Power control system and power control method

Abstract

To contribute to a reduction in emission of carbon oxide.SOLUTION: A power control system includes: a power generation unit that generates electric power using renewable energy; a stored energy unit that stores at least part of the power generated by the power generation unit; a power consumption unit that consumes the power generated by the power generation unit and the power stored by the stored energy unit; a prediction unit that predicts fluctuations in the power generated by the power generation unit and the power consumed by the power consumption unit, and predicts occurrence of excess and deficiency of the power stored by the stored energy unit; and a demand control unit that activates demand control for reducing the power consumption of the power consumption unit in the case where a shortage of the power stored by the stored energy power is predicted to occur.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power control system and a power control method. [Background technology]

[0002] In recent years, power generation using renewable energy such as solar power generation has become widespread in an effort to move towards a decarbonized society. However, in power generation using renewable energy, the amount of power generated is not kept constant, and it is difficult to stably supply electricity, as the amount of power generated by solar power generation is greatly affected by weather conditions.

[0003] Therefore, various technologies are being considered to store surplus electricity in storage batteries or hydrogen during periods when electricity generation is high, and use the stored electricity to cover power shortages during periods when electricity generation is low. By storing surplus electricity generated using renewable energy in this way, it is thought that it will be possible to eliminate the need for electricity derived from fossil fuels such as thermal power plants, and operate buildings such as buildings and factories without emitting carbon dioxide.

[0004] However, when the stored surplus electricity is insufficient, electricity must be received from outside, which leads to an increase in carbon dioxide emissions. That is, for example, when the amount of electricity generated by solar power generation is small or when the building's electricity demand is high, the surplus electricity stored in the storage battery or hydrogen may be insufficient. In such cases, electricity derived from fossil fuels must be received from an external power company or the like to make up for the shortage, which leads to an increase in carbon dioxide emissions. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2017 / 013751 [Patent Document 2] International Publication No. 2019 / 159377 [Patent Document 3] JP 2018-133939 A [Patent Document 4] Patent Publication No. 2022-77667 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a power control system and a power control method that can contribute to reducing carbon dioxide emissions. [Means for solving the problem]

[0007] According to one aspect of the present invention, a power control system has a power generation unit that generates power using renewable energy, an energy storage unit that stores at least a portion of the power generated by the power generation unit, a power consumption unit that consumes the power generated by the power generation unit and the power stored by the energy storage unit, a prediction unit that predicts fluctuations in the power generated by the power generation unit and the power consumed by the power consumption unit and predicts an occurrence of an surplus or shortage of power stored by the energy storage unit, and a demand control unit that activates demand control to reduce power consumption by the power consumption unit when a shortage of power stored by the energy storage unit is predicted to occur.

[0008] According to this configuration, when a shortage of stored power is predicted and external power reception is required, demand control is implemented to reduce power consumption and prevent external power reception. This avoids the need to receive fossil fuel-derived power from external power companies, thereby contributing to the reduction of carbon dioxide emissions.

[0009] According to another aspect of the present invention, the energy storage unit has a hydrogen generation unit that generates hydrogen by electrolyzing water using the electricity obtained by the power generation unit, a hydrogen storage unit that stores the hydrogen generated by the hydrogen generation unit, and a hydrogen power generation unit that generates electricity using the hydrogen stored in the hydrogen storage unit.

[0010] According to this configuration, energy is stored in the form of hydrogen, and when electricity is needed, it is possible to generate electricity with high efficiency and supply the electricity.

[0011] According to another aspect of the present invention, the energy storage unit includes a power storage unit that stores power in a storage battery that is charged with the power obtained by the power generation unit.

[0012] According to this configuration, electric power can be easily stored and supplied by charging and discharging the storage battery.

[0013] According to another aspect of the present invention, the demand control unit determines the level and period of the demand control to be activated depending on the predicted date and time of occurrence of external power reception, which occurs when the power stored by the energy storage unit is insufficient, and reverse power flow, which occurs when the power stored by the energy storage unit is excessive.

[0014] According to this configuration, power consumption can be reduced so that external power reception does not occur, depending on the predicted occurrence status of power reception from an external power system or reverse power flow to an external power system.

[0015] According to another aspect of the present invention, the demand control unit selects a level of the demand control capable of reducing the power corresponding to the external power reception from a plurality of levels each having a different amount of reduction in power consumption by the power consumption unit.

[0016] According to this configuration, for example, when reducing power consumption due to lighting, air conditioning, etc. in a building, it is possible to realize demand control that takes into account loss of comfort.

[0017] According to another aspect of the present invention, the demand control unit determines the period of the demand control so as to reduce the power corresponding to the external power reception after the date and time of the last reverse power flow occurring before the date and time of the external power reception.

[0018] According to this configuration, unnecessary demand control is not initiated before the date and time when reverse power flow occurs, and the occurrence of external power reception can be reliably avoided.

[0019] According to another aspect of the present invention, a power control method is a power control method in a power control system having a power generation unit that generates power using renewable energy, an energy storage unit that stores at least a portion of the power generated by the power generation unit, and a power consumption unit that consumes the power generated by the power generation unit and the power stored by the energy storage unit, the method predicts fluctuations in the power generated by the power generation unit and the power consumed by the power consumption unit, predicts an occurrence of an surplus or shortage of power stored by the energy storage unit, and when a shortage of power stored by the energy storage unit is predicted, invokes demand control to reduce power consumption by the power consumption unit.

[0020] According to this method, when a shortage of stored power is predicted and external power reception is required, power consumption is reduced by demand control, and external power reception is avoided. This means that fossil fuel-derived electricity is not received from external power companies, and this contributes to reducing carbon dioxide emissions. Effect of the Invention

[0021] The present invention can contribute to reducing carbon dioxide emissions. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a block diagram showing a configuration of a power control system according to an embodiment. [Diagram 2] FIG. 2 is a flow diagram showing an example of hydrogen production control. [Diagram 3] FIG. 3 is a flow diagram showing another example of hydrogen production control. [Figure 4] FIG. 4 is a flow diagram showing an example of hydrogen power generation control. [Diagram 5]FIG. 5 is a flow diagram showing another example of hydrogen power generation control. [Figure 6] FIG. 6 is a flow diagram illustrating a power control method according to one embodiment. [Figure 7] FIG. 7 is a flow diagram showing the external power reception prediction process. [Figure 8] FIG. 8 is a flow diagram showing the demand control determination process. [Figure 9] FIG. 9 is a diagram showing a specific example of demand control. [Figure 10] FIG. 10 is a diagram showing a specific example of an external power receiving prediction result. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The embodiment described below is merely an example, and should not be construed as being limited by this description.

[0024] Fig. 1 is a block diagram showing a configuration of a power control system 100 according to an embodiment. The power control system 100 is housed in a structure such as a building or a factory, and controls the power consumed in the structure. The power control system 100 shown in Fig. 1 includes a power receiving unit 110, a renewable energy power generation unit (hereinafter referred to as "renewable energy power generation unit") 120, an energy storage unit 130, a power consumption unit 140, an energy storage control unit (hereinafter referred to as "energy storage control unit") 150, a prediction unit 160, and a demand control unit 170.

[0025] The power receiving unit 110 receives power from an external power system, such as an electric power company. The power receiving unit 110 also receives power from the renewable energy power generation unit 120 and the energy storage unit 130. The power receiving unit 110 stores the received power in the energy storage unit 130 and causes the power consumption unit 140 to consume the power. Furthermore, the power receiving unit 110 transmits surplus power that cannot be stored in the energy storage unit 130 to the power system. Note that, hereinafter, power received from the power system is also referred to as "externally received power", and surplus power transmitted to the power system is also referred to as "reverse flow power".

[0026] The renewable energy power generation unit 120 generates power using renewable energy. Specifically, the renewable energy power generation unit 120 generates power using renewable energy such as solar power, wind power, or biomass. The renewable energy power generation unit 120 transmits the generated power to the power receiving unit 110.

[0027] The energy storage unit 130 stores surplus power when power generated by the renewable energy power generation unit 120 is not consumed. Furthermore, when power generated by the renewable energy power generation unit 120 is insufficient, the energy storage unit 130 discharges the insufficient power. Specifically, the energy storage unit 130 has a power storage unit 131, a hydrogen generation unit 132, a hydrogen storage unit 133, and a hydrogen power generation unit 134.

[0028] The power storage unit 131 has, for example, a storage battery, charges the storage battery with surplus power, and discharges the power from the storage battery when there is a power shortage.

[0029] The hydrogen generating unit 132 has, for example, a water electrolysis device, and generates hydrogen by electrolyzing water using surplus power. The hydrogen storage unit 133 stores the hydrogen generated by the hydrogen generation unit 132 . The hydrogen power generation unit 134 has, for example, a fuel cell, and generates electricity using the hydrogen stored in the hydrogen storage unit 133 .

[0030] In this way, the energy storage unit 130 stores power using the storage battery and hydrogen. The storage battery has a faster response speed than the hydrogen equipment, and therefore plays a role in short-term supply and demand adjustment, for example, on an hourly or daily basis, while the hydrogen equipment plays a role in long-term supply and demand adjustment, for example, on a monthly basis or longer.

[0031] The power consumption unit 140 consumes power according to the power demand of the building that houses the power control system 100. That is, the power consumption unit 140 has, for example, air conditioning and lighting, and consumes power supplied from the power receiving unit 110. Furthermore, when demand control is activated by the demand control unit 170, the power consumption unit 140 reduces the power it consumes. Demand control will be described in detail later.

[0032] The energy storage control unit 150 controls the storage of surplus power by the energy storage unit 130. That is, the energy storage control unit 150 controls the charging and discharging of the power storage unit 131, and also controls whether or not hydrogen generation by the hydrogen generation unit 132 and hydrogen power generation by the hydrogen power generation unit 134 are operated. The control of the power storage unit 131, the hydrogen generation unit 132, and the hydrogen power generation unit 134 by the energy storage control unit 150 will be described in detail later.

[0033] The prediction unit 160 predicts fluctuations in the amount of power generated by the renewable energy power generation unit 120 and the amount of power consumed by the power consumption unit 140. At this time, the prediction unit 160 predicts fluctuations in the amount of power generated and the amount of power consumed throughout the year for each hour, based on, for example, an annual weather forecast and past power consumption.

[0034] The prediction unit 160 predicts the occurrence of an excess or shortage of power stored by the energy storage unit 130 from the hourly fluctuations in the amount of power generated and the amount of power consumed. That is, the prediction unit 160 predicts the control of the power storage unit 131, the hydrogen generation unit 132, and the hydrogen power generation unit 134 by the energy storage control unit 150 based on the hourly fluctuations in the amount of power generated and the amount of power consumed, and predicts the occurrence of an excess or shortage of the amount of storage in the power storage unit 131 and the hydrogen storage unit 133. When the amount of storage is insufficient, external power reception occurs, in which the insufficient power is received from the power grid, and when the amount of storage is excessive, reverse power flow occurs, in which the surplus power is transmitted to the power grid. Therefore, the prediction unit 160 predicts the occurrence of external power reception and reverse power flow throughout the year using the prediction results of the hourly fluctuations in the amount of power generated and the amount of power consumed.

[0035] The demand control unit 170 initiates demand control to reduce the power consumed by the power consumption unit 140 based on the prediction result by the prediction unit 160. Specifically, when it is predicted that external power reception will occur throughout the year, the demand control unit 170 decides to initiate demand control. When it is decided to initiate demand control, the demand control unit 170 determines the level and period of demand control to be initiated according to the date and time when external power reception and reverse power flow will occur, and initiates demand control of the determined level and period. Demand control will be described in detail later.

[0036] Next, a description will be given of the control of the power storage unit 131, the hydrogen generation unit 132, and the hydrogen power generation unit 134 by the energy storage control unit 150. The energy storage control unit 150 controls the charging and discharging of the power storage unit 131 as follows.

[0037] Since the storage battery of the power storage unit 131 is used for short-term supply and demand adjustment, the energy storage control unit 150 controls charging and discharging while monitoring the operating status of each unit. That is, the energy storage control unit 150 monitors the amount of power generated by the renewable energy power generation unit 120, the power consumption according to the power demand in the power consumption unit 140, the power consumption by the hydrogen generation unit 132, and the amount of power generated by the hydrogen power generation unit 134, and controls the charging and discharging of the power storage unit 131 based on these amounts of power generation and power consumption. The charge / discharge amount of the power storage unit 131 is determined by the following formula (1). Charge / discharge amount = (renewable energy power generation amount + hydrogen power generation amount) - (demand power consumption + hydrogen generation power consumption) (1)

[0038] In formula (1), if the charge / discharge amount is positive, it indicates the charge amount, and if the charge / discharge amount is negative, it indicates the discharge amount. For example, when the amount of renewable energy power generation by the renewable energy power generation unit 120 is 50 kW, the power consumption according to the power demand in the power consumption unit 140 is 10 kW, and the power consumption of the hydrogen generation unit 132 is 32.5 kW, the charge / discharge amount in the above formula (1) is +7.5 kW, so the power storage unit 131 charges 7.5 kW. Also, for example, when the amount of renewable energy power generation by the renewable energy power generation unit 120 is 5 kW, the power generation by the hydrogen power generation unit 134 is 5 kW, and the power consumption according to the power demand in the power consumption unit 140 is 30 kW, the charge / discharge amount in the above formula (1) is -20 kW, so the power storage unit 131 discharges 20 kW. Such control of the power storage unit 131 is executed in a cycle of, for example, milliseconds to one second.

[0039] The energy storage control unit 150 controls the hydrogen generation unit 132 as follows. That is, the energy storage control unit 150 determines whether or not to operate hydrogen generation by the hydrogen generation unit 132 depending on the amount of power stored in the power storage unit 131. While the power storage unit 131 is controlled in cycles of, for example, milliseconds to one second, the hydrogen generation unit 132 is controlled in cycles of, for example, 30 minutes. This is because the response speed of the hydrogen equipment is slower than that of a storage battery.

[0040] A first example of hydrogen production control will be described with reference to the flow chart shown in FIG.

[0041] The energy storage control unit 150 compares the amount of power stored in the storage battery of the power storage unit 131 with a predetermined threshold value P1 (step S101). If the comparison shows that the amount of power stored is greater than the predetermined threshold value P1 (Yes in step S101), the energy storage control unit 150 decides to operate hydrogen generation by the hydrogen generation unit 132 (step S102). On the other hand, if the amount of power stored is equal to or less than the predetermined threshold value P1 (No in step S101), the energy storage control unit 150 decides to stop hydrogen generation by the hydrogen generation unit 132 (step S103).

[0042] Thus, according to the first example of hydrogen generation control, when there is sufficient electricity stored in the power storage unit 131 to be used for short-term supply and demand adjustment, hydrogen for long-term supply and demand adjustment is generated by the hydrogen generation unit 132 and stored in the hydrogen storage unit 133.

[0043] A second example of hydrogen production control will be described with reference to the flow chart shown in FIG.

[0044] The energy storage control unit 150 judges whether or not hydrogen generation by the hydrogen generation unit 132 is in operation (step S111). If the result of this judgment is that hydrogen generation is in operation (step S111 Yes), the energy storage control unit 150 compares the amount of power stored in the storage battery of the power storage unit 131 with a predetermined threshold value P1 (step S112). If the result of the comparison is that the amount of power storage is greater than the predetermined threshold value P1 (step S112 Yes), the energy storage control unit 150 judges whether or not the continuous operation time of hydrogen generation by the hydrogen generation unit 132 is equal to or less than a predetermined threshold value (step S113). Then, if the continuous operation time is equal to or less than the predetermined threshold value (step S113 Yes), the energy storage control unit 150 decides to continue hydrogen generation by the hydrogen generation unit 132 (step S114). On the other hand, if the amount of stored power is equal to or less than the predetermined threshold P1 (No in step S112) or if the continuous operation time exceeds the predetermined threshold (No in step S113), the energy storage control unit 150 decides to stop hydrogen generation by the hydrogen generation unit 132 (step S115).

[0045] On the other hand, if the result of the determination in step S111 is that hydrogen generation is not in operation (step S111 No), the energy storage control unit 150 compares the amount of power stored in the storage battery of the power storage unit 131 with a predetermined threshold value P1 (step S116). If the result of the comparison is that the amount of power storage is greater than the predetermined threshold value P1 (step S116 Yes), the energy storage control unit 150 determines whether the amount of power generated by the renewable energy power generation unit 120 is greater than the power consumption in the power consumption unit 140 (step S117). Then, if the amount of power generated by the renewable energy power generation unit 120 is greater than the power consumption (step S117 Yes), the energy storage control unit 150 decides to start hydrogen generation by the hydrogen generation unit 132 (step S118). In contrast, if the amount of stored power is equal to or less than the predetermined threshold P1 (No in step S116) or if the amount of power generated by the renewable energy power generation unit 120 is equal to or less than the power consumption (No in step S117), the energy storage control unit 150 decides to continue to stop hydrogen generation by the hydrogen generation unit 132 (step S119).

[0046] Thus, according to the second example of hydrogen generation control, hydrogen is generated by the hydrogen generation unit 132 and stored in the hydrogen storage unit 133, provided that sufficient power is stored in the power storage unit 131, the continuous operating time is not long, or power consumption can be covered by renewable energy power generation.

[0047] The energy storage control unit 150 controls the hydrogen power generation unit 134 as follows. That is, the energy storage control unit 150 determines whether or not to operate hydrogen power generation by the hydrogen power generation unit 134, depending on the amount of power stored in the power storage unit 131. When the amount of power generated by the renewable energy power generation unit 120 alone is insufficient, the power shortage is made up for by discharging from the power storage unit 131, but when the supply and demand adjustment capacity is insufficient with only this discharging, power generation using hydrogen is carried out.

[0048] A first example of hydrogen power generation control will be described with reference to the flow chart shown in FIG.

[0049] The energy storage control unit 150 compares the amount of power stored in the storage battery of the power storage unit 131 with a predetermined threshold value P2 (step S201). If the comparison shows that the amount of power stored is less than the predetermined threshold value P2 (step S201 Yes), the energy storage control unit 150 determines whether or not a sufficient amount of hydrogen for generating power is stored in the hydrogen storage unit 133 (step S202). If the amount of hydrogen stored is sufficient (step S202 Yes), the energy storage control unit 150 decides to operate hydrogen power generation by the hydrogen power generation unit 134 (step S203). On the other hand, if the amount of power stored is equal to or greater than the predetermined threshold value P2 (step S201 No) or if the amount of hydrogen stored is insufficient (step S202 No), the energy storage control unit 150 decides to stop hydrogen power generation by the hydrogen power generation unit 134 (step S204).

[0050] Thus, according to the first example of hydrogen power generation control, when the amount of electricity stored in the power storage unit 131 is low and sufficient hydrogen is stored, power is generated by the hydrogen power generation unit 134, thereby compensating for the supply and demand adjustment capability of the power storage unit 131.

[0051] A second example of hydrogen power generation control will be described with reference to the flow chart shown in FIG.

[0052] The energy storage control unit 150 determines whether hydrogen power generation by the hydrogen power generation unit 134 is in operation (step S211). If this determination results in hydrogen power generation being in operation (Yes in step S211), the energy storage control unit 150 determines whether the continuous operation time of hydrogen power generation by the hydrogen power generation unit 134 is equal to or less than a predetermined threshold (step S212). If the continuous operation time is equal to or less than the predetermined threshold (Yes in step S212), the energy storage control unit 150 decides to continue hydrogen power generation by the hydrogen power generation unit 134 (step S213). On the other hand, if the continuous operation time exceeds the predetermined threshold (No in step S212), the energy storage control unit 150 decides to stop hydrogen power generation by the hydrogen power generation unit 134 (step S214).

[0053] On the other hand, if the result of the determination in step S211 is that hydrogen power generation is not in operation (step S211 No), the energy storage control unit 150 compares the amount of power stored in the storage battery of the power storage unit 131 with a predetermined threshold value P2 (step S215). If the result of the comparison is that the amount of power storage is smaller than the predetermined threshold value P2 (step S215 Yes), the energy storage control unit 150 determines whether the power shortage in the power consumption unit 140 is greater than the amount of power that can be generated by the hydrogen power generation unit 134 (step S216). If the power shortage in the power consumption unit 140 is greater than the amount of power that can be generated by hydrogen (step S216 Yes), the energy storage control unit 150 determines whether a sufficient amount of hydrogen is stored in the hydrogen storage unit 133 to generate power (step S217). If the amount of hydrogen storage is sufficient (step S217 Yes), the energy storage control unit 150 decides to start hydrogen power generation by the hydrogen power generation unit 134 (step S218). In contrast, if the amount of stored power is equal to or greater than the predetermined threshold P2 (step S215 No), if the power shortage in the power consumption unit 140 is equal to or less than the amount of hydrogen power generation possible (step S216 No), or if the amount of hydrogen stored is insufficient (step S217 No), the energy storage control unit 150 decides to continue stopping hydrogen power generation by the hydrogen power generation unit 134 (step S219).

[0054] Thus, according to the second example of hydrogen power generation control, power generation is performed by the hydrogen power generation unit 134 under the conditions that the amount of power stored in the power storage unit 131 is insufficient and the amount of hydrogen stored is sufficient, and in addition, the continuous operating time is not extended or surplus power is not generated by hydrogen power generation.

[0055] Next, a power control method in the power control system configured as above will be described with reference to the flow chart shown in Fig. 6. In this power control method, the occurrence of external power reception from the power grid is predicted, for example, on an annual basis, and demand control is performed to reduce power consumption so that external power reception does not occur.

[0056] First, the prediction unit 160 predicts the annual power consumption by the power consumption unit 140 (step S301). That is, the power consumption by the power consumption unit 140 throughout the year is predicted for each hour based on, for example, an annual weather forecast and past power consumption. In addition, the prediction of the power consumption may take into account, for example, the schedule of activities of users of the building that houses the power control system.

[0057] Then, the prediction unit 160 predicts the annual amount of power generated by the renewable energy power generation unit 120 (step S302). That is, the amount of power generated by solar power generation or wind power generation throughout the year is predicted for each hour based on, for example, an annual weather forecast.

[0058] After the power consumption and power generation throughout the year are predicted, the prediction unit 160 subsequently simulates the charging and discharging of the storage battery and the operation of the hydrogen equipment, and executes an external power reception prediction process for predicting the occurrence of external power reception and reverse power flow throughout the year (step S303). That is, based on the predicted power consumption and power generation, the control of the power storage unit 131, the hydrogen generation unit 132, and the hydrogen power generation unit 134 by the energy storage control unit 150 is predicted, and the occurrence of external power reception and reverse power flow is predicted. At this time, if it is predicted that a power shortage will occur as a result of predicting the control by the energy storage control unit 150, it is predicted that external power reception will occur, and if it is predicted that a power surplus will occur, it is predicted that reverse power flow will occur. The external power reception prediction process will be specifically described later with reference to FIG. 7.

[0059] When the occurrence of external power reception and reverse power flow is predicted by the external power reception prediction process, the demand control unit 170 executes a demand control determination process for determining whether or not to activate demand control based on the prediction result (step S304). Specifically, when it is predicted that external power reception will occur throughout the year, the demand control unit 170 determines that demand control will be activated. When demand control is activated, the demand control unit 170 calculates the level of demand control and the period for which it will be activated. The demand control determination process will be specifically described later with reference to Figs. 8 to 10.

[0060] In this way, according to the power control method of the present embodiment, when an external power reception is predicted, demand control is initiated to reduce power consumption, thereby avoiding the occurrence of external power reception. This prevents the reception of fossil fuel-derived power from an external power company or the like, thereby contributing to the reduction of carbon dioxide emissions.

[0061] Next, the external power receiving prediction process will be specifically described with reference to the flow chart shown in Fig. 7. This external power receiving prediction process is mainly executed by the prediction unit 160.

[0062] First, a variable T representing time is set to 0 corresponding to the current time (step S401). Then, the prediction unit 160 acquires the amount of power storage and the amount of hydrogen storage at T=0 from the energy storage control unit 150 (step S402). That is, the amount of power storage in the power storage unit 131 and the amount of hydrogen storage in the hydrogen storage unit 133 at the current time are acquired from the energy storage control unit 150.

[0063] Then, the variable T representing time is incremented by 1 (step S403). Since the prediction unit 160 predicts the amount of power generation and power consumption throughout the year for each hour, it is determined whether or not power generation by the hydrogen power generation unit 134 is operating at time T based on these prediction results (step S404). In this determination, it is determined whether or not hydrogen power generation is operating, assuming that the energy storage control unit 150 executes, for example, the first hydrogen power generation control or the second hydrogen power generation control described above.

[0064] Similarly to the determination of whether hydrogen power generation is in operation, it is determined whether hydrogen generation by the hydrogen generation unit 132 is in operation at time T based on the predicted power generation and power consumption throughout the year (step S405). In this determination, it is determined whether hydrogen generation is in operation on the assumption that the energy storage control unit 150 executes, for example, the first hydrogen generation control or the second hydrogen generation control described above.

[0065] Then, based on whether hydrogen power generation and hydrogen generation are in operation and the predicted results of the power generation amount and power consumption, the charge / discharge amount of the power storage unit 131 is calculated by the above formula (1) (step S406). That is, the renewable energy power generation amount, hydrogen power generation amount, demand power consumption, and hydrogen generation power consumption in the above formula (1) are each found from whether hydrogen power generation and hydrogen generation are in operation and the predicted results of the power generation amount and power consumption, and the charge / discharge amount is calculated.

[0066] Once the charge and discharge amounts of the power storage unit 131 are calculated in this manner, the external received power and reverse flow power at time T are calculated based on the calculation results (step S407). Specifically, if discharging is decided even though there is no remaining power in the power storage unit 131, it is predicted that external power reception from the power grid will occur. The shortfall in the discharge amount in this case is then recorded as the external received power. On the other hand, if charging is decided even though the power storage unit 131 is full, it is predicted that reverse flow to the power grid will occur. The charge amount in this case is then recorded as the reverse flow power.

[0067] When the external received power and the reverse flow power at time T are calculated, the amount of power stored in power storage unit 131 at time T is calculated (step S408). Specifically, the amount of power stored at time T is calculated by the following formula (2). Energy storage amount (T) = Energy storage amount (T-1) + Charge amount (T) - Discharge amount (T) (2)

[0068] That is, the amount of power stored at time T is calculated from the amount of power stored at time (T-1) and the amount of charge and discharge at time T.

[0069] Similarly, the amount of hydrogen stored in hydrogen storage unit 133 at time T is calculated (step S409). Specifically, the amount of hydrogen stored at time T is calculated by the following formula (3). Hydrogen storage amount (T) = Hydrogen storage amount (T-1) + Hydrogen production amount (T) - Hydrogen consumption amount (T) (3)

[0070] In equation (3), the hydrogen production amount (T) indicates the amount of hydrogen produced by the hydrogen production unit 132 at time T, and the hydrogen consumption amount (T) indicates the amount of hydrogen consumed by the hydrogen power generation unit 134 at time T.

[0071] When the external received power, reverse flow power, power storage amount, and hydrogen storage amount at time T are predicted by the above processing, these predicted values ​​are stored in a predetermined memory or the like in association with time T. Then, by checking the value of variable T representing time, it is determined whether prediction for up to one year from the current time has been completed (step S410). If it is determined that prediction for up to one year from now has not been completed (step S410 No), the processing from step S403 is repeated.

[0072] On the other hand, if prediction up to one year from now has been completed (Yes in step S410), the dates and times when external power receiving and reverse flow will occur up to one year from the current time are identified (step S411). Specifically, the time T when external power receiving or reverse flow is predicted to occur is identified, and the external power receiving power or reverse flow power at each time T is read from a predetermined memory or the like. This completes the external power receiving prediction process for predicting external power receiving and reverse flow for the year.

[0073] Next, the demand control determination process will be specifically described with reference to the flow chart shown in Fig. 8. This demand control determination process is mainly executed by the demand control unit 170.

[0074] First, in the external power reception prediction process by the prediction unit 160, it is determined whether or not external power reception is predicted to occur within one year from the current time (step S501). That is, it is determined whether or not there is a time T at which external power reception is predicted to occur within one year from the current time. If the result of this determination is that external power reception will not occur within one year (step S501 No), it is determined that demand control is not required because fossil fuel-derived electricity is not used to operate the building that houses the power control system 100 (step S503).

[0075] On the other hand, if external power reception occurs within one year (Yes in step S501), it is determined that demand control is necessary because fossil fuel-derived power is used to operate the building that houses the power control system 100. Then, the level and period for invoking demand control are calculated (step S502). Specifically, the demand control has a plurality of levels, for example, as shown in FIG.

[0076] In the example shown in FIG. 9, for example, the demand control at level 1 is a control to reduce lighting by turning off unnecessary lights on the day when the building is in operation, and can reduce power consumption by 2.0 kWh per day. The demand control at level 1 is a control that can be implemented throughout the year. Similarly, the demand control at level 2 is a control to reduce lighting by turning off lights other than the minimum necessary lights in addition to the level 1, and can reduce power consumption by 4.0 kWh per day. The demand control at level 2 is a control that can be implemented throughout the year. Furthermore, the demand control at level 3 is a control to further relax the set temperature of the air conditioning (increasing the set temperature of the cooling and decreasing the set temperature of the heating) in addition to the level 2, and can reduce power consumption by 6.0 kWh per day. The demand control at level 3 is a control that can be implemented in summer or winter.

[0077] When it is determined that demand control is necessary, an activation level is determined from the above-mentioned multiple levels so that power equivalent to the predicted external received power is reduced, and an activation period is calculated. Here, the calculation of the activation level and activation period will be explained using a specific example. Consider a case where the external power receiving prediction process predicts that external power receiving will occur on dates D1, D2, D4, and D5, and reverse power flow will occur on date D3, as shown in FIG. 10. The date on which external power receiving will occur can be identified by aggregating the external power receiving power predicted for each hour on a daily basis.

[0078] In this case, it is necessary to reduce power consumption equivalent to external received power R1, R2 on dates D1, D2 by demand control before dates D1, D2, and to reduce power consumption equivalent to external received power R4, R5 on dates D4, D5 by demand control after date D3 and before dates D4, D5. In other words, external received power R4, R5 occurring on dates D4, D5 is reduced by demand control after date D3 when the last reverse power flow occurs before dates D4, D5.

[0079] Here, if the power consumption reduced per day by each level of demand control is DC1, DC2, and DC3, respectively, and the number of days for which each level of demand control is implemented is X1, X2, and X3, respectively, X1, X2, and X3 satisfy the following equation (4). DC1×X1+DC2×X2+DC3×X3>R1+R2+R4+R5...(4)

[0080] In addition, the number of days for which demand control at each level is to be performed during the period from the current time to date D1 is set to X 1,0-D1 , X 2,0-D1 , X 3,0-D1 Then, X 1,0-D1 , X 2,0-D1 , X 3,0-D1 satisfies the following equation (5). DC1×X 1,0-D1 +DC2×X 2,0-D1 +DC3×X 3,0-D1 >R1 (5)

[0081] In addition, the number of days for which each level of demand control is performed during the period from date D1 to date D2 is X 1,D1-D2 , X 2,D1-D2 , X 3,D1-D2 Then, X 1,D1-D2 , X 2,D1-D2 , X 3,D1-D2 satisfies the following equation (6). DC1×(X 1,0-D1 +X 1,D1-D2 )+DC2×(X 2,0-D1 +X 2,D1-D2 ) +DC3×(X 3,0-D1 +X3,D1-D2 )>R2 (6)

[0082] In addition, the number of days for which each level of demand control is performed during the period from date D3 to date D4 is X 1,D3-D4 , X 2,D3-D4 , X 3,D3-D4 Then, X 1,D3-D4 , X 2,D3-D4 , X 3,D3-D4 satisfies the following equation (7). DC1×(X 1,0-D1 +X 1,D1-D2 +X 1,D3-D4 ) +DC2×(X 2,0-D1 +X 2,D1-D2 +X 2,D3-D4 ) +DC3×(X 3,0-D1 +X 3,D1-D2 +X 3,D3-D4 )>R4 ···(7)

[0083] In addition, the number of days for which each level of demand control is performed during the period from date D4 to date D5 is set to X 1,D4-D5 , X 2,D4-D5 , X 3,D4-D5 Then, X 1,D4-D5 , X 2,D4-D5 , X 3,D4-D5 satisfies the following equation (8). DC1×(X 1,0-D1 +X 1,D1-D2 +X 1,D3-D4 +X 1,D4-D5 ) +DC2×(X 2,0-D1 +X 2,D1-D2 +X 2,D3-D4 +X 2,D4-D5 ) +DC3×(X 3,0-D1 +X 3,D1-D2 +X 3,D3-D4 +X 3,D4-D5 )>R5 ···(8)

[0084] In the above formulas (4) to (8), the number of days for which demand control is performed at each level has the following relationship. X1=X 1,0-D1 +X 1,D1-D2 +X 1,D3-D4 +X1,D4-D5 X2=X 2,0-D1 +X 2,D1-D2 +X 2,D3-D4 +X 2,D4-D5 X3=X 3,0-D1 +X 3,D1-D2 +X 3,D3-D4 +X 3,D4-D5

[0085] If it is determined that demand control is necessary, the number of days for implementing demand control at each level is determined so as to satisfy the above formulas (4) to (8), and the activation level and activation period of demand control are determined for each of the period from the current time to date D1, the period from date D1 to date D2, the period from date D3 to date D4, and the period from date D4 to date D5. This demand control reduces the power consumption equivalent to the externally received power predicted to occur on dates D1, D2, D4, and D5, and can avoid the occurrence of external power reception. As a result, there is no need to receive fossil fuel-derived power from an external power company, etc., which can contribute to reducing carbon dioxide emissions.

[0086] There may be multiple solutions for the number of days for which demand control is performed that satisfy the above formulas (4) to (8). In this case, since the higher the level of demand control, the more likely it is that comfort will be lost, the solution that results in the fewer number of days for which high-level demand control is performed may be the optimal solution. This makes it possible to reduce power consumption while suppressing loss of comfort in the building that houses the power control system.

[0087] As described above, according to this embodiment, the annual power consumption and the amount of power generation using renewable energy are predicted, and the occurrence of external power reception and reverse power flow is predicted from the prediction results. Then, when the occurrence of external power reception is predicted, demand control that reduces power consumption is activated to avoid the occurrence of external power reception. Therefore, there is no need to receive fossil fuel-derived power from an external power company or the like, and it is possible to contribute to reducing carbon dioxide emissions.

[0088] In the above embodiment, the power consumption and power generation are predicted for each hour throughout the year, but the time unit of the prediction does not necessarily have to be one year and one hour. That is, if the power consumption and power generation are predicted for a relatively long period, such as one year, in a relatively short time unit, such as one hour, and the occurrence of external power reception and reverse power flow is predicted, it is possible to determine whether or not to activate demand control, as in the above embodiment.

[0089] In the above embodiment, the power control system is described as being housed in a structure such as a building or a factory, but the power control system according to the present disclosure can be widely applied to facilities that share a power supply source, not limited to structures. Therefore, the power control system according to the present disclosure can be applied to a facility having multiple structures, for example. [Explanation of symbols]

[0090] 100 Power Control System 110 Power receiving unit 120 Renewable Energy Power Generation Department 130 Energy storage unit 131 Power Storage Unit 132 Hydrogen Generation Unit 133 Hydrogen storage unit 134 Hydrogen Power Generation Department 140 Power consumption section 150 Energy storage control unit 160 Prediction Department 170 Demand control unit

Claims

1. A power generation unit that generates electricity using renewable energy; an energy storage unit that stores at least a portion of the power generated by the power generation unit; a power consumption unit that consumes the power generated by the power generation unit and the power stored in the energy storage unit; a prediction unit that predicts fluctuations in the power generated by the power generation unit and the power consumed by the power consumption unit, and predicts occurrence of an excess or deficiency of the power stored in the energy storage unit; a demand control unit that initiates a demand control to reduce power consumption by the power consumption unit when it is predicted that the power stored in the energy storage unit will be insufficient; and A power control system having the following configuration:

2. The energy storage unit is a hydrogen generating unit that generates hydrogen by electrolyzing water using the electric power obtained by the power generating unit; A hydrogen storage unit that stores hydrogen generated by the hydrogen generation unit; a hydrogen power generation unit that generates electricity by utilizing the hydrogen stored in the hydrogen storage unit; 2. The power control system of claim 1, comprising:

3. The energy storage unit is The power control system according to claim 1 , further comprising a power storage unit that stores power in a storage battery that is charged with the power obtained by the power generation unit.

4. The demand control unit is The power control system according to any one of claims 1 to 3, wherein a level and a period of the demand control to be activated are determined according to a predicted date and time of occurrence of external power reception, which occurs when the power stored by the energy storage unit is insufficient, and a reverse power flow, which occurs when the power stored by the energy storage unit is excessive.

5. The demand control unit is The power control system according to claim 4 , wherein the demand control level capable of reducing the power corresponding to the external power reception is selected from a plurality of levels having different reduction amounts of power consumption by the power consumption unit.

6. The demand control unit is The power control system according to claim 4 , wherein the period of the demand control is determined so as to reduce power corresponding to the external power reception after the date and time of occurrence of the last reverse power flow before the date and time of occurrence of the external power reception.

7. A building having a power control system, The power control system includes: A power generation unit that generates electricity using renewable energy; an energy storage unit that stores at least a portion of the power generated by the power generation unit; a power consumption unit that consumes the power generated by the power generation unit and the power stored in the energy storage unit; a prediction unit that predicts fluctuations in the power generated by the power generation unit and the power consumed by the power consumption unit, and predicts occurrence of an excess or deficiency of the power stored in the energy storage unit; a demand control unit that initiates a demand control to reduce power consumption by the power consumption unit when it is predicted that the power stored in the energy storage unit will be insufficient; and A structure having:

8. A power control method in a power control system having a power generation unit that generates power by utilizing renewable energy, an energy storage unit that stores at least a portion of the power generated by the power generation unit, and a power consumption unit that consumes the power generated by the power generation unit and the power stored by the energy storage unit, predicting fluctuations in the power generated by the power generation unit and the power consumed by the power consumption unit; predicting an occurrence of an excess or deficiency of the power stored by the energy storage unit; When it is predicted that the power stored in the energy storage unit will be insufficient, a demand control is initiated to reduce the power consumption by the power consumption unit. Power control methods.

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