The present invention relates to a demand-supply planning device, a demand-supply planning method, a demand-supply planning program, and a recording medium.
Power demand and supply are approximately partitioned into a supply party and a consumer party. The supply party includes power companies and the like and the consumer party includes factories/buildings/ordinary homes. The contract capacity (maximum amount of power received) of each consumer is determined. However, due to the problem of cost, in general, the supply party does not prepare for power generation capacity corresponding to the total contract capacities of all the consumers but predicts an amount of power used by the consumers and prepares for an amount of power generated which is equal to or greater than the predicted amount of power to be used. Methods of creating such a demand-supply plan are disclosed, for example, in Patent Literatures 1 and 2 described below.
However, with recent tight demand-supply balance, the predicted power demand often exceeds the amount of power supplied which is prepared by the supply party and thus a response (demand response) of the consumer party based on a request from the supply party has been studied. On the other hand, there are a lot of consumers that have power generation facilities or power storage facilities, introduce their own plan control system, and perform an energy saving operation. Such consumers have a possibility of greatly contributing to reduction in power demand by an increase in an amount of power generated, discharging of storage batteries, or the like in addition to a simple load suppression.
Various types of demand responses have been thought out. For example, a type can be considered in which a rebate is given according to an amount of power decreased when an amount of power received in several hours in which the demand-supply tightness is predicted is made to be lower than an amount of power received in a normal state (for example, which is calculated based on results of amounts of power received in one week in the past) (when an amount of power purchased is decreased or an amount of power sold is increased).
Patent Literature 1: Japanese Patent Application Laid-Open No. 2005-004435
Patent Literature 2: Japanese Patent Application Laid-Open No. 2010-213477
However, in the method of creating a demand-supply plan of a consumer in the related art, an operation plan of a power generator or a storage battery is drawn up so as to minimize an operational cost (=power generation cost+power purchase cost−power selling cost) in a predetermined period (for example, the next one day or the next one week). In general, regarding a demand-supply plan, power demand is first predicted and then a power generation plan suitable for the predicted power demand is drafted. Accordingly, if the power demand is accurately predicted, an accurate operation plan with a minimized operational cost can be drafted. However, the smaller the demand scale becomes, the more it becomes difficult to predict the power demand. As a countermeasure, it can be considered that the power demand that is difficult to predict is treated probabilistically and, for example, a demand suppress request is treated as a probabilistic fluctuation of the power demand, as described in Patent Literatures 1 and 2.
On the other hand, when it is necessary to set an amount of power purchased in a specific time zone of a specific day (for example, a period of time of 13:00 to 16:00 on a day on which the temperature is particularly high and the power demand is predicted to be great in the whole nation in the summer) to be lower than that in the normal state (for example, an average value of amount of power purchased at a period of time of 13:00 to 16:00 in one week in the past) in response to a power purchase suppress request (demand response request) from the outside, there is no room to decrease the amount of power purchased if the power generator generates power with the maximum output power or the storage battery is maximally discharged in that time zone in the normal state. However, when the output power of the power generator is excessively lowered or the storage battery is excessively charged in the time zone in the normal state in preparation for the demand response, there is a possibility that power costs in the normal state will increase greatly.
In general, it is assumed that a demand response request is issued on a day or several hours before the time zone in which power consumption suppression is desired. Accordingly, it is preferable as a demand response measure that a normal optimal demand-supply plan be drawn up when no request is issued and the optimal demand-supply plan be drawn up again in consideration of a rebate when a request is issued, but there are following problems in this case.
From the viewpoint of the entire society, it can be thought that power which can be generated or discharged from the consumers having the power generation facilities or the electric storage facilities is reserve power for the whole society. Accordingly, it is preferable from the viewpoint of the whole society that the consumers having the power generation facilities or the electric storage facilities operate the power generators and the storage batteries possessed by the consumers, in normal operations in a time zone of a month in which there is a high possibility of power demand-supply tightness, in such a manner as to have appropriate reserve power (an amount of power which can be immediately generated/discharged when it is intended to generate/discharge more power).
The present invention is made in consideration of the above-mentioned circumstances and an object thereof is to provide a demand-supply planning device, a demand-supply planning method, a demand-supply planning program, and a recording medium that can create a demand-supply plan for operating a power generator and a storage battery to have appropriate reserve power for coping with a demand response request.
In order to solve the aforementioned problems, a demand-supply planning device according to one aspect of the present invention is so constructed as to include: a power demand predicting unit that performs prediction of power demand; an expected profit value predicting unit that calculates an expected profit value per unit amount of reduced power based on an occurrence probability of a demand response and a rebate value to be acquired through the demand response; and an optimal operation plan creating unit that sets an addition result of, a first cost for power purchase, a second cost for power generation by a power supply facility, and a multiplication result of the expected profit value and reserve power, which is an amount of power capable of being further generated by the power supply facility after an amount of power supplied satisfying the power demand is generated, as an evaluation function, and determines the reserve power and an operation plan of the power supply facility so as to satisfy the power demand with an amount of power purchased and the amount of power generated by the power supply facility, to satisfy a constraint condition of the power supply facility when the reserve power is generated, and to minimize the evaluation function.
According to the present invention, it is possible to create a demand-supply plan for operating a power generator and a storage battery to have appropriate reserve power for coping with a demand response request.
Hereinafter, a demand-supply planning device, a demand-supply planning method, a demand-supply planning program, and a recording medium according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments.
As illustrated in
In this embodiment, the demand-supply planning device 1 includes the facility control unit 20, but a control device other than the demand-supply planning device 1 may include the facility control unit 20 and the control device may control the power generators 2-1 to 2-n and the storage batteries 3-1 to 3-m based on an operation plan which is created by the demand-supply planning device 1.
Specifically, the demand-supply planning device 1 is a computer system (computer). By causing the computer system to execute a demand-supply planning program, the computer system functions as the demand-supply planning device 1.
In
Now, an operation example of the computer system until the demand-supply planning program according to the present invention is made executable will be described. In the computer system having the above-mentioned configuration, the demand-supply planning program is installed in the storage unit 103, for example, from a CD-ROM/DVD-ROM set into a compact disc (CD)-ROM/digital versatile disc (DVD)-ROM drive (not illustrated). When the demand-supply planning program is executed, the demand-supply planning program read from the storage unit 103 is stored in a predetermined area of the storage unit 103. In this state, the control unit 101 performs a demand-supply plan creating process according to this embodiment in accordance with the program stored in the storage unit 103.
In this embodiment, the program in which the demand-supply plan creating process is described using the CD-ROM/DVD-ROM as a recording medium (demand-supply planning program) is provided, but the present invention is not limited to this configuration and, for example, a program provided from a transmission medium such as the Internet via the communication unit 105 may be used in accordance with the configuration of the computer system, the capacity of the program to be provided, and the like.
The demand-supply planning unit 10 and the facility control unit 20 illustrated in
Operations of this embodiment will be described below. In this embodiment, first, an operation plan (next day operation plan) is created every predetermined period (for example, 24 hours) (first cycle). At the point in time at which the operation plan is created, since it is not determined whether a demand response is to be performed, a rebate for the demand response is introduced into an evaluation function based on the occurrence probability of the demand response. Then, for each predetermined update cycle (for example, one hour) (second cycle), the demand in the next day operation plan is corrected according to the newest information and a definite operation plan is created. The facility control unit 20 controls the power generators 2-1 to 2-n and the storage batteries 3-1 to 3-m in accordance with the definite operation plan. At this time, when the demand response is not performed, the definite operation plan is created without introducing the rebate for the demand response into the evaluation function based on the information on definition of whether to perform/not to perform the demand response. Hereinafter, in this embodiment, the predetermined period is set to 24 hours (a first operation plan is created every 24 hours) and the update cycle is set to one hour (a second operation plan is created every one hour), but the predetermined period and the update cycle are not limited to these values. For example, the predetermined period may be set to one week or may be set to any value as long as the predetermined period is greater than the update cycle.
Then, the expected rebate value predicting unit 12 calculates an expected profit value which is a unit profit (for example, per 1 kWh) resulting from a rebate to be returned when a demand response occurs (step S2). The expected profit value is specifically calculated, for example, as follows. The method of setting the rebate for a demand response is not particularly defined, and for example, a method of setting the rebate to X yens per 1 kWh as a decrease in an amount of power purchased (or an increase in an amount of power sold) from that in a normal state can be considered. X may be changed according to a time zone or a date, but is uniformly 40 yen herein. The demand response data in the storage unit 103 includes a rebate value (unit rebate value) per unit amount of power. The occurrence probability of the demand response varies according to the seasons or time zones. The probabilities according to the seasons and the time zones are stored as the demand response data in the storage unit 103. For example, the occurrence probability in a time zone 13:00 to 16:00 of July/August is stored to be high (for example, 50%) and the probabilities in other time zones are stored to be low (for example, 0%). The occurrence probability in each season and each time zone or the unit rebate value (for example, uniformly 40 yen per 1 kWh) can be changed by the supply party according to the predicted power demand-supply tightness of the nation. When these values are changed, for example, an operator of a consumer updates the demand response data in the storage unit 103. When the unit rebate value varies according to the time zones, the rebate value in each time zone is stored as the demand response data.
In a case in which several years have elapsed after an operation using the demand response is started, the occurrence probability of the demand response can be calculated on the basis of the frequency of the demand response in each time zone of the seasons or months in the past. If the past results in the past (results in which the demand response was performed or was not performed in the past) have not been stored, the occurrence probability that is predicted by prediction of the weather or the temperature or the like can be used.
When the probabilities of the demand response calculated based on the past results are finely acquired and the use thereof without any change is anticipated to cause a process to be described later complicated, the probabilities may be simplified to be used by setting the occurrence probability to 0 when the occurrence probability ranges from 0% to 10%, setting the occurrence probability to 20% when the occurrence probability ranges from 20% to 30%, and the like.
The expected rebate value predicting unit 12 reads the corresponding unit rebate value (the rebate value per unit amount of reduced power (unit reduced power)) and the occurrence probability thereof for each time zone of a next day from the demand response data in the storage unit 103. An expected rebate value is calculated by multiplying the unit rebate value by the occurrence probability for each time zone of the next day. For example, when the unit rebate value is uniformly 40 yen per 1 kWh, the occurrence probability thereof is 50% in the time zone of 13:00 to 16:00 of July/August, and the occurrence probability thereof is 0% in the other time zones, the expected rebate value in the time zone of 13:00 to 14:00 of July is 20 yen per 1 kWh and the expected rebate value in the time zone of 16:00 to 17:00 of July is 0 yen per 1 kWh.
The expected rebate value predicting unit 12 calculates the expected profit value by subtracting a cost such as a fuel cost for generating (generating or discharging) a unit amount of power (1 kWh herein) from the expected rebate value for each type of the power generators 2-1 to 2-n and the storage batteries 3-1 to 3-m. Here, the costs for generating a unit amount of power in the power generators 2-1 to 2-n are the same, the costs for generating a unit amount of power in the storage batteries 3-1 to 3-m are the same, the power supply facilities are divided into the power generators (the power generators 2-1 to 2-n) and the storage batteries (the storage batteries 3-1 to 3-m), and the expected profit value is calculated, for example, using Expression (1) as follows.
Expected profit value [power generator]=expected rebate value×unit fuel cost
Expected profit value [storage battery]=expected rebate value×storage battery loss×power purchase unit cost (1)
In Expression (1), the unit fuel cost is a cost of fuel used to generate the unit amount of power (1 kWh herein). The storage battery loss is a ratio (for example, 30%) of a charging-discharging loss in the storage battery to the amount of power used for the charging and discharging. The power purchase unit cost is a power purchase unit cost when power is purchased from a power company or the like at the time of charging the storage battery. The unit fuel cost, and the power purchase unit cost are stored in the unit cost data in the storage unit 103. The expected rebate value predicting unit 12 reads the values from the unit cost data in the storage unit 103 and uses the read values for the above-mentioned calculation.
When the power generators 2-1 to 2-n having different unit fuel costs are present, the expected profit value [power generator] only has to be calculated for each of the power generators 2-1 to 2-n. When the storage batteries 3-1 to 3-m having different storage battery losses are present, the expected profit value [storage battery] only has to be calculated for each of the storage batteries 3-1 to 3-m.
Referring to
The reserve power is an amount of power which can be generated (generated in case of the power generators and discharged or decreased in the charging power in case of the storage battery) by the facilities of the consumer party (the power generators 2-1 to 2-n and the storage batteries 3-1 to 3-m) when a demand response occurs, and is determined to minimize the evaluation function in consideration of the rebate for the demand response to be described later.
In setting the initial profiles of the power generation/charging-discharging profiles and the reserve power profiles, the optimal operation plan creating unit 13 reads the constraint condition data stored in the storage unit 103 and reflects the read constraint condition data. Specifically, the initial profiles are set such that the power generation/charging-discharging profiles alone satisfy the constraint conditions and profiles obtained by adding the reserve power profiles to the power generation/charging-discharging profiles satisfy the constraint conditions. For example, in the example illustrated in
(1) Constraint conditions of power generator
(2) Constraint conditions of storage battery
(3) Constraint conditions of amount of power purchased
The optimal operation plan creating unit 13 substitute the amount of power purchased, the amount of power generated, the amount of power discharged, and the reserve power for each time zone for the evaluation function, based on the power generation/charging-discharging profiles, the reserve power profiles, and the demand predicted in step S1 (step S4). For example, Expression (2) described below is used as the evaluation function.
Evaluation function=Σt(amount of power purchased×power purchase unit cost+amount of power generated×unit fuel cost+amount of power discharged×storage battery loss×power purchase unit cost [charging]−Σi(reserve power×expected profit value) (2)
The amount of power purchased is obtained by subtracting the amounts of power generated by the power generators 2-1 to 2-n and the amounts of power charged-discharged by the storage batteries 3-1 to 3-m from the amount of power corresponding to the predicted demand. Here, the amount of power charged-discharged is set to a plus sign in case of discharging and is set to a minus sign in case of charging. For example, in a time zone in which only the charging is performed, the amount of power required for the charging is added to the amount of power purchased. Σt in the head of Expression (2) refers to the total sum with respect to the time, is defined as the total sum of one day (24 hours) which is the cycle time of creating the operation plan, and is the total sum of the values in 24 time zones when the power demand and the like are calculated hourly. When the power purchase unit cost varies depending on the time zones, the power purchase unit cost which is multiplied by the storage battery loss is set to a unit cost at the time of charging. Σi in Expression (2) refers to the total sum in groups when the groups having different expected profit values such as the power generators and the storage batteries are present. For example, when the power generators 2-1 to 2-n can use the same expected profit value [power generator], and the storage batteries 3-1 to 3-m can use the same expected profit value [storage battery], Σi(reserve power×expected profit value) can be represented by Expression (3).
Σi(reserve power×expected profit value)=total reserve power of power generators 2-1 to 2-n×expected profit value [power generator]+total reserve power of storage batteries 3-1 to 3-m×expected profit value [storage battery] (3)
The amount of power purchased×power purchase unit cost (first cost) in Expression (2) refers to a cost required for power purchase, and the amount of power generated×unit fuel cost+amount of power discharged×storage battery loss (second cost refers to a cost required for generating power from the power supply facilities (the power generators 2-1 to 2-n and the storage batteries 3-1 to 3-m) of the consumer party.
In this embodiment, since the demand is demand in the facilities of the consumer party, a temporal distribution of the demand may be changed to a certain extent. In this case, the total demand of one day only has to be supplied on a daily basis. In this case, in step S8 described later on, a range of change is determined, including a case in which the temporal demand distribution is changed when the power generation/charging-discharging profiles are changed. Here, when the changeable range of the operation plan is constrained or an unchangeable load is present, these are also considered as the constraint conditions. For example, as for a manufacturing facility as a part of the load 4, the constraint condition is that the profiles are changeable in one hour before or after the start and end of the operation from the operation plan.
The optimal operation plan creating unit 13 determines whether the value of evaluation function for which the amount of power purchased, the amount of power generated, the amount of power discharged, the reserve power, and the like are substituted in step S4 is less than Cmin (step S5). A sufficiently great value (for example, a value greater than the obtainable maximum value of the evaluation function) is set as the initial value of Cmin. When the value of the evaluation function is less than Cmin (Yes in step S5), Cmin is set as the value of the evaluation function (step S6). Then, the optimal operation plan creating unit 13 determines whether the power generation/charging-discharging profiles and the reserve power profiles of the facilities to be changed are processed in the entire changeable range (step S7), changes the power generation/charging-discharging profiles and/or the reserve power profiles (step S8) when a range in which the processing is not yet performed is still present (No in step S7), and returns the process flow to step S4. In the changing in step S8, the profiles are changed such that the changed power generation/charging-discharging profiles alone satisfy the constraint conditions and the profiles obtained by adding the changed reserve power profiles to the changed power generation/charging-discharging profiles also satisfy the constraint conditions, in the same way as setting the initial profiles.
The entire changeable range is a range which can be set based on the above-mentioned constraint conditions (1) to (3). A constraint condition other than the constraint conditions (1) to (3) may be added to narrow the entire changeable range. For example, the power generators may be started and stopped once a day and the power generation profiles may be changed by changing only the operation start time with the operation time of a day determined. Regarding the reserve power profiles, the reserve power does not need to be set in a period during which the demand response is 0% in the example in which the occurrence probability of the demand response is set to 50% in the time zone of 13:00 to 16:00 of July/August and is set to 0% in the other time zones as described above. Accordingly, the value of the reserve power in only the time zone in which the occurrence probability is 50% may be changed to calculate a value that optimizes the evaluation function. The changing of the charging-discharging profiles and the reserve power profiles may be performed, for example, by changing the reserve power profiles with the power generation/charging-discharging profiles fixed and changing the power generation/charging-discharging profiles after the entire range of the reserve power profiles are processed or using other methods. In order to reduce a processing load, the power generation/charging-discharging profiles may be changed by providing plural power generation/charging-discharging profiles for each facility in advance and selecting the power generation/charging-discharging profiles therefrom.
When it is determined in step S7 that the entire range is processed (Yes in step S7), it is determined whether the changing for all the facilities is completed (are set as the facilities to be changed) (step S9), one of the facilities of which the changing is not completed is set as a facility to be changed when a facility of which the changing is not completed is present (No in step S9), and the process flow is returned to step S4. When the changing of all the facilities is completed (Yes in step S9), an operation plan is created on the basis of the power generation/charging-discharging profiles corresponding to Cmin (step S10) and is stored as a next day operation plan (first operation plan) in the storage unit 103, and the process flow ends. When the next day operation plan (first operation plan) is stored in the storage unit 103, the reserve power profiles are stored and the predicted power demand value calculated in step S1 and the preconditions (such as the predicted temperature) of the predicted value are stored in the storage unit 103 in correlation with each other. However, the above-mentioned process flow is an example, and the specific processes are not limited to the above-mentioned process flow as long as it can calculate the power generation/charging-discharging profiles and the reserve power profiles which minimize the value of the evaluation function.
Through the above-mentioned processes, it is possible to create an operation plan which can secure reserve power minimizing the evaluation function. The demand-supply planning device 1 according to this embodiment can draft a demand-supply plan in consideration of the rebate for the demand response through the above-mentioned processes.
Processes which are performed per update cycle will be described below.
Then, the definite operation plan creating unit 15 sets the evaluation function according to the result (definite information) as to whether the demand response is to be performed (step S12). Whether the demand response is performed may be input from an operator, for example, by operating the input unit 102 or may be input from another information device (not illustrated) via the communication unit 105.
In the process of step S12, specifically, Expression (4) is used when the demand response is performed, and Expression (5) from which the rebate is deleted is used when the demand response is not performed. Here, it is assumed that correction of the power demand in step S11 has been reflected in the amount of power purchased.
(When it is determined that the demand response is performed)
Evaluation function=amount of power purchased×power purchase unit cost+amount of power generated×unit fuel cost+amount of power discharged×storage battery loss×power purchase unit cost−Σi(reserve power×unit rebate value) (4)
(When it is determined that the demand response is not performed)
Evaluation function=amount of power purchased×power purchase unit cost+amount of power generated×unit fuel cost+amount of power discharged×storage battery loss×power purchase unit cost (5)
Then, the definite operation plan creating unit 15 determines an operation plan for the next one hour according to the evaluation function set in step S12 and stores the determined operation plan as a definite operation plan (second operation plan) in the storage unit 103 (step S13). At this time, it can be considered that the operation plan that minimizes the evaluation function is calculated by sequentially changing the amount of power generated and the amount of power discharged on the basis of the same constraint conditions as in creating the operation plan of the next day in
The facility control unit 20 controls the facilities in accordance with the definite operation plan (step S14). When an accurate operation plan is not necessary by separately performing the control of the facilities and the like, the operation plan determining process described with reference to
As described above, in this embodiment, the reserve power is calculated to minimize the evaluation function using a function, which is obtained by multiplying the reserve power by the expected profit value for the demand response in consideration of the occurrence probability of the demand response based on the costs (the cost for power purchase and the cost for power generation) necessary for securing the predicted power demand, as the evaluation function indicating the cost in a predetermined period. Accordingly, it is possible to create an operation plan (demand-supply plan) for operating the power generators and the storage batteries so as to have appropriate reserve power capable of coping with a demand response request.
As described above, the demand-supply planning device, the demand-supply planning method, the demand-supply planning program, and the recording medium according to the present invention can be suitably used to create a demand plan in a consumer having a power generator and a storage battery and can be particularly suitably used for a consumer receiving a demand response request.
1 demand-supply planning device, 2-1 to 2-n power generator, 3-1 to 3-m storage battery, 4 load, 10 demand-supply planning unit, 11 power demand predicting unit, 12 expected rebate value predicting unit, 13 optimal operation plan creating unit, 14 power demand correcting unit, 15 definite operation plan creating unit, facility control unit, 101 control unit, 102 input unit, 103 storage unit, 104 display unit, 105 communication unit, 106 output unit, 107 system bus
Filing Document | Filing Date | Country | Kind |
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PCT/JP2013/067560 | 6/26/2013 | WO | 00 |