Patent Publication Number: US-2019199131-A1

Title: Power management method, power management server, local control apparatus, and power management system

Description:
TECHNICAL FIELD 
     The present disclosure relates to a power management method, a power management server, a local control apparatus, and a power management system. 
     BACKGROUND ART 
     In recent years, a technology of suppressing a power flow amount from a power grid to a facility or a reverse power flow amount from the facility to the power grid in order to maintain a power demand-supply balance of the power grid has been known (see, for example, Patent Literatures 1 and 2). 
     Further, a system (hereinafter, referred to as a virtual power plant (VPP)) that uses distributed power supplies provided in a plurality of facilities as power supplies for supplying a power to a power grid has attracted attention. In the VPP, there is a need to interchange a power among the plurality of facilities, and a power management server that manages such power interchange is required. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Application Publication No. 2013-169104 
     Patent Literature 2: Japanese Application Publication No. 2014-128107 
     SUMMARY OF INVENTION 
     In the VPP, one of the tasks is to properly manage the distributed power supply installed in each facility. 
     Therefore, the present disclosure provides a power management method, a power management server, a local control apparatus, and a power management system that appropriately manage a distributed power supply. 
     A power management method according to a first disclosure comprises a step A of transmitting a power command message controlling a distributed power supply from a power management server to a local control apparatus, the power management server managing a plurality of facilities, the distributed power supply being individually provided in each facility, and the local control apparatus being individually provided in each facility. The step A includes a step of transmitting the power command message based on a specifying result or an estimating result of a local operation plan of the distributed power supply in each facility. 
     A power management server according to a second disclosure manages a plurality of facilities. The power management server comprises a transmitter configured to transmit a power command message for controlling a distributed power supply to a local control apparatus, the distributed power supply being individually provided in each facility and the local control apparatus being individually provided in each facility. The transmitter transmits the power command message based on a specifying result or an estimating result of a local operation plan of the distributed power supply in each facility. 
     A local control apparatus according to a third disclosure controls a distributed power supply provided in a target facility which is any one of a plurality of facilities managed by a power management server. The local control apparatus comprises a receiver configured to receive a power command message for controlling the distributed power supply from the power management server. The receiver receives the power command message generated based on a specifying result or an estimating result of a local operation plan of the distributed power supply in each facility in order to modify a local operation plan of the distributed power supply in the target facility. 
     A power management system according to a fourth disclosure comprises power management server configured to manage a plurality of facilities; and a local control apparatus configured to be individually provided in each facility. The power management server includes a transmitter configured to transmit a power command message for controlling a distributed power supply individually provided in each facility. The transmitter transmits the power command message based on a specifying result or an estimating result of a local operation plan of the distributed power supply in each facility. 
     According to one aspect, it is possible to provide a power management method, a power management server, a local control apparatus, and a power management system that appropriately manage a distributed power supply. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view showing a power management system  1  according to an embodiment. 
         FIG. 2  is a view showing a power management server  300  according to an embodiment. 
         FIG. 3  is a view showing a local control apparatus  400  according to an embodiment. 
         FIG. 4  is a view showing a power management method according to an embodiment. 
         FIG. 5  is a view showing a power management method according to Modified Example 1. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. 
     However, it should be noted that the drawings are schematic and ratios and the like of the respective dimensions may be different from actual ratios and the like of the respective dimensions. Therefore, concrete dimensions and the like should be decided with reference to the following description. In addition, parts having different dimensional relationships or ratios are included between the drawings. 
     Embodiment 
     (Power Management System) 
     Hereinafter, a power management system according to an embodiment will be described. In the embodiment, a system (hereinafter, referred to as a virtual power plant (VPP)) that uses a fuel cell apparatus  130  (fuel cell  131 ) provided in a facility  100  as a distributed power supply that supplies a power to at least a load or a power grid is described as an example. 
     As shown in  FIG. 1 , a power management system  1  includes a facility  100 , a network  200 , and a power management server  300 . In the embodiment, facilities  100 A to  100 C are exemplified as the facility  100 . However, the facilities  100 B and  100 C have the same configuration as that of the facility  100 A, and only the facility  100 A will thus be described here. The facility  100  includes an EMS  110 , a load  120 , and the fuel cell apparatus  130 . 
     The EMS  110  is an apparatus (energy management system (EMS)) that manages a power of an equipment provided in the facility  100 . The EMS  110  may be a cloud server through the network  200 . The EMS  110  is an example of a local control apparatus, and is an example of a virtual end node (VEN) apparatus. 
     The load  120  is an equipment or an machine that consumes a power. The load  120  includes an equipment or an machine such as a refrigerator, a freezer, a lighting apparatus, an air conditioner, or a television. The load  120  may include a single equipment or an machine and may include a plurality of equipments or machines. 
     The fuel cell apparatus  130  is an example of the distributed power supply used in the VPP. The fuel cell apparatus  130  includes the fuel cell  131 , a hot-water supply apparatus  132 , and a PCS  133 . The fuel cell  131  is an apparatus that generates a power using a fuel gas. The hot-water supply apparatus  132  includes a hot-water storage tank, and maintains or increases an amount of water (hot-water) stored in the hot-water storage tank or keeps a temperature of the water (hot-water) stored in the hot-water storage tank constant or raises the temperature of the water (hot-water) stored in the hot-water storage tank using exhaust heat of the fuel cell  131 . The PCS  133  is an apparatus (power conditioning system) that converts a direct current (hereinafter, referred to as DC) power output from the fuel cell  131  into an alternating current (hereinafter, referred to as AC) power. It should be noted that a storage battery apparatus or a solar battery apparatus may be used as the dispersed power supply. In such a case, the storage battery apparatus includes a PCS and a storage battery, and the solar cell apparatus includes a PCS and a solar cell (solar cell panel). 
     The fuel cell apparatus  130  (fuel cell  131 ) may be any one of a solid oxide fuel cell (hereinafter, referred to as an SOFC), a polymer electrolyte fuel cell (hereinafter, referred to as a PEFC), a phosphoric acid fuel cell (hereinafter, referred to as a PAFC), and a molten carbonate fuel cell (hereinafter, referred to as an MCFC). 
     For example, the SOFC has characteristics that a transition time from a power generation state to a stop state and a transition time from the stop state to the power generation state are long. Therefore, even though an event in which the amount of hot-water in the hot-water storage tank reaches a target amount of hot-water or an event in which the temperature of the hot-water in the hot-water storage tank reaches a target temperature of the hot-water occurs, it may be better to continue the power generation state of the SOFC even though exhaust heat of the SOFC is discarded. Meanwhile, the PEFC has characteristics that the transition times described above are shorter than those of the SOFC. Therefore, when the event described above occurs, power generation of the PEFC may be stopped without discarding exhaust heat of the PEFC. The target amount of hot-water or the target temperature of the hot-water described above is set by, for example, a user of the facility  100 . 
     Further, an operation state of the fuel cell apparatus  130  (fuel cell  131 ) is a state regarding an operation of the fuel cell apparatus  130 , and may be a current operation state, may be a future operation state, or may be a past operation state. Specifically, the operation state of the fuel cell apparatus  130  includes any one of a first operation state in which the fuel cell apparatus  130  generates a predetermined power for a predetermined time, a second operation state in which the fuel cell apparatus  130  generates a power with a load following operation, and a third operation state in which the fuel cell apparatus  130  stops power generation. The first operation state, the second operation state, and the third operation state are only examples, and for example, the operation state may include at least one of the first operation state, the second operation state, and the third operation state or may include other operation states. 
     For example, in the first operation state, the predetermined power may be a rated power determined by capability of any one of the fuel cell  131  or the PCS  133 . The rated power may be a recommended upper limit (for example, a catalog value) of a generated power determined by a maker of any one of the fuel cell  131  and the PCS  133 . The predetermined power is determined based on a history of a consumed power of the load  120  and a history of a hot-water consumption amount of the hot-water supply apparatus  132 , and may be a designated power smaller than the rated power. The designated power may be designated by the EMS  110  or may be designated by the PCS  133 . In the first operation state, a surplus power for the consumed power of the load  120  may be supplied to the power grid. That is, the fuel cell apparatus  130  is used in the VPP by a reverse power flow of the surplus power. 
     For example, in the second operation state, the fuel cell apparatus  130  generates a target power determined based on the consumed power of the load  120 . The target power may be the same as the consumed power of the load  120  or may be a power obtained by adding an offset power to the consumed power of the load  120 . In such a case, the offset power is a surplus power supplied to the power grid. 
     For example, the third operation state may be an operation state in which a power is not output from the fuel cell apparatus  130 . The third operation state may be an operation state (complete stop state) in which an operation of the fuel cell apparatus  130  is completely stopped, and may be an operation state (idling state) in which a chemical reaction to the extent that the temperature of the fuel cell apparatus  130  is kept at a predetermined temperature is performed. The chemical reaction to the extent that the temperature of the fuel cell apparatus is kept at the predetermined temperature may be a chemical reaction to the extent that a consumed power of the fuel cell apparatus  130  itself (for example, an auxiliary) is procured by the fuel cell apparatus  130 . In the SOFC described above, a transition time from the power generation state to the idling state is shortened. The first operation state and the second operation state described above are examples of the power generation state. 
     The network  200  is a communication line connecting the facility  100  and the power management server  300  to each other. The network  200  may be, for example, a public line such as the Internet or a mobile communication network or a dedicated line such as a virtual private network (VPN). For example, a line of a B route that does not pass through a smart meter provided in the facility  100  may be used as the public line. A line of an A route that passes through the smart meter provided in the facility  100  may be used as the dedicated line. The smart meter is a wattmeter managed by a power generation company such as an electric power company and used to calculate billing for a power used in the facility  100  or an incentive for a power sold by the facility  100 . A plurality of smart meters may be installed in the facility  100 . 
     The power management server  300  is a server managed by a company such as a power generation company, a power transmission/distribution company, or a power retail company. The power management server  300  may be managed by an aggregator corresponding to the power transmission/distribution company or the power retail company. The aggregator is a company managing a power demand-supply balance of the facility  100  contracted with the aggregator. The aggregator may be entrusted with management of the power demand-supply balance from the power generation company such as the electric power company. The power management server  300  is an example of a virtual top node (VTN) apparatus. The power demand-supply balance includes, for example, a balance regarding supply or demand of a power, and a balance of grid stability. 
     The power management server  300  may transmit a power command message for controlling the distributed power supply provided in the facility  100 . The power command message may be a power supply control message for requesting control of an operation of the distributed power supply installed in the facility  100 . The power command message may be a power flow control message for requesting control (increase, decrease or maintenance) of a power flow amount from the power grid to the facility  100 , or may be a reverse power flow control message for requesting control (increase, decrease, or maintenance) of a reverse power flow amount from the facility  100  to the power grid. A content for requesting the control of the operation of the distributed power supply may be included in the power supply control message. A content of the power flow control message for requesting the control of the power flow amount or a content of the reverse power flow control message for requesting the control of the reverse power flow amount may be included in the power supply control message or may not be included in the power supply control message. 
     As a format of the power command message, a unique format may be used or a format conforming to an automatic demand response (ADR) may be used. More specifically, as the power command message, a manner conforming to an Open ADR 2.0 standard can be used. 
     (Power Management Server) 
     Hereinafter, a power management server according to an embodiment will be described. 
     As shown in  FIG. 2 , a power management server  300  includes a communicator  310 , a manager  320 , and a controller  330 . The communicator  310  includes a communication module and the like, and communicates with the facility  100 . For example, the communicator  310  transmits a power command message to the facility  100 . The communicator  310  receives local information to be described below from the facility  100 . 
     The manager  320  includes a nonvolatile memory and/or a storage medium such as a hard disk drive (HDD), and manages a plurality of facilities  100  connected to the power grid. The controller  330  includes a central processing unit (CPU), a memory, and the like, and controls the communicator  310  and the manager  320 . The controller  330  controls a power demand-supply balance in all of the plurality of facilities  100  managed by the manager  320 . 
     In the embodiment, the controller  330  specifies a local operation plan of the fuel cell apparatus  130  in each facility  100  based on the local information, and modifies local operation plans of all of the plurality of facilities  100 . In order to realize such modification, the controller  330  instructs the communicator  310  to transmit the power command message described above. 
     (Local Control Apparatus) 
     Hereinafter, a local control apparatus according to an embodiment will be described. The local control apparatus may be an apparatus that controls the fuel cell apparatus  130  within the facility  100 . The local control apparatus may be the EMS  110  described above or may be the PCS  133  described above. The local control apparatus may include both of the EMS  110  and the PCS  133 . As shown in  FIG. 3 , the local control apparatus  400  includes a communicator  410  and a controller  420 . 
     The communicator  410  includes a communication module and the like, and communicates with the power management server  300 . For example, the communicator  410  receives a power command message from the power management server  300 . The communicator  410  transmits local information to be described below to the power management server  300 . 
     The controller  420  includes a CPU, a memory, and the like, and controls the communicator  410 . The controller  420  controls the fuel cell apparatus  130  within the facility  100 . 
     In the embodiment, the controller  420  determines a local operation plan of the fuel cell apparatus  130  based on the history of the consumed power of the load  120  and the history of the hot-water consumption amount of the hot-water supply apparatus  132 . The local operation plan is a plan indicating one of a plurality of predetermined operation states of the fuel cell apparatus  130  in a predetermined period in which the fuel cell apparatus  130  is operated in a predetermined time period. More specifically, the local operation plan is a plan indicating the operation state (the first operation state to the third operation state) for each time period of the fuel cell apparatus  130  in a predetermined period. 
     The controller  420  instructs the communicator  410  to transmit local information including information used to specify the local operation plan. The local information including the information used to specify the local operation plan may be considered as at least some of information elements constituting the local operation plan determined by the local control apparatus  400 . 
     Here, the controller  420  may determine the local operation plan so that the target amount of hot-water or the target temperature of the hot-water is obtained at a target time (for example, in the evening). The controller  420  may determine the local operation plan so as to minimize, for example, a power procurement cost (for example, a purchase amount of a power supplied from the power grid, a purchase amount of a fuel gas or the like). The controller  420  may determine the local operation plan based on utilization efficiency of exhaust heat of the fuel cell apparatus  130 . The controller  420  may determine the local operation plan based on characteristics (easiness of stop) of the fuel cell apparatus  130 . 
     For example, when the fuel cell apparatus  130  is an SOFC, it is difficult to stop the SOFC, and an idling state may thus be used as the third operation state. Since exhaust heat of the SOFC is often discarded, the local operation plan may be determined with priority given to the power procurement cost. On the other hand, when the fuel cell apparatus  130  is a PEFC, it is easy to stop the PEFC, and a complete stop state may thus be used as the third operation state. Since exhaust heat of the PEFC is not often discarded, the local operation plan may be determined with priority given to the amount of hot-water or the temperature of the hot-water. The local operation plan may be changed when the target amount of hot-water and the target temperature of the hot-water are reached. 
     In the embodiment, the local information may include the following information. 
     Specifically, the local information may include information indicating the operation state (the first operation state to the third operation state) for each time period of the fuel cell apparatus  130 . 
     The local information may include information indicating at least one of a power generation scheduled start time of the fuel cell apparatus  130 , a power generation scheduled end time of the fuel cell apparatus  130 , a power generation scheduled time period of the fuel cell apparatus  130 , and a power generation scheduled power of the fuel cell apparatus  130 . 
     The local information may include information indicating at least one of a current amount of hot-water of the hot-water supply apparatus  132 , a target amount of hot-water of the hot-water supply apparatus  132 , a current temperature of the hot-water of the hot-water supply apparatus  132 , and a target temperature of the hot-water of the hot-water supply apparatus  132 . The local information may include a scheduled time at which the target amount of hot-water or the target temperature of the hot-water will be realized. 
     The local information may include information indicating a consumed power for each time period of the load  120 . The local information may include information indicating a surplus power (reverse power flow power) for each time period. 
     The local information may include, for example, a measured value (° C.) of a temperature of hot-water of a water heater, a rated power generation amount (W), a heat amount (MJ) of a hot-water storage tank, a measured value of an instantaneous generated power (W) or an integrated value (kWh) thereof, a measured value of an instantaneous gas consumption amount (m 3 /h), a measured value of an in-home instantaneous consumed power (W) or an integrated value (kWh) thereof, a measured value of an amount (liter) of remaining hot-water, a tank capacity value (liter) and the like. 
     The local information may include a type of fuel cell apparatus  130 . The type of fuel cell apparatus  130  is information indicating whether the fuel cell apparatus  130  installed in the facility  100  is, for example, the SOFC, the PEFC, the PAFC or the MCFC. 
     (Power Management Method) 
     Hereinafter, a power management method according to an embodiment will be described. Only one local control apparatus  400  is shown in  FIG. 4 , but a plurality of local control apparatuses  400  may be actually present. 
     As shown in  FIG. 4 , in step S 11 , the local control apparatus  400  determines a local operation plan. The local operation plan is determined based on the history of the consumed power of the load  120  and the history of the hot-water consumption amount of the hot-water supply apparatus  132 . 
     In step S 12 , the power management server  300  transmits a message (local information request) for requesting local information to the local control apparatus  400 . 
     In step S 13 , the local control apparatus  400  transmits a message (local information response) including the local information to the power management server  300 . The local information includes information used to specify the local operation plan. 
     In step S 14 , the power management server  300  specifies a local operation plan of the fuel cell apparatus  130  in each facility  100  based on the local information, and modifies a local operation plan to be executed in each facility  100  based on a plurality of local operation plans. An object of the modification of the local operation plan in each facility  100  based on the plurality of local operation plans is, for example, to optimize all of the local operation plans, to individually optimize some of the local operation plans, or to reduce a fluctuation of a power frequency of the power grid. Hereinafter, a case where the object of the modification of the local operation plan is to optimize all of the local operation plans will be described. 
     Here, a case where excess of a surplus power occurs due to overlapping of power generation time periods between the facilities  100  and a case where a surplus power is insufficient due to overlapping of stop time periods between the facilities  100  are assumed. 
     In step S 15 , the power management server  300  transmits a power command message to the local control apparatus  400  in order to modify the local operation plans of all of the plurality of facilities  100 . 
     Here, in order to solve the excess or the insufficiency of the surplus power described above, the power management server transmits a power command message for shifting the power generation time period and the stop time period. The power command message may be a message for instructing that an operation state included in the local operation plan is changed. 
     In step S 16 , the local control apparatus  400  controls an operation state of the fuel cell apparatus  130 . 
     Here, since the local operation plan is optimized within the facility  100 , the local control apparatus  400  may control the operation state of the fuel cell apparatus  130  without following the power command message. However, in the embodiment, the local control apparatus  400  controls the operation state of the fuel cell apparatus  130  according to the power command message. 
     In step S 17 , the power management server  300  transmits a message (record request) for requesting an operation control record of the fuel cell apparatus  130  to the local control apparatus  400 . 
     In step S 18 , the local control apparatus  400  transmits a message (record response) including the operation control record of the fuel cell apparatus  130  to the power management server  300 . 
     In step S 19 , the power management server  300  gives an incentive according to a change in the local operation plan optimized within the facility  100 . The incentive may be a monetary reward, a reward by an intangible thing such as a gift certificate or a coupon, or may be a reward by a tangible thing such as a premium. 
     (Action and Effect) 
     In the embodiment, the power management server  300  can maintain the power demand-supply balance of the plurality of facilities  100  by transmitting the power command message in order to modify the local operation plan. 
     In the embodiment, the power management server  300  can increase effectiveness of the power command message by giving the incentive according to the change in the local operation plan optimized within the facility  100 . 
     Here, when the local information includes the information indicating the operation state of the fuel cell apparatus  130  for each time period, it is easy to specify a time period in which the excess or the insufficiency of the surplus power occurs. 
     When the local information includes the power generation scheduled start time of the fuel cell apparatus  130 , it is easy to specify a time period in which the excess of the surplus power occurs. When the local information includes the power generation scheduled end time of the fuel cell apparatus  130 , it is easy to specify a timing at which it is difficult for the surplus power to be generated. When the local information includes the power generation scheduled time period of the fuel cell apparatus  130 , it is easy to specify a time period in which the excess or the insufficiency of the surplus power occurs. When the local information includes the power generation scheduled power of the fuel cell apparatus  130 , it is easy to specify a level of the surplus power. 
     When the local information includes the current amount of hot-water of the hot-water supply apparatus  132  and the target amount of hot-water of the hot-water supply apparatus  132 , it is possible to improve accuracy in specifying a power generation end time of the fuel cell apparatus  130 . Likewise, when the local information includes the current temperature of the hot-water of the hot-water supply apparatus  132  and the target temperature of the hot-water of the hot-water supply apparatus  132 , it is possible to improve accuracy in specifying the power generation end time of the fuel cell apparatus  130 . When the local information includes the scheduled time at which the target amount of hot-water or the target temperature of the hot-water will be realized, it is possible to further improve the accuracy in specifying the power generation end time of the fuel cell apparatus  130 . 
     When the local information includes the information indicating the consumed power for each time period of the load  120 , it is easy to specify a level of the surplus power for each time period. Likewise, when the local information includes the information indicating the surplus power (reverse power flow power) for each time period, it is easy to specify a level of the surplus power for each time period. 
     When the local information includes the type of fuel cell apparatus  130 , in a case where different types of fuel cell apparatuses  130  are installed in the plurality of facilities  100 , it is possible to shift power generation time periods, power generation start times, power generation end times, or the like depending on characteristics of the respective types of fuel cell apparatuses  130 . Specifically, for example, it is conceivable to utilize characteristics that a time from a start to a state where a power can be generated is shorter in the PEFC than in the SOFC. By transmitting the power command message so that a power generation start time of the PEFC becomes earlier than that of the SOFC, it is possible to maintain the power demand-supply balance of the plurality of facilities  100  without causing a delay time. In such a case, the power management server  300  may change the power generation start time by transmitting the power command message at different timings or may transmit a power command message for designating different power generation start times. 
     Modified Example 1 
     Hereinafter, Modified Example 1 of the embodiment will be described. Portions different from those of the embodiment will be described below. 
     In the embodiment, the local control apparatus  400  determines the local operation plan, and the local information used to specify the local operation plan is transmitted to the power management server  300 . On the other hand, in Modified Example 1, a power management server  300  estimates a local operation plan. 
     Specifically, the power management server  300  according to Modified Example 1 receives local information used to estimate the local operation plan. The power management server  300  estimates the local operation plan based on the local information. The local information including the information used to estimate the local operation plan may be considered as information elements other than information elements constituting the local operation plan determined by the local control apparatus  400 . 
     The local information according to Modified Example 1 may be information indicating an operation record of the fuel cell apparatus  130 . The operation record may be information indicating a history of a generated power amount for each time period, information indicating an amount of stored hot-water for each time period, or information indicating a history of a reverse power flow power amount for each time period. The local information may be a history of a consumed power of the load  120 , information indicating a history of a hot-water consumption amount of the hot-water supply apparatus  132 , or information indicating a history of a supply water temperature or an outside air temperature. With these pieces of information, it is possible to estimate the local operation plan decided by the local control apparatus  400 . 
     (Power Management Method) 
     Hereinafter, a power management method according to an embodiment will be described. In  FIG. 5 , processes similar to those in  FIG. 4  are given the same step numbers. A description of the same processes as those in  FIG. 4  will be omitted. 
     As shown in  FIG. 5 , in step S 13 A, the local control apparatus  400  transmits a message (local information response) including the local information to the power management server  300 . The local information includes information used to estimate the local operation plan. 
     In step S 14 A, the power management server  300  estimates the local operation plan based on the local information. 
     In step S 14 B, the power management server  300  modifies the local operation plans (estimated) of all of the plurality of facilities  100 . 
     Other Embodiments 
     Although the present invention has been described with reference to the abovementioned embodiment, it should not be understood that the description and the drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples, and operational technologies will be apparent to those skilled in the art. 
     Although not particularly limited, in  FIGS. 4 and 5 , the local control apparatus  400  may periodically transmit a polling signal to the power management server  300 . The power management server  300  transmits various messages to the local control apparatus  400  depending on reception of the polling signal. The local control apparatus  400  may autonomously transmit a message to the power management server  300  even though the local control apparatus  400  does not receive a request from the power management server  300 . 
     Although not particularly limited, in a case where communication between the power management server  300  and the local control apparatus  400  is performed in a manner conforming to an Open ADR standard, for example, ordrPoll can be used as the polling signal. For example, oadrDistributeEvent can be used as a power command message. TELEMETRY USAGE and TELEMETRY STATUS can be used as a local information response and a record response. 
     Although not particularly limited, flows shown in  FIGS. 4 and 5  may be periodically performed. The term ‘periodically’ means that the flows may be performed once/n days (n is an integer of 0 or more) or may be performed once/n hours (n is an integer of 0 or more), for example. The flows shown in  FIGS. 4 and 5  may also be performed depending on occurrence of a predetermined event. The predetermined event may be an event in which a power demand-supply balance collapses in a management area managed by the power management server  300 , may be an event in which a power demand-supply balance collapses in a wide area wider than the management area, or may be a natural disaster or the like. 
     Although not particularly limited, the “power” described above may be an instantaneous value (kW). The “power” described above may also be called electric energy (kWh) when being accompanied by a concept of time. 
     Although not particularly limited, information elements required for modifying the local operation plan may not be necessarily transmitted from the local control apparatus  400 . For example, information indicating at least one of a rated power of the fuel cell apparatus  130  and a type of fuel cell apparatus  130  may be registered in advance in the power management server  300  in installation application or the like of the fuel cell apparatus  130 . Information indicating at least one of the target amount of hot-water of the hot-water supply apparatus and the target temperature of the hot-water of the hot-water supply apparatus may be registered in advance in the power management server  300  in installation application or the like of the fuel cell apparatus  130 . Information indicating the history of the consumed power of the load  120  and the history of the hot-water consumption amount of the hot-water supply apparatus  132  may be registered in advance in the power management server  300  by a questionnaire or the like. 
     The case where the distributed power supply is the fuel cell apparatus  130  has been described in the embodiment, but it is obvious that the distributed power supply may be a storage battery apparatus. Even in a case where the distributed power supply is the storage battery apparatus, an operation state of the storage battery apparatus is specified by the power management server  300 . The operation state of the storage battery apparatus may be a past operation state, a current operation state, or a future operation state, similar to the fuel cell apparatus  130 . The operation state may include the following operation states. The operation state is a charging state, a discharging state, and a stop state. Further, the operation state may be a state in which discharging or charging of a predetermined power is performed. The predetermined power may be, for example, a rated power, a rated voltage, or a maximum current determined by capability of any one of the storage battery or the PCS. The rated power may be a recommended upper limit (for example, a catalog value) of an output power determined by a maker of any one of the storage battery and the PCS. 
     In addition, in the case where the distributed power supply is the storage battery apparatus, the local control apparatus  400  may transmit local information including information indicating a type of storage battery apparatus (more specifically, storage battery) to the power management server  300 . Examples of the type of storage battery apparatus include a lithium ion battery, a nickel cadmium battery, a nickel hydrogen battery, a lead storage battery, and the like. A case where supplementary charging is appropriate and a case where supplementary charging is not appropriate can be considered due to a difference between types of storage battery apparatuses. Therefore, it is possible to appropriately manage the storage battery apparatus by transmitting the type of storage battery apparatus. In addition, the local information may include information indicating at least one of the number of days in which the storage battery is used, a capacity of the storage battery, the number of times of charging of the storage battery, and the number of times of discharging of the storage battery, in addition to the type of storage battery apparatus. 
     The present application claims the priority of Japanese Patent Application No. 2016-168918 (filed on Aug. 31, 2016), the contents of which are incorporated herein in its entirety.