JP7669308B2 - POWER TRADING SUPPORT SYSTEM, POWER TRADING SUPPORT METHOD, AND POWER TRADING SUPPORT PROGRAM - Google Patents

Description

Embodiments of the present invention relate to an energy trading support system, an energy trading support method, and an energy trading support program.

Consumers (electricity consumers, e.g., heat supply companies) who own electric heat source equipment generally plan their operations to procure electricity at the lowest possible cost, taking into account fluctuations in the electricity procurement price, and to operate the heat source equipment. As a conventional technique, for example, there is a method for minimizing the electricity purchasing cost for a heat source equipment network that includes multiple heat source equipment, subject to constraints on carbon dioxide emissions and gas usage.

Consumers may also enter into contracts with electricity retailers to purchase electricity. In such cases, the retailer purchases electricity at wholesale prices from wholesale electricity exchanges and other sources, and sells the purchased electricity to consumers at retail prices. In such cases, consumers generally take into account fluctuations in the retail price of electricity (e.g., electricity is cheaper at night than during the day) and create operating plans to procure electricity at the lowest possible cost and operate their heat source equipment.

Patent No. 6582755

However, while the wholesale price of electricity fluctuates from moment to moment depending on the amount of electricity supplied and demanded, the retail price of electricity is determined in advance according to the time of day, day of the week, amount of electricity used, etc. through prior contracts between consumers and retailers. Therefore, increases and decreases in the wholesale price do not necessarily correspond to increases and decreases in the retail price. As a result, even if consumers minimize their electricity purchasing costs, it is not necessarily the case that the overall profits of retailers and consumers will be maximized, and there is room for improvement.

The objective of the present invention is to provide an electricity trading support system, an electricity trading support method, and an electricity trading support program that can help improve the overall profits of electricity retailers and consumers.

The electricity trading support system of the embodiment includes an operation plan creation unit that creates an operation plan for one or more electric heat source devices owned by a consumer based on wholesale price information, which is price information when an electricity retailer procures electricity.

FIG. 1 is a diagram showing an overall configuration of an energy trading support system according to a first embodiment. FIG. 2 is a diagram showing an example of time-of-day retail prices per unit amount of electricity in the first embodiment. FIG. 3 is a diagram illustrating an example of a time-based wholesale price per unit amount of power in the first embodiment. FIG. 4 is a diagram illustrating an example of an operation plan according to the first embodiment. FIG. 5 is a diagram illustrating a configuration of the demand forecasting unit according to the first embodiment. FIG. 6 is a diagram illustrating an example of demand information according to the first embodiment. FIG. 7 is a diagram illustrating an example of weather information according to the first embodiment. FIG. 8 is a diagram showing the configuration of the wholesale price prediction unit in the first embodiment. FIG. 9 is a diagram showing an example of wholesale price information in the first embodiment. FIG. 10 is a flowchart showing the process executed in the energy trading support system according to the first embodiment. FIG. 11 is a diagram illustrating an example of the configuration of the heat source device group according to the first embodiment. FIG. 12 is a diagram showing an overall configuration of an energy trading support system according to the second embodiment. FIG. 13 is a diagram illustrating an example of the configuration of a heat source device group according to the second embodiment. FIG. 14 is a diagram showing an overall configuration of an energy trading support system according to the third embodiment. FIG. 15 is a flowchart showing the process executed in the energy trading support system according to the third embodiment.

Hereinafter, the embodiments (first to third embodiments) of the energy trading support system, the energy trading support method, and the energy trading support program of the present invention will be described with reference to the drawings.

First Embodiment
First, the first embodiment will be described with reference to Fig. 1 to Fig. 11. Fig. 1 is an overall configuration diagram showing an overview of an energy trading system S according to the first embodiment. The energy trading system S includes a consumer device 100 and a retailer device 200.

The consumer device 100 is owned by a consumer, includes a group of heat source equipment 103, and performs processes such as purchasing electricity at retail prices from the retailer device 200.

Here, FIG. 2 is a diagram showing an example of the time-of-day retail price per unit amount of electricity in the first embodiment. In this example, the retail price of electricity is set to be cheaper at night than during the day. Note that here, the retail price is a flat rate system with two stages for day and night, but this is not limited to this, and it may also be, for example, a pay-as-you-go system that varies depending on the amount of electricity consumed.

Returning to FIG. 1, the retail business device 200 is owned by a retail business and performs processes such as procuring (purchasing) electricity at wholesale prices from the wholesale electricity exchange 300 and selling electricity at retail prices to the consumer device 100.

Here, FIG. 3 is a diagram showing an example of the wholesale price by time per unit of power in the first embodiment. The wholesale price of electricity fluctuates from moment to moment depending on the supply and demand of electricity.

Returning to FIG. 1, the explanation will continue. Note that in the first embodiment, there is one consumer (consumer device 100), but this is not limited to this. For example, one retailer (retailer device 200) may trade electricity with multiple consumers. Furthermore, retailers may procure electricity through P2P trading, where they trade directly with power generation companies and consumers, rather than trading with the wholesale electricity exchange 300.

The consumer device 100 and the retailer device 200 are each configured to include, for example, a PC (Personal Computer). The PC includes, for example, a CPU (Central Processing Unit), memory, a HDD (Hard Disk Drive), a communication interface (I/F), a display device such as a display, and an input device such as a keyboard and a mouse.

The consumer device 100 includes an energy trading unit 101, an operation control unit 102, and a group of heat source equipment 103.

The retail business device 200 includes an energy trading unit 201, an operation plan creation unit 202, a demand forecasting unit 203, a wholesale price forecasting unit 204, a balance calculation unit 205, a display unit 206, an input unit 207, and a memory unit 208.

Note that the arrows in Figure 1 (other than the white arrows) indicate the main flow of signals and information, and signals and information may flow through parts without arrows.

The energy trading unit 101 of the consumer device 100 performs a process of purchasing electricity from the energy trading unit 201 of the retail business device 200. The operation control unit 102 receives an operation plan from the operation plan creation unit 202, and controls the heat source equipment group 103 in accordance with the received operation plan. The heat source equipment group 103 includes at least one electric heat source equipment such as a heat storage tank and heat production equipment (such as a turbo chiller). Note that the heat source equipment group 103 may also include equipment other than heat source equipment such as a storage battery. The consumer device 100 is, for example, a heat supply plant that supplies heat to the outside, or a large-scale plant that consumes heat itself.

The energy trading unit 201 of the retail business device 200 procures (purchases) electricity from the wholesale electricity exchange 300 and sells the electricity to the energy trading unit 101 of the consumer device 100. The operation plan creation unit 202 creates an operation plan for the heat source equipment group 103 based on the demand information received from the demand prediction unit 203 and the wholesale price information received from the wholesale price prediction unit 204. The operation plan creation unit 202 transmits the created operation plan to the operation control unit 102, and transmits an electricity procurement plan based on the created operation plan to the energy trading unit 201.

The demand prediction unit 203 and the wholesale price prediction unit 204 are examples of prediction units that predict relevant information related to the operation of the heat source equipment group 103. The relevant information is, for example, information such as heat demand, cold demand, and wholesale prices (details will be described later).

Figure 4 is a diagram showing an example of an operation plan for the first embodiment. The operation plan is composed of information such as the amount of electricity purchased for each hour (every 30 minutes), the amount of power consumed by the heat pump, the amount of power consumed by the turbo chiller, and the amount of heat stored in the hot water thermal storage tank.

Figure 5 is a diagram showing the configuration of the demand forecasting unit 203 in the first embodiment. The demand forecasting unit 203 includes a demand information storage unit 203a, a meteorological information storage unit 203b, a demand forecast calculation unit 203c, and a demand forecast information transmission unit 203d. Note that the demand information storage unit 203a and the meteorological information storage unit 203b are shown as being configured separately from the storage unit 208 (Figure 1), but may be realized by the storage unit 208.

Here, FIG. 6 is a diagram showing an example of demand information in the first embodiment. The demand information is composed of information on non-thermal demand, hot heat demand, and cold heat demand for each hour of the day. Non-thermal demand refers to electricity demand other than the electricity demand corresponding to hot heat demand and cold heat demand (e.g., electricity demand for lighting devices). Hot heat demand refers to the demand for hot heat generation using electricity. Cold heat demand refers to the demand for cold heat generation using electricity. The demand information storage unit 203a stores the collected past demand information.

Figure 7 is a diagram showing an example of weather information in the first embodiment. The weather information is composed of information on temperature, relative humidity, atmospheric pressure, and precipitation for each time. The weather information storage unit 203b stores past weather information that has been collected.

The demand forecast calculation unit 203c forecasts at least one of the heat demand (including hot water demand and steam demand (used for turbine rotation, sterilization, etc.)) and cold demand in the heat source equipment group 103. Specifically, for example, the demand forecast calculation unit 203c forecasts the amount of heat demand and cold demand from the heat source equipment group 103 based on the demand information stored in the demand information storage unit 203a and the weather information stored in the weather information storage unit 203b.

The demand forecast information transmission unit 203d transmits the demand information predicted by the demand forecast calculation unit 203c to the operation plan creation unit 202.

Figure 8 is a diagram showing the configuration of the wholesale price prediction unit 204 in the first embodiment. The wholesale price prediction unit 204 includes a wholesale price information storage unit 204a, a weather information storage unit 204b similar to the weather information storage unit 203b, a wholesale price prediction calculation unit 204c, and a wholesale price prediction information transmission unit 204d.

Here, FIG. 9 is a diagram showing an example of wholesale price information in the first embodiment. The wholesale price information is composed of information on wholesale prices for each time period. The wholesale price information storage unit 204a stores collected past wholesale price information. The wholesale price prediction calculation unit 204c predicts wholesale prices based on the wholesale price information stored in the wholesale price information storage unit 204a and the weather information stored in the weather information storage unit 204b.

Note that for convenience of explanation and illustration, the weather information storage unit 203b (FIG. 5) and the weather information storage unit 204b (FIG. 8) are shown as separate units. However, for example, they may be realized as a single unit, and the demand forecasting unit 203 and the wholesale price forecasting unit 204 may share the single weather information storage unit. Furthermore, the single weather information storage unit may be located within the demand forecasting unit 203 or the wholesale price forecasting unit 204, or may be located outside both of them.

The wholesale price prediction information transmission unit 204d transmits the wholesale price information predicted by the wholesale price prediction calculation unit 204c to the operation plan creation unit 202.

Figure 10 is a flowchart showing the processing executed by the energy trading support system S of the first embodiment.

First, the demand forecasting unit 203 forecasts the demand of consumers for each hour of the next day and transmits it to the operation plan creation unit 202 (S1).

Next, the wholesale price prediction unit 204 predicts the wholesale price for each hour of the next day and transmits it to the operation plan creation unit 202 (S2). Note that S1 and S2 may be executed in the reverse order or in parallel.

Next, the operation plan creation unit 202 creates an operation plan (Figure 4) for the heat source equipment group 103 for each time unit based on the demand information predicted in S1 and the wholesale price information predicted in S2, transmits the operation plan to the operation control unit 102, and transmits an electricity procurement plan based on the operation plan to the energy trading unit 201 (S3).

Here, FIG. 11 is a diagram showing an example of the configuration of the heat source equipment group 103 in the first embodiment. In more detail about S3, assuming that the heat source equipment group 103 has the configuration shown in FIG. 11, the operation plan creation unit 202 calculates an operation plan for each device of the heat source equipment group 103 for each time unit by calculating an optimal solution of an optimization model (optimization problem) that minimizes the objective function of equation (1) under the constraint conditions shown in the following equations (2) to (19). The optimization problem of equations (1) to (19) is a problem called a linear programming problem. The operation plan creation unit 202 calculates an optimal solution that minimizes the objective function of equation (1) by a method such as the simplex method or the interior point method.

Here, the variables are as follows:

And the parameters are as follows:

Equation (1) represents the total electricity cost of the retailer. Here, the time unit is 30 minutes, and T is 24 hours from the day after the operation plan creation process is performed. In other words, T=48.
Equation (2) is a constraint equation that represents the balance between the total power consumption amount and the power purchase amount.

Equation (3) is a constraint equation that represents the relationship between the amount of cold heat produced by the centrifugal chiller and the amount of power consumption.
Equation (4) is a constraint equation that represents the upper and lower limits of the amount of cold energy produced by the centrifugal chiller.

Equation (5) is a constraint equation that represents the relationship between the amount of heat produced by the heat pump and the amount of power consumed.
Equation (6) is a constraint equation that represents the upper and lower limits of the amount of heat produced by the heat pump.
Equation (7) is a constraint equation that represents the upper and lower limits of the amount of cold energy produced by the heat pump.

Equation (8) is a constraint equation that represents the change in the amount of heat stored in the hot water heat storage tank over time.
Equation (9) is a constraint equation that represents the upper and lower limits of the amount of heat stored in the hot water heat storage tank.

Equation (10) is a constraint equation that represents the change in the amount of heat stored in the cold water heat storage tank over time.
Equation (11) is a constraint equation that represents the upper and lower limits of the amount of heat stored in the cold water heat storage tank.

Equation (12) is a constraint equation that represents the relationship between the amount of heat dissipated from the hot water heat storage tank and the amount of power consumption.
Equation (13) is a constraint equation that represents the upper and lower limits of the amount of heat dissipation from the hot water heat storage tank.

Equation (14) is a constraint equation that represents the relationship between the amount of heat dissipated from the cold water heat storage tank and the amount of power consumption.
Equation (15) is a constraint equation that represents the upper and lower limits of the amount of heat radiation from the cold water heat storage tank.

Equation (16) is a constraint equation that represents the balance between heat demand and the amount of heat supply.
Equation (17) is a constraint equation that represents the balance between the demand for cold energy and the amount of cold energy supplied.

Equation (18) is a constraint equation that expresses the balance between the amount of produced heat and its destination.
Equation (19) is a constraint equation that represents the balance between the amount of produced cold energy and its destination.

The operation plan creation unit 202 finds the values of each variable that make the value of equation (1) smaller while satisfying equations (2) to (19). The operation plan creation unit 202 transmits the created operation plan to the operation control unit 102, and transmits the power procurement plan based on the operation plan to the energy trading unit 201.

The energy trading unit 201 procures electricity from the wholesale electricity exchange 300 based on the electricity procurement plan (S4). The operation control unit 102 controls the heat source equipment group 103 in accordance with the operation plan (S4).

In addition, the operation plan creation unit 202 creates a second operation plan for the heat source equipment based on retail price information, which is price information when the retailer sells electricity to the consumer (details will be described later).

Finally, the balance calculation unit 205 performs a balance calculation for the electricity transaction between the consumer and the retailer based on the operation plan and the second operation plan (S5). This will be described in detail below. The balance calculation unit 205 calculates and compares the profits of the consumer and the retailer when the wholesale price information is used and when it is not used, and performs a balance calculation between the consumer and the retailer. Specifically, the operation plan when the wholesale price is used is plan A, and the second operation plan when the retail price is used without using the wholesale price is plan B. The balance calculation unit 205 first calculates the electricity cost of the consumer when the retail price is used by using the value of P ^BUY (t) in plan A calculated in S3 using the following formula (20). Next, the electricity cost of the consumer in plan B is calculated by calculating the optimal solution of the optimization problem that minimizes formula (20) under the constraint conditions shown in formulas (2) to (19). Furthermore, the electricity cost of the retailer when the wholesale price is not used is calculated by calculating formula (1) using the value of P ^BUY (t) in plan B.

Here, the parameters are as follows:

The variables are as follows:

Then, the following equations (21) to (24) hold.

Furthermore, the variables are as follows:

Then, the income/expense calculation unit 205 uses the following equations (25) to (27) to calculate the profits of the retailer and the consumer resulting from the change from plan B to plan A, as well as the total profit of both.

In addition, since plan A minimizes the electricity procurement cost of the retailer, C _r ^Bp ≧C _r ^Ap , and from equation (27), R _all is always 0 or greater. In other words, by operating the heat source equipment group 103 in plan A, the overall total profit of the retailer and consumers does not decrease compared to plan B. In other words, when considering the retailer and consumers as a whole, the overall total profit of the retailer and consumers is maximized by minimizing the cost of procuring electricity from the wholesale electricity exchange 300.

If the increased profit is to be shared between the retailer and the consumer by some means, the calculation results of these profits may be used. For example, profit sharing can be realized by the retailer returning to the consumer a certain percentage of the increase in profit resulting from the change from plan B to plan A.

The results of the income and expenditure calculation may also be displayed on the display unit 206. This allows the user to recognize the results of the income and expenditure calculation.

In this way, according to the first embodiment of the electricity trading support system S, by creating an operation plan for the heat source equipment group 103 based on the wholesale price of electricity rather than the retail price of electricity, it is possible to help improve the overall profits of electricity retailers and consumers.

In other words, consumers generally operate heat source equipment taking into account the retail price at which they purchase electricity, without considering fluctuations in wholesale prices or the profits of retail businesses. In the method of the first embodiment, cost optimization is performed based on the wholesale price, making it possible to improve the total profits of retail businesses and consumers compared to when the wholesale price is not considered. Furthermore, since the wholesale price is generally high during times when there is high demand for wholesale electricity, cost optimization based on the wholesale price can be used to avoid receiving electricity during times when the wholesale price is high, thereby realizing a peak shift in electricity usage.

Second Embodiment
Next, the second embodiment will be described with reference to Fig. 12 and Fig. 13. Fig. 12 is an overall configuration diagram showing an overview of an energy trading support system S of the second embodiment. Fig. 13 is a diagram showing an example of the configuration of a heat source device group 103 of the second embodiment. Note that the same reference numerals are used for the same configuration as in the first embodiment, and duplicated explanations will be omitted as appropriate.

The difference from the first embodiment (Fig. 1) is that, as shown in Fig. 12, the heat source equipment group 103 includes gas-powered heat source equipment such as a cogeneration system, and the energy trading unit 101 procures not only electricity but also gas. Note that, although in the second embodiment, the consumer procures gas from outside, gas may be procured via a retailer. Also, as shown in Fig. 13, not only is a cogeneration system added, but the heat pump is also gas-powered.

10, the process is different from the first embodiment in S3 and S5. First, in S3, the operation plan creation unit 202 adds equations (29) to (34) to the constraint conditions in the first embodiment, and calculates an optimal solution of an optimization model (optimization problem) that minimizes the objective function of equation (28), thereby calculating an operation plan for each device in the heat source device group 103 for each time unit. However, instead of equations (2) and (18), the following equations (2') and (18') are used as constraint conditions.

Here, the variables and parameters are as follows:

Equation (28) represents the sum of the gas purchasing cost and the retailer's electricity purchasing cost.
Equation (29) is a constraint equation that represents the balance between the total gas consumption amount and the gas purchase amount.

Equation (30) is a constraint equation that represents the relationship between the amount of power generation and the amount of gas consumption of the cogeneration system.
Equation (31) is a constraint equation that represents the relationship between the amount of power generated and the amount of power consumed by the cogeneration system.

Equation (32) is a constraint equation that represents the relationship between the amount of power generated by the cogeneration system and the amount of heat produced.
Equation (33) is a constraint equation that represents the upper and lower limits of the amount of heat produced by the cogeneration system.
Equation (34) is a constraint equation that expresses the relationship between the amount of heat produced by the heat pump and the amount of gas consumed.

Next, in S5, the income/expense calculation unit 205 calculates each profit using the following formula (20') instead of formula (20).

Here, the variables are as follows:

Then, equations (21) and (23) and the following equations (35) and (36) hold.

Furthermore, the income/expense calculation unit 205 calculates the profits of the retailer and the consumer resulting from the change from plan B to plan A, as well as the total profit of both, using the following equations (37) to (39).

Here, as can be seen from equation (39), similar to the first embodiment, operating the heat source equipment group 103 according to plan A does not result in a decrease in the overall total profit of the retailer and consumers compared to plan B.

In this way, according to the second embodiment, even if the heat source equipment group 103 includes gas-type heat source equipment, the same effects as those of the first embodiment can be obtained.

Third Embodiment
Next, the third embodiment will be described with reference to Fig. 14 and Fig. 15. Fig. 14 is an overall configuration diagram showing an overview of an energy trading support system S according to the third embodiment. Note that the same components as those in at least one of the first and second embodiments are denoted by the same reference numerals, and duplicated descriptions will be omitted as appropriate.

Compared to the second embodiment (FIG. 12), when the operation plan creation unit 202 determines that it is not possible to procure power from the wholesale power exchange 300 according to the created operation plan, it receives information on the amount of power that can be procured from the energy trading unit 201, as shown in FIG. 14, and creates an operation plan again based on that information.

Next, the processing will be described. FIG. 15 is a flowchart showing the processing executed by the energy trading support system S of the third embodiment. It differs from the first and second embodiments in that S11 is added after S3. In S3, the operation plan creation unit 202 creates an operation plan for the next day, and then transmits an electricity procurement plan based on the operation plan to the energy trading unit 201.

Next, in S11, the operation plan creation unit 202 determines whether the planned power can be procured on the day, and if Yes, proceeds to S4, and if No, returns to S3 to receive information on the amount of power that can be procured from the energy trading unit 201 and create an operation plan again. S4 and S5 are the same as in the second embodiment.

In this way, according to the third embodiment, the same effects as the first and second embodiments can be obtained even when the operation plan is recreated.

The programs executed by the consumer device 100 and the retailer device 200 of this embodiment are provided by being recorded in an installable or executable file format on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a digital versatile disk (DVD). The programs may also be configured to be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. The programs may also be configured to be provided or distributed via a network such as the Internet. The programs may also be configured to be provided by being pre-installed in a ROM or the like.

Although an embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This new embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

For example, consumers are not limited to heat supply plants or large-scale plants, but may be ordinary homes or hospitals if they have a heat storage device or are able to change their operating plan.

In addition, the location of the operation plan creation unit 202 is not limited to the retailer device 200, but may be the consumer device 100, or a cloud computing environment external to the consumer device 100 and the retailer device 200, etc.

100... Consumer device, 101... Energy trading unit, 102... Operation control unit, 103... Heat source equipment group, 200... Retail business device, 201... Energy trading unit, 202... Operation plan creation unit, 203... Demand forecast unit, 203a... Demand information storage unit, 203b... Weather information storage unit, 203c... Demand forecast calculation unit, 203d... Demand forecast information transmission unit, 204... Wholesale price forecast unit, 204a... Wholesale price information storage unit, 204b... Weather information storage unit, 204c... Wholesale price forecast calculation unit, 204d... Wholesale price forecast information transmission unit, 205... Balance calculation unit, 206... Display unit, 207... Input unit, 208... Storage unit, 300... Wholesale power exchange, S... Power trading support system

Claims (7)

an operation plan creation unit that creates an operation plan for one or more electric heat source devices owned by the consumer based on wholesale price information, which is price information when a power retailer procures power, and creates a second operation plan for the heat source devices based on retail price information, which is price information when the power retailer sells power to the consumer;
an income/expense calculation unit that performs income/expense calculation regarding the electricity trading between the consumer and the retailer based on the operation plan and the second operation plan . A prediction unit that predicts related information related to the operation of the heat source equipment,
The energy trading support system according to claim 1 , wherein the operation plan creation unit creates the operation plan based on the related information and the wholesale price information. The electricity trading support system according to claim 2, wherein the prediction unit includes a demand prediction unit that predicts at least one of the demand for hot heat and the demand for cold heat in the heat source equipment as the related information. The energy trading support system according to claim 2, wherein the prediction unit includes a wholesale price prediction unit that predicts the wholesale price information as the related information. The energy trading support system of claim 1, wherein the operation plan creation unit creates an operation plan again based on information about the amount of energy that can be procured when it is determined that the power in the operation plan cannot be procured. an operation plan creation step of creating an operation plan for one or more electric heat source devices owned by the consumer based on wholesale price information, which is price information when a power retailer procures power, and creating a second operation plan for the heat source devices based on retail price information, which is price information when the power retailer sells power to the consumer;
and a balance calculation step of performing a balance calculation regarding the electricity trading between the consumer and the retailer based on the operation plan and the second operation plan . Computer,
an operation plan creation unit that creates an operation plan for one or more electric heat source devices owned by the consumer based on wholesale price information, which is price information when a power retailer procures power , and creates a second operation plan for the heat source devices based on retail price information, which is price information when the power retailer sells power to the consumer;
an electricity trading support program for causing the electricity trading support program to function as an income/expense calculation unit that performs income/expense calculation regarding the electricity trading between the consumer and the retailer based on the operation plan and the second operation plan .

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