Patent Publication Number: US-9851734-B2

Title: Alert presentation apparatus and alert presentation method

Description:
TECHNICAL FIELD 
     The present invention relates to an alert presentation apparatus and an alert presentation method which present a list of loads including power consumption of the loads in order to reduce an accumulated amount of power supplied from a grid in a prescribed period equal to or smaller than a prescribed amount of power. 
     BACKGROUND ART 
     Recently, as sense of environmental consideration is growing, techniques to reduce power consumption of load are proposed (for example, Patent Literature 1). 
     Then, in order to reduce an accumulated amount of power supplied from a grid in a prescribed period equal to or smaller than a prescribed amount of power, techniques to present a list of loads including power consumption of the loads to a user have been proposed. 
     CITATION LIST 
     Patent Literature 
     [Patent Literature 1] Japanese Patent Application Publication No. 2008-236913 
     SUMMARY OF INVENTION 
     By the way, if the list of loads is updated frequently, there is a possibility that a user may be confused about which power consumption of a load should be reduced. On the other hand, when an update interval of the list of loads is long, there is a possibility that the user is not able to effectively know the load in which power consumption should be reduced. 
     Then, the present invention has been made to solve the above-described problems and has an object to provide an alert presentation apparatus and an alert presentation method capable of letting a user effectively know a load in which power consumption should be reduced while suppressing confusion of the user. 
     An alert presentation apparatus according to a first feature presents a list of loads including power consumption of the loads connected to a grid in order to reduce an accumulated amount of power supplied from the grid in a prescribed period equal to or smaller than a prescribed amount of power. The alert presentation apparatus includes: a first power acquisition unit which acquires power consumed by the loads; and a presentation unit which presents the list based on an amount of power acquired by the first power acquisition unit. The presentation unit presents the list so that frequency of replacement of the loads included in the list becomes low. 
     In the first feature, the presentation unit presents the list including a prescribed number of loads listed in a descending order of power consumption among the loads, or presents the list which including a prescribed number of loads listed in a descending order of an increment in power consumption among the loads. 
     In the first feature, the presentation unit presents the list in which a prescribed number of loads are highlighted in a descending order among the loads, or presents the list in which a prescribed number of loads are highlighted in a descending order of an increment in power consumption among the loads. 
     In the first feature, the prescribed period includes a first period and a second period after the first period. An update interval of the list in the first period is longer than an update interval of the list in the second period. 
     In the first feature, the alert presentation apparatus includes: a second power acquisition unit which acquires power supplied from the grid; and a prediction unit which predicts the accumulated amount of power based on the power acquired by the second power acquisition unit. The presentation unit presents the list as an alert when a predictive value of the accumulated amount of power predicted by the prediction unit reaches a prescribed threshold value. 
     In the first feature, the presentation unit presents the list constantly. 
     In the first feature, the presentation unit presents the list by use of an application which acquires power consumption of the load or a browser at a presentation of the list. 
     An alert presentation method according to a second feature presents a list of loads including power consumption of the loads connected to a grid in order to reduce an accumulated amount of power supplied from the grid in a prescribed period equal to or smaller than a prescribed amount of power. The alert presentation method includes: a step A of acquiring power consumed by the load; and a step B of presenting the list based on the amount of power acquired in the step A. The step B includes a step of presenting the list so that frequency of replacement of the loads included in the list becomes low. 
     According to the present invention, it is possible to provide alert presentation apparatus and alert presentation method capable of letting a user effectively know a load in which power consumption should be reduced while suppressing confusion of the user. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram illustrating an energy management system  100  according to a first embodiment. 
         FIG. 2  is a diagram illustrating a consumer facility  10  according to the first embodiment. 
         FIG. 3  is a diagram for describing an applicative scene of the first embodiment. 
         FIG. 4  is a diagram illustrating an EMS  200  according to the first embodiment. 
         FIG. 5  is a diagram illustrating presentation information  400  according to the first embodiment. 
         FIG. 6  is a diagram illustrating a power monitoring graph according to the first embodiment. 
         FIG. 7  is a diagram for describing a first form according to the first embodiment. 
         FIG. 8  is a diagram for describing the first form according to the first embodiment. 
         FIG. 9  is a diagram for describing the first form according to the first embodiment. 
         FIG. 10  is a diagram for describing the first form according to the first embodiment. 
         FIG. 11  is a flowchart illustrating an alert presenting method according to the first embodiment. 
         FIG. 12  is a flowchart illustrating an alert presenting method according to Modification 1. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an alert presentation apparatus and an alert presenting method according to an embodiment of the present invention will be described with reference to the drawings. In the following drawings, identical or similar components are denoted by identical or similar reference numerals. 
     It should be understood that the drawings are schematic only and the ratio of dimensions is not to scale. Therefore, specific dimensions should be determined with reference to the description below. It is needless to mention that different relationships and ratio of dimensions may be included in different drawings. 
     Outline of Embodiments 
     An alert presentation apparatus according to some of embodiments presents a list of loads including power consumption of the loads connected to a grid in order to reduce an accumulated amount of power supplied from the grid in a prescribed period equal to or smaller than a prescribed amount of power. The alert presentation apparatus includes: a first power acquisition unit which acquires power consumed by the loads; and a presentation unit which presents the list based on an amount of power acquired by the first power acquisition unit. The presentation unit presents the list so that frequency of replacement of the loads included in the list becomes low. 
     In some of embodiments, the alert presentation apparatus presents the list so that frequency of replacement of the loads included in the list becomes low. Therefore, a user can effectively know a load in which power consumption should be reduced while suppressing confusion of the user. 
     For example, the alert presentation apparatus may present a list which includes a prescribed number of loads listed in a descending order of power consumption or may present a list which includes a prescribed number of loads listed in a descending order of an increment in power consumption among the loads connected to the grid. In this manner, frequency of replacement of the loads included in the list becomes low. 
     Alternatively, the alert presentation apparatus may present a list in which a prescribed number of loads are highlighted in a descending order of power consumption among the loads connected to the grid, or may present a list in which a prescribed number of loads are highlighted in a descending order of an increment in power consumption among the loads connected to the grid. In this manner, frequency of replacement of the highlighted loads included in the list becomes low. 
     Alternatively, the prescribed period may include a first period and a second period after the first period, and an update interval of the list in the first period may be longer than an update interval of the list in the second period. Therefore, in a period with low urgency to reduce power consumption (i.e., the first period), confusion of a user can be reduced. On the other hand, in a period with high urgency to reduce power consumption (i.e., the second period), the user can effectively know the load in which power consumption should be reduced. 
     First Embodiment 
     (Energy Management System) 
     Hereinafter, an energy management system according to a first embodiment will be described.  FIG. 1  is a diagram illustrating an energy management system  100  according to the first embodiment. 
     As illustrated in  FIG. 1 , the energy management system  100  is provided with a consumer facility  10 , a CEMS  20 , a substation  30 , a smart server  40  and a power plant  50 . The consumer facility  10 , the CEMS  20 , the substation  30  and the smart server  40  are connected via a network  60 . 
     The consumer facility  10  is provided with, for example, a power generating apparatus and a power storage apparatus. The power generating apparatus is, for example, an apparatus which outputs power using fuel gas like a fuel cell. The power storage apparatus is, for example, an apparatus which stores power like a secondary battery. 
     The consumer facility  10  may be, for example, a residence such as a detached house, housing complex such as a condominium, a commercial institution such as a building, or a factory. 
     In the first embodiment, a consumer facility group  10 A and a consumer facility group  10 B are constituted by a plurality of consumer facilities  10 . The consumer facility group  10 A and the consumer facility group  10 B are classified according to, for example, geographical areas. 
     The CEMS  20  controls interconnection between a plurality of consumer facilities  10  and a power system. Note that the CEMS  20  may be referred to as CEMS (Cluster/Community Energy Management System) because the CEMS  20  manages a plurality of consumer facilities  10 . In particular, the CEMS  20  disconnects a plurality of consumer facilities  10  from the power system at the time of, for example, a power failure. On the other hand, the CEMS  20  performs interconnection between a plurality of consumer facilities  10  and the power system at the time of, for example, power return. 
     In the first embodiment, a CEMS  20 A and a CEMS  20 B are provided. The CEMS  20 A controls, for example, interconnection between the consumer facilities  10  included in the consumer facility group  10 A and the power system. The CEMS  20 B controls, for example, interconnection between the consumer facilities  10  included in the consumer facility group  10 B and the power system. 
     The substation  30  supplies a plurality of consumer facilities  10  with power via a distribution line  31 . In particular, the substation  30  lowers a voltage supplied from the power plant  50 . 
     In the first embodiment, a substation  30 A and a substation  30 B are provided. The substation  30 A supplies power to, for example, the consumer facilities  10  included in the consumer facility group  10 A via a distribution line  31 A. The substation  30 B supplies power to, for example, the consumer facilities  10  included in the consumer facility group  10 B via a distribution line  31 B. 
     The smart server  40  manages a plurality of CEMS  20  (here, the CEMS  20 A and the CEMS  20 B). Further, the smart server  40  manages a plurality of substations  30  (here, the substation  30 A and the substation  30 B). In other words, the smart server  40  collectively manages consumer facilities  10  included in the consumer facility group  10 A and the consumer facility group  10 B. The smart server  40  has, for example, a function to balance the power to be supplied to the consumer facility group  10 A and the power to be supplied to the consumer facility group  10 B. 
     The power plant  50  generates power by fire power, wind power, hydraulic power, atomic power and the like. The power plant  50  supplies a plurality of substations  30  (here, the substation  30 A and the substation  30 B) with power via a power line  51 . 
     The network  60  is connected to each apparatus via a signal line. The network  60  is, for example, the Internet, a broadband communication network, a narrowband communication network, a portable telephone network, and the like. 
     (Consumer Facility) 
     Hereinafter, the consumer facility according to the first embodiment will be described.  FIG. 2  is a diagram illustrating details of the consumer facility  10  according to the first embodiment. 
     As illustrated in  FIG. 2 , the consumer facility  10  is provided with a distribution board  110 , a load  120 , a PV unit  130 , a storage battery unit  140 , a fuel cell unit  150 , a hot water storage unit  160  and the EMS  200 . 
     The distribution board  110  is connected to the distribution line  31  (i.e., the grid). The distribution board  110  is connected to the load  120 , the PV unit  130 , the storage battery unit  140  and the fuel cell unit  150  via a power line. 
     The load  120  is an apparatus which consumes power supplied via the power line. For example, the load  120  includes an apparatus, such as a refrigerator, a freezer, a lighting apparatus or an air conditioner. 
     The PV unit  130  is provided with a PV  131  and a PCS  132 . The PV  131  is an exemplary power generating apparatus, and is a photovoltaic power generating apparatus which generates power upon reception of sunlight. The PV  131  outputs generated DC power. An amount of generated power of the PV  131  changes depending on an amount of solar radiation with which the PV  131  is irradiated. The PCS  132  is an apparatus which converts DC power output from the PV  131  into AC power (i.e., a Power Conditioning System). The PCS  132  outputs the AC power to the distribution board  110  via the power line. 
     In the first embodiment, the PV unit  130  may be provided with a pyranometer for measuring the amount of solar radiation with which the PV  131  is irradiated. 
     The PV unit  130  is controlled by the MPPT (Maximum Power Point Tracking) method. In detail, the PV unit  130  optimizes an operating point of the PV  131  (i.e., a point defined by an operating point voltage value and the power value, or a point defined by the operating point voltage value and a current value). 
     The storage battery unit  140  is provided with a storage battery  141  and a PCS  142 . The storage battery  141  is an apparatus which stores power. The PCS  142  is an apparatus (i.e., a Power Conditioning System) which converts AC power supplied from the distribution line  31  (i.e., the grid) into DC power. Further, the PCS  142  converts the DC power output from the storage battery  141  into AC power. 
     The fuel cell unit  150  is provided with a fuel cell  151  and a PCS  152 . The fuel cell  151  is an exemplary power generating apparatus, and is an apparatus which outputs power using fuel gas. The fuel cell  151  is, for example, SOFC (Solid Oxide Fuel Cell) or PEFC (Polymer Electrolyte Fuel Cell). The PCS  152  is an apparatus (i.e., a Power Conditioning System) which converts DC power output from the fuel cell  151  into AC power. 
     The fuel cell unit  150  is operated by load following control. In detail, the fuel cell unit  150  controls the fuel cell  151  so that power output from the fuel cell  151  becomes the target power of the load following control. 
     The hot water storage unit  160  is an exemplary heat storage apparatus which converts power into heat, stores heat, or stores heat generated by a cogeneration apparatus, such as the fuel cell unit  150 , as hot water. In particular, the hot water storage unit  160  is provided with a hot water storage tank and heats water supplied from the hot water storage tank with exhaust heat produced by operation (i.e., power generation) of the fuel cell  151 . In detail, the hot water storage unit  160  heats water supplied from the hot water storage tank and flows back the heated hot water to the hot water storage tank. 
     The EMS  200  is an apparatus (i.e., an Energy Management System) which controls the PV unit  130 , the storage battery unit  140 , the fuel cell unit  150  and the hot water storage unit  160 . In particular, the EMS  200  is connected to the PV unit  130 , the storage battery unit  140 , the fuel cell unit  150  and the hot water storage unit  160  via a signal line and controls the PV unit  130 , the storage battery unit  140 , the fuel cell unit  150  and the hot water storage unit  160 . Further, the EMS  200  controls power consumption of the load  120  by controlling an operation mode of the load  120 . 
     Further, the EMS  200  is connected to various servers via network  60 . Various servers store information including, for example, a purchase unit price of the power supplied from the grid, a sales unit price of the power supplied from the grid and a purchase unit price of the fuel gas (hereafter, referred to as energy rate information). 
     Alternatively, various servers store information used for, for example, predicting power consumption of the load  120  (hereafter, referred to as energy consumption prediction information). The energy consumption prediction information may be, for example, generated based on a past actual value of power consumption of the load  120 . Alternatively, the energy consumption prediction information may be a model of power consumption of the load  120 . 
     Alternatively, various servers store, for example, information used for predicting the amount of generated power of the PV  131  (hereafter, referred to as prediction information about the amount of generated PV power). The PV power generation prediction information may be a predictive value of the amount of solar radiation with which the PV  131  is irradiated. Alternatively, the PV power generation prediction information may be weather report, season, daylight hours and the like. 
     (Applicative Scene) 
     Hereinafter, an applicative scene of the first embodiment will be described.  FIG. 3  is a diagram for describing an applicative scene of the first embodiment.  FIG. 3  mainly describes an information flow in the consumer facility  10 . 
     As illustrated in  FIG. 3 , the consumer facility  10  is provided with a grid power meter  310 , a power measurement unit  320 , a power monitoring unit  330 , a load power meter  340 , a smart sensor  350  and a hub  360 . As described above, the consumer facility  10  is provided with the EMS  200 . 
     The grid power meter  310  measures power supplied from the distribution line  31  (i.e., the grid). In particular, the grid power meter  310  is disposed further toward the distribution line  31  (i.e., the grid) than the distribution board  110 , and measures the power supplied to the entire consumer facility  10 . 
     The power measurement unit  320  accumulates the power measured by the grid power meter  310  in the prescribed period. In other words, the power measurement unit  320  accumulates the power measured by the grid power meter  310  from the start of the prescribed period to the expiration of the prescribed period. That is, the power measurement unit  320  resets the accumulated value (i.e., the accumulated amount of power) in each prescribed period. 
     In Japan, for example, the total power rate of a high-voltage power user is defined by a basic rate and a metered power rate. The basic rate is defined based on the accumulated amount of power supplied from the grid in the past demand period (i.e., a peak amount of power). Therefore, it is desirable to control power consumption of each load so that the accumulated amount of power in a demand period does not exceed the prescribed amount of power. Then, the demand period (for example, 30 minutes) may be defined as the prescribed period. 
     The power monitoring unit  330  monitors whether the predictive value of the accumulated amount of power at the time of expiration of the prescribed period exceeds the prescribed amount of power based on the accumulated value (i.e., the accumulated amount of power) acquired from the power measurement unit  320 . In particular, the power monitoring unit  330  predicts the accumulated amount of power based on the actual value of power measured by the grid power meter  310 . Alternatively, the power monitoring unit  330  predicts the accumulated amount of power based on a variation amount of the power measured by the grid power meter  310 . That is, in the first embodiment, the power monitoring unit  330  configures the second power acquisition unit and the prediction unit. 
     Here, it is desirable that the power monitoring unit  330  predicts, in a first half (i.e., a first period) of the prescribed period, the accumulated amount of power based on the actual value of power measured by the grid power meter  310 . It is desirable that the power monitoring unit  330  predicts, in a second half (i.e., a second period) of the prescribed period, the accumulated amount of power based on the variation amount of the power measured by the grid power meter  310 . 
     For example, the first half of the prescribed period is a period from the start of the prescribed period to the ½ of the prescribed period, and the second half of the prescribed period is a period from the ½ of the prescribed period to the expiration of the prescribed period. Alternatively, the first half of the prescribed period is a period from the start of the prescribed period to the ⅔ of the prescribed period, and the second half of the prescribed period is the period from the ⅔ of the prescribed period to the expiration of the prescribed period. The timing at which the first half and the second half are divided may be defined at any timing within the prescribed period. 
     When the predictive value of the accumulated amount of power at the time of expiration of the prescribed period exceeds the prescribed amount of power, the power monitoring unit  330  transmits, to the EMS  200 , information which indicates that the predictive value of the accumulated amount of power exceeds the prescribed amount of power. 
     The load power meter  340  is provided at each load  120  and measures power consumed at each load  120 . That is, in the first embodiment, the load power meter  340  configures the first power acquisition unit. In the first embodiment, as the load power meter  340 , first power meters  340 A 1  to  340 An and second power meters  340 B 1  to  340 Bn are provided. The first power meters  340 A 1  to  340 An are connected to a power line A provided under the control of a breaker A of the distribution board  110 , and the second power meters  340 B 1  to  340 Bn are connected to a power line B provided under control of a breaker B of the distribution board  110 . 
     The smart sensor  350  collects power measured by the load power meter  340  provided under the control of the smart sensor  350 . In the first embodiment, a smart sensor  350 A and a smart sensor  350 B are provided as the smart sensor  350 . The smart sensor  350 A collects power measured by the first power meters  340 A 1  to  340 An. The smart sensor  350 B collects power measured by the second power meters  340 B 1  to  340 Bn. 
     The smart sensor  350  transmits, to the EMS  200 , information which indicates power measured by each load power meter  340  together with an identifier of each load power meter  340 . Alternatively, the smart sensor  350  transmits, to the EMS  200 , information which indicates a total value of power measured by the load power meter  340 . 
     The hub  360  is connected to the EMS  200 , the power monitoring unit  330  and the smart sensor  350  via a signal line. The hub  360  relays information output from the power monitoring unit  330  and the smart sensor  350  to the EMS  200 . 
     (Configuration of EMS) 
     Hereinafter, the EMS of the first embodiment will be described.  FIG. 4  is a block diagram illustrating the EMS  200  of the first embodiment. 
     As illustrated in  FIG. 4 , the EMS  200  is provided with a reception unit  210 , a transmission unit  220 , a control unit  230  and a presentation unit  240 . 
     The reception unit  210  receives various signals from the apparatuses connected via the signal line. For example, the reception unit  210  receives, from the power monitoring unit  330 , information which indicates that the predictive value of the accumulated amount of power exceeds the prescribed amount of power. The reception unit  210  receives, from the smart sensor  350 , information which indicates power measured by each load power meter  340  together with an identifier of each load power meter  340 . Alternatively, the reception unit  210  may receive, from the smart sensor  350 , information which indicates power totaled by the smart sensor  350 . 
     In the first embodiment, the reception unit  210  may receive, from the PV unit  130 , information which indicates the amount of generated power of the PV  131 . The reception unit  210  may receive, from the storage battery unit  140 , information which indicates an amount of stored power of the storage battery  141 . The reception unit  210  may receive, from the fuel cell unit  150 , information which indicates an amount of generated power of the fuel cell  151 . The reception unit  210  may receive, from the hot water storage unit  160 , information which indicates an amount of stored hot water of the hot water storage unit  160 . 
     In the first embodiment, the reception unit  210  may receive, from various servers, the energy rate information, the energy consumption prediction information and the prediction information about the amount of generated PV power via the network  60 . However, the energy rate information, the energy consumption prediction information and the prediction information about the amount of generated PV power may be stored in the EMS  200  in advance. 
     The transmission unit  220  transmits various signals to the apparatuses connected via the signal line. For example, the transmission unit  220  transmits signals used to control the PV unit  130 , the storage battery unit  140 , the fuel cell unit  150  and the hot water storage unit  160  to each unit using a communication protocol, such as the ECHONET Lite or the ZigBee (registered trademark). The transmission unit  220  transmits, to the load  120 , a control signal for controlling the load  120  using a communication protocol, such as the ECHONET Lite. 
     The control unit  230  controls the load  120 , the PV unit  130 , the storage battery unit  140 , the fuel cell unit  150  and the hot water storage unit  160 . 
     In the first embodiment, the control unit  230  generates a list of loads including power consumption of the load. The list of loads may be a list presented constantly or may be a list presented when the predictive value of the accumulated amount of power exceeds the prescribed amount of power. 
     In particular, the control unit  230  generates a list of loads based on the power measured by each load power meter  340 . The list of loads at least includes, for example, the name of the load and power consumption of the load. The list of loads may include the variation amount of the power consumption in addition to the information above. 
     For example, when the predictive value of the accumulated amount of power predicted based on the actual value of power measured by the grid power meter  310  exceeds the prescribed amount of power, the control unit  230  generates, in the first form, a list of loads in which power consumption should be reduced. On the other hand, when the predictive value of the accumulated amount of power predicted based on the variation amount of the power measured by the grid power meter  310  exceeds the prescribed amount of power, the control unit  230  generates, in the second form, a list of loads in which power consumption should be reduced. 
     The first form is a form in which a list of loads is presented in a descending order of the actual value of power acquired by the load power meter  340 . The second form is a form in which a list of loads is presented in a descending order of the increment in power acquired by the load power meter  340 . 
     Here, the control unit  230  generates the list so that frequency of replacement of the loads included in the list becomes low. 
     For example, the control unit  230  may generate a list which includes a prescribed number of loads listed in a descending order of power consumption or may generate a list which includes a prescribed number of loads listed in a descending order of an increment in power consumption among the loads connected to the grid. 
     Alternatively, the control unit  230  may generate a list in which a prescribed number of loads are highlighted in a descending order of power consumption among the loads connected to the grid, or may generate a list in which a prescribed number of loads are highlighted in a descending order of an increment in power consumption among the loads connected to the grid. 
     Alternatively, the update interval of the list in the first half (i.e., the first period) of the prescribed period may be longer than the update interval of the list in the second half (i.e., the second period) of the prescribed period. 
     The presentation unit  240  presents various types of information to the user. In particular, the presentation unit  240  is a display which displays each piece of information. However, the presentation unit  240  may be a speaker which outputs each piece of information as sound. 
     In the first embodiment, the presentation unit  240  presents the list of loads. Here, the presentation unit  240  may present a list of loads by using an application which acquires power consumption of the load  120  or a browser. 
     In the first embodiment, the presentation unit  240  displays, for example, presentation information  400  as illustrated in  FIG. 5 . The presentation information  400  includes date and time information  410 , state outline information  420 , state detail information  430 , state explanatory note information  440 , link information  450 , a facility change list  460  and an energy saving action list  470 . 
     The date and time information  410  is information which indicates the present date and time. 
     The state outline information  420  is information which indicates an outline of a state of power supplied from the grid in the current prescribed period. The state outline information  420  is represented by, for example, four stages (extra, caution, alert and danger). 
     The state detail information  430  is information which indicates details of the state of power supplied from the grid in the current prescribed period. The state detail information  430  includes, for example, a target power value, a predictive power value and excessive power. The target power value is a target value of the accumulated amount of power supplied from the grid in the prescribed period. The predictive power value is a predictive value of the accumulated amount of power predicted by the power monitoring unit  330  described above. The excessive power is the amount of power in which the predictive power value exceeds the target power value. The unit of the power value is kWh. 
     The state explanatory note information  440  is information which indicates an explanatory note of the state outline information  420 . The state explanatory note information  440  includes, for example, a threshold of each stage (extra, caution, alert and danger) and color expressing each stage and the like. 
     The link information  450  is information which indicates various types of information that can be switched from the presentation information  400  (i.e., a power monitoring graph, a power record/day and a power record/month). The “power monitoring graph” is, for example, a graph illustrated  FIG. 6  described later. The “power record/day” and the “power record/month” are totaled results of past histories. By the selection (i.e., click) of the link information  450 , the information presented by the presentation unit  240  is switched to the selected information. 
     The facility change list  460  is a list of loads which is presented constantly. The facility change list  460  includes, for example, the name of loads and power consumption of the loads. 
     Here, the facility change list  460  may be a list which includes a prescribed number of loads listed in a descending order of power consumption, or may be a list in which a prescribed number of loads are highlighted in a descending order of power consumption among the loads connected to the grid. 
     The energy saving action list  470  is a list of loads presented when the predictive value of the accumulated amount of power exceeds the prescribed amount of power. The energy saving action list  470  is an exemplary alert which indicates a list of loads in which power consumption should be reduced. 
     In the first embodiment, the energy saving action list  470  is presented in the first form or the second form. As described above, the first form is a form in which a list of loads is presented in a descending order of the actual value of power acquired by the load power meter  340 . The second form is a form in which a list of loads is presented in a descending order of the variation amount of the power acquired by the load power meter  340 . 
     Here, when the energy saving action list  470  is presented in the first form, the energy saving action list  470  may be a list which includes a prescribed number of loads listed in a descending order of power consumption, or may be a list in which a prescribed number of loads are highlighted in a descending order of power consumption among the loads connected to the grid. On the other hand, when the energy saving action list  470  is presented in the second form, the energy saving action list  470  may be a list which includes a prescribed number of loads listed in a descending order of an increment in power consumption among the loads connected to the grid, or may be a list in which a prescribed number of loads are highlighted in a descending order of an increment in power consumption among the loads connected to the grid. 
     Subsequently, a power monitoring graph according to the first embodiment will be described.  FIG. 6  is a diagram illustrating the power monitoring graph according to the first embodiment. 
     As illustrated in  FIG. 6 , at the present date included in the prescribed period (for example, 30 minutes), the power monitoring graph includes an accumulated value of power (i.e., an accumulated amount of power) supplied from the grid. In detail, an actual value of the accumulated amount of power is illustrated by a solid line and a predictive value of the accumulated amount of power is illustrated by a dotted line. 
     The power monitoring graph includes a target amount of power and a limit amount of power as the prescribed amount of powers. The power monitoring graph may also include a target amount of power reference line which indicates a transition of the accumulated amount of power of which accumulated amount of power is set to be the target amount of power at the time of expiration of the prescribed period. The power monitoring graph may also include a limit amount of power reference line which indicates a transition of the accumulated amount of power of which accumulated amount of power is set to be the limit amount of power at the time of expiration of the prescribed period. The power monitoring graph may also include a predictive value of the accumulated amount of power (i.e., a predictive power value) at the time of expiration of the prescribed period. 
     Here, a case in which the accumulated amount of power at the time of expiration of the prescribed period is predicted at time t n  will be described. The accumulated amount of power at time t n  is W n  and the accumulated amount of power at time t n-1  is W n-1 . Here, a case in which the prescribed period is set to 30 minutes (i.e., 0.5 h) will be illustrated. 
     In a case in which the accumulated amount of power is predicted based on the actual value, the predictive value of the accumulated amount of power is indicated by an approximation straight line of the actual value at each timing. The predictive value of the accumulated amount of power at the time of expiration of the prescribed period is expressed by “Y/X×0.5.” Y/X is a slope of the approximation straight line. 
     That is, when “Y/X×0.5” exceeds the target amount of power (or the limit amount of power), the power monitoring unit  330  determines that the predictive value of the accumulated amount of power exceeds the prescribed amount of power. Alternatively, when “W n ” exceeds the target amount of power reference line (or the limit amount of power reference line), the power monitoring unit  330  may determine that the predictive value of the accumulated amount of power exceeds the prescribed amount of power. 
     In a case in which the accumulated amount of power is predicted based on the variation amount, the slope of the predictive value of the accumulated amount of power is expressed by “(W n −W n-1 )/(t n −t n-1 ).” The predictive value of the accumulated amount of power at the time of expiration of the prescribed period is expressed by “W n +{(W n −W n-1 )/(t n −t n-1 )}×(0.5−t n ).” 
     That is, when “W n +{(W n −W n-1 )/(t n −t n-1 )}×(0.5−t n )” exceeds the target amount of power (or the limit amount of power), the power monitoring unit  330  determines that the predictive value of the accumulated amount of power exceeds the prescribed amount of power. 
     Here, the predictive power value is obtained based on the predictive value of the accumulated amount of power predicted by the power monitoring unit  330  described above. The unit of the predictive power value is kWh. 
     (First Form) 
     Hereinafter, a first form of the energy saving action list  470  according to the first embodiment will be described.  FIGS. 7 and 8  are diagrams for describing the first form of the energy saving action list  470  according to the first embodiment. 
     As described above, it is desirable that the first form is a form applied when the predictive value of the accumulated amount of power predicted based on the actual value of power measured by the grid power meter  310  exceeds the prescribed amount of power. 
     As illustrated in  FIG. 7 , when “Y/X×0.5” exceeds the target amount of power (or the limit amount of power), a list of loads is presented, as an energy saving action list  470 , in a descending order of the actual value of power acquired by the load power meter  340  as illustrated in  FIG. 8 . 
     As described above, it is desirable that prediction of the accumulated amount of power based on the actual value of power measured by the grid power meter  310  is performed in the first half (i.e., the first period) of the prescribed period. 
     (Second Form) 
     Hereinafter, the second form of the energy saving action list  470  according to the first embodiment will be described.  FIGS. 9 and 10  are diagrams for describing the second form of the energy saving action list  470  according to the first embodiment. 
     As described above, it is desirable that the second form is a form applied when the predictive value of the accumulated amount of power predicted based on the variation amount of the power measured by the grid power meter  310  exceeds the prescribed amount of power. 
     As illustrated in  FIG. 9 , when “W n +{(W n −W n-1 )/(t n −t n-1 )}×(0.5−t n )” exceeds the target amount of power or the limit amount of power), a list of loads is presented, as the energy saving action list  470 , in a descending order of the variation amount of the power acquired by the load power meter  340  as illustrated in  FIG. 10 . 
     As described above, it is desirable that prediction of the accumulated amount of power based on the variation amount of the power measured by the grid power meter  310  is performed in the second half (i.e., the second period) of the prescribed period. 
     (Alert Presentation Method) 
     Hereinafter, an alert presentation method according to the first embodiment will be described.  FIG. 11  is a flowchart illustrating the alert presentation method according to the first embodiment. The flowchart illustrated in  FIG. 11  is performed at an update interval (for example, 1 minute) of a list. Here, it is desirable that the update interval of the list in a first half (i.e., a first period) of the prescribed period (for example, 5 minutes) is longer than the update interval of the list in a second half (i.e., a second period) of the prescribed period (for example, 1 minute). Alternatively, the update interval of the list may be shortened as the time approaches the expiration of the prescribed period. 
     As illustrated in  FIG. 11 , in step S 10 , each load power meter  340  measures power consumed in the load  120 . The smart sensor  350  collects power measured by the load power meter  340  provided under the control of the smart sensor  350 . The EMS  200  acquires, from the smart sensor  350 , information which indicates the power measured by each load power meter  340 . 
     In step S 20 , the EMS  200  updates information presented by the presentation unit  240 . In particular, the EMS  200  updates information (here, facility change list  460 ) presented by the presentation unit  240  based on the power measured by each load power meter  340 . 
     In step S 30 , the grid power meter  310  measures the power supplied from the distribution line  31  (i.e., the grid). The power measurement unit  320  accumulates the power measured by the grid power meter  310  in the prescribed period (for example, 30 minutes). The power monitoring unit  330  acquires the accumulated value (i.e., the accumulated amount of power) from the power measurement unit  320 . 
     In step S 40 , the power monitoring unit  330  predicts the predictive value of the accumulated amount of power at the time of expiration of the prescribed period based on the accumulated value (i.e., the accumulated amount of power) acquired from the power measurement unit  320 . 
     In particular, the power monitoring unit  330  predicts, in a first half (i.e., a first period) of the prescribed period, the accumulated amount of power based on an actual value of power measured by the grid power meter  310 . On the other hand, the power monitoring unit  330  predicts, in a second half (i.e., a second period) of the prescribed period, the accumulated amount of power based on a variation amount of the power measured by the grid power meter  310 . 
     In step S 50 , the power monitoring unit  330  determines whether the predictive value of the accumulated amount of power has exceeded the prescribed power (i.e., the target amount of power or the limit amount of power). If the determination result is “YES,” a process in step S 60  is performed. If the determination result is “NO,” a process in step S 70  is performed. 
     In step S 60 , the EMS  200  updates the information presented by the presentation unit  240 . In particular, the EMS  200  updates the information presented by the presentation unit  240  (here, the energy saving action list  470 ) based on the predictive value of the accumulated amount of power (that is, the power measured by the grid power meter  310 ). 
     In particular, when the predictive value of the accumulated amount of power predicted based on the actual value of power acquired by the grid power meter  310  exceeds the prescribed amount of power, the EMS  200  presents, in the first form, a list of the loads in which power consumption should be reduced. For example, in the first half (i.e., the first period) of the prescribed period, the EMS  200  presents, as an energy saving action list  470 , the list of loads in a descending order of the actual value of power acquired by the load power meter  340 . 
     On the other hand, when the predictive value of the accumulated amount of power predicted based on the variation amount of the power acquired by the grid power meter  310  exceeds the prescribed amount of power, the EMS  200  presents, in the second form, the list of loads in which power consumption should be reduced. For example, in the second half (i.e., the second period) of the prescribed period, the EMS  200  presents, as an energy saving action list  470 , the list of loads in a descending order of the variation amount of the power acquired by the load power meter  340 . 
     In step S 70 , the power measurement unit  320  determines whether the prescribed period has elapsed. If the determination result is “YES,” a process in step S 80  is performed. If the determination result is “NO,” a series of processes are completed. 
     In step S 80 , the power measurement unit  320  resets the accumulated value of power (i.e., the accumulated amount of power) measured by the grid power meter  310 . 
     As described above, in the first embodiment, when the predictive value of the accumulated amount of power predicted based on the actual value of power acquired by the grid power meter  310  or the predictive value of the accumulated amount of power predicted based on the variation amount of the power acquired by the grid power meter  310  reaches the prescribed amount of power, the alert presentation apparatus (i.e., the EMS  200 ) presents an alert which indicates a list of loads in which power consumption should be reduced. That is, the alert presentation apparatus (i.e., the power monitoring unit  330 ) uses the method for predicting the accumulated amount of power at the time of expiration of the prescribed period properly. This reduces repetition of an alert ON state and an alert OFF state. 
     For example, in the first half (i.e., the first period) of the prescribed period, the alert presentation apparatus (i.e., the power monitoring unit  330 ) predicts the accumulated amount of power at the time of expiration of the prescribed period based on the actual value of power acquired by the grid power meter  310 . Therefore, repetition of the alert ON state and the alert OFF state due to instantaneous increase and decrease in power consumption does not occur. 
     On the other hand, in the second half (i.e., the second period) of the prescribed period, the alert presentation apparatus (i.e., the power monitoring unit  330 ) predicts the accumulated amount of power at the time of expiration of prescribed period based on the variation amount of the power acquired by the grid power meter  310 . Therefore, it is possible to accurately determine whether the predictive value of the accumulated amount of power at the time of expiration of the prescribed period exceeds the prescribed amount of power. 
     In the first embodiment, when the predictive value of the accumulated amount of power predicted based on the actual value of power acquired by the grid power meter  310  exceeds the prescribed amount of power, the alert presentation apparatus (i.e., the EMS  200 ) presents, as the energy saving action list  470 , the list of loads in a descending order of the actual value of power acquired by the load power meter  340  (the first form). Therefore, the load in which power consumption should be reduced can be presented to the user properly. 
     On the other hand, when the predictive value of the accumulated amount of power predicted based on the variation amount of the power acquired by the grid power meter  310  exceeds the prescribed amount of power, the EMS  200  presents, as the energy saving action list  470 , the list of loads in a descending order of the variation amount of the power acquired by the load power meter  340  (the second form). Therefore, the load in which power consumption should be reduced can be presented to the user properly. 
     In the first embodiment, the alert presentation apparatus (i.e., the EMS  200 ) presents the list so that frequency of replacement of the loads included in the list becomes low. Therefore, a user can effectively know a load in which power consumption should be reduced while suppressing confusion of the user. 
     For example, the alert presentation apparatus (i.e., the EMS  200 ) presents a list which includes a prescribed number of loads listed in a descending order of power consumption or presents a list which includes a prescribed number of loads listed in a descending order of an increment in power consumption among the loads connected to the grid. In this manner, frequency of replacement of the loads included in the list becomes low. 
     Alternatively, the control unit  230  may present a list in which a prescribed number of loads are highlighted in a descending order of power consumption among the loads connected to the grid, or may present a list in which a prescribed number of loads are highlighted in a descending order of an increment in power consumption among the loads connected to the grid. In this manner, frequency of replacement of the highlighted loads included in the list becomes low. 
     Alternatively, the update interval of the list in the first half (i.e., the first period) of the prescribed period may be longer than the update interval of the list in the second half (i.e., the second period) of the prescribed period. Therefore, in a period with low urgency to reduce power consumption (i.e., the first period), confusion of a user can be reduced. On the other hand, in a period with high urgency to reduce power consumption (i.e., the second period), the user can effectively know the load in which power consumption should be reduced. 
     [Modification 1] 
     Hereinafter, Modification 1 of the first embodiment will be described. Hereinafter, differences between the first embodiment and Modification 1 will be mainly described. 
     In particular, in the first embodiment, the interval at which the power consumed by the load  120  is acquired and the update interval of the list are the same. In contrast, in Modification 1, the interval at which the power consumed by load  120  is acquired differs from the update interval of the list. 
     For example, the interval at which the power consumed by the load  120  is acquired may be 1 minute and the update interval of the list may be a prescribed time interval (for example, 5 minutes). The update interval of the list may be variable similarly to the first embodiment. 
     (Alert Presentation Method) 
     Hereinafter, an alert presentation method according to Modification 1 will be described.  FIG. 12  is a flowchart illustrating the alert presentation method according to Modification 1. In  FIG. 12 , a step  15  is added between step  10  and step  20  to the flowchart illustrated in  FIG. 11 . 
     In step  15 , the EMS  200  determines whether a prescribed time interval has elapsed. If the determination result is “YES,” a process in step  20  is performed. If the determination result is “NO,” a process in step  10  is performed. 
     In this manner, if the prescribed time interval (i.e., the update interval of the list) is longer than the interval at which the power consumed by the load  120  is acquired, confusion of the user due to frequent updating of the list can be reduced. 
     [Modification 2] 
     Hereinafter, Modification 2 of the first embodiment will be described. Hereinafter, differences between the first embodiment and Modification 2 will be mainly described. 
     In particular, in Modification 2, the EMS  200  suspends the presentation of the energy saving action list  470  until a predetermined period (for example, 10 minutes) elapses since the start of the prescribed period (for example, 30 minutes). Therefore, in a state in which predictive accuracy in the accumulated amount of power at the time of expiration of the prescribed period is low, repetition of the alert ON state and the alert OFF state is reduced. 
     [Modification 3] 
     Hereinafter, Modification 3 of the first embodiment will be described. Hereinafter, differences between the first embodiment and Modification 3 will be mainly described. 
     In particular, in Modification 3, the power measurement unit  320  may continuously manage the accumulated value of power measured by the grid power meter  310  without resetting, in each prescribed period, the accumulated value of power (i.e., the accumulated amount of power) measured by the grid power meter  310 . That is, the power measurement unit  320  predicts the accumulated amount of power at the time of expiration of the current prescribed period based on power measured by the grid power meter  310  in the period before the current prescribed period in addition to the current prescribed period. Therefore, immediately after the start of the current prescribed period, a decrease in predictive accuracy in the accumulated amount of power at the time of expiration of the current prescribed period is reduced. 
     However, it is needless to mention that the information presented by the EMS  200  (for example, the presentation information  400  and the power monitoring graph) is reset in each prescribed period. 
     Other Embodiment 
     Although the present invention has been described with reference to the embodiment described above, it should not be understood that the discussion and drawings constituting a part of the disclosure are limiting the present invention. Various alternative embodiments, examples and operation technology will be apparent to a person skilled in the art from the present disclosure. 
     In the embodiment, the alert presentation apparatus is configured by the EMS  200  and the power monitoring unit  330 . However, the embodiment is not limited to the same. The function of the power monitoring unit  330  may be provided in the EMS  200 . Alternatively, the alert presentation apparatus may be provided in the CEMS  20  or provided in the smart server  40 . Here, the EMS  200  may be a HEMS (Home Energy Management System), a BEMS (Building Energy Management System), an FEMS (Factory Energy Management System) or a SEMS (Store Energy Management System). 
     Although not especially mentioned in the embodiment, the load power meter  340  may be a current sensor or the like. 
     In the embodiment, the consumer facility  10  is provided with the load  120 , the PV unit  130 , the storage battery unit  140 , the fuel cell unit  150  and the hot water storage unit  160 . However, it is only necessary that the consumer facility  10  should be provided at least with the load  120 . 
     In the embodiment, the list of loads is configured so as to include power consumption for each load. However, the embodiment is not limited to the same. The list of loads may be configured so as to include power consumption for each group of loads connected to the power line provided under the control of a breaker of the distribution board  110 . In such a case, it is desirable that the smart sensor  350  transmits, to the EMS  200 , information which indicates the total value of power measured by a plurality of load power meters  340  together with an identifier of the smart sensor  350 . 
     Although not especially mentioned in the embodiment, the predictive value of the accumulated amount of power may be corrected based on the PV power generation prediction information. For example, when the amount of generated power of the PV  131  tends to increase, the predictive value of the accumulated amount of power may be revised downward. Alternatively, the predictive value of the accumulated amount of power may be corrected based on the power generation extra capacity of the fuel cell  151  (i.e., a value excluding the current amount of generated power from the maximum amount of generated power). For example, the predictive value of the accumulated amount of power may be revised downward as the power generation extra capacity of the fuel cell  151  is larger. Alternatively, the predictive value of the accumulated amount of power may be corrected based on a remaining amount of stored power of the fuel cell  151 . For example, the predictive value of the accumulated amount of power may be revised downward as the remaining amount of stored power of the fuel cell  151  is larger. 
     Although not especially mentioned in the embodiment, the presentation information  400  may include PV power generation prediction information. Alternatively, the presentation information  400  may include information which indicates power generation extra capacity of the fuel cell  151 . Alternatively, the presentation information  400  may include the remaining amount of stored power of the fuel cell  151 . 
     Although not especially mentioned in the embodiment, it is desirable that the EMS  200  controls the PV unit  130 , the storage battery unit  140 , the fuel cell unit  150  and the hot water storage unit  160  so that the accumulated amount of power at the time of expiration of the prescribed period does not exceed the prescribed amount of power. 
     Although not especially mentioned in the embodiment, in Japan, for example, the basic rate in the total power rate of a high-voltage power user is defined based, for example, on the amount of power in the past demand period (for example, 30 minutes). That is, the amount of power (i.e., usage amount of power) for 30 minutes is measured by the grid power meter  310 . Then average power usage in the 30 minutes (kW) is calculated. The average power usage is referred to as a 30-minute demand value. Further the largest 30-minute demand value in one month is referred to as the maximum demand power (i.e., the maximum demand value) of the month. Then, the largest value in the maximum demand value of the month or the maximum demand value in the past one year is used for calculation of the basic rate. That is, if once a large demand value is caused in one month or one year, the basic rate using the demand value will be applied to the next month or to the next year. The basic rate is defined in this manner. 
     As described above, as for the present invention, it is needless to mention that various embodiments that are not described here are included. Moreover, it is also possible to combine the above-described embodiments and modifications. Accordingly, the technical range of the present invention is to be defined only by the inventive specific matter according to the adequate claims from the above description. 
     It is noted that the entire content of Japan Patent Application No. 2012-112906 (filed on May 16, 2012) is incorporated in the present application by reference. 
     INDUSTRIAL APPLICABILITY 
     According to the present invention, it is possible to provide alert presentation apparatus and alert presentation method capable of letting a user effectively know a load in which power consumption should be reduced while suppressing confusion of the user.