Power control device and water heater control method

Abstract

To appropriately control boiling-up of a storage water heater on the basis of information on an earthquake that has occurred, even when prediction is difficult.SOLUTION: An electric power control device includes: an electric power control section that manages a user electric power system having an electric power load including a storage water heater and connected to a system electric power network and controls boiling-up of the storage water heater; an earthquake information acquisition section that acquires information related to earthquake occurrence from outside; and a hot water storage amount setting section for setting an emergency hot water storage amount that is a hot water storage amount to be secured in the storage water heater when the information related to earthquake occurrence is acquired. The electric power control section controls boiling-up of the storage water heater so as to secure the set emergency hot water storage amount until passage of an earthquake information linkage period that is preset as a period after the acquisition of the information related to earthquake occurrence.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This invention relates to a power control device and a water heater control method for controlling the boiling of a storage water heater, which is one of the power loads.

Background Art

[0002] There is known a power system for a home or a business establishment that includes a storage battery that is charged using power generated from renewable energy and power supplied from the grid power network, and can discharge to a power load and the grid power network. In addition, storage water heaters that boil water using electricity, such as heat pump water heaters sold under names such as EcoCute (registered trademark), are applied to homes and business establishments. The water heater control of the storage water heater in such a power system is as follows.

[0003] During the nighttime when the unit price of grid power is low, boil the amount of hot water predicted to be used the next day with a storage water heater, and provide the hot water stored in the storage water heater that has been boiled during other time periods when the unit price is high. Alternatively, by boiling the storage water heater with surplus power generated by self-generation using renewable energy such as solar power generation outside the nighttime, the amount of power supplied from the grid power network for boiling is suppressed as much as possible. The prediction of the amount of hot water used, in other words, the prediction of the target amount of stored hot water, is performed, for example, by learning the amount of hot water used daily in the past. Since the amount of hot water used varies depending on the season or time, for example, learn the amount of hot water used (history) in the past two weeks and predict the amount of stored hot water for each day that should be the target.

[0004] However, since heating water takes a certain amount of time, it is necessary to start heating early to avoid running out of hot water. For example, if the amount of hot water to be stored during nighttime hours is determined based on the average amount of hot water used in the past, the amount of hot water to be heated is not excessive because the storage amount is not set with a margin, but a shortage will occur on days with high usage. To prevent running out of hot water, it is necessary to predict the amount of hot water to be insufficient early and heat more water. Heating can be started manually by the user, but some systems use sensors to detect the amount of hot water used in the storage-type water heater, and a processor that controls the storage-type water heater makes a decision to start heating based on the trend of the stored amount and the amount of hot water used.

[0005] In addition to determining the amount of hot water to store based on historical data, the system may also heat the water until it is full, for example, if the user requests it. This might happen if the user wants to be prepared for a power outage in the grid due to a disaster. Regarding the control of water heating, there are known systems that acquire weather information related to weather disasters that are likely to cause power outages, such as special warnings, warnings, and advisories for heavy rain and strong winds. When a special warning or warning selected in advance by the user is issued, the system heats and secures a larger amount of hot water than usual in conjunction with the warning, and returns to normal heating when the warning is lifted.

[0006] Furthermore, although this concerns the charging control of storage batteries rather than storage-type water heaters, there is a known charge / discharge control device that has a mode for acquiring weather information related to weather disasters that are likely to cause power outages and controlling the charging and discharging of storage batteries according to the urgency of the acquired information (see, for example, Patent Document 1). In addition, there is a known device that controls charging and discharging in conjunction with thunderstorm advisories, not just with heavy rain warnings, heavy snow warnings, and storm warnings (see, for example, Patent Document 2). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2012-235541 [Patent Document 2] Japanese Patent Publication No. 2021-132494 [Overview of the project] [Problems that the invention aims to solve]

[0008] As mentioned above, some water heaters increase the hot water storage capacity to more than usual as a countermeasure against power outages caused by natural disasters. Of these natural disasters, earthquakes are the one that causes the most anxiety for electricity consumers. However, with current technology, it is practically impossible to predict the occurrence of earthquakes by specifying the date, time, and region, and the reality is that it is impossible to know when and where an earthquake will occur. Therefore, there has been no system that controls water heaters in conjunction with earthquake-related information. However, past examples have shown that there is a risk of a second earthquake occurring after a major earthquake, and that this second earthquake may cause a major power outage. In other words, it is empirically known that when a major earthquake occurs, the risk of aftershocks or main shocks related to the initial earthquake occurring in quick succession is higher than usual.

[0009] When faced with severe situations that could lead to natural disasters such as earthquakes, electricity consumers hope that even if a power outage occurs, they will have enough hot water stored in their water heaters to minimize the impact of the outage. However, providing disaster prevention weather information that specifies the date, time, and region, as is the case with typhoons, rainfall, low pressure systems, strong winds and the resulting floods, landslides, storm surges, and river overflows, is difficult when it comes to earthquakes. Patent Document 1 describes considering natural phenomena such as typhoons and thunderstorms, as well as earthquake swarms and volcanic eruptions, as precursors to earthquakes. Specifically, it describes receiving earthquake information from a server as precursor information, representing the region where an earthquake swarm occurred, the timing of the earthquake, and changes in the frequency of earthquake swarms, and then heating the water in an electric vehicle's storage-type water heater based on the received precursor information.

[0010] However, with current technology, there is a significant difference between the prediction accuracy of disaster prevention weather information and the accuracy of earthquake prediction. Disaster prevention weather information is issued as forecasts, including special warnings, warnings, and advisories, which provide information categorized by level of alert, allowing us to prepare for the risk of future disasters. On the other hand, the Japan Meteorological Agency does not issue special warnings, warnings, or advisories equivalent to forecasts for earthquakes. It only issues earthquake early warnings and earthquake information for earthquakes that have already occurred. Treating the two as equivalent is not realistic in some respects. From the perspective of electricity consumers, they feel more anxious about earthquakes, which are difficult to predict, than about typhoons or thunderstorms, which can be forecasted, and therefore want to prepare for earthquakes. This invention was made in consideration of the circumstances described above, and provides a method for appropriately securing the amount of hot water stored in a storage-type water heater based on information regarding earthquakes that have occurred, even if they are difficult to predict. [Means for solving the problem]

[0011] This invention provides a power control device that manages a consumer power system connected to a power grid and having a power load including a storage-type water heater, and controls the heating of the storage-type water heater; an earthquake information acquisition unit that acquires information related to the occurrence of an earthquake from an external source; and a storage volume setting unit that sets an emergency storage volume, which is the amount of hot water to be kept in the storage-type water heater when the information related to the occurrence of an earthquake is acquired. The power control unit controls the heating of the storage-type water heater to ensure the set emergency storage volume is secured until a predetermined earthquake information linkage period has elapsed since the information related to the occurrence of an earthquake was acquired.

[0012] Furthermore, from a different perspective, this invention provides a water heater control method comprising: a control unit that controls the heating of a storage-type water heater using electricity, the steps of: acquiring information related to the occurrence of an earthquake from an external source; setting an emergency hot water storage amount, which is the amount of hot water to be kept in the storage-type water heater, when the information related to the occurrence of an earthquake is acquired; and controlling the heating of the storage-type water heater to secure the set emergency hot water storage amount until a predetermined earthquake information linkage period has elapsed since the information related to the occurrence of an earthquake was acquired. [Effects of the Invention]

[0013] In the power control device according to this invention, the power control unit controls the heating of the storage-type water heater to secure a set emergency hot water storage amount until a predetermined earthquake information linkage period has elapsed, which is the period from when information related to the occurrence of an earthquake is acquired. Therefore, the amount of hot water stored in the storage-type water heater can be appropriately secured based on the information related to the earthquake that has occurred. The water heater control method according to this invention also produces similar effects. [Brief explanation of the drawing]

[0014] [Figure 1] This block diagram shows the configuration of a power control system including a power control device and a storage-type water heater according to this embodiment. [Figure 2] Figure 1 is an explanatory diagram showing an example of the weather and earthquake linkage settings screen related to power control, which is displayed on the control unit. [Figure 3] Figure 1 is an explanatory diagram showing the setting of emergency hot water storage capacity by the power control device and an example of the change in that hot water storage capacity. [Figure 4] Figure 1 is an explanatory diagram showing an example of the state transitions in the water heater control performed by the power control unit. [Figure 5] This is the first part of a flowchart showing an example of water heater control performed by the power control unit of the power control device shown in Figure 1. [Figure 6]It is the second part of a flowchart showing an example of water heater control executed by a power control unit etc. of the power control device shown in FIG. 1.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, this invention will be described in more detail with reference to the drawings. Note that the following description is illustrative in all respects and should not be construed as limiting this invention. (Embodiment 1) ≪Configuration of a Power Control System including a Power Control Device and a Storage-Type Water Heater≫ The configuration of a power control system including the power control device and the storage-type water heater according to this embodiment will be described based on FIG. 1. FIG. 1 is a block diagram showing the configuration of a power control system including the power control device and the storage-type water heater according to this embodiment. Note that FIG. 1 shows an example of a power control system installed in a detached house, but the installation location of the power control system is not limited to this. Also, in FIG. 1, the utility power grid 21 and the HEMS (Home Energy Management System) server 22 are also shown together with the power control system 10.

[0016] The power control system 10 according to this embodiment includes a solar cell module 11 as a self-power generation device using renewable energy, a storage battery 13, and a storage-type water heater 24. Further, it includes a water heater control device 25 for controlling the storage-type water heater 24 and a power control device 16. The self-power generation device using renewable energy is not limited to the solar cell module 11. For example, it may be wind power generation, biomass power generation, etc., or a combination thereof. The power control device 16 controls the transmission and reception of power to the solar cell module 11, the battery 13, the grid power 21, and the power loads that receive power, as well as to the battery 13 and the grid power 21 as recipients of power. It may also include a configuration for presenting power generation status to power consumers and for acquiring information necessary for power control from external sources. Furthermore, the power control device 16 has a function to set the amount of hot water stored in the hot water storage type water heater 24. It may also include a configuration for acquiring information related to the amount of hot water stored and used in the hot water storage type water heater 24. However, the configuration for acquiring information related to the amount of hot water stored and used is not mandatory and is optional.

[0017] The power control system 10 shown in Figure 1 further includes a power conditioner 12, a distribution board 14, a smart meter 15, a communication interface circuit 17, and an operation unit 18. The solar cell module 11 is a module that converts the light energy of sunlight into electrical energy. The power conditioner 12 is a device that converts the generated electricity so that it can be consumed by the load. Specifically, the power conditioner 12 converts the DC current output by the solar cell module 11 into AC current, etc.

[0018] The storage battery 13 is a hot water heater that stores electrical energy, and stores electrical energy generated by the solar cell module 11 or supplied from the power grid 21. The distribution board 14 collects electricity drawn in from the power grid 21 via the smart meter 15, as well as electricity from the solar cell modules 11 and the storage battery 13, and distributes the collected electricity to indoor electrical appliances 23 and the hot water heater 24. The smart meter 15 is a digital electricity meter that measures the amount of electricity used by electricity consumers (supply contract holders) and transmits the data to power generators and grid operators.

[0019] The power control device 16 acquires power information related to power generation from the power control system 10 and controls the operation of the power conditioner 12 according to that power information. Examples of power information include information indicating whether or not commercial power is purchased, information indicating the power generated by the solar cell module 11, and information indicating the charging power or discharging power of the storage battery 13. Furthermore, the power control device includes a hot water storage volume setting unit 16B for setting the amount of hot water stored in the hot water storage type water heater 24. Whether or not commercial electricity is purchased, and the amount of electricity purchased, can be determined by connecting a sensor to the power line connecting the smart meter 15 and the power grid 21, and analyzing the output value of that sensor. In addition, information indicating the power generated by the solar cell module 11 and the charging power of the storage battery 13 can be obtained via the power conditioner 12. Furthermore, since the battery 13 is connected to the power conditioner 12, the power control device 16 can control the battery 13, such as switching between charging and discharging, via the power conditioner 12.

[0020] In this embodiment, the power control device 16 is primarily composed of a CPU (Central Processing Unit) or MPU (Micro Processing Unit) and memory, from a hardware configuration standpoint. The CPU or MPU (hereinafter collectively referred to as the CPU) executes a processing program stored in the memory, thereby realizing the functions related to water heater control. Furthermore, it includes input / output circuits for controlling the power conditioner 12, communication interface circuit 17, etc. Furthermore, from a functional configuration standpoint, the system includes an earthquake information acquisition unit 16E, a remaining storage amount setting unit 16R, a power control unit 16C, and a hot water storage amount setting unit 16B. It also optionally includes a weather information acquisition unit 16W.

[0021] The earthquake information acquisition unit 16E acquires information related to earthquake occurrences from an external server connected via a communication interface circuit 17, which will be described later. Here, the information related to earthquake occurrences is, for example, an earthquake early warning issued by the Japan Meteorological Agency. An Earthquake Early Warning is issued by the Japan Meteorological Agency when a maximum seismic intensity of 5-minus or higher is expected at two or more seismic observation points. It provides information that quickly predicts the arrival time and intensity of strong shaking in various locations immediately after an earthquake occurs. The Earthquake Early Warning is information related to earthquake occurrences issued by the Japan Meteorological Agency with the aim of enabling disaster preparedness before strong shaking occurs at locations far from the epicenter.

[0022] Information related to earthquake occurrences may include, for example, earthquake information released by the Japan Meteorological Agency. Earthquake information is information that is released sequentially as data related to an earthquake becomes available after the earthquake occurs. Earthquake information is a general term for several pieces of information, including seismic intensity reports, information on the epicenter, information on seismic intensity in various locations, and other information. Seismic intensity reports announce the names of the areas that observed a seismic intensity of 3 or higher and the time the shaking was detected, approximately 1.5 minutes after the earthquake occurs. Information on the epicenter announces the epicenter and magnitude when a seismic intensity of 3 or higher is observed. Information on seismic intensity in various locations announces the locations that observed a seismic intensity of 1 or higher, as well as the epicenter and magnitude. The earthquake information acquisition unit 16E acquires updated information by sequentially obtaining information from the server that provides earthquake occurrence information as described above. This can be done by receiving information from the server or by accessing the server to acquire information.

[0023] The hot water storage volume setting unit 16B sets the amount of hot water (storage volume) to be stored in the storage-type water heater 24 when information regarding an earthquake is acquired. When the earthquake information acquisition unit 16E acquires information regarding an earthquake, the hot water storage volume setting unit 16B assumes that the power supply from the grid 21 will be cut off, i.e., a power outage will occur as the worst-case scenario. Then, it sets the emergency storage volume to be stored in the storage-type water heater 24 in preparation for a power outage. If no information regarding the occurrence of an earthquake is obtained and it is outside the earthquake information sharing period, the amount of hot water stored in the hot water storage type water heater 24 will be set by the water heater control device 25, regardless of the emergency hot water storage amount set by the hot water storage amount setting unit 16B. The emergency hot water storage capacity may be set by the user via the operation unit 18, or, for example, the hot water storage capacity setting unit 16B may set a predetermined hot water storage capacity. The predetermined hot water storage capacity may be full capacity, or the hot water storage capacity setting unit 16B may set an emergency hot water storage capacity that is larger than past usage based on the amount of hot water stored in the hot water storage type water heater 24. For example, it may be set to 50% more than past usage. Of course, the upper limit of the setting is full capacity.

[0024] Regarding the charging and discharging of the battery 13, the remaining charge setting unit 16R sets the remaining charge that should be stored in the battery 13. When the earthquake information acquisition unit 16E acquires information related to the occurrence of an earthquake, the remaining charge setting unit 16R sets an emergency remaining charge that should be stored in the battery 13 in preparation for a power outage. Furthermore, the emergency reserve capacity of the battery 13 may be set by the user via the operation unit 18. Alternatively, the reserve capacity setting unit 16R may predict the amount of power consumed by the load from the present until a predetermined period of independent operation has elapsed, and calculate an amount of power corresponding to the predicted amount of power as the emergency reserve capacity. In this case, the reserve capacity setting unit 16R obtains the current time, the preset emergency reserve capacity, and the predicted amount of power consumed from the present until the period of independent operation has elapsed, and calculates the reserve capacity of the battery 13 that can cover the predicted power consumption until the period of independent operation has elapsed. However, if power generation from a power generation device using renewable energy such as a solar cell module 11 can be expected under the predicted weather conditions, that amount of power generation may be subtracted.

[0025] The predicted power consumption from the present until the period of independent operation has elapsed can be predicted, for example, based on past power consumption data, i.e., history. The history data may be stored as history by the power control device 16, or it may be stored in a HEMS server 22 that can communicate via the communication interface circuit 17. The predicted power consumption may be based on past normal daily power consumption. Alternatively, it may be set to a value greater than normal daily consumption in preparation for emergencies. It may be calculated by multiplying the normal daily power consumption by a predetermined percentage (for example, a 20% increase), or by adding a predetermined amount of power consumption.

[0026] Unlike information such as disaster prevention weather information, which is issued and then cancelled, information regarding earthquake occurrences is not cancelled. Therefore, the setting of emergency hot water storage capacity and emergency remaining capacity, which is initiated upon acquisition of earthquake occurrence information, will remain valid from the time the information is acquired until the predetermined earthquake information sharing period has elapsed. It should be noted that after an earthquake occurs, a new earthquake may occur several hours to several days later, and this new earthquake may cause a power outage. For this reason, it is preferable that the earthquake information sharing period be one day or longer, for example, three days. When the earthquake information sharing period ends, the hot water storage volume setting unit 16B disables the emergency hot water storage volume setting, and the hot water heater control device 25 controls the heating of the hot water storage type water heater 24 in the state it was in before the earthquake information was acquired.

[0027] Regarding the charge and discharge control of the battery 13, when information related to an earthquake is acquired, the power control unit 16C controls the charge and discharge of the battery 13 so as to store the emergency reserve amount set by the reserve amount setting unit 16R in the battery 13. For example, every 15 minutes, the power control unit 16C compares the emergency reserve amount set by the reserve amount setting unit 16R with the remaining capacity of the battery 13 and determines whether to charge, discharge, or maintain the current state of the battery 13 without charging or discharging. 15 minutes is just an example, but it is preferable to set an interval long enough for the predicted value to follow the changes in power consumption of the power control system 10. Also, when the reserve amount setting unit 16R updates the reserve amount, it is preferable that the timing is synchronized with the update of the predicted value.

[0028] In this embodiment, the power control device 16 manages information related to the power control system 10 and performs processing related to communication with the outside. Specifically, the power control device 16 transmits power information acquired by at least one of the power conditioner 12, distribution board 14, and smart meter 15 to an information management server (not shown) of the power generator or grid operator. Furthermore, it may acquire information related to the amount of hot water stored and used from the hot water storage type water heater 24. In addition, the power control device 16 acquires information necessary for power control of the power control system 10 from an information management server of the power generator or grid operator outside the system.

[0029] The communication interface circuit 17 is a device that connects the power control device 16 to the network NW. Furthermore, in Figure 1, the communication interface circuit 17 constitutes a local area network within the electricity consumer's home and communicates with the external network NW (e.g., the Internet). Although not shown in Figure 1, the local area network within the home may also be connected to a storage-type water heater 24, and various other devices such as air conditioners (so-called air conditioners and air purifiers), televisions, and cooking appliances, which are specific examples of electrical equipment 23. This makes it possible to allow the electricity consumer to check the operating status of each device, including the storage-type water heater 24, via the HEMS server 22, and to allow the electricity consumer to control the operation of each device. In addition, sensors that detect the amount of hot water stored and used by the storage-type water heater 24, and data transmitters that transmit sensing information such as detected values ​​of power or current supplied to each device, or room temperature, may also be connected. In this case, the power control device 16 can recognize the power consumption of the devices within the home. Furthermore, it can be presented to electricity consumers.

[0030] In this embodiment, the operation unit 18 consists of a portable communication terminal equipped with communication and information output functions. Power consumers of the power control system 10 can use the operation unit 18 to check the power generation status of the power control system 10 and set the emergency hot water storage capacity. The operating unit 18 is preferably, more specifically, a smartphone or tablet device, but is not limited to such mobile communication terminals; it may also be a stationary terminal device such as a personal computer. The operating unit 18 communicates via a local area network or an external network NW. In the case of a mobile communication terminal, communication is assumed to be wireless, but in the case of a stationary terminal device, wired communication may be used.

[0031] The weather information acquisition unit 16W acquires weather information from an external server that provides weather information, which is connected via the communication interface circuit 17. Here, the weather information is, for example, disaster prevention weather information issued by the Japan Meteorological Agency, and types such as special warnings, warnings, and advisories are set for each category such as heavy rain, strong winds, and lightning. However, because it is difficult to predict lightning with high accuracy, special warnings and warnings are not provided, and only advisories are provided. The weather information is updated as needed. The weather information acquisition unit 16W accesses the server that provides weather information sequentially to acquire the updated weather information. As an example, the weather information acquisition unit 16W accesses the server at intervals of about 15 minutes to acquire weather information.

[0032] In an embodiment equipped with a weather information acquisition unit 16W, when the weather information acquisition unit 16W acquires information related to the issuance of disaster prevention weather information, the hot water storage volume setting unit 16B assumes a power outage in the grid 21 as the worst-case scenario. Then, according to the level of alert, such as a special warning, warning, and advisory, it instructs the hot water heater control device 25 to store the emergency reserve amount to be stored in the storage battery 13.

[0033] If disaster prevention weather information is acquired along with information related to the occurrence of an earthquake, the hot water storage volume setting unit 16B may adopt the larger of the emergency storage volume corresponding to the occurrence of the earthquake and the emergency storage volume corresponding to the alert level of the disaster prevention weather information as the emergency storage volume. In other words, the hot water storage volume setting unit 16B has separate setting values ​​for the emergency storage volume corresponding to the occurrence of an earthquake and the emergency storage volume corresponding to the disaster prevention weather information. The emergency storage volume corresponding to the disaster prevention weather information may also be an emergency hot water storage volume corresponding to the type and alert level of the disaster prevention weather information.

[0034] The hot water storage volume setting unit 16B applies the emergency hot water storage volume corresponding to the earthquake to the hot water storage type water heater 24 as the emergency hot water storage volume from the time information related to the occurrence of an earthquake is acquired until the earthquake information linkage period has elapsed. At the same time, it allows heating, which is normally only done during nighttime hours, to occur outside of nighttime hours as well, so that the amount of hot water stored decreases due to use and is quickly restored. On the other hand, during the period from the issuance of disaster prevention weather information until it is lifted (weather information linkage period), the hot water storage volume setting unit 16B applies the emergency hot water storage volume corresponding to the issued disaster prevention weather information to the hot water storage type water heater 24 as the emergency hot water storage volume. If the earthquake information linkage period and the weather information linkage period overlap, the hot water storage volume setting unit 16B should apply the larger of the emergency hot water storage volume corresponding to the earthquake occurrence and the emergency hot water storage volume corresponding to the issued disaster prevention weather information.

[0035] The above describes the emergency hot water storage capacity of the storage-type water heater 24, but the same can be said for the emergency remaining capacity of the storage battery 13. However, with respect to the emergency remaining capacity of the storage battery 13, if it is expected that electricity will be generated by a power generation device using renewable energy such as a solar cell module 11 under predicted weather conditions, that amount of electricity may be deducted.

[0036] Figure 2 is an explanatory diagram showing an example of the weather and earthquake linkage settings screen displayed on the operation unit 18. The operation unit 18 shown in Figure 2 is a mobile communication terminal. The weather and earthquake linkage settings screen 19 shown in Figure 2 has a setting display area 19a at the top that displays the currently selected weather linkage function. In the example shown in Figure 2, the system accepts settings to enable / disable the weather information linkage, thunderstorm warning linkage, and earthquake information linkage functions for the charge / discharge control of the battery 13 and the water heating control of the hot water heater 24, respectively. The weather information linkage, thunderstorm warning linkage, and earthquake information linkage functions can be selected and deselected by the user in the settings described later within the weather / earthquake linkage settings screen 19. A home icon is located at the far right of the settings display area 19a. Tapping the home icon transitions the user from the weather / earthquake linkage settings screen 19 (shown in Figure 2) to a home screen (not shown). The home screen displays the current power flow and power amount of the power control system 10, indicating whether it is currently purchasing or selling electricity. Furthermore, it displays the current generated power, power consumption, battery charging or discharging power, and power received or transmitted from the grid 21. If information on the amount of hot water stored in the hot water heater 24 and the amount of hot water used can be obtained, this information may also be displayed. Below the setting display area 19a, the regional setting 19b is located. The regional setting 19b is a screen for setting the region from which the weather information acquisition unit 16W should acquire weather information. This item is for setting the region in which the power control system 10 is installed. In the example in Figure 2, the regional setting is accepted by postal code.

[0037] Below the regional setting 19b, the weather information linkage setting 19c is located. The weather information linkage setting 19c accepts settings to enable weather information linkage for both the charge / discharge control of the battery 13 and the water heating control of the hot water storage type water heater 24. Furthermore, it accepts individual selections of weather information for which warnings and special warnings will be issued. In the example shown in Figure 2, individual selections are accepted for various weather information such as storm, blizzard, heavy rain, flood, storm surge, heavy snow, and high waves. In addition, regarding the level of alert for the selected weather information, it accepts selections of alert levels, such as whether to target only special warnings or special warnings and warnings. In the example shown in Figure 2, the selection of various weather information is common to both the charge / discharge control of the battery 13 and the water heating control of the hot water storage type water heater 24. However, it is not limited to this, and individual selections of various weather information may be accepted for each of the charge / discharge control of the battery 13 and the water heating control of the hot water storage type water heater 24. In the example shown in Figure 2, for weather information linkage setting 19c, only warnings and special warnings, which are higher in alert level than advisories, are set for each weather information category: storm, blizzard, heavy rain, flood, storm surge, heavy snow, and high waves. As a variation, advisories may also be included as options.

[0038] Lightning strikes are likely to cause power outages in the power grid, but no warnings or special warnings are issued for lightning strikes. Therefore, the thunderstorm warning linkage setting 19d is placed below the weather information linkage setting 19c. The thunderstorm warning linkage setting 19d accepts the option to enable or disable the thunderstorm warning linkage function for the charging and discharging control of the battery 13 and the heating control of the hot water heater 24, in addition to the weather information linkage function described above. The lightning warning linkage setting 19d accepts settings for enabling or disabling the lightning warning linkage function, as well as settings for the hold time related to the charge / discharge control of the battery 13. The hold time setting is displayed below the setting for enabling or disabling the lightning warning linkage function for the charge / discharge control of the battery 13.

[0039] The retention time related to the setting is the retention time that the remaining battery level setting unit 16R applies as the emergency remaining battery level corresponding to the thunderstorm warning when the thunderstorm warning linkage function is enabled and a thunderstorm warning has been issued. Therefore, for example, if the weather information linkage function and earthquake information linkage function are disabled, the thunderstorm warning linkage function is enabled, and a thunderstorm warning has been issued, the remaining battery level of the storage battery 13 corresponding to the retention time set in the thunderstorm warning linkage setting 19d (i.e., the period during which independent operation is possible) will be applied as the emergency remaining battery level. Alternatively, if the weather information linkage function, earthquake information linkage function, and thunderstorm warning linkage function are enabled, but a thunderstorm warning has been issued and no other weather information has been issued and no information related to the occurrence of an earthquake has been acquired, the remaining battery level corresponding to the retention time set in the thunderstorm warning linkage setting 19d will be applied as the emergency remaining battery level. Furthermore, water heating, which is normally only performed during nighttime hours, will now be permitted outside of nighttime hours as well.

[0040] Please note that the holding time set in the lightning warning linkage setting 19d is a target value for charge / discharge control and is not guaranteed. This is because the remaining charge corresponding to the set holding time is based on a power consumption prediction and may contain errors. In the example shown in Figure 2, the emergency hot water storage capacity for the hot water heating control of the storage-type water heater 24 is assumed to be a predetermined value, and there is no menu to accept user settings. The amount of hot water storage capacity is not an intuitive value. In general, hot water use is intermittent, so setting the emergency hot water storage capacity by the holding time, similar to the emergency remaining capacity of the storage battery 13, is not a setting that is easy for the user to understand.

[0041] Below the lightning warning linkage setting 19d, the earthquake information linkage setting 19e is located. The earthquake information linkage setting 19e accepts the selection of whether to enable or disable the control that stores emergency reserve capacity in the storage battery 13 in response to information related to the occurrence of an earthquake, for both the charge / discharge control of the storage battery 13 and the heating control of the storage-type water heater 24. The earthquake information linkage setting 19e accepts the setting of the hold time for the charge and discharge control of the battery 13. The hold time setting is displayed below the setting for enabling or disabling the earthquake information linkage function for the charge and discharge control of the battery 13. The hold time set is the hold time that the remaining hold amount setting unit 16R applies as the remaining hold amount corresponding to the earthquake information when the earthquake information linkage function is enabled and information related to the occurrence of an earthquake is acquired. Therefore, when the weather information linkage function and the thunderstorm warning linkage function are disabled, the earthquake information linkage function is enabled, and information related to the occurrence of an earthquake is acquired, the hot water storage amount setting unit applies the remaining hold amount of the battery 13 corresponding to the hold time set in earthquake information linkage setting 19e (i.e., the period during which independent operation is possible) as the emergency remaining hold amount. Note that the hold time set in earthquake information linkage setting 19e is a target value for charge and discharge control and is not guaranteed. This is because the remaining hold amount corresponding to the set hold time is based on a power consumption prediction and may contain errors.

[0042] In the example shown in Figure 2, the emergency hot water storage capacity for the hot water heating control of the storage-type water heater 24 is assumed to be a predetermined value, and there is no menu to accept user settings. The amount of hot water storage capacity is not an intuitive value. In general, hot water use is intermittent, so setting the emergency hot water storage capacity by the holding time, similar to the emergency remaining capacity of the storage battery 13, is not a setting that is easy for the user to understand.

[0043] Below the earthquake information linkage setting 19e are two operation buttons 19f. When the "Set" button is pressed, the power control device 16 confirms the settings from the regional setting 19b to the earthquake information linkage setting 19e shown on the weather / earthquake linkage setting screen 19 in Figure 2 and executes water heater control. On the other hand, if the "Cancel" button is pressed, the weather / earthquake linkage settings screen 19 will revert to its state before the settings were made, without confirming the aforementioned settings. The above is an explanation of the weather and earthquake linkage settings screen 19 shown in Figure 2.

[0044] Thus, in this embodiment, based on information related to the occurrence of an earthquake and disaster prevention weather information, the hot water storage volume setting unit 16B can accept a setting for whether or not to perform hot water heating control of the hot water storage type water heater 24 in order to secure a predetermined emergency hot water storage volume.

[0045] In this embodiment, the power control system 10 is connected to an external power grid 21. Furthermore, the power control system 10 is connected to the HEMS server 22 via a network NW. The power grid 21 is a power grid that supplies electricity to power-consuming facilities and is provided by power generators, grid operators, etc. This electricity supply is usually for a fee (purchase). Conversely, it is also possible to supply electricity generated by the power control system 10 to the power grid 21 (reverse power flow) and have that electricity purchased by power generators, grid operators, etc. (sale of electricity). The HEMS server 22 is a server that acquires and manages power information from the power control system 10. Power consumers can access the HEMS server 22 using the operation unit 18 to check the power generation status, etc.

[0046] <<Control of storage-type water heaters based on information related to earthquake occurrences>> Next, we will describe an example of water heater control by the power control device 16 shown in Figure 1. Figure 3 is an explanatory diagram showing an example of setting the emergency hot water storage amount by the power control device 16 and the change in the amount of stored hot water. Note that the water heater control in Figure 3 focuses only on the earthquake information linkage function and ignores the weather information linkage function and the thunderstorm warning linkage function. Also, the explanation of the charge and discharge control of the storage battery 13 is omitted. In Figure 3, the X-axis represents the passage of time. Specifically, it shows the period from 7:00 AM to 10:00 PM. It is assumed that the earthquake early warning was received at 10:00 AM on the same day. In the example shown in Figure 3, the hot water storage volume setting unit 16B is set to full capacity (100% of the storage volume) as the emergency hot water storage volume. In Figure 3, the dashed line shows the target hot water storage volume, and the target hot water storage volume during the earthquake information sharing period after an earthquake early warning is received is the full emergency hot water storage volume. In Figure 3, the curve shows the change in the hot water storage volume. The Y-axis direction shows the hot water storage volume. The illustration also shows the hot water storage volume of the hot water storage type water heater 24 at 7:00, 10:00, 13:00, 17:30 and 20:00.

[0047] As of 7:00 AM, the storage-type water heater 24 has finished heating water using nighttime electricity, meaning its storage capacity is 60% of the amount of hot water it would normally heat. At the same time, no earthquake early warning has been issued. In this case, the amount of hot water stored may be determined by the water heater control device 25 based on past usage data, taking into account the season, the weather expected for that day, the temperature, etc. Unless the amount of hot water used on a given day significantly exceeds expectations, the water heater control device 25 will control the system to refrain from heating water outside of nighttime hours. In other words, it will not heat water unless a shortage of hot water is anticipated before nighttime hours begin.

[0048] In the example shown in Figure 3, the hot water storage capacity is 60% at 7:00, but by 10:00, it has decreased to 50% due to use. At 10:00, an earthquake early warning is issued, and the earthquake information acquisition unit 16E acquires the issued earthquake early warning. From that point until the earthquake information sharing period has elapsed, the hot water storage capacity setting unit 16B instructs the hot water heater control device 25 to control the heating process with the emergency hot water storage capacity (100%) as the target hot water storage capacity. Upon receiving the instruction from the hot water storage capacity setting unit 16B, the hot water heater control device 25 applies the emergency hot water storage capacity instructed as the target hot water storage capacity and controls the heating process of the storage-type water heater 24. Unlike normal heating control, if the hot water storage capacity falls below the target (emergency hot water storage capacity) of 100%, the water is heated to secure the target hot water storage capacity, even if it is not nighttime. At 10:00, the water heater control device 25 applies the emergency hot water storage amount to the target hot water storage amount and controls the heating of the storage-type water heater 24 to secure the emergency hot water storage amount while the earthquake information sharing function remains active (earthquake information sharing state) until the earthquake information sharing period has elapsed. When the heating is controlled to secure the emergency hot water storage amount, the amount of hot water stored in the storage-type water heater 24 gradually increases. In the example shown in Figure 3, at 13:00, the amount of hot water stored reaches 100% of the target (emergency hot water storage amount), which is the full amount.

[0049] Subsequently, the hot water storage capacity remains at 100% until 5 PM when no hot water is used. However, from 5 PM onwards, hot water is used and the storage capacity decreases. When the storage capacity decreases, the water heater control device 25 attempts to reheat the water to compensate for the shortage. However, hot water does not heat up instantly and takes some time, so if hot water continues to be used during that time, the storage capacity gradually decreases. In the example shown in Figure 3, the storage capacity has decreased to 80% by 5:30 PM. If the use of hot water stops at 5:30 PM, the amount of stored hot water will gradually increase due to reheating. In the example shown in Figure 3, at 7:00 PM, the amount of stored hot water will again reach 100% of the target (emergency storage capacity). From 7 PM, a large amount of hot water is used, and by 8 PM, the amount of stored hot water decreases to 40%. When the use of hot water stops at 8 PM, the amount of stored hot water gradually increases due to reheating. In the example shown in Figure 3, by 10:30 PM, the amount of stored hot water returns to almost 100% of the target (emergency storage capacity).

[0050] ≪Operating Mode State Transitions≫ The following describes the processing of combinations when the weather information linkage function, thunderstorm warning linkage function, and earthquake information linkage function are all set to enabled. This is an example of a state transition in which the power control unit 16C switches whether or not to apply the emergency hot water storage capacity of the hot water storage type water heater 24 based on the issuance and cancellation of disaster prevention weather information, acquisition of information related to the occurrence of an earthquake, and the end of the earthquake information linkage period. The power control unit 16C also controls the charging and discharging of the storage battery 13. However, as shown in the example of the weather / earthquake linkage setting screen in Figure 2, in this embodiment, the settings for weather information linkage, thunderstorm warning linkage, and earthquake information linkage can be individually enabled / disabled for the charging and discharging control of the storage battery 13 and the water heating control of the hot water storage type water heater 24. If the enabled / disabled settings are different, the state transitions related to the charging and discharging control of the storage battery 13 and the state transitions related to the water heating control of the hot water storage type water heater 24 will not be linked and may take on different states. The following describes the state transitions of the water heating control for the storage-type water heater 24. The state transitions of the storage battery 13 will also be similar if the enabled / disabled setting is the same. Figure 4 is an explanatory diagram showing an example of state transitions in the water heater control performed by the power control unit shown in Figure 1. As shown in Figure 4, in this embodiment, the control of the power control unit 16C takes on four states. The first state is the "Weather Information, Thunderstorm Warning, and Earthquake Warning Non-Cooperation State," which corresponds to a state in which none of the weather information cooperation function, thunderstorm warning cooperation function, or earthquake information cooperation function is functioning. Hereinafter, this will be abbreviated as the non-cooperation state. The second state is the "Thunderstorm Warning Cooperation State," which is a state in which only the thunderstorm warning cooperation function is functioning. The third state is the "Weather Information Cooperation State," which is a state in which only the weather information cooperation function is functioning. The fourth state is the "Earthquake Information Cooperation State," which is a state in which only the earthquake information cooperation function is functioning. In this embodiment, the four states take on different levels of alert, and the necessity of applying the emergency hot water storage capacity of the storage-type water heater 24 by the power control unit 16C will take on one of the four states. The events that cause a state transition from one state to another are the issuance and cancellation of disaster prevention weather information with different levels of alert, the acquisition of information related to earthquake occurrence, and the end of the earthquake information cooperation period.

[0051] The non-coordination state corresponds to a zero alert level. This state occurs when weather information coordination is disabled in the weather information coordination setting 19c shown in Figure 2, or when it is enabled but no selected warnings or special warnings related to the selected weather information have been issued. Furthermore, when thunderstorm warning coordination is disabled in the thunderstorm warning coordination setting 19d, or when it is enabled but no thunderstorm warning has been issued. In addition, no information related to earthquake occurrences has been acquired, and the state is outside the earthquake information coordination period. In the non-coordination state, the hot water storage volume setting unit 16B does not apply the emergency hot water storage volume to the hot water storage volume of the hot water storage type water heater 24. The water heater control device 25 controls heating to target the normal hot water storage volume. Also, as in normal times, heating is basically performed only during nighttime hours.

[0052] The thunderstorm warning linkage status indicates a low level of alert. That is, the alert level is higher than the non-linkage status, but lower than the earthquake information linkage status and the weather information linkage status. This status corresponds to a state where weather information linkage is disabled in the weather information linkage setting 19c shown in Figure 2, or even if it is enabled, no selected warnings or special warnings related to the selected weather information have been issued. Furthermore, earthquake information linkage is disabled in the earthquake information linkage setting 19e, or even if it is enabled, no information related to earthquake occurrences has been acquired and it is outside the earthquake information linkage period. And, in the thunderstorm warning linkage setting 19d, thunderstorm warning linkage is enabled and a thunderstorm warning has been issued. In the event of a thunderstorm warning, the hot water storage volume setting unit 16B instructs the water heater control device 25 to apply the emergency hot water storage volume to the hot water storage volume of the hot water storage unit 24. Furthermore, it instructs the control device 25 to allow heating outside of nighttime hours, which is normally only done at night. In response to these instructions, the water heater control device 25 will heat the hot water in the hot water storage unit 24 if the amount of hot water stored in the hot water storage unit 24 falls below the emergency hot water storage volume predetermined in response to the issuance of a thunderstorm warning. If the amount of hot water stored in the hot water storage unit 24 exceeds the emergency hot water storage volume, heating will not be performed.

[0053] The earthquake information linkage status is at a medium alert level. That is, the alert level is higher than the non-linkage status and the thunderstorm warning linkage status, but lower than the weather information linkage status. This status corresponds to a state where weather information linkage is disabled in the weather information linkage setting 19c shown in Figure 2, or even if it is enabled, no selected warnings or special warnings related to the selected weather information have been issued. Furthermore, the thunderstorm warning linkage is disabled in the thunderstorm warning linkage setting 19d, or even if it is enabled, no thunderstorm warning has been issued. In addition, information related to the occurrence of an earthquake has been acquired and the earthquake information linkage period is underway. In the earthquake information linkage status, the hot water storage volume setting unit 16B instructs the water heater control device 25 to apply the emergency hot water storage volume to the hot water storage volume of the hot water storage type water heater 24. Furthermore, it instructs the control device 25 to allow hot water heating, which is normally only performed during nighttime hours, to occur outside of nighttime hours as well. In response to these instructions, the water heater control device 25 will start heating the water in the storage-type water heater 24 if the amount of hot water stored in the storage-type water heater 24 falls below the emergency hot water storage amount predetermined in response to an earthquake. If the amount of hot water stored in the storage-type water heater 24 exceeds the emergency hot water storage amount, it will not start heating the water.

[0054] The weather information linkage status is high alert level. That is, it is a higher alert level than any of the non-linkage, thunderstorm warning linkage, and earthquake information linkage statuses. This status corresponds to the state in which weather information linkage is enabled in the weather information linkage setting 19c shown in Figure 2, and the selected warning or special warning related to the selected weather information has been issued. Furthermore, the state in which thunderstorm warning linkage is disabled in the thunderstorm warning linkage setting 19d, or even if enabled, no thunderstorm warning has been issued. And the state in which earthquake information linkage is enabled in the earthquake information linkage setting 19e, information related to the occurrence of an earthquake has been acquired, and the earthquake information linkage period is in effect. In the earthquake information linkage status, the hot water storage volume setting unit 16B instructs the water heater control device 25 to apply the emergency hot water storage volume to the hot water storage volume of the hot water storage type water heater 24. Furthermore, it instructs the control device to allow heating outside of nighttime hours as well, whereas under normal circumstances it is basically only done during nighttime hours. In response to these instructions, the water heater control device 25 will start heating the water in the storage-type water heater 24 if the amount of hot water stored in the storage-type water heater 24 falls below the predetermined emergency storage amount corresponding to the warning or special warning issued as weather information. If the amount of hot water stored in the storage-type water heater 24 exceeds the aforementioned emergency storage amount, it will not start heating the water.

[0055] This section describes events related to state transitions. In the non-coordination state, if lightning warning coordination is enabled and a lightning warning is issued, the power control unit 16C transitions its state from the non-coordination state to the lightning warning coordination state. Also, in the non-coordination state, if weather information coordination is enabled and a selected warning or special warning related to selected weather information is issued, the power control unit 16C transitions its state from the non-coordination state to the weather information coordination state. Furthermore, in the non-coordination state, if earthquake information coordination is enabled and information related to the occurrence of an earthquake is acquired, the power control unit 16C transitions its state from the non-coordination state to the earthquake information coordination state.

[0056] In the weather information linkage state, if the selected warning or special warning is canceled or the weather information linkage is disabled, and information related to the occurrence of an earthquake is acquired during the earthquake information linkage period, the power control unit 16C transitions the state from the weather information linkage state to the earthquake information linkage state. Also, in the weather information linkage state, if the selected warning or special warning is canceled or the weather information linkage is disabled, and it is outside the earthquake information linkage period, and the thunderstorm warning linkage is active and a thunderstorm warning is in effect, the power control unit 16C transitions the state from the weather information linkage state to the thunderstorm warning linkage state. In the weather information linkage state, if the selected warning or special warning is canceled or the weather information linkage is disabled, and it is outside the earthquake information linkage period, and a thunderstorm warning is not in effect or the thunderstorm warning linkage is disabled, the state transitions to the non-linkage state.

[0057] In the earthquake information linkage state, if weather information linkage is enabled and a selected warning or special warning related to the selected weather information is issued, the power control unit 16C transitions its state from the non-linkage state to the weather information linkage state. Also, in the earthquake information linkage state, if the earthquake information linkage period has ended and thunderstorm warning linkage is enabled and a thunderstorm warning is in effect, the power control unit 16C transitions its state from the earthquake information linkage state to the thunderstorm warning linkage state. In the earthquake information linkage state, if the earthquake information linkage period has ended and no selected warning or special warning has been issued, or if weather information linkage is disabled, and no thunderstorm warning has been issued, or if thunderstorm warning linkage is disabled, the power control unit 16C transitions its state to the non-linkage state.

[0058] In the thunderstorm warning linkage state, if weather information linkage is enabled and a selected warning or special warning related to the selected weather information is issued, the power control unit 16C transitions to the weather information linkage state. Also, in the thunderstorm warning linkage state, if earthquake information linkage is enabled and information related to the occurrence of an earthquake is acquired, the power control unit 16C transitions from the non-linkage state to the earthquake information linkage state. Furthermore, in the thunderstorm warning linkage state, if the thunderstorm warning is canceled or the thunderstorm warning linkage is disabled, if the selected warning or special warning has not been issued or weather information linkage is disabled, and it is outside the earthquake information linkage period, the state transitions to the non-linkage state. The above describes the state transitions related to the application of emergency hot water storage capacity and the control of water heating for the storage-type water heater 24.

[0059] Thus, in this embodiment, when different types of weather information are issued simultaneously with the same or different levels of alert, the water heater of the storage-type water heater can be appropriately controlled by taking those weather information into consideration. For example, the weather information issued by the Japan Meteorological Agency includes information on various weather conditions such as heavy rain, heavy snow, and strong winds, and different types of weather information are often issued simultaneously. Furthermore, for each type of weather information, special warnings, warnings, and advisories are issued according to the level of alert. For the same type of weather condition, special warnings, warnings, and advisories are issued interchangeably, but for some types of weather conditions, only advisories are specified and special warnings and warnings are not issued, or only advisories and warnings are specified and special warnings are not issued. In this embodiment, by setting the weather information linkage function and the thunderstorm advisory linkage function, when different types of weather information are issued simultaneously with the same or different levels of alert, the water heater of the storage-type water heater can be appropriately controlled by taking those weather information into consideration. Furthermore, by setting the earthquake information linkage function, the water heater of the storage-type water heater can be appropriately controlled from the time information related to the occurrence of an earthquake is acquired until the end of the earthquake information linkage period.

[0060] Flowchart The following describes an example of the process performed by the power control device 16, with reference to the flowchart. Figures 5 and 6 are flowcharts illustrating an example of the control performed by the power control device shown in Figure 1 regarding the application of emergency hot water storage capacity. Here, the control of applying emergency hot water storage capacity in the earthquake information linkage state is described as a representative example. The processing in the non-linkage state, the thunderstorm warning linkage state, and the weather information linkage state can be easily inferred by those skilled in the art from the processing in the earthquake information linkage state. The processes shown in Figures 5 and 6 are executed sequentially.

[0061] In Figure 5, the CPU of the power control device 16 checks whether the earthquake information linkage mode is enabled (step S11). That is, it checks the setting of the earthquake information linkage setting 19e related to the hot water storage type water heater 24 shown in Figure 2. If the earthquake information linkage function is disabled (No. in step S11), it determines that there is no earthquake information linkage state to be taken (there is no processing to be executed) and terminates the process. If the earthquake information sharing function is enabled (Yes in step S11), check whether the weather information sharing function is disabled, or if it is enabled but the selected warnings, etc. related to the selected weather information have been canceled (step S13). This is because the weather information sharing function has a higher level of alert than the earthquake information sharing function and should be processed with priority. If the weather information sharing function is enabled and the selected warnings, etc. related to the selected weather information have been issued (No in step S13), the system transitions to the weather information sharing state, which has a higher priority than the earthquake information sharing state, and executes the processing. At this point, it is determined that there is no processing to be executed in the earthquake information sharing state and the processing is terminated.

[0062] If the weather information linkage function is disabled, or even if it is enabled but no selected warnings or other alerts related to the selected weather information have been issued (Yes in step S13), the CPU of the power control device 16 checks whether information related to the occurrence of an earthquake has been received (step S15). An example of information related to the occurrence of an earthquake is an earthquake early warning. Another example is earthquake information such as seismic intensity reports, information on the epicenter, and information on seismic intensity in various locations. Since earthquake early warnings are issued only for earthquakes expected to have a seismic intensity of 5 or higher, if you are preparing for a smaller earthquake, you should acquire earthquake information such as seismic intensity reports. Although not shown in the earthquake information linkage setting 19e in Figure 2, if the earthquake information acquisition unit 16E acquires information related to the occurrence of an earthquake, the hot water storage volume setting unit 16B may decide whether or not to start the earthquake information linkage function based on the seismic intensity included in the acquired earthquake information. The threshold for that seismic intensity may be set by the user as one of the setting items in the earthquake information linkage setting 19e. For example, the threshold may be set to seismic intensity 3 or higher, seismic intensity 4 or higher, etc. If no information regarding the occurrence of an earthquake has been obtained (No. in step S17), the CPU of the power control device 16 will not apply the emergency hot water storage amount to the hot water heating control of the hot water storage type water heater 24, similar to the operating mode in the non-cooperative state. That is, it will have the hot water heater control device 25 perform hot water heating control targeting the normal hot water storage amount (step S19), and the processing of the earthquake information cooperation state will be terminated.

[0063] If, as determined in step S17, information related to the occurrence of an earthquake has been acquired, the power control device 16 may, depending on the situation, notify the user of the start of the earthquake information linkage state (step S21). The notification may be displayed on the screen of the operation unit 18, or it may be an audio notification, for example. An example of a notification is as follows: An example of a screen display is, "An earthquake early warning has been issued, so we will keep the hot water storage type water heater full. If you do not need it, tap the link to uncheck 'Enable earthquake information linkage'. (Until you enable it again, earthquake early warnings and earthquake information will not be acquired)." In addition, a link to the settings screen is displayed next to this notification display. Audio notifications should be simpler and easier for the user to understand than screen displays. An example is, "An earthquake early warning has been issued, so we will keep the hot water storage type water heater full in preparation for a power outage." Next, the CPU of the power control device 16 instructs the water heater control device 25 to apply a predetermined emergency hot water storage amount as the target hot water storage amount in response to the occurrence of the earthquake shown in Figure 2 (step S25). Upon receiving this instruction, the water heater control device 25 uses the emergency hot water storage amount as the target hot water storage amount instead of the amount that was normally targeted, and performs heating control to secure the target hot water storage amount.

[0064] Next, the power control device 16 checks whether the earthquake information sharing period is still ongoing (step S33 shown in Figure 6). If the earthquake information sharing period has ended (No. in step S33), it cancels the earthquake information sharing state and transitions to another state (step S35). At this time, the user may be notified that the earthquake information sharing has been canceled. The notification may be displayed on the screen of the operation unit 18, or it may be an audio notification, for example. An example of a notification, both on the screen and as an audio notification, is as follows: "The control of the storage-type water heater has been returned to the operating mode it was in before the earthquake early warning was issued."

[0065] On the other hand, if the determination in step S33 indicates that the earthquake information linkage period is continuing (Yes in step S33), the power control device 16 then checks whether weather information linkage is disabled or, even if enabled, whether the selected warnings, etc., for the selected weather information have not been issued (step S37). If a predetermined period has elapsed since the previous acquisition of weather information, weather information is acquired again at this point. If weather information linkage, which triggers a transition to a weather information linkage state with a higher alert level than the earthquake information linkage state, is enabled and the selected warnings, etc., for the selected weather information have been issued (No in step S37), the earthquake information linkage state is canceled (step S35), and the system transitions to the weather information linkage state that should be prioritized. At that time, the user may be notified that the earthquake information linkage function has been canceled.

[0066] If weather information linkage is disabled, or if it is enabled but no selected warnings or alerts for the selected weather information have been issued (Yes in step S37), the power control device 16 then performs the following processing. First, it confirms that the setting to enable the earthquake information linkage function remains in the earthquake information linkage setting 19e shown in Figure 2 (Yes in step S39). If the earthquake information sharing function is disabled in the determination in step S39 (No. in step S39), the earthquake information sharing state is canceled and the system is transitioned to another state (step S35).

[0067] If the setting for step S39 remains to enable the earthquake information linkage function (Yes in step S39), the power control device 16 returns to step S25 (see Figure 5). Then, it repeats the process of determining the updated emergency hot water storage amount based on the minimum holding time and predicted power consumption, instructing the water heater control device 25 to apply the emergency hot water storage amount as the target hot water storage amount. The above describes the process that the power control device 16 performs regarding whether or not to apply the emergency hot water storage capacity of the hot water storage type water heater 24 when earthquake information is shared.

[0068] (Embodiment 2) In Embodiment 1, the weather / earthquake linkage setting screen 19 shown in Figure 2 does not have a menu that allows the user to set the emergency hot water storage amount related to the heating control of the hot water storage type water heater 24, and the emergency hot water storage amount is assumed to be a predetermined value. The reason for this is that the amount of hot water storage is not an intuitive value. Furthermore, since the use of hot water is generally intermittent, the method of setting the emergency hot water storage amount by the holding time, similar to the emergency remaining capacity of the storage battery 13, is also not a setting that is easy for the user to understand. However, even if this is the case, there may still be a way to allow the user to set the emergency hot water storage amount. For example, even without quantitative expressions, one could consider providing a menu that allows users to easily recognize a larger amount of hot water storage than normal, such as "more" or "plenty," based on the normal amount of hot water storage, and accepting user settings. To accept multiple settings, settings such as "even more" and "even more" could be provided. Additionally, you may want to allow the user to set a "full" level.

[0069] (Embodiment 3) This embodiment describes the case where information regarding a new earthquake is acquired during the earthquake information sharing period. It is possible that information regarding aftershocks may be acquired during the earthquake information sharing period. That is, the earthquake information acquisition unit 16E may acquire information regarding a new earthquake after the start of the earthquake information sharing period.

[0070] According to this embodiment, if new earthquake information is acquired during the earthquake information sharing period, the hot water storage volume setting unit 16B updates the earthquake information sharing period with the time when the new earthquake information was acquired as the new starting point and continues to calculate the emergency hot water storage volume. The power control unit 16C controls the heating of the hot water storage type water heater 24 to ensure the emergency hot water storage volume during the extended earthquake information sharing period. If aftershocks continue and information regarding new earthquakes is repeatedly acquired during the earthquake information sharing period, the earthquake information sharing period will be repeatedly extended.

[0071] The seismic intensity threshold for information related to a new earthquake that triggers an extension of the earthquake information sharing period may be different from the seismic intensity threshold used to start the earthquake information sharing period. For example, the seismic intensity threshold for information related to the first earthquake is seismic intensity 5-minus, and the acquisition of an earthquake early warning is used as the trigger to start the earthquake information sharing period. In that case, when the earthquake information sharing period starts due to the acquisition of an earthquake early warning, the hot water storage volume setting unit 16B will extend the period during which the emergency hot water storage volume is applied, i.e., the earthquake information sharing period, even if the seismic intensity is smaller than seismic intensity 5-minus (for example, seismic intensity 3), assuming that there is a risk of power outage. In this way, even if the seismic intensity is smaller than the seismic intensity at the start of the earthquake information sharing period, if aftershocks continue, the earthquake information sharing period will be extended in preparation for power outages.

[0072] Furthermore, the system may also accept additional regional settings for areas other than those where the power control system 10 is installed. These other areas include, for example, areas where major power generation and transmission facilities of the grid power 21 are located. Even if the impact of an earthquake is minor in the area where the power control system 10 is installed, power generation and transmission facilities may be damaged by the earthquake, potentially leading to a power supply and demand shortage warning. To prepare for such a situation, the system accepts settings in advance for areas where power generation and transmission facilities are located, in addition to the area where the power control system 10 is installed. When information regarding an earthquake is obtained for any of the registered areas, the hot water storage volume setting unit 16B starts or extends the earthquake information linkage period for applying the emergency hot water storage volume. The hot water heater control device 25 controls the heating of the hot water storage type water heater 24 to secure the emergency hot water storage volume and prepare for a power outage.

[0073] As stated above, (i) The power control device according to Embodiment 1 of the present invention comprises a power control unit that manages a consumer power system having a power load including a storage-type water heater and connected to a grid power system, and controls the heating of the storage-type water heater; an earthquake information acquisition unit that acquires information related to the occurrence of an earthquake from an external source; and a storage volume setting unit that sets an emergency storage volume, which is the amount of hot water to be kept in the storage-type water heater, when the information related to the occurrence of an earthquake is acquired, wherein the power control unit controls the heating of the storage-type water heater to secure the set emergency storage volume until the earthquake information linkage period, which is set in advance as the period from when the information related to the occurrence of an earthquake is acquired, has elapsed.

[0074] In this invention, the consumer power system is a power system owned by a consumer that has a power supply contract with a power company that operates the grid power network, and is a power system connected to the grid power network. Specific examples include, for example, the power systems of households and businesses. Furthermore, the consumer power system may also have a private power generation device. The private power generation device is a small-scale power generation device installed within the consumer power system and is typified by a solar power generation device, but is not limited to a solar power generation device; it may also be a wind power generation device or a power generation device using other renewable energy sources. The solar power generation device in the above-described embodiment corresponds to the renewable energy power generation device of this invention. The consumer power system may also have an energy storage device. The energy storage device is a device that stores electrical energy, such as a battery. The type of battery is not limited. In the above-described embodiment, the battery corresponds to the energy storage device. A storage-type water heater heats and stores water using electricity, and then supplies the stored water. A specific example of this is the heat pump water heater, known as EcoCute. However, any type or configuration of a storage-type water heater that uses electricity to heat water is acceptable. Information related to earthquake occurrences includes, specifically, earthquake early warnings and earthquake information. That is, in this specification, information related to earthquake occurrences includes at least one of the following: earthquake early warnings and earthquake information relating to a seismic intensity above a certain level. Furthermore, if earthquake-related information is improved or changed in the future due to advancements in earthquake observation and analysis technology, the specification will include such improved or changed information.

[0075] An earthquake early warning system is a piece of information that is issued as quickly as possible immediately after an earthquake occurs, predicting the arrival time and intensity of strong shaking in various locations, when a maximum seismic intensity of 5-minus or higher is expected at two or more seismic observation points. Earthquake information is information that is released sequentially as data related to an earthquake becomes available after the earthquake occurs. Earthquake information is a general term for several pieces of information, including seismic intensity reports, information on the epicenter, information on seismic intensity in various locations, and other information. Seismic intensity reports announce the names of the areas that observed a seismic intensity of 3 or higher and the time the shaking was detected, approximately 1.5 minutes after the earthquake occurs. Information on the epicenter announces the epicenter and magnitude when a seismic intensity of 3 or higher is observed. Information on seismic intensity in various locations announces the locations that observed a seismic intensity of 1 or higher, as well as the epicenter and magnitude.

[0076] Information related to earthquake occurrences may include, but is not limited to, emergency earthquake warnings and earthquake information issued by the Japan Meteorological Agency; it may also include information provided by weather information service providers or other entities. Furthermore, the emergency hot water storage capacity is the amount of hot water stored in the storage-type water heater in the event of a power outage at some point in time. For example, if the emergency hot water storage capacity is 50 liters, the power control unit will ensure that 50 liters of hot water are stored in the storage-type water heater so that a power outage can be supplied at that time. Storage-type water heaters are designed to heat the amount of hot water needed for the next day during off-peak hours when electricity rates are cheaper, and do not heat water during the daytime when electricity rates are more expensive. However, if the amount of hot water heated during the night is insufficient, they can heat water during the day if necessary. However, heating water takes a certain amount of time, so to avoid running out of hot water, it is necessary to heat water before the storage amount reaches zero. Similarly, to ensure that an emergency supply of hot water is stored even if a power outage occurs, water can be heated during the day if necessary.

[0077] The water heating of a storage-type water heater may be powered by electricity supplied from the grid, or it may be powered by one or more types of renewable energy generation devices. Specific examples of renewable energy generation devices include solar cell modules, but are not limited to these; wind power generation and other power generation devices may also be used. The solar cell modules in the above-described embodiments are included in the devices used to heat the water in the storage-type water heater according to this invention.

[0078] Furthermore, the power control unit manages the power of the power control system to control the charging and discharging of the storage battery, as well as setting the storage capacity of the hot water heater. Specifically, it has a hardware configuration centered on a CPU and memory, and the CPU executes a control program stored in memory to realize the functions related to power control and setting the storage capacity. The earthquake information sharing period refers to a predetermined period from the time the earthquake information acquisition unit acquires information related to the occurrence of an earthquake. Upon acquiring information related to the occurrence of an earthquake, the hot water storage volume setting unit applies the emergency reserve amount, and the power control unit controls the heating of the hot water storage type water heater so that the emergency hot water storage volume is secured even if a power outage occurs. The earthquake information sharing period indicates how long this control will continue. Therefore, the starting point of the earthquake information sharing period can be said to be the time when information related to the occurrence of an earthquake is acquired.

[0079] Until the earthquake information sharing period ends, the hot water storage volume setting unit instructs the hot water storage type water heater to apply the emergency hot water storage volume setting corresponding to the earthquake. Furthermore, the power control unit controls the charging and discharging of the storage battery to store an emergency reserve amount in the battery.

[0080] Furthermore, preferred embodiments of this invention will be described. (ii) The power control device of embodiment 2 is the power control device of embodiment 1, wherein the hot water storage volume setting unit sets the emergency hot water storage volume based on the predicted usage from the time the information related to the occurrence of the earthquake is acquired until the earthquake information linkage period has elapsed, and the power control unit controls the heating of the hot water storage type water heater to secure the set emergency hot water storage volume. According to this embodiment, the hot water storage volume setting unit can appropriately control the heating of the hot water storage type water heater based on information regarding the earthquake that has occurred. Hot water usage may be predicted, for example, based on historical data, which may include data from multiple users, not just one. This historical data may be stored by the power control device, or it may be obtained from an external device connected via communication.

[0081] (iii) The power control device of embodiment 3 is a power control device of embodiment 2 in which, when information relating to the occurrence of an earthquake is obtained, the hot water storage volume setting unit predicts a larger amount of hot water storage than in normal times when information relating to the occurrence of an earthquake is not obtained, and sets the emergency hot water storage volume based on that prediction. Because earthquakes are difficult to predict, electricity consumers tend to be more vigilant than they are with predictable disaster prevention weather information. In this configuration, if information regarding an earthquake is obtained, the hot water stored in the storage-type water heater can be kept on hand with a margin greater than normal. Alternatively, the emergency hot water storage capacity may be set to full capacity. Setting it to full capacity will allow the hot water stored in the storage-type water heater to be kept on hand with an even greater margin.

[0082] (iv) The power control device of embodiment 4 further comprises an operation unit that accepts user operations in any of embodiments 1 to 3, and the hot water storage volume setting unit may comprise at least one of the following: an emergency hot water storage volume setting unit that sets the emergency hot water storage volume by operation via the operation unit, and an earthquake information linkage period setting unit that sets the earthquake information linkage period by operation via the operation unit. According to this configuration, at least one of the emergency hot water storage capacity or the earthquake information sharing period can be set based on the user's wishes and circumstances.

[0083] (v) The power control device of embodiment 5 is a power control device of embodiment 1 to 4, further comprising a weather information acquisition unit that acquires one or more disaster prevention weather information, and the hot water storage volume setting unit sets the emergency hot water storage volume according to the type or level of alert of the acquired earthquake information and disaster prevention weather information, until the weather information linkage period until the disaster prevention weather information is canceled and the earthquake information linkage period have both elapsed, and the power control unit may control the heating of the hot water storage type water heater to secure the set emergency hot water storage volume until the earthquake information linkage period and the weather information linkage period have both elapsed. Weather information is information about the weather, including various atmospheric phenomena such as heavy rain, heavy snow, and strong winds. Disaster prevention weather information is particularly relevant to severe strong winds, blizzards, heavy rain, floods, storm surges, heavy snow, and high waves that could cause power outages in the grid. Unlike information related to earthquake occurrences, this disaster prevention weather information is predictable and can therefore be canceled based on predictions. The weather information linkage period is the period from when disaster prevention weather information is acquired until it is canceled. Disaster prevention weather information is provided as special warnings, warnings, and advisories depending on the level of alert. Weather information may include, but is not limited to, various advisories, warnings, and special warnings issued by the Japan Meteorological Agency; it may also include information provided by businesses that provide weather information services or by other parties. According to this configuration, in addition to information related to the occurrence of an earthquake, disaster prevention weather information is acquired, and the hot water storage volume setting unit sets the emergency hot water storage volume according to the type of weather information or the level of alert, in addition to the information related to the occurrence of an earthquake, in order to prepare for a power outage.

[0084] (vi) In the power control device of embodiment 6, the hot water storage amount setting unit may set the largest hot water storage amount among the information related to the earthquake and the hot water storage amounts corresponding to each of the weather information as the emergency hot water storage amount if the earthquake information acquisition unit has acquired one or more types of disaster prevention weather information in addition to the information related to the earthquake. According to this embodiment, the hot water storage volume setting unit sets a hot water storage volume corresponding to the occurrence of an earthquake, as well as a hot water storage volume corresponding to weather information, and then sets the largest of these volumes as the emergency hot water storage volume. Therefore, even if different types and levels of weather information are acquired in addition to information related to the occurrence of an earthquake, an appropriate emergency hot water storage volume can be set.

[0085] (vii) The power control device of embodiment 7 is a power control device of any of embodiments 1 to 6, in which the power control unit may, if it obtains information relating to an earthquake of a predetermined magnitude 1 or higher outside of the earthquake information sharing period, start control during the earthquake information sharing period, and if it obtains information relating to a new earthquake of a predetermined magnitude 2 or higher during the earthquake information sharing period, extend the earthquake information sharing period based on the time of acquisition of the information relating to the new earthquake. According to this embodiment, if aftershocks of magnitude 2 or higher continue during the earthquake information sharing period, the charge / discharge control unit extends the earthquake information sharing period using the time when information regarding the occurrence of the aftershock is acquired as a new starting point, and continues to control the heating of the storage-type water heater to secure the emergency hot water storage capacity. Therefore, if aftershocks continue, the water heater can be appropriately controlled based on the extended earthquake information sharing period.

[0086] (viii) In the power control device of embodiment 8, the second seismic intensity may be smaller than the first seismic intensity in the power control device of embodiment 7. According to this configuration, even if aftershocks continue with a seismic intensity smaller than that of the initial earthquake, which was acquired outside of the earthquake information sharing period, the power control unit can extend the earthquake information sharing period to continue the control to secure emergency hot water storage capacity and appropriately control the hot water heaters of the storage type.

[0087] (ix) In the power control device of embodiment 9, in any of the power control devices of embodiments 1 to 8, the earthquake information acquisition unit may accept a setting to acquire information on earthquake occurrences in other regions in addition to the region where the hot water storage type water heater is installed. According to this embodiment, it is possible to acquire not only information regarding earthquake occurrences in areas where storage-type water heaters are installed, but also information regarding earthquake occurrences in areas where power plants are located, for example, in order to prepare for a tightening of electricity supply and demand due to damage to power plants.

[0088] (x) One aspect of the present invention includes a water heater control method comprising: a control unit that controls the heating of a storage-type water heater using electricity, the steps of: acquiring information relating to the occurrence of an earthquake from an external source; setting an emergency hot water storage amount, which is the amount of hot water to be kept in the storage-type water heater, when the information relating to the occurrence of an earthquake has been acquired; and controlling the heating of the storage-type water heater to secure the set emergency hot water storage amount until a predetermined earthquake information linkage period has elapsed since the information relating to the occurrence of an earthquake was acquired.

[0089] The embodiments of this invention also include combinations of any of the embodiments described above. In addition to the embodiments described above, various modifications of this invention are possible. These modifications should not be considered outside the scope of this invention. This invention should include the meaning of the claims and equivalents and all variations within that scope. [Explanation of Symbols]

[0090] 10: Power control system, 11: Solar cell module, 12: Power conditioner, 13: Storage battery, 14: Distribution board, 15: Smart meter, 16: Power control device, 16B: Hot water storage volume setting unit, 16C: Power control unit, 16E: Earthquake information acquisition unit, 16R: Remaining amount setting unit, 16W: Weather information acquisition unit, 17: Communication interface circuit, 18: Operation unit, 19: Weather / earthquake linkage setting screen, 19a: Setting display area, 19b: Regional setting, 19c: Weather information linkage setting, 19d: Lightning warning linkage setting, 19e: Earthquake information linkage setting, 19f: Operation buttons, 21: Grid power network, 22: HEMS server, 23: Electrical equipment, 24: Storage type water heater, 25: Water heater control device NW: Network

Claims

1. A power control unit manages a consumer power system connected to the grid, which has a power load including a storage-type water heater, and controls the heating of the storage-type water heater. An earthquake information acquisition unit that obtains information related to earthquake occurrences from external sources, When information regarding the occurrence of the aforementioned earthquake is obtained, the hot water storage volume setting unit sets the emergency hot water storage volume, which is the amount of hot water that should be kept in the hot water storage type water heater. The hot water storage volume setting unit sets the emergency hot water storage volume based on the predicted usage amount until the earthquake information linkage period, which is set in advance as the period from when the information related to the occurrence of the earthquake is acquired, has elapsed. The power control unit is a power control device that controls the heating of the hot water storage type water heater to ensure a set emergency hot water storage amount until the earthquake information sharing period has elapsed.

2. The power control device according to claim 1, wherein the hot water storage volume setting unit predicts a larger usage amount than during normal times when no information regarding the occurrence of an earthquake has been obtained, and sets the emergency hot water storage volume based on that prediction.

3. A power control unit that manages a consumer power system connected to a power grid and having a power load including a storage-type water heater, and controls the heating of the storage-type water heater, An earthquake information acquisition unit that obtains information related to earthquake occurrences from external sources, When information regarding the occurrence of the aforementioned earthquake is obtained, the hot water storage volume setting unit sets the emergency hot water storage volume, which is the amount of hot water that should be kept in the hot water storage type water heater, It comprises a weather information acquisition unit that acquires one or more disaster prevention weather information items, When disaster prevention weather information is acquired in addition to the information related to the earthquake, the hot water storage volume setting unit sets the emergency hot water storage volume according to the type or level of alert of the acquired earthquake information and disaster prevention weather information until the weather information linkage period until the disaster prevention weather information is canceled and the earthquake information linkage period which is set in advance as the period from when the information related to the earthquake was acquired have both elapsed. The power control unit is a power control device that controls the heating of the hot water storage type water heater to ensure a set emergency hot water storage amount until the earthquake information sharing period and the weather information sharing period have both elapsed.

4. The power control device according to claim 3, wherein, if the earthquake information acquisition unit has acquired one or more types of disaster prevention weather information in addition to the information relating to the occurrence of an earthquake, the hot water storage amount setting unit sets the largest hot water storage amount among the information relating to the occurrence of an earthquake and the hot water storage amounts corresponding to each weather information as the emergency hot water storage amount.

5. Further comprising an operation unit that accepts operations by the user, The power control device according to any one of claims 1 to 4, wherein the hot water storage volume setting unit is further comprising an earthquake information linkage period setting unit that sets the earthquake information linkage period by operation via the operation unit.

6. A power control unit that manages a consumer power system connected to a power grid and having a power load including a storage-type water heater, and controls the heating of the storage-type water heater, An earthquake information acquisition unit that obtains information related to earthquake occurrences from external sources, When information regarding the occurrence of the aforementioned earthquake is obtained, the hot water storage volume setting unit sets the emergency hot water storage volume, which is the amount of hot water that should be kept in the hot water storage type water heater. The power control unit controls the heating of the hot water storage type water heater to secure a set emergency hot water storage amount until the earthquake information sharing period, which is set in advance as the period from when the information related to the occurrence of the earthquake is acquired, has elapsed. The power control unit, when it obtains information relating to an earthquake of a predetermined magnitude 1 or higher outside of the earthquake information sharing period, starts control during the earthquake information sharing period, and when it obtains information relating to a new earthquake of a predetermined magnitude 2 or higher during that earthquake information sharing period, it extends the earthquake information sharing period based on the time of acquisition of the information relating to the new earthquake.

7. The power control device according to claim 6, wherein the second seismic intensity is smaller than the first seismic intensity.

8. Further comprising an operating unit that accepts operations by a user, The power control device according to claim 6 or 7, wherein the hot water storage volume setting unit comprises at least one of the following: an emergency hot water storage volume setting unit for setting the emergency hot water storage volume by operation via the operation unit, and an earthquake information linkage period setting unit for setting the earthquake information linkage period by operation via the operation unit.

9. The power control device according to any one of claims 1 to 4, 6, or 7, wherein the earthquake information acquisition unit accepts a setting to acquire information on earthquake occurrences in other regions in addition to the region where the hot water storage type water heater is installed.

10. A control unit manages a consumer power system connected to the grid, which has a power load including a storage-type water heater, and also controls the heating of the storage-type water heater. Steps include obtaining information related to the occurrence of an earthquake from external sources, When information regarding the occurrence of the aforementioned earthquake is obtained, the step of setting the emergency hot water storage amount, which is the amount of hot water that should be kept in the hot water storage type water heater, The system includes a step of controlling the heating of the hot water storage type water heater to secure a set emergency hot water storage amount until a predetermined earthquake information sharing period has elapsed since the acquisition of information related to the occurrence of the earthquake, A water heater control method in which the emergency hot water storage capacity is based on the predicted usage amount from the time the information related to the occurrence of the earthquake is acquired until the earthquake information sharing period has elapsed.

11. A control unit that manages a consumer power system connected to a power grid and having a power load including a storage-type water heater, and controls the heating of the storage-type water heater, Steps include obtaining information related to the occurrence of an earthquake from external sources, When information regarding the occurrence of the aforementioned earthquake is obtained, the step of setting the emergency hot water storage amount, which is the amount of hot water that should be kept in the hot water storage type water heater, The system includes the step of obtaining one or more disaster prevention weather information, The control unit, If disaster prevention weather information is acquired in addition to the information relating to the occurrence of the earthquake, the emergency hot water storage amount will be set according to the type or level of alert of the acquired earthquake information and disaster prevention weather information until the weather information linkage period until the disaster prevention weather information is lifted, and the earthquake information linkage period which is predetermined as the period from when the information relating to the occurrence of the earthquake was acquired, have both elapsed. A power control method for controlling the heating of a storage-type water heater to ensure a set emergency hot water storage capacity until the weather information sharing period and the earthquake information sharing period have both elapsed.

12. A control unit that manages a consumer power system connected to a power grid and having a power load including a storage-type water heater, and controls the heating of the storage-type water heater, Steps include obtaining information related to the occurrence of an earthquake from external sources, The system includes a step of setting an emergency hot water storage amount, which is the amount of hot water that should be kept in the hot water storage type water heater, when information regarding the occurrence of the earthquake is obtained. The control unit, if it obtains information regarding an earthquake of a predetermined magnitude 1 or higher outside of the earthquake information linkage period which is set in advance as the period from when the information regarding the occurrence of the earthquake was obtained, starts control during the earthquake information linkage period, and if it obtains information regarding a new earthquake of a predetermined magnitude 2 or higher during the earthquake information linkage period, extends the earthquake information linkage period based on the time of acquisition of the new earthquake information.

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