The charge / discharge plan creation system according to claim 1.

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