JP2021193861A - Energy management system - Google Patents

Abstract

To provide an energy management system in which a renewable energy utilization rate in power consumption in a micro grid is easily improved.SOLUTION: An energy management system is connected to a grid to which at least a first renewable energy power generation device is connected, and configured to perform energy management of a micro grid including a fire power generation facility and a second renewable energy power generation device different from the first renewable energy power generation device. The energy management system comprises an operation schedule generation section for planning an operation schedule of the micro grid including a scheduled power quantity to be bought from the grid in such a manner that a power demand in the micro grid is satisfied and a target utilization rate of renewable energy in the micro grid is achieved on the basis of a power generation quantity prediction result of the second renewable energy power generation device.SELECTED DRAWING: Figure 2

Description

This disclosure relates to an energy management system.

In energy supply systems such as microgrids, renewable energy power generation equipment and thermal power generation equipment may be used together as power generation equipment in the region in order to meet the power demand in the region. In addition, in order to meet the power demand in the region, the power generated by the power generation equipment in the region and the purchased power purchased from the grid may be used together.

Patent Document 1 discloses an energy supply system including a cogeneration system (thermal power generation facility) and a photovoltaic power generation device (renewable energy power generation facility), and a control device for managing the energy supply system. This control device is based on the power demand forecast in the region and the power generation forecast by the solar power generation device so as to meet the power demand and heat demand in the energy supply target (factory, etc.), and the amount of power generated by the cogeneration system ( The amount of power generation) and the amount of power purchased from the grid (the amount of power purchased) are determined.

Japanese Patent No. 6011702

In the control device of the energy supply system described in Patent Document 1, the amount of power purchased from the grid is determined so as to make up for the shortage of the power demand in the region, which is insufficient for the amount of power generation in the region. Therefore, the ratio of the amount of renewable energy power generation to the total amount of power consumption in the region (renewable energy utilization rate) may be low, and in this case, the environmental load becomes large.

In view of the above circumstances, at least one embodiment of the present invention aims to provide an energy management system that can easily improve the renewable energy utilization rate in terms of power consumption in a microgrid.

The energy management system according to at least one embodiment of the present invention is
Energy management of a microgrid that is connected to a grid to which at least the first renewable energy power generation device is connected and includes a thermal power generation facility and a second renewable energy power generation device different from the first renewable energy power generation device. It is an energy management system for
Based on the power generation amount prediction result of the second renewable energy power generation device, the planned power purchase amount from the grid that can satisfy the power demand in the microgrid and achieve the target utilization rate of the renewable energy in the microgrid. It is provided with an operation plan generation unit for formulating an operation plan of the microgrid including.

According to at least one embodiment of the present invention, there is provided an energy management system that easily improves the renewable energy utilization rate in terms of power consumption in a microgrid.

It is a schematic block diagram of the microgrid which concerns on one Embodiment. It is a schematic block diagram of the energy management system which concerns on one Embodiment. It is a figure which shows an example of the display image of the screen data which concerns on one Embodiment. It is a chart which shows an example of the power source composition and electric power demand of electric power in a microgrid. It is a chart which shows an example of the power source composition and electric power demand of electric power in a microgrid. It is a flowchart which shows an example of the operation plan making by the energy management system which concerns on one Embodiment. It is a flowchart which shows an example of the operation plan making by the energy management system which concerns on one Embodiment. It is a graph which shows typically the relationship between the renewable energy ratio in grid power, and economy.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely explanatory examples. No.

(Composition of microgrid)
FIG. 1 is a schematic configuration diagram of a microgrid to be managed by the energy management system according to the embodiment. The microgrid 2 shown in FIG. 1 has a distribution line 5, and is connected to the grid (system) 4 via the interconnection point 3 by the distribution line 5. Further, the microgrid 2 is connected to the heat supply network 8 via the heat transfer line 9.

The grid 4 is a power system outside the region of the microgrid 2, which is managed by a power company different from the manager of the microgrid 2. The first renewable energy power generation device 6 is connected to the grid 4. Here, another power source (not shown) may be connected to the grid 4. That is, the grid 4 can supply the microgrid 2 (consumer) with electric power including the electric power generated by the first renewable energy power generation device 6 (electric power derived from the renewable energy). The ratio of power derived from renewable energy (hereinafter referred to as the renewable energy ratio) and the amount of power in the power purchased from the grid of the consumer are usually between the consumer and the power company that manages the grid. Specified in the contract.

The first renewable energy power generation device 6 is a device that generates electric power using renewable energy such as solar power, wind power, hydraulic power, and geothermal power, and may be, for example, a solar power generation device or a wind power generation device.

The microgrid 2 includes a thermal power generation facility 12 connected to a distribution line 5, a second renewable energy power generation device 14, and a power storage device 16, respectively.

The thermal power generation facility 12 is a facility including a thermal power generation device that converts the reaction heat energy of fuel such as oil, coal, natural gas, or waste into electric power. The thermal power generator is configured to be driven by a turbine (gas turbine, steam turbine, etc.) or engine (gas engine, etc.) configured to be driven via the reaction heat energy of the fuel, and the turbine or engine. It may include a generator and the like. The electric power generated by the thermal power generation device is sent to the distribution line 5.

The thermal power generation facility 12 may include a heat recovery device (boiler, water heater, etc.) that recovers the heat generated by the thermal power generation device. That is, the thermal power generation facility 12 may be a cogeneration facility capable of generating electric power and heat. As shown in FIG. 1, the electric power generated by the cogeneration facility (thermal power generation facility 12) is sent to the distribution line 5. Further, the heat generated by the cogeneration facility is sent to the heat transfer line 9 via a heat medium (described later).

The second renewable energy power generation device 14 is a renewable energy power generation device different from the first renewable energy power generation device 6. That is, the second renewable energy power generation device 14 and the first renewable energy power generation device 6 are separated from each other via the distribution line 5 and the interconnection point 3. The second renewable energy power generation device 14 is a device that generates electric power using renewable energy such as solar power, wind power, hydraulic power, and geothermal power, and may be, for example, a solar power generation device or a wind power generation device.

The power storage device 16 is configured to store surplus power among the power generated in the microgrid 2 (power generated by the thermal power generation facility 12 or the second renewable energy power generation device 14 or the like). The power storage device 16 may be configured to store power from the grid 4. Further, the power storage device 16 can discharge the stored power and send it to the distribution line 5.

The electric power of the microgrid 2 is supplied to the consumer 10 (for example, a factory) connected to the distribution line 5 via the distribution line 5. The electric power supplied to the consumer 10 via the distribution line 5 is the electric power generated in the microgrid 2 region, the electric power supplied from the grid 4, or a mixture of these.

The microgrid 2 further includes a heat pump 18 and a heat storage device 19, respectively, which are connected to the heat transfer line 9. The heat transfer line 9 is configured to transfer heat through a heat medium. The heat medium may be water, and may be hot water or cold water.

The heat pump 18 is configured to heat or cool the heat medium of the heat transfer line 9 to a desired temperature range. The components (compressor, etc.) of the heat pump 18 may be configured to be driven by the electric power supplied from the distribution line 5 of the microgrid 2. The heat medium (hot water, cold water, etc.) heated or cooled by the heat pump 18 is sent to the heat transfer line 9 or the heat storage device 19.

The heat storage device 19 is configured to store the heat energy of the heat medium (hot water, cold water, etc.) from the heat pump 18 and send the stored heat energy to the heat transfer line 9 via the heat medium.

The energy management system 20 is configured to manage electric power energy or thermal energy in the microgrid 2. The energy management system 20 may be configured to control each of the above-mentioned devices constituting the microgrid 2.

(Structure of energy management system)
FIG. 2 is a schematic configuration diagram of the energy management system 20 according to the embodiment. As shown in FIG. 2, the energy management system 20 includes an operation plan generation unit 24, an operation result calculation unit 30, an evaluation result generation unit 32, and a screen data generation unit 34. Further, the operation plan generation unit 24 includes a planned power purchase amount determination unit 25 and a load determination unit 26.

The energy management system 20 includes a processor (CPU, GPU, etc.) and a computer provided with a storage device (ROM, RAM, external storage device, etc.). Then, the processor operates (calculates, etc.) according to the instructions of the program loaded in the memory (main storage device), thereby realizing each of the above-mentioned functional units included in the energy management system 20. In other words, the above program is software for realizing each of the above functional units in a computer.

The operation plan generation unit 24 is configured to formulate an operation plan for the microgrid 2. This operation plan may be an operation plan for a specified period (for example, the next day (1 day)). In addition, based on this operation plan, the equipment (thermal power generation equipment 12, the second renewable energy power generation device 14, the power storage device 16, etc.) constituting the microgrid 2 may be operated, or may be operated. The power reception from the grid 4 or the power supply to the grid 4 may be controlled based on the above-mentioned operation plan.

The operation plan of the microgrid 2 includes the planned power purchase amount from the grid 4 (that is, the amount of electric power supplied from the grid 4 to the microgrid 2; hereinafter, also simply referred to as the planned power purchase amount). The above-mentioned operation plan includes the load (that is, the amount of power generation) of the thermal power generation device of the thermal power generation facility 12 constituting the microgrid 2 and / or the charge amount and the discharge amount of the power storage device 16 constituting the microgrid 2. You may. In addition, the above-mentioned operation plan includes the target utilization rate of renewable energy in the microgrid 2 (hereinafter, also referred to as the target utilization rate of renewable energy) and the regeneration of the power supplied from the grid 4 to the microgrid 2 (power purchase power). It may include a possible energy ratio (hereinafter, also referred to as a grid power renewable energy ratio).

The operation plan generation unit 24 generates power from a predicted value of power demand in the microgrid 2 (hereinafter, also referred to as a predicted value of power demand) and a renewable energy power generation device (second renewable energy power generation device 14 or the like) in the microgrid 2. It is configured to receive the predicted value of the amount (hereinafter, also referred to as the predicted value of the amount of renewable energy power generation), the above-mentioned target utilization rate of renewable energy, and the above-mentioned system power renewable energy ratio as inputs. Further, the operation plan generation unit 24 may be configured to receive a heat demand forecast value (hereinafter, also referred to as a heat demand forecast value) in the microgrid 2 as an input. The operation plan generation unit 24 may be configured to formulate the above-mentioned operation plan based on these inputs. The operation plan generation unit 24 may be configured to receive these inputs from the storage device or the input device. The storage device or input device may be provided at a remote location away from the microgrid 2.

The power demand forecast value may be calculated using the power demand actual measurement value in the microgrid 2 and the actual measurement value of the outside air temperature sensor, etc., or correlation analysis or machine learning based on past data is used. It may be derived from the prediction. The heat demand forecast value may be calculated using the heat demand actual measurement value in the microgrid 2 and the actual measurement value of the outside air temperature sensor, etc., or correlation analysis or machine learning based on past data is used. It may be derived from the prediction. The predicted value of the amount of renewable energy power generation may be calculated using weather forecast data or the like. The operation plan generation unit 24 may be configured to acquire the power demand forecast value, the heat demand forecast value, or the renewable energy power generation amount forecast value in the above-mentioned specified period (for example, the next day (1 day)).

The renewable energy target utilization rate is a value predetermined by the administrator of the microgrid 2 or the like, and is, for example, a period longer (for example, one year) than the above-mentioned specified period (for example, one day) which is the target period of the operation plan. This is the target utilization rate of renewable energy power generation that we aim to achieve through.

The grid power re-energy ratio is usually a value specified in a contract with an electric power company that manages the grid 4, and may be changed according to the contract, but is typically a fixed value.

In some embodiments, the operation plan generation unit 24 determines the power demand (eg, the above-mentioned renewable energy power generation amount prediction value) in the microgrid 2 based on the power generation amount prediction result of the second renewable energy power generation device (that is, the above-mentioned renewable energy power generation amount prediction value). , The above-mentioned power demand forecast value), and the target utilization rate of renewable energy in the microgrid 2 (that is, the above-mentioned renewable energy target utilization rate) can be achieved. It is configured to formulate an operation plan for grid 2.

As described above, the renewable energy ratio (system power renewable energy ratio) and the amount of power in the power purchased from the grid 4 are usually specified by the contract with the electric power company that manages the grid 4. According to the above-described embodiment, based on the predicted value of the amount of re-energy power generation in the microgrid 2, it is possible to satisfy the power demand in the microgrid 2 and to achieve the re-energy target utilization rate in the microgrid 2. As described above, an operation plan including the planned power purchase amount from the grid 4 is drafted. Therefore, by operating the microgrid 2 based on the operation plan formulated in this way, it becomes easier to achieve the renewable energy target utilization rate in the microgrid 2. As a result, it is possible to easily improve the renewable energy utilization rate (renewable energy utilization rate) in the total power consumption of the microgrid 2.

In one embodiment, the planned power purchase amount determination unit 25 of the operation plan generation unit 24 operates based on the power demand forecast value of the microgrid 2, the re-energy target utilization rate in the microgrid 2, and the grid power re-energy ratio. It is configured to calculate the planned power purchase amount from the grid 4, which is a part of the plan. In addition to these, the planned power purchase amount determination unit 25 is based on the predicted value of the amount of renewable energy power generation in the microgrid 2 and / or the load (or the amount of power generation) of the thermal power generation facility 12 calculated as described later. The planned power purchase amount may be calculated.

According to the above-described embodiment, the planned power purchase amount of the microgrid 2 is determined based on the power demand forecast value in the microgrid 2, the target re-energy utilization rate in the microgrid 2, and the grid power re-energy ratio from the grid 4. It can be calculated appropriately. Therefore, by operating the microgrid 2 based on the operation plan including the planned power purchase amount calculated in this way, it becomes easy to achieve the renewable energy target utilization rate in the microgrid 2.

In one embodiment, the operation plan generation unit 24 is configured to determine the load (or power generation amount) of the thermal power generation facility 12 of the microgrid 2 by the load determination unit 26. The load determination unit 26 may be configured to determine the load of the thermal power generation facility 12 based on the electric power demand (electric power demand forecast value) in the microgrid 2. Alternatively, when the thermal power generation facility 12 is a cogeneration facility, it may be configured to determine the load of the thermal power generation facility 12 based on the heat demand (heat demand forecast value) in the microgrid 2.

In one embodiment, the operation plan generation unit 24 charges and discharges the power storage device 16 based on the planned power purchase amount calculated as described above, the load of the thermal power generation facility 12, and the predicted value of the renewable energy power generation amount. It may be configured to calculate the quantity.

The operation record calculation unit 30 is configured to calculate the operation record of the microgrid 2 including the record of the amount of electric charge purchased from the grid 4. This operation result is from the start date of the period (for example, one year) aiming to achieve the renewable energy target utilization rate to the time when the operation plan generation unit 24 generates the operation plan of the grid 4 (one day (next day) which is the target period of the operation plan). It may be the operation results up to the day before)).

The above-mentioned operation results are the amount of power generated by the thermal power generation facility 12 in the microgrid 2 (actual value) and the amount of power generated by the second renewable energy power generation device 14 in the microgrid 2 (actual value) during the calculation target period of this operation result. ), And the amount of power purchased from the grid 4 (actual value) may be included, or the average value per day of these may be included. The operation result calculation unit 30 is configured to continuously or intermittently receive signals indicating actual values of load or power generation amount from the thermal power generation facility 12, the second renewable energy power generation device 14, and the like, and based on these signals. Therefore, it may be configured to calculate the above-mentioned operation results.

Further, the above-mentioned operation results may include a renewable energy utilization rate (hereinafter, also referred to as a renewable energy utilization rate) indicating the total power consumption in the microgrid 2 during the calculation target period of the operation results. The operation result calculation unit 30 has the amount of power generated by the thermal power generation facility 12 in the microgrid 2 (actual value), the amount of power generated by the second renewable energy power generation device 14 in the microgrid 2 (actual value), and the amount of power purchased from the grid 4 (actual value). The above-mentioned renewable energy utilization rate in the microgrid 2 may be calculated based on the actual value) and the grid power renewable energy ratio.

The evaluation result generation unit 32 is configured to generate an operation evaluation result indicating a difference between the operation result of the microgrid 2 and the operation plan.

In one embodiment, the operation evaluation result generated by the evaluation result generation unit 32 is the difference between the amount of renewable energy used in the operation plan of the microgrid 2 and the amount of renewable energy used in the operation results of the microgrid 2. It may indicate a magnitude relationship. Here, the amount of renewable energy used means the amount of power derived from renewable energy including the power generated by the first renewable energy power generation device 6 and the power generated by the second renewable energy power generation device 14. The amount of renewable energy used in the operation plan may be the product of the power demand of the microgrid 2 in the operation plan and the target utilization rate of renewable energy. Alternatively, the above-mentioned operation evaluation result may indicate the difference or magnitude relationship between the re-energy target utilization rate in the operation plan of the microgrid 2 and the re-energy utilization rate in the operation results of the microgrid 2.

The screen data generation unit 34 is configured to generate screen data for displaying the operation evaluation result generated by the evaluation result generation unit 32 on the display device 36 (display terminal). The screen data generated by the screen data generation unit 34 may indicate the difference or magnitude relationship between the amount of renewable energy used in the above-mentioned operation plan and the amount of renewable energy used in the above-mentioned operation results. Alternatively, it may indicate the difference or magnitude relationship between the renewable energy target utilization rate in the above-mentioned operation plan and the renewable energy utilization rate in the above-mentioned operation results.

Here, FIG. 3 is a diagram showing an example of a display image of screen data according to an embodiment. In the example shown in FIG. 3, the left side portion 41 of the display image 40 shows the magnitude relationship between the amount of renewable energy used in the above-mentioned operation plan and the amount of renewable energy used in the above-mentioned operation results. In the illustrated example, the above-mentioned magnitude relationship is shown by the illustration of the precision balance, and if the amount of renewable energy used in the operation results exceeds the operation plan, the plate on the right side will be on the lower side as shown in FIG. A pattern in which the balance is tilted is displayed, which indicates that the environmental performance is good. On the other hand, if the amount of renewable energy used in the operation results is lower than the operation plan, a pattern is displayed in which the balance is tilted so that the plate on the left side is on the lower side, which means that the economic performance is better than the environmental performance (that is,). , The amount of electric power derived from thermal power generation, which is excellent in cost merit, is relatively large in the electric power consumed by the microgrid 2.). If it is assumed that the economic efficiency will be improved by increasing the amount of renewable energy used, a symbol different from that shown in FIG. 3 will be used.

Further, in the right side portion 42 of the display image 40 shown in FIG. 3, a graph showing the time change of the predicted value in the operation plan of the power demand in a certain specified period (for example, one day) and the actual value in the operation result is shown. It is shown.

According to the above-described embodiment, the evaluation result generation unit 32 generates an operation evaluation result showing the difference between the operation result and the operation plan of the microgrid 2. Therefore, for example, an image showing the operation evaluation result is displayed. By displaying it on the device 36, it is possible to easily grasp the achievement status of the target utilization rate of renewable energy in the microgrid 2 based on the operation evaluation result. Alternatively, the operation evaluation result by the evaluation result generation unit 32 described above can be utilized for planning the operation plan of the microgrid 2. This makes it easier to achieve the target utilization rate of renewable energy in the microgrid 2.

In some embodiments, the planned power purchase amount determination unit 25 (operation plan generation unit 24) reduces the load of the thermal power generation facility 12 so as to increase the utilization rate of renewable energy in the microgrid 2 from the grid 4. It is configured to determine the planned power purchase amount so as to increase the power purchase amount.

For example, in one embodiment, the operation plan generation unit 24 is in the economic priority mode when the amount of renewable energy used in the operation results exceeds the operation plan based on the operation evaluation result by the evaluation result generation unit 32. When the operation plan is formulated so that the microgrid 2 is operated and the amount of renewable energy used in the operation results is lower than the operation plan, the load of the thermal power generation facility 12 is higher than that of the operation in the economic priority mode. It may be configured to formulate (or modify) an operation plan including the planned power purchase amount so that the microgrid 2 is operated in the environment priority mode in which the power purchase amount from the grid 4 is increased and the planned power purchase amount is increased.

Here, FIGS. 4 and 5 show the power source configuration of the electric power based on the operation plan of the microgrid 2 and the electric power demand in the microgrid 2 in the specified period (here, one day) which is the target period of the operation plan, respectively. It is a chart which shows an example. FIG. 4 shows the electric power in the operation plan in the above-mentioned economic priority mode, and FIG. 5 shows the electric power in the operation plan in the above-mentioned environment priority mode. In the charts of FIGS. 4 and 5, curve D indicates the power demand in the microgrid 2, reference numeral 102 is the power generated by the thermal power generation facility 12, 104 is the power purchased from the grid 4, and 106 is the second regeneration. The electric power generated by the renewable energy power generation device 14 and 108 indicate the electric power supplied from the power storage device 16. Further, reference numerals 110a and 110b are surplus electric power exceeding the demand among the electric power generated by the second renewable energy power generation device 14, and are electric power stored in the power storage device 16.

As shown in FIG. 4, in an example of operation in the economic priority mode, the thermal power generation facility 12 is operated with a constant load throughout the specified period (1 day), and the power generated by the thermal power generation facility 12 is micro. It is assumed that the base load is constant on the grid 2 (indicated by the straight line B). Further, during the time zone in which the second renewable energy 106 can generate electricity, the second renewable energy 106 is used to generate electricity to cover a part of the electric power demand D. Further, a part of the electric power demand D is covered by the discharge power from the electric power storage device 16 according to the electric power storage amount of the electric power storage device 16. Then, the rest of the electric power demand D is covered by the electric power purchased from the grid 4. The planned power purchase amount is determined so that a relatively large amount of power is purchased during peak hours of power demand D (for example, daytime) and a relatively small amount of power is purchased at other times (for example, nighttime). ..

On the other hand, in an example of operation in the environment priority mode, the thermal power generation facility 12 is placed on the above-mentioned base load (straight line B) only during a part of the specified period (1 day) (for example, the peak time of the power demand D). It operates with the same load as the above, and in other time zones, the load of the thermal power generation facility 12 is reduced to reduce the amount of power generated by the thermal power generation facility 12. As for the second renewable energy 106, as in the above-mentioned economic priority mode, power is generated by the second renewable energy 106 during the time when power generation is possible to cover a part of the power demand D. Further, a part of the electric power demand D is covered by the discharge power from the electric power storage device 16 according to the electric power storage amount of the electric power storage device 16. Then, the rest of the electric power demand D is covered by the electric power purchased from the grid 4. Here, the amount of power purchased in the peak time zone (for example, daytime) of the electric power demand D is the same as in the case of the economic priority mode, and the amount of power purchased is larger than that in the economic priority mode in other time zones (for example, nighttime). As a result, the planned amount of electricity purchased is determined. In this way, the utilization rate of renewable energy in the microgrid 2 can be increased by relatively reducing the amount of power generated by the thermal power generation facility 12 and relatively increasing the amount of power purchased from the grid 4.

Further, for example, in one embodiment, the planned power purchase amount determination unit 25 (operation plan generation unit 24) may determine the planned power purchase amount based on the market price of renewable energy (renewable energy market price). Specifically, for example, when the renewable energy market price falls below the specified value, the planned power purchase amount is determined so as to reduce the load of the thermal power generation facility 12 and increase the power purchase amount from the grid 4. May be good. The operation plan generation unit 24 may be configured to receive the data of the renewable energy market price from the storage device or the input device.

The renewable energy market price may fluctuate depending on the time of day. Here, FIG. 8 is a graph schematically showing the relationship between the renewable energy ratio and the economic efficiency in the grid power. The approximate straight line 110 in FIG. 8 shows the above-mentioned relationship in the normal time, and the approximate straight line 112 shows the above-mentioned relationship when the renewable energy market price falls from the normal time. As shown in FIG. 8, normally, the renewable energy ratio of the grid power and the economic efficiency (or the low price of the power purchased from the grid 2) are inversely proportional (see the approximate straight line 110), but the time zone. Depending on the market, the renewable energy market price may fall due to excessive market introduction of renewable energy, and as shown by the approximate straight line 112 in the figure, the one with a certain high renewable energy ratio (in FIG. 7, the renewable energy ratio is r ₀ or more). (When) Economical efficiency may increase.

Therefore, when the renewable energy market price falls below the specified value, the amount of power generated by the thermal power generation facility 12 is relatively small, and the amount of power purchased from the grid 4 is relatively large, so that the cost in the microgrid 2 is reduced. It is possible to increase the utilization rate of renewable energy while trying to reduce it.

In the above-described embodiment, the load of the thermal power generation facility 12 is reduced so that the utilization rate of the renewable energy in the microgrid 2 increases, for example, when the operation in the environment priority mode or the renewable energy market price falls. An operation plan for the microgrid 2 including the planned power purchase amount is formulated so as to increase the power purchase amount from. Therefore, for example, when the utilization rate of renewable energy in the microgrid 2 is lower than the target utilization rate, the above-mentioned target utilization rate can be further achieved by performing the operation based on the operation plan formulated as described above. Can be made easier. As a result, it is possible to easily improve the renewable energy utilization rate in the power consumption of the microgrid 2.

In one embodiment, the planned power purchase amount determination unit 25 (operation plan generation unit 24) determines the planned power purchase amount from the grid 4 so that the amount of power supplied from the power storage device 16 to the microgrid 2 falls within the specified range. Configured to determine.

Since the amount of power generated by renewable energy is affected by the weather and the like, the prediction accuracy of the amount of power generation is usually lower than 100%, and the amount of power generated by renewable energy in the microgrid 2 is lower than the prediction, so that the power storage device 16 is supplied. The amount of electricity stored may be less than expected. In this regard, according to the above configuration, the amount of electric power supplied from the power storage device 16 constituting the microgrid 2 is within the specified range (for example, 80% or more of the total capacity of the power storage device is supplied to the microgrid 2). Since the planned power purchase amount is determined so as to be within the range that does not occur), the risk of interrupting the power demand D in the microgrid 2 can be eliminated by purchasing power according to this determination. Therefore, even when the amount of renewable energy power generation in the microgrid 2 is lower than expected, the electric power of the power storage device 16 can be used as the power supply to the microgrid 2. Therefore, it becomes easy to achieve the target utilization rate of renewable energy while appropriately satisfying the electric power demand in the microgrid 2.

In one embodiment, the operation plan generation unit 24 covers at least a part of the power generated by the second renewable energy power generation device 14 (for example, FIG. 4 or) while covering a part of the power demand by the power purchased from the grid 4. The portions of reference numerals 110a and 110b shown in FIG. 5) may be configured to store power in the power storage device 16.

In this case, it becomes easy to maintain the amount of electricity stored in the electricity storage device 16 within the above-mentioned specified range. Therefore, it becomes easy to achieve the target utilization rate of renewable energy while appropriately satisfying the electric power demand in the microgrid 2.

In one embodiment, the thermal power generation facility 12 is a cogeneration facility, and the load determination unit 26 is configured to determine the load of the thermal power generation facility 12 (cogeneration facility) based on the heat demand in the microgrid 2. .. Then, the planned power purchase amount determination unit 25 (operation plan generation unit 24) covers at least a part of the power shortage amount for the power demand of the power obtained by operating the thermal power generation facility 12 with the load determined as described above. It is configured to calculate the planned power purchase amount from the grid 4, which is possible and can achieve the renewable energy target utilization rate.

Here, FIG. 6 is a flowchart showing an example of operation plan planning by the operation plan generation unit 24 according to the above-described embodiment. In the embodiment shown in FIG. 6, first, the load determination unit 26 determines the load of the cogeneration facility based on the heat demand in the microgrid 2 (S20). Next, it is determined whether or not the heat supply (heat supply heat) of the microgrid 2 and the heat demand are balanced (that is, whether there is excess or deficiency) by operating the cogeneration facility with the load determined in S20 (that is, whether there is excess or deficiency). S40). Here, "balanced" means that the heat supply and the heat demand are equal, but if the difference is within a preset allowable range, it may be determined to be "balanced". ..

When it is determined in step S40 that the heat supply and the heat demand of the microgrid 2 are balanced (there is no excess or deficiency) (Yes in S40), the process proceeds to the next step S60 (described later).

On the other hand, in step S40, it is determined that the heat supply and heat demand of the microgrid 2 are not balanced (there is an excess or deficiency) (No in S40), and the heat demand in the microgrid 2 is relative to the heat supply. If there is a shortage (Yes in S42), heat is supplied to the microgrid 2 by the heat pump 18 (S44), and the process proceeds to the next step S60. In step S40, it is determined that the heat supply and heat demand of the microgrid 2 are not balanced (there is an excess or deficiency) (No in S40), and the heat supply in the microgrid 2 exceeds the heat demand. In the case (No in S42), excess heat is stored in the heat storage device 19. As a result, it is determined whether or not the surplus heat is less than the heat storage capacity of the heat storage device 19 (S48), and if the surplus heat is less than the heat storage capacity (Yes in S48), the process proceeds to the next step S60. On the other hand, when the excess heat is equal to or larger than the heat storage capacity (No in S48), the load of the cogeneration equipment is adjusted so that the amount of heat generated by the cogeneration equipment is reduced (S49), and the process returns to step S40.

In step S60, it is determined whether or not the power supply and the power demand of the microgrid 2 are balanced (that is, whether there is excess or deficiency) by operating the cogeneration facility (S60). When it is determined in step S60 that the power supply and the power demand of the microgrid 2 are balanced (there is no excess or deficiency) (Yes in S60), this flow ends. That is, the planned power purchase amount is determined so that the power is not received (purchased) from the grid 4. Here, "balanced" means that the power supply and the power demand are equal, but if the difference is within a preset allowable range, it may be determined to be "balanced". ..

On the other hand, in step S60, it is determined that the power supply and the power demand of the microgrid 2 are not balanced (there is an excess or deficiency) (No in S60), and the power demand in the microgrid 2 is relative to the power supply. If there is a shortage (Yes in S62), the planned power purchase amount is determined so as to receive the power (power purchase power) from the grid 4 (step S64), and this flow ends. In step S60, it is determined that the power supply and the power demand of the microgrid 2 are not balanced (there is an excess or deficiency) (No in S60), and the power supply in the microgrid 2 exceeds the power demand. In the case (No in S62), the load of the cogeneration facility and / or the second renewable energy power generation facility is adjusted so that the amount of power generated by the cogeneration facility and / or the second renewable energy power generation facility is reduced (S66). , Return to step S40.

According to the above-described embodiment, the power shortage for the power demand of the power obtained by the operation of the thermal power generation facility 12 (cogeneration facility) at the load determined based on the heat demand in the microgrid 2 is covered. Since the planned power purchase amount from the grid 4 is calculated, it becomes easy to achieve the target utilization rate of renewable energy in the microgrid 2 while satisfying the heat demand in the microgrid 2. As a result, it is possible to easily improve the renewable energy utilization rate in the power consumption of the microgrid 2.

In one embodiment, the thermal power generation facility 12 is a cogeneration facility, and the load determination unit 26 loads the thermal power generation facility 12 (cogeneration facility) based on the planned power purchase amount determined by the planned power purchase amount determination unit 25. Is configured to determine. The load determination unit 26 may be configured to determine the load of the thermal power generation facility 12 (cogeneration facility) based on the amount of electricity stored in the power storage device 16 in addition to the planned amount of electricity purchased. The load determination unit 26 may be configured to change the load of the thermal power generation facility 12 according to the planned power purchase amount and / or the change of the power storage amount of the power storage device 16.

Here, FIG. 7 is a flowchart showing an example of operation plan planning by the operation plan generation unit 24 according to the above-described embodiment. In the embodiment shown in FIG. 7, first, the planned power purchase amount determination unit 25 determines the grid 4 based on the power demand forecast value of the microgrid 2, the re-energy target utilization rate in the microgrid 2, and the grid power re-energy ratio. Calculate (determine) the planned power purchase amount from (S70). That is, in step S70, the planned power purchase amount based on the power demand forecast value of the microgrid 2 and the grid power re-energy ratio so as to satisfy the re-energy utilization rate set to reach the above-mentioned re-energy target utilization rate. Is calculated.

Next, the load determination unit 26 determines the load of the cogeneration facility based on the planned power purchase amount determined in step S70 so as to satisfy the demand power in the microgrid 2 (S72). In step S72, the load determination unit 26 may determine the load of the cogeneration facility based on the amount of electricity stored in the electricity storage device 16 in addition to the planned amount of electricity purchased.

Next, it is determined whether or not the heat supply (heat supply heat) of the microgrid 2 and the heat demand are balanced (that is, whether there is excess or deficiency) by operating the cogeneration facility with the load determined in step S72. (S74). When it is determined in step S74 that the heat supply and the heat demand of the microgrid 2 are balanced (there is no excess or deficiency) (Yes in S74), the process proceeds to the next step S82 (described later). Here, "balanced" means that the heat supply and the heat demand are equal, but if the difference is within a preset allowable range, it may be determined to be "balanced". ..

On the other hand, in step S74, it is determined that the heat supply and heat demand of the microgrid 2 are not balanced (there is an excess or deficiency) (No in S74), and the heat demand in the microgrid 2 is relative to the heat supply. If there is a shortage (Yes in S76), heat is supplied to the microgrid 2 by the heat pump 18 (S78), and the process proceeds to the next step S82. In step S74, it is determined that the heat supply and heat demand of the microgrid 2 are not balanced (there is an excess or deficiency) (No in S74), and the heat supply in the microgrid 2 exceeds the heat demand. In the case (No in S76), excess heat is stored in the heat storage device 19, and the process proceeds to the next step S82.

In step S82, it is determined whether or not the renewable energy utilization rate in the demand power of the microgrid 2 has been changed. For example, the renewable energy utilization rate may be changed to a higher value in order to achieve the renewable energy target utilization rate in the microgrid 2. In this way, when the re-energy utilization rate in the microgrid 2 is changed (Yes in S82), the process returns to step S70, the planned power purchase amount is determined again so as to satisfy the changed re-energy utilization rate, and the changed power purchase amount is determined again. Subsequent steps (steps S72 to) are repeatedly executed based on the planned power purchase amount.

(Example of calculation method of planned power purchase amount)
Hereinafter, some specific examples of the method of calculating the planned power purchase amount by the operation plan generation unit 24 will be described.

(A) When maximizing the use of renewable energy generated power in the microgrid 2 If the power supply-demand balance in the microgrid 2 and the renewable energy target utilization rate Xr * in the microgrid 2 are mathematically expressed, the following equation (1) ( 2) is obtained.
Pd * -Pr * -Pth = Pg (1)
Pg = (Xr * × Pd * -Pr *) / xgr (2)
In the above formula, Pd * is the planned power demand value in the microgrid 2, Pg is the planned power purchase amount from the grid 4, Pr * is the predicted value of the renewable energy power generation amount in the microgrid 2, and Pth is the microgrid. 2 is the amount of power generated by the thermal power generation facility 12 (cogeneration facility, etc.) (thermal power generation amount), Xr * is the target utilization rate of renewable energy in the microgrid 2, and xgr is the grid power in the power purchased from the grid 4. It is the renewable energy ratio. By solving the simultaneous equations (1) and (2) above for two variables (Pg, Pth), Pg that satisfies the power supply and demand balance and also satisfies the renewable energy target utilization rate Xr * can be obtained.

(B) Correction of calculated planned power purchase power When daily operation is performed based on the calculated operation plan (Pg, Pth), the re-energy target utilization rate Xr * and the actual re-energy utilization rate Xr in the microgrid 2 are performed. There is a possibility that the deviation ΔXr from the above will increase. When ΔXr reaches an unacceptable level, it may be necessary to shift to operation in the environment priority mode and revise the operation plan based on the solutions (Pg, Pth) of the simultaneous equations in (1) and (2) above. be.

For example, by adding a correction amount according to the magnitude of ΔXr to Pg,
Pg'= Pg (1 + ΔXr / Xr *) (3)
Pth'= Pth- (Pg'-Pg) (4)
Operate with (Pg', Pth') obtained by modifying. In the above formula, Pg'is the modified planned power purchase amount, and Pth'is the modified thermal power generation amount.

(C) Combined use of power storage device 16 (battery) When the power storage device 16 is used in combination, the planned power demand value Pd * and the planned power purchase amount Pg can be expressed by the following equations (5) and (6).
Pd * -Pr * -Pth-Pbat = Pg (5)
Pg = (Xr * × Pd * -Pr * -Pbat) / xgr (6)
In the above formula, Pbat is the amount of charge / discharge from the power storage device 16. It should be noted that Pr * and Pbat are electric powers that do not overlap with each other. That is, Pr * indicates the predicted value of the amount of re-energy power generation at a certain time point, and Pbat indicates the amount of discharge based on the electric power stored in the power storage device 16 before the time point.
It should be noted that the electric power stored in the power storage device 16 is considered to be derived from renewable energy, and "Pbat" is considered as the renewable energy component in the molecule of the formula (6).

Here, the charge / discharge amount Pbat of the power storage device 16 is treated as a variable parameter under the constraint that the charge / discharge amount SOC of the power storage device 16 does not exceed the limit value SOClim.
That is, Pbat_lim that satisfies the following equation (7) is calculated, and Pbat is variable within a range that does not exceed Pbat_lim.
Pbat_lim = (SOClim-SOC (t)) / Δt (7)

By solving the simultaneous equations of (5) and (6) above for two variables (Pg, Pbat) on the premise that the thermal power generation amount Pth is the base load in principle, the power supply-supply balance is satisfied and the target utilization rate of renewable energy is satisfied. The planned power purchase amount Pg that satisfies Xr * can be obtained.

(D) When the thermal power generation facility is a cogeneration facility When the thermal power generation facility 12 is a cogeneration facility, the load Hc of the thermal power generation facility 12 (cogeneration facility) is represented by the following equation (8).
Hc = Hd * -Hg (8)
In the above formula, Hd * is the heat demand planned value, and Hg is the heat supplied from the heat supply network 8.
From the above equation (8), the load Hc of the thermal power generation facility 12 (cogeneration facility) that satisfies the heat demand Hd * is calculated.

Since the load Hc of the thermal power generation facility 12 (cogeneration facility) correlates with the thermal power generation amount Pth which is the electrical output of the thermal power generation facility 12, Pth can be obtained by the following equation (9).
Pth = f (Hc) (9)
The following equations (10) and (11) can be obtained by formulating the power supply-demand balance and the renewable energy target utilization rate Xr *.
Pd * -Pr * -Pth-Pbat = Pg (10)
Pg = (Xr * × Pd * -Pr * -Pbat) / xgr (11)

Since Pth is known by the above equation (9), by solving the simultaneous equations of the above (10) and (11) for two variables (Pg, Pbat), the heat demand and the power supply and demand balance are satisfied, and the renewable energy target is achieved. The planned power purchase amount Pg that satisfies the utilization rate Xr * can be obtained.
As described in (c) above, the charge / discharge amount Pbat of the power storage device 16 is treated as a variable parameter under the constraint that the power storage amount SOC of the power storage device 16 does not exceed the limit value SOClim.

The contents described in each of the above embodiments are grasped as follows, for example.

(1) The energy management system (20) according to at least one embodiment of the present invention is
A second renewable energy power generation device that is connected to a grid (4) to which at least the first renewable energy power generation device (6) is connected and is different from the thermal power generation facility (12) and the first renewable energy power generation device. It is an energy management system for performing energy management of the microgrid (2) including (14).
Based on the power generation amount prediction result of the second renewable energy power generation device, the planned power purchase amount from the grid that can satisfy the power demand in the microgrid and achieve the target utilization rate of the renewable energy in the microgrid. It is provided with an operation plan generation unit (24) for formulating an operation plan of the microgrid including the above.

The ratio of renewable energy in the electricity purchased from the grid is usually specified in the contract with the electric power company that manages the grid. According to the configuration of (1) above, the target of renewable energy in the microgrid is to be satisfied with the power demand in the microgrid based on the power generation amount prediction by the second renewable energy power generation device constituting the microgrid. Develop an operation plan that includes the planned amount of electricity purchased from the grid so that the utilization rate can be achieved. Therefore, by operating the microgrid based on the operation plan formulated in this way, it becomes easier to achieve the target utilization rate of renewable energy in the microgrid. As a result, it is possible to easily improve the renewable energy utilization rate in terms of power consumption in the microgrid.

(2) In some embodiments, in the configuration of (1) above,
The energy management system is
It is provided with an evaluation result generation unit (32) for generating an operation evaluation result showing a difference between the operation result of the microgrid and the operation plan.

According to the configuration of (2) above, the operation evaluation result showing the difference between the operation result of the microgrid and the operation plan is generated. Therefore, for example, the renewable energy in the microgrid is generated based on the operation evaluation result. It is possible to grasp the achievement status of the target utilization rate of the above, and to utilize the operation evaluation result for the formulation of the operation plan of the microgrid. Therefore, it is possible to more easily achieve the target utilization rate of renewable energy in the microgrid.

(3) In some embodiments, in the configuration of (2) above,
The energy management system is
Based on the operation evaluation result, the screen data of the display terminal (36) showing the magnitude relationship between the amount of the renewable energy used in the operation plan of the microgrid and the amount of the renewable energy used in the operation result is displayed. Screen data generation unit for generation (34)
To prepare for.

According to the configuration of (3) above, based on the operation evaluation result, screen data showing the magnitude relationship between the amount of renewable energy used in the operation plan of the microgrid and the amount of renewable energy used in the operation results is generated. .. Therefore, by displaying the screen data on the display terminal, it is possible to grasp the achievement status of the target utilization rate of renewable energy in the microgrid, or to formulate an operation plan of the microgrid in consideration of the achievement status. Can be used for. Therefore, it is possible to more easily achieve the target utilization rate of renewable energy in the microgrid.

(4) In some embodiments, in any of the configurations (1) to (3) above,
The operation plan generation unit is based on the predicted value of the power demand of the microgrid, the target utilization rate of the renewable energy in the microgrid, and the renewable energy ratio in the power supplied from the grid. It is configured to calculate the planned power purchase amount.

According to the configuration of (4) above, the plan of the microgrid is based on the predicted value of the power demand in the microgrid, the target utilization rate of the renewable energy in the microgrid, and the ratio of the renewable energy in the power supplied from the grid. The amount of electricity purchased can be calculated appropriately. Therefore, by operating the microgrid based on the operation plan including the planned power purchase amount calculated in this way, it becomes easy to achieve the target utilization rate of renewable energy in the microgrid. As a result, it is possible to easily improve the renewable energy utilization rate in terms of power consumption in the microgrid.

(5) In some embodiments, in any of the configurations (1) to (4) above,
The operation plan generation unit is configured to determine the planned power purchase amount so as to reduce the load of the thermal power generation facility and increase the power purchase amount from the grid so that the utilization rate of the renewable energy in the microgrid increases.

According to the configuration of (5) above, the microgrid including the planned power purchase amount is used to reduce the load of the thermal power generation equipment and increase the power purchase amount from the grid so that the utilization rate of renewable energy in the microgrid increases. An operation plan is drafted. Therefore, for example, when the utilization rate of renewable energy in the microgrid is lower than the target utilization rate, the above-mentioned target utilization rate can be further achieved by performing the operation based on the operation plan formulated as described above. Can be made easier.

(6) In some embodiments, in any of the configurations (1) to (5) above,
The thermal power generation facility is a cogeneration facility capable of supplying electric power and heat to the microgrid.
The energy management system is
A load determination unit (26) configured to determine the load of the thermal power generation facility based on the heat demand in the microgrid is provided.
The operation plan generation unit can cover at least a part of the power shortage for the power demand of the power obtained by operating the thermal power generation facility under the load, and can achieve the target utilization rate. It is configured to calculate the planned power purchase amount from the grid.

According to the configuration of (6) above, a planned purchase from the grid is made so as to cover the power shortage for the power demand of the power obtained by operating the thermal power generation facility with the load determined based on the heat demand in the microgrid. Since the amount of electricity is calculated, it becomes easier to achieve the target utilization rate of renewable energy in the microgrid while satisfying the heat demand in the microgrid. As a result, it is possible to easily improve the renewable energy utilization rate in terms of power consumption in the microgrid.

(7) In some embodiments, in any of the configurations (1) to (6) above,
The operation plan generation device has the planned power purchase amount from the grid so that the amount of power supplied to the microgrid from the power storage device (16) for storing surplus power in the microgrid is within a specified range. Is configured to determine.

Since the amount of power generated by renewable energy is affected by the weather, etc., the prediction accuracy of the amount of power generation is usually lower than 100%, and the amount of power generated by renewable energy on the microgrid is lower than the prediction, so that the amount of power stored in the power storage device May be less than expected. In this regard, according to the above configuration, the amount of power supplied from the power storage device constituting the microgrid is within the specified range (for example, within the range in which 80% or more of the total capacity of the power storage device is not supplied to the microgrid. ), The planned amount of electricity purchased is determined, so by purchasing electricity according to this decision, the risk of interrupting the electricity demand in the microgrid can be eliminated. Therefore, even when the amount of renewable energy power generation in the microgrid is lower than expected, the power of the power storage device can be used as the power supply to the microgrid. Therefore, it becomes easier to achieve the target utilization rate of renewable energy while appropriately satisfying the power demand in the microgrid.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and includes a modification of the above-mentioned embodiment and a combination of these embodiments as appropriate.

In the present specification, an expression representing a relative or absolute arrangement such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial". Strictly represents not only such an arrangement, but also a tolerance or a state of relative displacement at an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
Further, in the present specification, the expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also within a range in which the same effect can be obtained. , The shape including the uneven portion, the chamfered portion, etc. shall also be represented.
Further, in the present specification, the expression "comprising", "including", or "having" one component is not an exclusive expression excluding the existence of another component.

2 Microgrid 3 Interconnection points 4 Grid 5 Distribution line 6 1st renewable energy power generation device 8 Heat supply network 9 Heat transfer line 10 Consumer 12 Thermal power generation equipment 14 2nd renewable energy power generation device 16 Power storage device 18 Heat pump 19 Heat storage Device 20 Energy management system 24 Operation plan generation unit 25 Planned power purchase amount determination unit 26 Load determination unit 30 Operation result calculation unit 32 Evaluation result generation unit 34 Screen data generation unit 36 Display device 40 Display image 41 Left side part 42 Right side parts 101a, 101b Surplus power generated by the second renewable energy power generator 102 Power generated by the thermal power generation facility 104 Purchased power 106 Power generated by the second renewable energy 108 Discharge power of the power storage device B Base load D Power demand

Claims (7)

Energy management of a microgrid that is connected to a grid to which at least the first renewable energy power generation device is connected and includes a thermal power generation facility and a second renewable energy power generation device different from the first renewable energy power generation device. It is an energy management system for
Based on the power generation amount prediction result of the second renewable energy power generation device, the planned power purchase amount from the grid that can satisfy the power demand in the microgrid and achieve the target utilization rate of the renewable energy in the microgrid. An energy management system including an operation plan generation unit for formulating an operation plan for the microgrid including. The energy management system according to claim 1, further comprising an evaluation result generation unit for generating an operation evaluation result indicating a difference between the operation results of the microgrid and the operation plan. In order to generate screen data of a display terminal showing a magnitude relationship between the amount of renewable energy used in the operation plan of the microgrid and the amount of renewable energy used in the operation results based on the operation evaluation result. The energy management system according to claim 2, further comprising a screen data generation unit of the above. The operation plan generation unit is based on the predicted value of the power demand of the microgrid, the target utilization rate of the renewable energy in the microgrid, and the renewable energy ratio in the power supplied from the grid. The energy management system according to any one of claims 1 to 3, which is configured to calculate the planned power purchase amount. The operation plan generation unit reduces the load of the thermal power generation facility so that the utilization rate of renewable energy in the microgrid increases, and the planned purchase amount from the grid increases from the planned power purchase amount. The energy management system according to any one of claims 1 to 4, which is configured to determine the amount of electricity. The thermal power generation facility is a cogeneration facility capable of supplying electric power and heat to the microgrid.
A load determination unit configured to determine the load of the thermal power generation facility based on the heat demand in the microgrid is provided.
The operation plan generation unit can cover at least a part of the power shortage for the power demand of the power obtained by operating the thermal power generation facility under the load, and can achieve the target utilization rate. The energy management system according to any one of claims 1 to 5, which is configured to calculate the planned power purchase amount from the grid. The operation plan generation unit is configured to determine the planned power purchase amount from the grid so that the amount of power supplied from the power storage device for storing surplus power to the microgrid is within a specified range. The energy management system according to any one of claims 1 to 6.

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