JP2023026234A - Energy storage system and method for controlling the same - Google Patents

Abstract

To enhance energy utilization efficiency.SOLUTION: An energy storage system includes: an electrical energy conversion storage device; a material generation storage device; a hydrogen generation device; a hydrogen storage device; a hydrogen energy supply device; a heating/cooling device; and a control device. The control device includes: a power generation prediction section for predicting an amount of power generation by renewable energy; a demand prediction section for predicting an amount of demand power; an external state prediction section for predicting an external state; a setting section for setting a parameter of an evaluation value; a plan creation section for creating an operation plan based on the amount of power generation, the amount of demand power, the external state, and the evaluation value; and an operation section for operating the electric energy conversion storage device, the material generation storage device, the hydrogen generation device, the hydrogen storage device, the hydrogen energy supply device, and the heating/cooling device based on the operation plan.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to energy storage systems and methods of controlling energy storage systems.

Measures against global warming due to the depletion of fossil fuels and the release of carbon dioxide into the atmosphere are being promoted in various industrial fields. Renewable energy represented by sunlight, wind power, geothermal heat, etc. is used as an energy source that does not depend on fossil fuels. Renewable energy has time fluctuations. For this reason, energy storage systems are used to store energy generated by renewable energy in order to adapt renewable energy to the time and place of use.

Energy storage systems are known to store short-term energy as electrical energy and long-term energy storage as hydrogen. This energy storage system uses, for example, an electrolyzer to generate hydrogen from electrical energy and water, stores the generated hydrogen in a hydrogen storage device, and converts the stored hydrogen to electrical energy using, for example, a fuel cell. converted to and supplied.

For example, when using photovoltaic power generation as renewable energy, the electrolytic device operates during the daytime with sunlight, but stops at night when there is no sunlight. When the electrolyser is shut down, the temperature of the water used in the electrolyser drops, and if the water temperature drops below freezing, the water can freeze. In addition, when the temperature of water drops in the electrolyzer, the energy utilization efficiency may drop.

Japanese Patent No. 6005503 Japanese Patent Application Laid-Open No. 2003-282122

SUMMARY OF THE INVENTION It is an object of the present invention to provide an energy storage system and a method of controlling the energy storage system that can improve energy utilization efficiency.

An energy storage system according to an embodiment includes an electrical energy conversion storage device that converts renewable energy into electrical energy and stores it, and a raw material that is generated and stored from the electrical energy stored in the electrical energy conversion storage device and natural substances. A raw material generation and storage device, a hydrogen generation device for generating hydrogen from the electrical energy stored in the electric energy conversion and storage device and the raw material stored in the raw material generation and storage device, and hydrogen for storing the hydrogen generated by the hydrogen generation device A storage device, a hydrogen energy supply device that converts the chemical energy of hydrogen stored in the hydrogen storage device into electrical energy and supplies it, an electrical energy conversion storage device, a raw material generation storage device, a hydrogen generation device, a hydrogen storage device, and hydrogen A heating and cooling device that heats or cools each device by circulating a heat medium in an energy supply device, an electric energy conversion storage device, a raw material generation storage device, a hydrogen generation device, a hydrogen storage device, a hydrogen energy supply device, and a heating and cooling a controller for controlling the device. The control device includes a power generation prediction unit that predicts the amount of power generated by renewable energy, a demand prediction unit that predicts the amount of power demand, an external state prediction unit that predicts an external state, and a setting unit that sets parameters for evaluation values. , the power generation amount, the demand power amount, the external state, and the evaluation value, a plan creation unit that creates an operation plan; an operating unit for operating the storage device, the hydrogen energy supply device, and the heating and cooling device.

In addition, in the control method of the energy storage system according to the embodiment, the energy storage system includes an electrical energy conversion storage device that converts renewable energy into electrical energy and stores it, and the electrical energy stored in the electrical energy conversion storage device and the natural energy. a raw material generation and storage device for generating and storing a raw material from the substance of the above, a hydrogen generation device for generating hydrogen from the electrical energy stored in the electrical energy conversion and storage device and the raw material stored in the raw material generation and storage device, and hydrogen generation A hydrogen storage device for storing hydrogen generated by the device, a hydrogen energy supply device for converting the chemical energy of the hydrogen stored in the hydrogen storage device into electrical energy and supplying it, an electrical energy conversion storage device, a raw material generation storage device, a heating and cooling device for heating or cooling each device by circulating a heat medium in the hydrogen generator, the hydrogen storage device, and the hydrogen energy supply device. A control method for an energy storage system according to an embodiment includes a power generation prediction step of predicting the amount of power generated by renewable energy, a demand prediction step of predicting the amount of power demand, an external state prediction step of predicting an external state, and an evaluation value a setting step of setting the parameters of, a planning step of creating an operation plan based on the power generation amount, the demand power amount, the external state, and the evaluation value, and an electric energy conversion storage device and raw material generation based on the operation plan and an operation step of operating the storage device, the hydrogen generator, the hydrogen storage device, the hydrogen energy supply device, and the heating and cooling device.

According to the present embodiment, energy utilization efficiency can be improved.

FIG. 1 is a configuration diagram of an energy storage system according to an embodiment. FIG. 2 is a configuration diagram of the control device of FIG. FIG. 3 is a diagram showing an example of the amount of power generated by renewable energy predicted by the power generation prediction unit in FIG. 2 . FIG. 4 is a diagram showing an example of power demand predicted by the demand prediction unit in FIG. 2 . FIG. 5 is a diagram showing an example of temperatures predicted by the external state prediction unit in FIG. FIG. 6 is a diagram showing an example of the surplus power amount of renewable energy predicted by the plan creating unit in FIG. 2 . FIG. 7 is a diagram showing an example of the temperature of the raw material water stored in the raw material generation storage device predicted by the planning section of FIG.

An energy storage system according to an embodiment of the present invention will be described below with reference to the drawings.

(First embodiment)
First, an energy storage system according to a first embodiment will be described with reference to FIGS. 1 to 7. FIG.

As shown in FIG. 1, an energy storage system 1 according to the present embodiment includes an electrical energy conversion storage device 10, a raw material generation storage device 20, a hydrogen generation device 30, a hydrogen storage device 40, and a hydrogen energy supply device 50. , a heating and cooling device 60 , and a control device 70 .

The electrical energy conversion and storage device 10 is configured to convert renewable energy E1 into electrical energy E2 and store it. Renewable energy E1 is, for example, sunlight, wind power, and geothermal power. When the renewable energy E1 is sunlight, the renewable energy E1 which is sunlight is converted into electric energy E2 by photovoltaic power generation (PV). When the renewable energy E1 is wind power, the wind power renewable energy E1 is converted into electrical energy E2 by a wind farm (WF). When the renewable energy E1 is geothermal, the geothermal renewable energy E1 is converted into electrical energy E2 by binary power generation. The converted electrical energy E2 is stored, for example, in a secondary battery. The electrical energy E2 stored in the electrical energy conversion storage device 10 can be supplied to the raw material generation storage device 20 and the hydrogen generation device 30 .

The raw material generation and storage device 20 is configured to generate and store a raw material M2 from the electrical energy E1 stored in the electrical energy conversion and storage device 10 and the natural material M1. The natural substance M1 is, for example, a substance existing in the earth or the atmosphere. The raw material M2 is, for example, water, nitrogen, or oxygen. When the raw material M2 is water, the natural substance M1 is, for example, surface water or groundwater. In this case, the raw material production and storage device 20 produces the raw material M2 by separating water from surface water or groundwater by membrane separation or distillation. If the raw material M2 is nitrogen or oxygen, the natural substance M1 is, for example, air. In this case, the raw material production and storage device 20 produces the raw material M2 by separating nitrogen and oxygen from the atmosphere by cryogenic separation or membrane separation. The raw material M2 stored in the raw material generation and storage device 20 can be supplied to the hydrogen generator 30 .

The hydrogen generator 30 is configured to generate hydrogen H2 from the electrical energy E2 stored in the electrical energy conversion and storage device 10 and the raw material M2 stored in the raw material generation and storage device 20 . The hydrogen generator 30 is composed of, for example, an electrolytic device and its auxiliary equipment, and generates hydrogen H2 and oxygen O2 from electric energy E2 and raw material M2. An electrolytic device has, for example, electrodes including an anode and a cathode, and an electrolyte including a solid polymer membrane, a solid oxide membrane, or the like. Auxiliary machines include, for example, a heat exchange device, a pressurization device, a separation and purification device, a storage pretreatment device, and the like. The heat exchange device cools the electrolytic device by heat exchange with the heat medium, and cools the hydrogen H2 by heat exchange with the heat medium. The pressurizing device pressurizes the raw material M2 and the electrolytic device. The separation and purification device separates impurities, moisture, etc. from the hydrogen H2 and purifies the hydrogen H2. This separation includes membrane separation, adsorptive regeneration, cryogenic, etc., and uses energy. The storage pretreatment device treats the hydrogen H2 so as to bring it into conditions (three states, pressure, temperature) suitable for storage. This process involves compressing the hydrogen H2 to a higher pressure and cooling the hydrogen H2 to a liquid so that the storage volume is small, and uses energy. Compression includes a method of mechanically compressing with a compressor or the like and a method of chemically compressing with a pressurized electrolytic device or the like. Liquefaction involves cooling a gas below its critical point to a liquid. The oxygen O2 generated by the hydrogen generator 30 may be released to the outside. The hydrogen H2 generated by the hydrogen generator 30 can be supplied to the hydrogen storage device 40. FIG.

The hydrogen storage device 40 is configured to store the hydrogen H2 produced by the hydrogen generator 30 . The hydrogen storage device 40 stores hydrogen H2 under conditions (three states, pressure, temperature) suitable for storing hydrogen H2. The hydrogen storage device 40 can, for example, store the hydrogen H2 as liquid hydrogen, compress the hydrogen H2 at a high pressure and store it, or store the hydrogen H2 after storing it in a hydrogen storage alloy. Also, when moving hydrogen H2 from a generation site to a usage site, hydrogen H2 can be stored in the hydrogen storage device 40 and transported. The hydrogen H 2 stored in the hydrogen storage device 40 can be supplied to the hydrogen energy supply device 50 .

The hydrogen energy supply device 50 is configured to convert the chemical energy of the hydrogen H2 stored in the hydrogen storage device 40 into electrical energy E3 and supply the electrical energy E3. The hydrogen energy supply device 50 is, for example, a fuel cell or a gas fuel generator. A fuel cell has, for example, electrodes including an anode and a cathode, and an electrolyte including a solid polymer membrane, a solid oxide membrane, or the like. The fuel cell converts the chemical energy of hydrogen H2 into electrical energy E3 by electrochemically reacting hydrogen H2 stored in hydrogen storage device 40 with oxygen O2 from the atmosphere. The electric energy E3 generated by the hydrogen energy supply device 50 can be supplied to the outside.

The heating/cooling device 60 heats or cools each device by circulating the heat medium HM in the electrical energy conversion storage device 10, the raw material generation storage device 20, the hydrogen generation device 30, the hydrogen storage device 40, and the hydrogen energy supply device 50. configured to do so.

In the electrical energy conversion storage device 10, part of the generated electrical energy E2 is converted into thermal energy. As a result, the temperature of the electrical energy conversion storage device 10 rises. The heating/cooling device 60 cools the electrical energy conversion/storage device 10 by exchanging heat between the electrical energy conversion/storage device 10 and the heat medium HM. Generally, the higher the temperature of the device, the shorter the life of the device. Therefore, heat is exchanged with the heat medium HM having a temperature such that the temperature of the electrical energy conversion storage device 10 does not exceed a predetermined temperature. This heat exchange heats the heat medium HM.

In the raw material producing and storing device 20, water is stored when the raw material M2 is water. When the air temperature is cold, the temperature of the water drops, and when the temperature of the water drops below freezing, the water can freeze. The heating/cooling device 60 heats the water of the raw material M2 by exchanging heat between the water of the raw material M2 stored in the raw material generation and storage device 20 and the heat medium HM. As a result, freezing of the water of the raw material M2 can be prevented. This heat exchange cools the heat medium HM.

In the hydrogen generator 30, thermal energy is generated when hydrogen H2 is generated from the electric energy E2. As a result, the temperature of the hydrogen generator 30 rises. The heating/cooling device 60 cools the hydrogen generator 30 by exchanging heat between the hydrogen generator 30 and the heat medium HM. In general, the higher the temperature of the electrolyzer, the higher the efficiency of electrolysis, but the shorter the life of the electrolyzer. Therefore, heat is exchanged with the heat medium HM having a temperature such that the temperature of the electrolytic device does not exceed a predetermined temperature. Further, during adsorption regeneration for refining hydrogen H2, heat exchange is performed between the hydrogen generator 30 and the heat medium HM, thereby cooling the adsorption column of the separation refiner. Further, when the hydrogen H2 is compressed, heat is exchanged between the hydrogen generator 30 and the heat medium HM, thereby preventing the temperature of the compressor and the like from becoming higher than a predetermined temperature. The heat medium HM is heated by these heat exchanges.

The hydrogen storage device 40 stores hydrogen H2. The hydrogen H2 is heated when it is supplied to the hydrogen energy supply device 50 in order to improve the energy utilization efficiency. The heating/cooling device 60 heats or cools the hydrogen storage device 40 by exchanging heat between the hydrogen storage device 40 and the heat medium HM. This heat exchange cools or heats the heat medium HM.

In the hydrogen energy supply device 50, part of the chemical energy of hydrogen H2 is converted into thermal energy. As a result, the temperature of the hydrogen energy supply device 50 rises. The heating/cooling device 60 cools the hydrogen energy supply device 50 by exchanging heat between the hydrogen energy supply device 50 and the heat medium HM. This heat exchange heats the heat medium HM.

The heating/cooling device 60 may adjust the temperature of the heat medium HM by adjusting the flow rate of the heat medium HM. The flow rate of the heat medium HM can be adjusted, for example, by changing the operating conditions of the pump used in the heating/cooling device 60 .

The heating/cooling device 60 may be of any type as long as it uses the heat medium HM. The heating/cooling device 60 may be, for example, a heat pump heat exchanger, a Peltier heat exchanger, a vortex tube heat exchanger, or the like. Also, a plurality of heat exchangers may be connected in series or in parallel to adjust the temperature of the heat medium HM.

The heating/cooling device 60 may have a plurality of heat mediums HM. For example, the multiple heat carriers HM may include multiple heat carriers having different temperatures. Then, the heat medium that heats or cools each device may be changed according to external conditions such as air temperature. For example, when the air temperature is low, the heat medium may be changed to a high temperature heat medium so as to heat each device, and when the air temperature is high, it may be changed to a low temperature heat medium so as to cool each device. Further, for example, the plurality of heat carriers HM may include a liquid heat carrier and a gaseous heat carrier. In this case, for example, it is changed to a liquid heat carrier when heating or cooling a small (closed) space, and to a gaseous heat carrier when heating or cooling a large (open) space. may

The control device 70 is configured to control the electrical energy conversion storage device 10 , the raw material generation storage device 20 , the hydrogen generation device 30 , the hydrogen storage device 40 , the hydrogen energy supply device 50 and the heating/cooling device 60 . The control device 70 periodically acquires sensing data of each device. The control device 70 predicts the amount of power generated by renewable energy, the amount of power demand, and the external state, and based on the evaluation values, creates an operation plan that increases the energy utilization efficiency and controls each device. The operation planning period (planned period) may be, for example, yearly, seasonally, monthly, weekly, or daily.

As shown in FIG. 2, the control device 70 includes a storage unit 71, a power generation prediction unit 72, a demand prediction unit 73, an external state prediction unit 74, a setting unit 75, a plan creation unit 76, and an operation unit 77. and have

The storage unit 71 stores data used for prediction by the power generation prediction unit 72 , data used for prediction by the demand prediction unit 73 , and data used for prediction by the external state prediction unit 74 . For example, the storage unit 71 stores the weather conditions (sunny/cloudy/rainy) at the past date and time as the data used for the prediction by the power generation prediction unit 72, and the actual electric energy conversion storage device 10 under the weather conditions at the past date and time. stores the actual amount of power generated by conversion (power generation). In addition, the storage unit 71 stores actual power demand as data used for prediction by the demand prediction unit 73 together with date and time and weather conditions. The storage unit 71 also stores external conditions (for example, temperature) together with date and time and weather conditions as data used for prediction by the external condition prediction unit 74 .

The power generation prediction unit 72 predicts the amount of power generated by renewable energy. The power generation prediction unit 72 accesses the storage unit 71, and the weather conditions (sunny/cloudy/rainy) at the past date and time stored in the storage unit 71 and the actual electrical energy conversion and storage under the weather conditions at the past date and time. Acquires the actual power generation amount converted (generated) by the device 10 . The power generation prediction unit 72 classifies the acquired information into three weather conditions, for example, fine, cloudy, and rainy. The power generation prediction unit 72 calculates the probability distribution of the actual power generation amount converted (generated) by the electrical energy conversion and storage device 10 under each weather condition. The power generation prediction unit 72 predicts the power generation amount within the planned period from the probability distribution of the actual power generation amount. The power generation prediction unit 72 then stores the calculation result in the storage unit 71 . The power generation prediction unit 72 may calculate the probability distribution of the actual power generation amount for each season based on the date and time. As a result, the power generation prediction unit 72 can calculate the probability distribution of the actual power generation amount converted (generated) by the electrical energy conversion and storage device 10 under each weather condition more suitable for the date and time to be predicted. Quantities can be predicted more accurately.

The probability distribution of the amount of power generation may be divided into a deterministic term and a stochastic term. The deterministic term is represented by, for example, a function of the elevation angle of the sun and the conversion efficiency (power generation efficiency) of the electrical energy conversion and storage device 10 . The probability term is represented by, for example, a function of the probability distribution of the amount of solar radiation. The elevation angle of the sun can be calculated from the date and time, for example. Conversion efficiency (power generation efficiency) can be calculated from air temperature, for example, using a function of temperature. The temperature function can be calculated, for example, from the relationship between the actual power generation amount when the weather is fine and the estimated power generation amount based on the actual temperature. The amount of solar radiation can be estimated from the actual amount of power generation, the elevation angle of the sun, and the conversion efficiency (power generation efficiency), for example, using a prediction function for the amount of power generation. The probability distribution of the amount of solar radiation can be calculated, for example, from the estimated amount of solar radiation when the weather conditions (sunny/cloudy/rainy) are the same.

The demand prediction unit 73 predicts the amount of power demand. The demand forecasting unit 73 accesses the storage unit 71 and acquires from the storage unit 71 the past actual power demand under conditions close to the current date and time and weather conditions. The demand forecasting unit 73 calculates the probability distribution of the amount of power demand, and predicts the amount of power demand within the planning period from the probability distribution of the amount of power demand. The probability distribution of power demand can be calculated, for example, from the actual power demand when the days of the week (weekdays/holidays) are the same and the weather conditions (clear/cloudy/rainy) are the same. Electricity demand can be calculated, for example, as a function of the day of the week and weather conditions. The influence of the day of the week on the power demand can be calculated, for example, from the power demand when the weather conditions are the same. The influence of weather conditions on the amount of power demand can be calculated from the amount of power demand for the same day of the week, for example.

The external state prediction unit 74 predicts an external state. The external state prediction unit 74 accesses the storage unit 71 and acquires from the storage unit 71 past actual external states under conditions close to the current date and time and weather conditions. The external condition is, for example, the temperature of the atmosphere, ie the air temperature. The external state prediction unit 74 calculates the temperature probability distribution and predicts the temperature within the planning period from this temperature probability distribution. The temperature probability distribution can be calculated, for example, from actual temperatures under the same weather conditions (clear/cloudy/rainy).

The setting unit 75 sets parameters for evaluation values. The evaluation value can be represented, for example, by the following formula.
Evaluation value = Σ (use value + BCP value - operation cost - maintenance cost)

Here, the value to be used is, for example, the value (price) obtained by multiplying the power generation amount (kWh) by the unit price (yen/kWh) of the parameter. The BCP value is, for example, a value (price) obtained by multiplying the power generation amount (kWh) by the unit price (yen/kWh) of a parameter added during abnormal weather or the like. The operating cost is, for example, a value (cost) obtained by multiplying the power consumption (kWh) of each device by the unit price (yen/kWh) of the parameter. The maintenance cost is, for example, the cost of repairing parameters when the device breaks down due to freezing of water or the like. Σ means summation calculation, and calculates the summation of each value within the planning period.

The plan creation unit 76 calculates the power generation amount predicted by the power generation prediction unit 72, the power demand predicted by the demand prediction unit 73, the external state predicted by the external state prediction unit 74, and the parameters set by the setting unit 75. Create an operation plan based on the evaluation value in The plan creation unit 76 uses the power generation amount predicted by the power generation prediction unit 72, the power demand predicted by the demand prediction unit 73, and the external state predicted by the external state prediction unit 74 to determine the internal state of each device. to predict. Then, the plan creating unit 76 creates an operation plan so that the evaluation value with the parameters set by the setting unit 75 is optimal.

The internal state of each device is, for example, the calorific value and temperature of each device, and the state of raw materials contained in each device. The calorific value of the device can be calculated from, for example, the calorific value during rated operation and the rated power ratio of the device. The temperature of the device can be calculated, for example, from the heat capacity of the device, the amount of heat generated by the device, and the amount of heat released to the outside. The state of the raw material is, for example, three states (gas/liquid/solid). For example, the temperature of raw material water can be calculated from the heat capacity, the amount of heat generated by the device, and the amount of heat released to the outside. can be predicted from

The operation plan includes the amount of hydrogen H2 generated by the hydrogen generator 30, the amount of electric energy E3 generated by the hydrogen energy supply device 50, the amount of heating and cooling of each device by the heating and cooling device 60, and the heating or cooling by the heating and cooling device 60. A change of the heat medium HM for cooling is included. The plan creation unit 76 predicts the internal state of each device from the operation pattern in the initial setting of each device within the planning period, and calculates an evaluation value. Also, the operation pattern of each device is changed, the internal state of each device is predicted from the operation pattern, and an evaluation value is calculated. By repeating these steps, an operation pattern with the optimum evaluation value is determined. The operation pattern is changed within the limits of each device (within the limits of the production amount, heating amount, cooling amount, etc.).

For example, when the water of the raw material M2 stored in the raw material production and storage device 20 freezes, the parameter of the evaluation value is set so that the maintenance cost becomes high. In this case, the operating time of the raw material production and storage device 20 is lengthened, or the amount of heating of the raw material production and storage device 20 by the heating and cooling device 60 is increased, so as to prevent the water of the raw material M2 from freezing. create.

The operation unit 77 operates each device, that is, the electrical energy conversion and storage device 10, the raw material generation and storage device 20, the hydrogen generation device 30, the hydrogen storage device 40, the hydrogen energy supply device 50, and the heating and cooling device 60, based on the operation plan. to drive. For example, the operation unit 77 heats the water of the raw material M2 by exchanging heat between the water of the raw material M2 stored in the raw material production and storage device 20 and the heat medium HM of the heating/cooling device 60 based on the operation plan, The heating/cooling device 60 is operated so as to prevent freezing of the water of the raw material M2.

Next, the operation of this embodiment having such a configuration will be described.

When the energy storage system 1 operates, the electrical energy conversion storage device 10 converts renewable energy E1 such as sunlight into electrical energy E2 and stores the electrical energy.

The electric energy E2 stored in the electric energy conversion and storage device 10 is supplied to the raw material generation and storage device 20, and the raw material generation and storage device 20 converts the electric energy E2 and the water of the raw material M2 from surface water and groundwater, which are natural substances M1. is generated.

The electric energy E2 and the raw material M2 are supplied to the hydrogen generator 30, and the hydrogen generator 30 generates hydrogen H2 and oxygen O2 from the electric energy E2 and the raw material M2.

Oxygen O2 generated by the hydrogen generator 30 is released to the outside. Further, the hydrogen H2 generated by the hydrogen generator 30 is supplied to the hydrogen storage device 40 and stored.

The hydrogen H2 stored in the hydrogen storage device 40 is supplied to the hydrogen energy supply device 50. The hydrogen energy supply device 50 electrochemically reacts the hydrogen H2 with oxygen O2 from the atmosphere to generate the chemical energy of the hydrogen H2. is converted into electrical energy E3.

The electric energy E3 generated by the hydrogen energy supply device 50 is supplied to the outside.

In addition, the heat medium HM of the heating/cooling device 60 circulates in the electric energy conversion storage device 10, the raw material generation storage device 20, the hydrogen generation device 30, the hydrogen storage device 40, and the hydrogen energy supply device 50, and heats or heats each device. Allow to cool.

More specifically, the heat medium HM of the heating/cooling device 60 exchanges heat with the electrical energy conversion and storage device 10 to cool the electrical energy conversion and storage device 10 . This heat exchange heats the heat medium HM.

In addition, the heat medium HM of the heating/cooling device 60 exchanges heat with the water of the raw material M2 stored in the raw material generation and storage device 20 to heat the water of the raw material M2. This heat exchange cools the heat medium HM.

Also, the heat medium HM of the heating/cooling device 60 exchanges heat with the hydrogen generator 30 to cool the hydrogen generator 30 . This heat exchange heats the heat medium HM.

Heat medium HM of heating/cooling device 60 heat-exchanges with hydrogen storage device 40 to heat or cool hydrogen storage device 40 . This heat exchange cools or heats the heat medium HM.

Also, the heat medium HM of the heating/cooling device 60 exchanges heat with the hydrogen energy supply device 50 to cool the hydrogen energy supply device 50 . This heat exchange heats the heat medium HM.

Here, the electric energy conversion storage device 10 , the raw material generation storage device 20 , the hydrogen generation device 30 , the hydrogen storage device 40 , the hydrogen energy supply device 50 and the heating/cooling device 60 are controlled by the control device 70 . A control method for the energy storage system 1 according to this embodiment will be described below.

First, the power generation prediction unit 72 predicts the amount of power generated by the renewable energy E1 (power generation prediction step). For example, the weather conditions (sunny/cloudy/rainy) at the past date and time stored in the storage unit 71 and the actual power generation amount actually converted (generated) by the electrical energy conversion storage device 10 under the weather conditions at the past date and time Based on , the probability distribution of the actual power generation amount is calculated, and the power generation amount within the planning period is predicted from the probability distribution of the actual power generation amount.

FIG. 3 shows an example of the amount of power generated by renewable energy predicted by the power generation prediction unit 72 . Here, the planning period is one day. In FIG. 3, the vertical axis indicates the amount of power generation S (kWh: for example, an hourly average of generated power), and the horizontal axis indicates time t. The graph in (a) of FIG. 3 shows the amount of power generated by photovoltaic power generation in fine weather, and the graph in (b) of FIG. 3 shows the amount of power generated by photovoltaic power generation in cloudy weather. The graph in (a) of FIG. 3 shows a larger amount of power generation as a whole than the graph in (b) of FIG. 3 . In the example shown in FIG. 3, all power generation amounts peak around 12:00 noon.

Next, the demand prediction unit 73 predicts the power demand (demand prediction step). For example, the probability distribution of power demand is calculated based on past actual power demand under conditions close to the current date and time and weather conditions, and the power demand within the planned period is predicted from this probability distribution of power demand. be done.

FIG. 4 shows an example of power demand predicted by the demand prediction unit 73 . In FIG. 4, the vertical axis indicates the amount of power demand D (kWh: for example, an hourly average of power demand), and the horizontal axis indicates time t. In the example shown in FIG. 4, the power demand peaks around 18:00 in the evening.

Subsequently, the external state prediction unit 74 predicts the external state (external state prediction step). For example, a temperature probability distribution is calculated based on past actual external conditions under conditions close to the current date and time and weather conditions, and the temperature within the planning period is predicted from this temperature probability distribution.

FIG. 5 shows an example of temperature predicted by the external state prediction unit 74. In FIG. In FIG. 5, the vertical axis indicates temperature T (° C.) and the horizontal axis indicates time t. In the example shown in FIG. 5, the temperature peaks around 14:00.

Also, the setting unit 75 sets parameters for the evaluation values (setting step). For example, the evaluation value is calculated as a value obtained by subtracting the total sum of operating costs and maintenance costs within the planned period from the total sum of the value of use and the BCP value within the planned period. The maintenance costs include repair costs when the device breaks down due to freezing of the water of the raw material M2 or the like. That is, when the water of the raw material M2 stored in the raw material production and storage device 20 freezes, the maintenance cost increases and the evaluation value decreases.

Next, the plan creation unit 76 generates the power generation predicted by the power generation prediction unit 72, the power demand predicted by the demand prediction unit 73, the external state predicted by the external state prediction unit 74, and the setting by the setting unit 75. An operation plan is created based on the evaluation values of the parameters obtained (plan creation step). First, the plan creation unit 76 determines the power generation amount predicted by the power generation prediction unit 72, the power demand predicted by the demand prediction unit 73, and the external state predicted by the external state prediction unit 74. Internal states such as the amount of heat generated, the temperature, and the state of raw materials contained in each device are predicted. Then, an operation plan is created so that the evaluation value with the parameters set by the setting unit 75 is optimal. An example of creating an operation plan will be described below with reference to FIGS. 6 and 7. FIG.

FIG. 6 shows an example of the surplus power generation amount of renewable energy predicted by the plan creation unit 76 . The surplus power generation amount of renewable energy can be predicted from the difference between the power generation amount S predicted by the power generation prediction unit 72 and the power demand amount D predicted by the demand prediction unit 73 . The graph in FIG. 6(a) shows the difference between the graph in FIG. 4(a) and the graph in FIG. 5, and the graph in FIG. 6(b) shows the graph in FIG. shows the difference from the graph of

In the case of the graph of (a) of FIG. 6, the amount of power generation S exceeds the amount of power demand D in the time period from about 6:00 in the morning to about 18:00 in the evening. It greatly exceeds the quantity D. Therefore, an operation plan is created so that the hydrogen generator 30 generates hydrogen H2 during this time period. Moreover, in this case, the hydrogen generator 30 generates heat, and the temperature of the hydrogen generator 30 rises. Therefore, an operation plan is created so that the heat medium HM of the heating/cooling device 60 and the hydrogen generator 30 are heat-exchanged and the hydrogen generator 30 is cooled during this period of time.

In addition, in the case of the graph of (b) of FIG. 6, the power demand D exceeds the power generation S in all time zones, and in particular around 18:00 in the evening, the power demand D significantly exceeds the power generation S. there is Therefore, in order to appropriately supply power to the outside, an operation plan is created so that the hydrogen energy supply device 50 generates the electric energy E3 during this time period. Also, in this case, the hydrogen energy supply device 50 generates heat. Therefore, an operation plan is created so that the heat medium HM of the heating/cooling device 60 and the hydrogen energy supply device 50 are heat-exchanged and the hydrogen energy supply device 50 is cooled during this time period.

FIG. 7 shows an example of the temperature of the water of the raw material M2 stored in the raw material generation storage device 20 predicted by the planning unit 76. As shown in FIG. In FIG. 7, the vertical axis indicates temperature T (° C.) and the horizontal axis indicates time t. The graph (dashed line) in FIG. 7(a) shows the same air temperature as the graph in FIG. 5, and the graph (solid line) in FIG. 7(b) shows the temperature of the water of the raw material M2. The temperature of the water of the raw material M2 can be predicted from the air temperature predicted by the external state prediction section 74 . As shown in FIG. 7, the temperature of the water of the raw material M2 changes slightly behind the air temperature.

As shown in FIG. 7, the temperature of the water of the raw material M2 is below freezing after midnight. Therefore, the water of the raw material M2 can freeze during this period of time. If the water in raw material M2 freezes, the maintenance cost will increase and the rating will be low. Therefore, as shown in the graph (chain line) of (b′) in FIG. 7, the heating and cooling device 60 heats the raw material production and storage device 20 in a time zone before the water of the raw material M2 freezes, for example, around noon. Then, an operation plan is created so as to raise the temperature of the water of the raw material M2 and prevent the water of the raw material M2 from freezing in the middle of the night. Thermal energy of the hydrogen generator 30 may be used to heat the raw material generation storage device 20 . That is, in the case shown in the graph of FIG. 6(a), the water of the raw material M2 is heated using the thermal energy of the heat medium HM of the heating/cooling device 60 heated by heat exchange with the hydrogen generator 30. You may Also, the thermal energy of the hydrogen energy supply device 50 may be used to heat the raw material generation and storage device 20 . That is, in the case shown in the graph of FIG. 6B, the heat energy of the heat medium HM of the heating/cooling device 60 heated by heat exchange with the hydrogen energy supply device 50 is used to convert the water of the raw material M2. May be heated. As a result, it is possible to prevent freezing of the water of the raw material M2 and create an operation plan that increases the evaluation value.

Based on the above operation plan, the operation unit 77 operates the electrical energy conversion and storage device 10, the raw material generation and storage device 20, the hydrogen generation device 30, the hydrogen storage device 40, the hydrogen energy supply device 50, and the heating and cooling device. 60 is operated (operating step).

In this way, the control device 70 controls the electric energy conversion storage device 10 , the raw material generation storage device 20 , the hydrogen generation device 30 , the hydrogen storage device 40 , the hydrogen energy supply device 50 and the heating/cooling device 60 .

Thus, according to the present embodiment, the power generation amount predicted by the power generation prediction unit 72, the power demand predicted by the demand prediction unit 73, the external state predicted by the external state prediction unit 74, and the setting unit 75 An operation plan is created based on the evaluation values of the parameters set by. As a result, each device of the energy storage system 1 can be operated in consideration of the amount of power generated by renewable energy, the amount of power demand, and the external state. Therefore, it is possible to improve the energy utilization efficiency.

Further, according to the present embodiment, the operation plan is created so as to prevent the water of the raw material M2 stored in the raw material production and storage device 20 from freezing. As a result, each device can be operated so that the water of the raw material M2 used in the hydrogen generator 30 does not freeze within the planned period. Therefore, it is possible to reduce the maintenance cost of the device and improve the energy utilization efficiency.

Further, according to the present embodiment, the thermal energy of the heat medium HM heated by heat exchange with the hydrogen generator 30 or the hydrogen energy supply device 50 is used to prevent the water of the raw material M2 from freezing. , an operation plan is created. As a result, the thermal energy generated by the hydrogen generator 30 or the hydrogen energy supply device 50 can be effectively utilized as energy for preventing the water of the raw material M2 from freezing. Therefore, it is possible to improve the energy utilization efficiency.

Moreover, according to the present embodiment, the heating/cooling device 60 has a plurality of heat mediums HM, and the heat medium HM for heating or cooling is changed according to the external state. As a result, each device can be efficiently heated or cooled according to external conditions such as air temperature. Therefore, it is possible to improve the energy utilization efficiency.

(Second embodiment)
Next, an energy storage system according to a second embodiment will be described.

The second embodiment is mainly different in that a thermal energy storage device for storing thermal energy generated by any one of the electrical energy conversion storage device, the hydrogen generation device, and the hydrogen energy supply device is provided. , and other configurations are substantially the same as those of the first embodiment shown in FIGS.

The energy storage system 1 according to this embodiment further includes a thermal energy storage device 80 . Thermal energy storage device 80 may be placed at any location.

Thermal energy storage device 80 is configured to store thermal energy generated by any of electrical energy conversion storage device 10 , hydrogen generation device 30 , and hydrogen energy supply device 50 . For example, thermal energy storage device 80 may store thermal energy generated by hydrogen energy supply device 50 . In this case, the thermal energy storage device 80 may be, for example, a hot water storage tank that stores hot water (hot water) generated by the fuel cell of the hydrogen energy supply device 50 . In this case, the thermal energy storage device 80 may be arranged between the hydrogen energy supply device 50 and the heating and cooling device 60 .

The heating/cooling device 60 uses the thermal energy stored in the thermal energy storage device 80 to heat the raw material M1 stored in the raw material generation storage device 20 and the hydrogen H2 stored in the hydrogen storage device 40 . That is, the heating/cooling device 60 uses the thermal energy of the heat medium HM heated by heat exchange with the thermal energy storage device 80 to store the raw material M2 stored in the raw material generation and storage device 20 and the hydrogen storage device 40. The hydrogen H2 is heated.

The thermal energy storage device 80 may, for example, store thermal energy during the day when the temperature is high and release thermal energy during the night when the temperature is low. However, since energy loss occurs when thermal energy is stored, an operation plan is created in consideration of the energy loss so as to improve the overall energy utilization efficiency within the planning period.

The thermal energy storage device 80 may have multiple heat storage materials. For example, the multiple heat storage materials may include the hot water storage tank and the hydrogen storage alloy described above. The hydrogen storage alloy generates heat when absorbing hydrogen H2 and absorbs heat when releasing hydrogen H2. That is, the hydrogen storage alloy releases thermal energy when storing hydrogen H2, and absorbs thermal energy when releasing hydrogen H2. Hot water storage tanks tend to lose heat energy to the outside, whereas hydrogen storage alloys are less likely to lose heat energy to the outside and are suitable for long-term storage. Therefore, the heat storage material that stores the thermal energy may be changed according to the storage period. For example, if the storage period is long, the temperature of the hot water stored in the hot water tank will drop, resulting in loss of thermal energy. Therefore, thermal energy may be stored in a hydrogen storage alloy. Also, the heat storage material that stores the thermal energy may be changed according to the external conditions. For example, when the temperature is low, thermal energy is stored in a heat storage material that emits thermal energy and heats each device, and when the temperature is high, thermal energy is stored in a heat storage material that absorbs thermal energy and cools each device. You may make it

When the heat storage material of the thermal energy storage device 80 is a hydrogen storage alloy, the hydrogen storage alloy stores and releases hydrogen H2. Therefore, as shown in FIG. may

Thermal energy storage device 80 may comprise multiple hydrogen storage alloys. In this case, the hydrogen H2 may be circulated between the hydrogen storage alloys to heat or cool the heat medium HM of the heating/cooling device 60 . For example, the heat medium HM of the heating/cooling device 60 may be heated by thermal energy generated when each hydrogen storage alloy stores hydrogen H2. Further, for example, the heat medium HM of the heating/cooling device 60 may be cooled when each hydrogen storage alloy releases hydrogen H2.

When the hydrogen storage device 40 stores the hydrogen H2 as liquid hydrogen, the liquid hydrogen absorbs heat when vaporized.

Thermal energy storage device 80 is controlled by controller 70 . Therefore, the operation of the thermal energy storage device 80 described above is performed based on the operation plan created by the plan creation unit 76 .

Thus, according to the present embodiment, the thermal energy storage device 80 stores thermal energy generated by any one of the electrical energy conversion storage device 10, the hydrogen generation device 30, and the hydrogen energy supply device 50. A storage device 80 is provided. As a result, the thermal energy generated by each device can be stored, and the thermal energy can be effectively utilized. Therefore, it is possible to improve the energy utilization efficiency.

Further, according to the present embodiment, heating/cooling device 60 heats raw material M1 stored in raw material production/storage device 20 using thermal energy stored in thermal energy storage device 80 . As a result, the thermal energy stored by the thermal energy storage device 80 can be effectively utilized as energy for heating the raw material M2. Therefore, it is possible to improve the energy utilization efficiency.

Further, according to the present embodiment, the heat storage material of the thermal energy storage device 80 includes a hydrogen storage alloy, and the hydrogen storage alloy releases thermal energy when storing hydrogen H2. to absorb heat energy. By using a hydrogen storage alloy for storing thermal energy in this way, thermal energy can be stored for a long period of time, and the loss of thermal energy to the outside that can occur when the storage period is long can be suppressed. Therefore, it is possible to improve the energy utilization efficiency. In addition, since the hydrogen storage alloy can store and release hydrogen H2, the hydrogen storage device 40 can be used as the thermal energy storage device 80. FIG. Therefore, it is possible to suppress an increase in system size and an increase in equipment cost.

Further, according to the present embodiment, the heat storage material that stores thermal energy is changed according to the external conditions. As a result, thermal energy can be selectively stored in an appropriate heat storage material according to external conditions such as air temperature. Therefore, it is possible to improve the energy utilization efficiency.

(Other embodiments)
Next, energy storage systems according to other embodiments will be described.

The plan creation unit 76 may create an operation plan so as to change the ratio of electrical energy and thermal energy generated by the hydrogen energy supply device 50 according to external conditions.

The ratio of electrical energy to thermal energy can be changed, for example, by changing the operating temperature of the fuel cell of the hydrogen energy supply device 50 . The ratio of electric energy and thermal energy is changed so that the evaluation value with the parameters set by the setting unit 75 is optimized.

For example, during the planning period, when the temperature is low and there is a possibility that the water of the raw material M2 stored in the raw material production and storage device 20 will freeze, the water of the raw material M2 is adjusted to prevent the water of the raw material M2 from freezing. requires a lot of heat energy. In such a case, the ratio of electrical energy and thermal energy generated by the hydrogen energy supply device 50 is changed so that thermal energy is increased. Also, for example, if the air temperature is high and there is no possibility that the water of the raw material M2 stored in the raw material production and storage device 20 will freeze within the planning period, much thermal energy is not required. In such a case, the ratio of electrical energy and thermal energy generated by the hydrogen energy supply device 50 is changed so that electrical energy is increased.

In this way, by changing the ratio of the electrical energy and the thermal energy generated by the hydrogen energy supply device 50 according to the external conditions such as the temperature, it is possible to effectively utilize the energy as a whole. Utilization efficiency can be improved.

In the above-described embodiment, the electric energy conversion and storage device 10, the raw material generation and storage device 20, the hydrogen generation device 30, the hydrogen storage device 40, and the hydrogen energy supply device 50 are configured as separate devices. explained. However, without being limited to this, at least two of the electrical energy conversion and storage device 10, the raw material generation and storage device 20, the hydrogen generation device 30, the hydrogen storage device 40, and the hydrogen energy supply device 50 are combined into one device. It may be configured by As a result, it is possible to suppress an increase in the size of the system and an increase in facility costs.

According to the embodiment described above, it is possible to improve the energy utilization efficiency.

Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

1: Energy storage system, 10: Electric energy conversion storage device, 20: Raw material generation storage device, 30: Hydrogen generation device, 40: Hydrogen storage device, 50: Hydrogen energy supply device, 60: Heating and cooling device, 70: Control device , 72: Power generation prediction unit, 73: Demand prediction unit, 74: External state prediction unit, 75: Setting unit, 76: Planning unit, 77: Operation unit, 80: Thermal energy storage device, A: Atmosphere, E1: Regeneration Possible energy, E2: electric energy, E3: electric energy, H2: hydrogen, HM: heat medium, M1: natural substance, M2: raw material, O2: oxygen

Claims (12)

an electrical energy conversion and storage device that converts renewable energy into electrical energy and stores it;
a raw material generation and storage device for generating and storing raw materials from the electric energy stored in the electric energy conversion and storage device and natural substances;
a hydrogen generator for generating hydrogen from the electrical energy stored in the electrical energy conversion storage device and the raw material stored in the raw material generation storage device;
a hydrogen storage device for storing hydrogen generated by the hydrogen generator;
a hydrogen energy supply device that converts the chemical energy of hydrogen stored in the hydrogen storage device into electrical energy and supplies it;
a heating and cooling device for heating or cooling each device by circulating a heat medium in the electrical energy conversion storage device, the raw material generation storage device, the hydrogen generation device, the hydrogen storage device, and the hydrogen energy supply device;
a control device that controls the electrical energy conversion storage device, the raw material generation storage device, the hydrogen generation device, the hydrogen storage device, the hydrogen energy supply device, and the heating and cooling device;
The control device includes a power generation prediction unit that predicts the amount of power generated by renewable energy, a demand prediction unit that predicts the amount of power demand, an external state prediction unit that predicts an external state, and a setting unit that sets parameters for evaluation values. a plan creation unit that creates an operation plan based on the power generation amount, the power demand amount, the external state, and the evaluation value; and the electric energy conversion storage device and the raw material generation based on the operation plan. An energy storage system, comprising: a storage device, the hydrogen generator, the hydrogen storage device, the hydrogen energy supply device, and an operating section that operates the heating and cooling device. The raw material contains water,
2. The energy storage system according to claim 1, wherein said plan creation unit creates said operation plan so as to prevent freezing of said raw material water. The plan creation unit uses the thermal energy of the heat medium heated by heat exchange with the hydrogen generator or the hydrogen energy supply device to prevent the raw material water from freezing. 3. The energy storage system of claim 2, which creates a The energy storage according to any one of claims 1 to 3, wherein the heating and cooling device has a plurality of the heat medium, and the heat medium that performs heating or cooling is changed according to the external state. system. 5. The apparatus according to any one of claims 1 to 4, further comprising a thermal energy storage device that stores thermal energy generated by any one of the electrical energy conversion storage device, the hydrogen generation device, and the hydrogen energy supply device. energy storage system. 6. The energy storage system according to claim 5, wherein the heating and cooling device heats the raw material stored in the raw material generation and storage device using the thermal energy stored in the thermal energy storage device. 7. Energy storage system according to claim 5 or 6, wherein the thermal energy storage device comprises a plurality of heat storage materials. 8. The energy storage system according to claim 7, wherein the heat storage material includes a hydrogen storage alloy, and the hydrogen storage alloy releases thermal energy when storing hydrogen and absorbs thermal energy when releasing hydrogen. . 9. The energy storage system according to claim 7 or 8, wherein the heat storage material storing thermal energy is changed according to the external condition. 10. The operation plan according to any one of claims 1 to 9, wherein the plan creation unit creates the operation plan so as to change the ratio of electrical energy and thermal energy generated by the hydrogen energy supply device according to the external condition. The energy storage system according to any one of the preceding items. 11. At least two of the electrical energy conversion storage device, the raw material generation storage device, the hydrogen generation device, the hydrogen storage device, and the hydrogen energy supply device are configured by one device. The energy storage system according to any one of Claims 1 to 3. A method of controlling an energy storage system, comprising:
The energy storage system comprises:
an electrical energy conversion and storage device that converts renewable energy into electrical energy and stores it;
a raw material generation and storage device for generating and storing raw materials from the electric energy stored in the electric energy conversion and storage device and natural substances;
a hydrogen generator for generating hydrogen from the electrical energy stored in the electrical energy conversion storage device and the raw material stored in the raw material generation storage device;
a hydrogen storage device for storing hydrogen generated by the hydrogen generator;
a hydrogen energy supply device that converts the chemical energy of hydrogen stored in the hydrogen storage device into electrical energy and supplies it;
a heating and cooling device for heating or cooling each device by circulating a heat medium in the electrical energy conversion storage device, the raw material generation storage device, the hydrogen generation device, the hydrogen storage device, and the hydrogen energy supply device; prepared,
The control method is
a power generation prediction step of predicting the amount of power generated by renewable energy;
a demand forecasting step of forecasting the amount of power demand;
an external state prediction step of predicting an external state;
a setting step of setting evaluation value parameters;
a plan creation step of creating an operation plan based on the power generation amount, the power demand amount, the external state, and the evaluation value;
an operating step of operating the electrical energy conversion storage device, the raw material generation storage device, the hydrogen generation device, the hydrogen storage device, the hydrogen energy supply device, and the heating and cooling device based on the operation plan. , a control method for an energy storage system.

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