Energy management apparatus, energy storage apparatus, and energy management method

An EMS that manages an energy storage apparatus includes a communicator that notifies the energy storage apparatus of a discharge power setting value for setting power to be discharged by the energy storage apparatus. The communicator sets, as a part of the discharge power setting value, whether load following discharge is performed (whether there should be no reverse power flow).

RELATED APPLICATIONS

The present application is a National Phase of International Application No. PCT/JP2020/002467, filed Jan. 24, 2020, which claims priority based on Japanese Patent Application No. 2019-013678, filed Jan. 29, 2019.

TECHNICAL FIELD

The present disclosure relates to an energy management apparatus, an energy storage apparatus, and an energy management method.

BACKGROUND ART

An energy management system (EMS) that is provided in a power consumer's facility and that controls a plurality of devices has attracted attention in recent years. For such an EMS, a communication protocol has been introduced for an energy management apparatus to control devices provided by various manufacturers.

One such communication protocol, ECHONET Lite (registered trademark), defines device classes for each type of device, and defines information and control targets of each device as properties for each device class.

For example, an energy storage apparatus belongs to a storage battery class, and the properties corresponding to the storage battery class include a discharge power setting value, an operation mode setting, and a grid connection state (for example, see Non-Patent Document 1).

CITATION LIST

SUMMARY

An embodiment of the present disclosure has a first feature in that an energy management apparatus that manages an energy storage apparatus includes a communicator configured to issue a notification, to the energy storage apparatus, to set a discharge power setting value for setting power to be discharged by the energy storage apparatus, and when setting the energy storage apparatus to perform the load following discharge, the communicator issues a notification, to the energy storage apparatus, of a predetermined value indicating load following discharge as the discharge power setting value.

An embodiment of the present disclosure has a second feature in that an energy management apparatus that manages an energy storage apparatus includes a communicator configured to issue a notification, to the energy storage apparatus, to set an operation mode setting for setting an operation mode of the energy storage apparatus, and the communicator sets, as the operation mode in the operation mode setting, discharging with a reverse power flow from the energy storage apparatus to a grid and discharging without the reverse power flow as distinguished from each other.

An embodiment of the present disclosure has a third feature in that an energy management apparatus that manages an energy storage apparatus includes a communicator configured to issue a notification, to the energy storage apparatus, to set a grid connection state for setting a connection state between the energy storage apparatus and a grid and an operation mode setting for setting an operation mode of the energy storage apparatus, and the communicator sets, in the grid connection state, a grid connection with a reverse power flow from the energy storage apparatus to the grid and a grid connection without the reverse power flow as distinguished from each other, and sets, as the operation mode in the operation mode setting, discharging.

An embodiment of the present disclosure has a fourth feature in that an energy management apparatus that manages an energy storage apparatus includes a communicator configured to issue a notification, to the energy storage apparatus, to set a specified discharge state for setting one of performing rated maximum discharge, performing specified output discharge, and performing load following discharge.

An embodiment of the present disclosure has a fifth feature in that an energy storage apparatus controlled by an energy management apparatus includes a communicator configured to receive, from the energy management apparatus, a notification of a discharge power setting value for setting power to be discharged by the energy storage apparatus; and a controller configured to set load following discharge when the received discharge power setting value is a predetermined value indicating load following discharge.

An embodiment of the present disclosure has a sixth feature in that an energy storage apparatus controlled by an energy management apparatus includes a communicator configured to receive, from the energy management apparatus, a notification of an operation mode setting for setting an operation mode of the energy storage apparatus; and a controller configured to set the operation mode in accordance with the operation mode setting, and the operation mode setting enables, as the operation mode, setting of discharging with a reverse power flow from the energy storage apparatus to a grid and discharging without the reverse power flow as distinguished from each other.

An embodiment of the present disclosure has a seventh feature in that an energy storage apparatus controlled by an energy management apparatus includes a communicator configured to receive, from the energy management apparatus, a notification of a grid connection state for setting a connection state between the energy storage apparatus and a grid and an operation mode setting for setting an operation mode of the energy storage apparatus; and a controller configured to set the connection state in accordance with the grid connection state and set the operation mode in accordance with the operation mode setting, and the grid connection state enables setting of a grid connection with a reverse power flow from the energy storage apparatus to the grid and a grid connection without the reverse power flow as distinguished from each other, and the operation mode setting enables, as the operation mode, setting of discharging.

An embodiment of the present disclosure has an eighth feature in that an energy storage apparatus controlled by an energy management apparatus includes a communicator configured to receive a notification of a specified discharge state for setting one of performing rated maximum discharge, performing specified output discharge, and performing load following discharge from the energy management apparatus; and a controller configured to set the performing rated maximum discharge, the performing specified output discharge, or the performing load following discharge, in accordance with the specified discharge state.

An embodiment of the present disclosure has a ninth feature in that an energy management method for managing an energy storage apparatus includes issuing a notification, to the energy storage apparatus, to set a discharge power setting value for setting power to be discharged by the energy storage apparatus, and in the issuing, whether load following discharge is performed is set as a part of the discharge power setting value.

An embodiment of the present disclosure has a tenth feature in that an energy management method for managing an energy storage apparatus includes issuing a notification, to the energy storage apparatus, to set an operation mode setting for setting an operation mode, and in the issuing, as the operation mode in the operation mode setting, discharging with a reverse power flow from the energy storage apparatus to a grid and discharging without the reverse power flow are set as distinguished from each other.

An embodiment of the present disclosure has an eleventh feature in that an energy management method for managing an energy storage apparatus includes issuing a notification, to the energy storage apparatus, to set a grid connection state for setting a connection state between the energy storage apparatus and a grid and an operation mode setting for setting an operation mode of the energy storage apparatus, and in the issuing, in the grid connection state, a grid connection with a reverse power flow from the energy storage apparatus to the grid and a grid connection without the reverse power flow are set as distinguished from each other, and, as the operation mode in the operation mode setting, discharging is set.

An embodiment of the present disclosure has a twelfth feature in that an energy management method for managing an energy storage apparatus includes issuing a notification, to the energy storage apparatus, to set a specified discharge state for setting one of performing rated maximum discharge, performing specified output discharge, and performing load following discharge.

DESCRIPTION OF EMBODIMENTS

Under the current Feed-in Tariff (FIT), power generated by photovoltaic (PV) devices for residential use and stored in energy storage apparatuses is regulated so as not to be dischargeable to the power grid side.

Still, this regulation may be relaxed in the future to enable also the power generated by photovoltaic devices for residential use and stored in energy storage apparatuses to be discharged to the power grid side.

However, communication protocols such as ECHONET Lite are not built based on such a prospect. Thus, there is a problem in that these protocols cannot be set to cause the power stored in energy storage apparatuses to be discharged toward the power grid side.

For example, ECHONET Lite has a problem in that the storage battery class or the like is not provided with a property for discharging the stored power to the power grid side.

Thus, the present disclosure is made in view of the above problem, and provides a control system enabling power stored in an energy storage apparatus to be appropriately discharged to the power grid side, with a communication protocol between an energy management apparatus and an energy storage apparatus.

A control system according to an embodiment of the present invention will be described below with reference to the drawings. Note that in the drawings used for the following description, the same or similar components are denoted with the same or similar reference numerals.

First Embodiment

A first embodiment of the present invention will be described below with reference toFIGS.1to6.FIG.1is a diagram illustrating an example of a configuration of an energy system100according to the present embodiment.

As illustrated inFIG.1, the energy system100includes an energy management server200, a facility300, an equipment management server400, and a predetermined server500. InFIG.1, facilities300A to300C are illustrated as examples of the facility300. Here, the energy management server200and the equipment management server400may be separate servers or may be integrated.

Each facility300is connected to a power grid110. One facility300corresponds to one consumer.

In the following description, the flow of power from the power grid110to the facility300is referred to as a power flow, and the flow of power from the facility300to the power grid110is referred to as a reverse power flow. The power grid110may be a transmission network that is outside consumers in a region isolated from a power company, and is used for power interchange between the consumers.

The energy management server200is a server that controls a distributed power supply (for example, an energy storage apparatus310described later). The energy management server200transmits, to an EMS330provided in the facility300, a message as an instruction to control the energy storage apparatus310provided in the facility300. For example, the energy management server200may transmit a power flow control message (for example, demand response (DR)) requesting control of the power flow and may transmit a reverse power flow control message requesting control of the reverse power flow. For example, the energy management server200is managed by a power supplier such as a power producer, a power distributor, or a retailer.

As illustrated inFIG.2, the energy management server200includes a database210, a communicator220, and a controller230. The energy management server200is an example of a virtual top node (VTN).

The database210includes a storage medium, such as a non-volatile memory and/or an HDD, and stores data on the facility300managed by the energy management server200. The facility300managed by the energy management server200may be a facility300in contract with the power operator. For example, the data on the facility300may be required power supplied from the power grid110to the facility300. The data on the facility300may be the type of distributed power supply310provided in the facility300, the specification of the distributed power supply310provided in the facility300, and/or the like. The specification may be rated generated power (W) and maximum output power (W) of the distributed power supply310, for example.

The communicator220includes a communication module, and communicates with the EMS330via the predetermined server500. The communicator220communicates with the predetermined server500according to a first communication protocol. For example, as the first communication protocol, a communication protocol supporting Open Automated Demand Response (ADR) 2.0b or a unique dedicated communication protocol may be used.

The controller230includes a control circuit including a memory, a CPU, and the like, and controls each configuration provided in the energy management server200.

The equipment management server400is a server that monitors the distributed power supply (for example, the energy storage apparatus310described later). The equipment management server400transmits a message to the EMS330provided in the facility300, for performing maintenance of the distributed power supply310provided in the facility300. For example, the maintenance includes: inspection to check the deterioration status of equipment, maintenance for performing minor repair during the inspection, repair for equipment failure, replacement of existing equipment with new equipment, and/or the like. Note that the maintenance may be performed while the energy storage apparatus310is stopped or may be performed while the energy storage apparatus310is operating.

As illustrated inFIG.3, the equipment management server400includes a database410, a communicator420, and a controller430.

The database410includes a storage medium, such as a non-volatile memory and/or an HDD, and manages information on a plurality of the facilities300. The database410may store basic information on equipment provided in each of the plurality of facilities300. For example, the database410stores a facility name, facility ID, equipment name, equipment ID, introduction year, age, and service life associated with each other.

The communicator420includes a communication module, and communicates with the EMS330via the predetermined server500. The communicator420communicates with the predetermined server500according to the first communication protocol. For example, as the first communication protocol, a communication protocol supporting Open ADR 2.0b or a unique dedicated communication protocol may be used.

The controller430includes a control circuit including a memory, a CPU, and the like, and controls each configuration provided in the equipment management server400.

The predetermined server500is a server that relays communication between the facility300and the energy management server200and the equipment management server400. For example, the predetermined server500is managed by a resource aggregator. The resource aggregator is a power supplier that provides power of a reverse power flow to a power producer, a power distributor, a retailer, and the like in a virtual power plant (VPP). The resource aggregator may be a power supplier that creates excess power (negative watts) by reducing the power consumption of the facility managed by the resource aggregator. Such excess power may be regarded as generated power. The resource aggregator may be a power supplier that absorbs excessive power by increasing the power consumption of the facility managed by the resource aggregator (for example, by increasing the charging amount of the energy storage apparatus).

As illustrated inFIG.1, the facility300includes the distributed power supply (in particular, the energy storage apparatus310), a load device320, and the EMS330.

The distributed power supply may be a fuel cell apparatus that generates power using fuel. The fuel cell apparatus is an apparatus that generates power using fuel. Examples of the fuel cell apparatus may include a solid oxide fuel cell (SOFC), a polymer electrolyte fuel cell (PEFC), a phosphoric acid fuel cell (PAFC), and/or a molten carbonate type fuel cell (MCFC). The distributed power supply may be a power generation device that generates power using natural energy such as sunlight, wind, water, or geothermal energy. Note that the description of the present embodiment is given assuming that the distributed power supply is the energy storage apparatus310that charges power and discharges power.

The energy storage apparatus310is a device that is controlled by the EMS330to perform charging and discharging. For example, the energy storage apparatus310is a lithium-ion energy storage apparatus, a lead energy storage apparatus, a nickel hydrogen energy storage apparatus, or the like.

Note that the power discharged by the energy storage apparatus310may be supplied to the load device320within the facility300or may be supplied to the power grid110. In the present embodiment, operation may be performed under a “boost mode” in which power generated by the power generation device is sold and the power demanded by the load device320in the facility300is supplied by the power discharged from the energy storage apparatus310. The energy storage apparatus310can store, for example, power supplied by the power grid110or the excess power of the power generation device.

The load device320is a device that consumes power. Examples of the load device320include an air conditioner, a lighting apparatus, a hot water supply device, an audio visual (AV) apparatus, an electric vehicle, a charge/discharge device, and the like.

The EMS330is an energy management apparatus that manages the power of the facility300. The EMS330may control the operating state of the energy storage apparatus310and the load device320. The EMS330is an example of a virtual end node (VEN).

As illustrated inFIG.4, the EMS330includes a communicator331and a controller332.

The communicator331includes a communication module, and communicates with the predetermined server500, the energy storage apparatus310, and the load device320. The communicator331communicates with the predetermined server500according to the first communication protocol. For example, as the first communication protocol, a communication protocol supporting Open ADR 2.0b or a unique dedicated communication protocol may be used. On the other hand, the communicator331communicates with the energy storage apparatus310and the load device320according to a second communication protocol. For example, as the second communication protocol, a communication protocol supporting ECHONET Lite, Smart Energy Profile (SEP) 2.0, KNX, or a unique dedicated communication protocol may be used.

The communicator331issues a notification, to the energy storage apparatus310, to set a discharge power setting value for setting the power to be discharged by the energy storage apparatus310. The communicator331sets whether load following discharge is to be performed (that is, whether there should be no reverse power flow) as a part of the discharge power setting value. In other words, when the communicator331sets the energy storage apparatus310to perform load following discharge, the communicator331notifies the energy storage apparatus310of a predetermined value indicating load following discharge as the discharge power setting value. The load following discharge is control with which the discharge power is increased/decreased in accordance with an increase/decrease in the power consumed by the load device320.

For example, in a case where ECHONET Lite is used as the second communication protocol, the communicator331issues to the energy storage apparatus310a notification to set the discharge power setting value described above by using “Set” (a Set command) (seeFIG.5) of a discharge power setting value property of the storage battery class.

The discharge power setting value property of the storage battery class illustrated inFIG.5includes content newly defining whether “load following discharge is performed (whether there should be no reverse power flow)” and includes a range of values newly defining “0xFFFFFFFF: load following discharge (no reverse power flow)”, in addition to that of the existing discharge power setting value property. Note that the value indicating this “load following discharge (no reverse power flow)” may not be “0xFFFFFFFF”, and may be, for example, the maximum value in the range of values, a value larger than the rated output, and the like.

The discharge power setting value property of the storage battery class illustrated inFIG.5is newly defined such that it can be used not only as “Get” for acquiring information from the energy storage apparatus310, but also as “INF” for notifying the state of the energy storage apparatus310, and “Set” for performing setting for the energy storage apparatus310.

The controller332controls the operating state of the distributed power supply, such as the energy storage apparatus310, and the load device320within the facility300.

As illustrated inFIG.6, the energy storage apparatus310includes a communicator311and a controller312.

The communicator311includes a communication module, and communicates with the EMS330. As described above, the communicator311performs communications according to the second communication protocol.

The communicator311receives the notification of the discharge power setting value for setting the power discharged by the energy storage apparatus310, from the EMS330. For example, in a case where ECHONET Lite is used as the second communication protocol, the communicator311acquires the discharge power setting value described above, from “Set” (seeFIG.5) in the discharge power setting value property of the storage battery class transmitted from the EMS330.

The controller312controls the operating state (such as power storage and discharge) of the energy storage apparatus310in accordance with an instruction from the EMS330.

The controller312sets whether the energy storage apparatus310performs load following discharge, based on a value defined as a part of the discharge power setting value acquired by the communicator311. In other words, the controller312sets load following discharge when the discharge power setting value acquired by the communicator311is a predetermined value indicating load following discharge.

For example, ECHONET Lite may be used as the second communication protocol. In this case, the controller312sets whether the energy storage apparatus310performs load following discharge based on a value defined in “0xFFFFFFFF” in the range of values of the discharge power setting value property of the storage battery class. Specifically, the controller312sets the energy storage apparatus310to perform load following discharge when no value is set in “0xFFFFFFFF” in the range of values of the discharge power setting value property of the storage battery class. On the other hand, the controller312sets the energy storage apparatus310not to perform load following discharge when a value is set in “0xFFFFFFFF” in the range of values of the discharge power setting value property of the storage battery class.

Note that the present disclosure is not limited to the case where the EMS330is provided in the facility300as described in the present embodiment, and is also applicable to a case where the EMS330is provided in the predetermined server500. In such a case, communication is performed between the predetermined server500and the energy storage apparatus310, for example, according to ECHONET Lite.

According to the present embodiment, the power stored in the energy storage apparatus310can be set to be discharged to the power grid110side based on a communication protocol between the EMS330and the energy storage apparatus310, with minimum modification to an existing communication protocol.

Second Embodiment

A second embodiment of the present invention will be described below with reference toFIG.7, while focusing on differences from the first embodiment described above.

The communicator331of the EMS330issues a notification, to the energy storage apparatus310, to set an operation mode setting for setting the operation mode of the energy storage apparatus310. Here, in such an operation mode setting, the communicator331sets discharge with a reverse power flow from the energy storage apparatus310to the power grid110and discharge without the reverse power flow from the energy storage apparatus310to the power grid110as operation modes that are distinguished from each other.

For example, in a case where ECHONET Lite is used as the second communication protocol, the communicator331issues a notification to set the above operation modes to the energy storage apparatus310by using “Set” of the operation mode setting property of the storage battery class (seeFIG.7).

Here, the operation mode setting property of the storage battery class illustrated inFIG.7indicates, as such an operation mode, any one of rapid charging, charging, discharging (no reverse power flow), standby, testing, automatic operation, reactivation, effective capacity recalculation processing, and discharging (with a reverse power flow).

In other words, the operation mode setting property of the storage battery class illustrated inFIG.7newly defines discharging (no reverse power flow) and discharging (with a reverse power flow) for the operation mode setting property of the existing storage battery class.

Specifically, in the operation mode setting property of the storage battery class, “discharging” in the operation mode setting property of the existing storage battery class may be regarded as “discharging (no reverse power flow)”, and “discharging (with a reverse power flow)” may be newly added, or both “discharging (with a reverse power flow)” and “discharging (no reverse power flow)” may be newly added.

Similarly, an operation operating state property of the storage battery class illustrated inFIG.7indicates, as such an operation operating state, any one of rapid charging, charging, discharging (no reverse power flow), standby, testing, automatic operation, reactivation, effective capacity recalculation processing, and discharging (with a reverse power flow).

In other words, the operation operating state property of the storage battery class illustrated inFIG.7newly defines discharging (no reverse power flow) and discharging (with a reverse power flow) for the operation operating state property of the existing storage battery class.

The communicator311of the energy storage apparatus310receives a notification of the operation mode setting for setting the operation mode from the EMS330. For example, in a case where ECHONET Lite is used as the second communication protocol, the communicator311acquires the operation mode setting described above, from “Set” (seeFIG.7) in the operation mode setting property of the storage battery class transmitted from the EMS330.

For example, in a case where ECHONET Lite is used as the second communication protocol, the communicator311notifies the EMS330of the operation operating state of the energy storage apparatus310based on “Get” (seeFIG.7) of the operational operating state property transmitted by the EMS330.

The controller312of the energy storage apparatus310sets the operation mode of the energy storage apparatus310in accordance with the operation mode setting acquired by the communicator311.

For example, ECHONET Lite may be used as the second communication protocol. In this case, in a case where “0x43” is set in the range of values of the operation mode setting of the storage battery class, the controller312sets discharging without the reverse power flow as the operation mode. On the other hand, in a case where “0x40” is set in the range of values of the operation mode setting of the storage battery class, the controller312sets discharging with a reverse power flow as the operation mode. Note that compatibility with the existing ECHONET Lite can be maintained by such setting.

According to the present embodiment, the power stored in the energy storage apparatus310can be set to be discharged to the power grid110side based on a communication protocol between the EMS330and the energy storage apparatus310, with minimum modification to an existing communication protocol.

Third Embodiment

A third embodiment of the present invention will be described below with reference toFIG.8, while focusing on differences from the first embodiment and the second embodiment described above.

The communicator331of the EMS330issues a notification, to the energy storage apparatus310, to set a grid connection state for setting a connection state with the power grid110and an operation mode setting for setting the operation mode.

Here, the communicator331sets a grid connection with a reverse power flow and a grid connection without the reverse power flow in the above grid connection state as distinguished from each other, and sets discharging in the above operation mode setting.

For example, in a case where ECHONET Lite is used as the second communication protocol, the communicator331issues to the energy storage apparatus310a notification to set the grid connection state described above by using “Set” (a Set command) (seeFIG.8) of a grid connection state property of the storage battery class. Furthermore, the communicator331issues a notification to set the above operation mode to the energy storage apparatus310by using “Set” (seeFIG.8) of the operation mode setting property of the storage battery class.

Here, the operation mode setting property of the storage battery class illustrated inFIG.8indicates, like the existing operation mode setting property, as such an operation mode, any one of rapid charging, charging, discharging, standby, testing, automatic operation, reactivation, effective capacity recalculation processing, and others. In other words, the operation mode setting property of the storage battery class illustrated inFIG.8is the same as the existing operation mode setting property of the storage battery class.

The grid connection state property of the storage battery class illustrated inFIG.8is newly defined such that it can be used not only as “Get” for acquiring information from the energy storage apparatus310, but also as “INF” for notifying the state of the energy storage apparatus310and/or “Set” for performing setting for the energy storage apparatus310.

Note that the communicator331may issue a notification, to the energy storage apparatus310, to set the above grid connection state and then a notification to set the above operation mode setting, or may simultaneously issue a notification to set the above grid connection state and operation mode setting.

For example, in a case where ECHONET Lite is used as the second communication protocol, the communicator331issues to the energy storage apparatus310a notification to set the grid connection state described above by using “Set” (seeFIG.8) of the grid connection state property of the storage battery class. Furthermore, the communicator331issues a notification to set the above operation mode to the energy storage apparatus310by using “Set” (seeFIG.8) of the operation mode setting property of the storage battery class.

For example, in a case where ECHONET Lite is used as the second communication protocol, the communicator331may simultaneously transmit “Set” of the grid connection state property of the storage battery class and “Set” of the operation mode setting property of the storage battery class.

Alternatively, in a case where ECHONET Lite is used as the second communication protocol, the communicator331may transmit “Set” of the grid connection state property of the storage battery class and then transmit “Set” of the operation mode setting property of the storage battery class.

The communicator311of the energy storage apparatus310receives a notification of the grid connection state and the operation mode setting described above from the EMS330. For example, in a case where ECHONET Lite is used as the second communication protocol, the communicator311acquires the grid connection state described above from “Set” (seeFIG.8) in the grid connection state property transmitted from the EMS330. In addition, the communicator311acquires the operation mode setting described above from “Set” (seeFIG.8) of the operation mode setting property of the storage battery class transmitted from the EMS330.

Here, the communicator311may receive the notification of the operation mode setting described above after receiving the notification of the grid connection state described above, or may simultaneously receive the notification of the grid connection state and the notification of the operation mode setting described above.

The controller312of the energy storage apparatus310sets the connection state of the energy storage apparatus310with the power grid110in accordance with the grid connection state acquired by the communicator311. The controller312also sets the operation mode of the energy storage apparatus310in accordance with the operation mode setting acquired by the communicator311.

For example, ECHONET Lite may be used as the second communication protocol. In this case, in a case where “0x00” is set in the range of values of the grid connection state property of the storage battery class and “0x43” is set in the range of values of the operation mode setting of the storage battery class, the controller312sets discharging with a reverse power flow as the operation mode. On the other hand, in a case where “0x02” is set in the range of values of the grid connection state property of the storage battery class and “0x43” is set in the range of values of the operation mode setting of the storage battery class, the controller312sets discharging without the reverse power flow as the operation mode.

According to the present embodiment, the power stored in the energy storage apparatus310can be set to be discharged to the power grid110side based on a communication protocol between the EMS330and the energy storage apparatus310, with minimum modification to an existing communication protocol.

Fourth Embodiment

A fourth embodiment of the present invention will be described below with reference toFIG.9, while focusing on differences from the first embodiment to the third embodiment described above.

The communicator331of the EMS330issues, to the energy storage apparatus310, a notification to set a specified discharge state for setting whether rated maximum discharge is performed, specified output discharge is performed, or load following discharge is performed. In other words, the communicator331of the EMS330issues a notification, to the energy storage apparatus310, to set the specified discharge state for setting one of performing rated maximum discharge, performing specified output discharge, and performing load following discharge. Here, the specified power is set to “Set” of the discharge power setting value property of the storage battery class.

For example, in a case where ECHONET Lite is used as the second communication protocol, the communicator331issues to the energy storage apparatus310a notification to set the specified discharge state described above by using “Set” (seeFIG.9) of the specified discharge state property of the storage battery class. Note that the specified discharge state property of the storage battery class is a property not defined by the existing ECHONET Lite. The content of the specified discharge state property of the storage battery class illustrated inFIG.9includes setting how to discharge power from the energy storage apparatus310and acquiring a set state.

The communicator311of the energy storage apparatus310receives a notification of the specified discharge state described above from the EMS330. For example, in a case where ECHONET Lite is used as the second communication protocol, the communicator311acquires the specified discharge state described above from the specified discharge state property of the storage battery class (seeFIG.9).

The controller312of the energy storage apparatus310sets whether rated maximum discharge is performed, specified output discharge is performed or load following discharge is performed, in accordance with the specified discharge state acquired by the communicator311. In other words, the controller312of the energy storage apparatus310sets performing rated maximum discharge, performing specified output discharge, or performing load following discharge, in accordance with the specified discharge state acquired by the communicator311.

For example, ECHONET Lite may be used as the second communication protocol. In this case, in a case where “0x41” is set in the range of values of the specified discharge state of the storage battery class, the controller312sets performing rated maximum (or specified output) discharge. On the other hand, in a case where “0x42” is set in the range of values of the specified discharge state of the storage battery class, the controller312sets performing load following discharge.

According to the present embodiment, the power stored in the energy storage apparatus310can be set to be discharged to the power grid110side based on a communication protocol between the EMS330and the energy storage apparatus310, while utilizing an existing communication protocol.

Modifications

In the second embodiment and the third embodiment described above, the communicator331of the EMS330may notify the energy storage apparatus310of a power purchase target value for preventing a reverse power flow.

Here, the communicator331may issue a notification, as the power purchase target value, of a margin between the load power and the discharge amount in a case where the discharging without the reverse power flow is set to be performed. For example, the communicator331may issue a notification, as the power purchase target value, of a ratio such as 0% or 5% or a power value such as 0 W or 100 W.

When the controller312of the energy storage apparatus310is set to perform discharging without the reverse power flow, the controller312controls discharging in the energy storage apparatus310based on the margin notified as the above power purchase target value.

OTHER EMBODIMENTS

Although the present disclosure has been described with reference to the above embodiments, it should be understood that the discussion and drawings that form a part of this disclosure do not limit the present invention. Various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art from the present disclosure.

In the above embodiments, a case in which the energy management server200, the equipment management server400, and the predetermined server500manage a plurality of the facilities300is illustrated. However, the energy management server200, the equipment management server400, and the predetermined server500may manage one facility300. In such a case, the energy management server200, the equipment management server400, and the predetermined server500may be included in the EMS330.

In the above embodiments, some of the functions of the EMS330may be provided by a cloud server provided on the Internet. That is, the EMS330may be considered to include a cloud server.

In the above embodiments, a case in which the first communication protocol is a protocol supporting Open ADR 2.0b or a unique dedicated communication protocol, and the second communication protocol is a protocol supporting ECHONET Lite, SEP2.0, KNX, or a unique dedicated communication protocol is described. However, the embodiments are not limited to this case. The first communication protocol may be a protocol standardized as a protocol used for communication between the energy management server200and the EMS330. The second communication protocol may be a protocol standardized as a protocol used in the facility300.

The present application claims priority to Japanese Patent Application No. 2019-013678, filed on Jan. 29, 2019, the contents of which are incorporated herein by reference in their entirety.