A method and system for integrated energy system capacity planning

Abstract

The application provides a kind of integrated energy system capacity planning method and system, belong to integrated energy station capacity configuration technical field, including: the reversible solid oxide cell power generation / hydrogen production system model and integrated energy system model are constructed;The mixed integer linear programming model of the integrated energy system model is established, the objective function is system thermal power total cost, constraint condition includes energy balance, mass balance, reversible solid oxide cell full working condition constraint and each component constraint;Input renewable energy output time series data, user demand time series data and component technical and economic parameters;Solve the solution of objective function under constraint condition, output integrated energy system each component optimal capacity configuration and each typical day under different time scene operation optimization result. By considering the dynamic change of reversible solid oxide cell efficiency with its load in capacity planning process, it is favorable to improve the accuracy of capacity optimization and economic analysis of system components.

Description

Technical Field

[0001] This invention belongs to the field of integrated energy station capacity configuration technology, and specifically relates to an integrated energy system capacity planning method and system. Background Technology

[0002] To address the global energy crisis and environmental pollution, the replacement of fossil fuels with renewable energy is gradually becoming a trend. Statistics from the International Energy Agency show that in 2023, global newly installed renewable energy capacity increased by 50% year-on-year, reaching 510 GW. my country has also achieved remarkable results in renewable energy development; by the end of 2023, the installed capacity of renewable energy power generation, including hydropower, wind power, solar power, and biomass, had reached 1.45 billion kW. Integrated energy services, as one of the important pathways to promote energy transformation and upgrading and implement the energy revolution, are in line with the national energy development strategy.

[0003] Reversible solid oxide batteries (SOBs) can switch between fuel cell power generation and electrolyzer hydrogen production modes, achieving efficient conversion between electrical and chemical energy within a compact structure while significantly improving equipment utilization. Therefore, they are widely used in integrated energy systems to participate in the regulation of fluctuating renewable energy loads and contribute to carbon reduction and emission reduction in the energy sector. Currently, numerous studies have focused on the application of reversible SOBs in integrated energy systems; however, most studies typically set the efficiency to a fixed value or directly cite other literature, lacking consideration of the dynamic changes in efficiency with load, i.e., a full-condition performance analysis of reversible SOBs. This simplistic approach may lead to insufficient model accuracy, significantly impacting the capacity optimization and economic analysis of system components.

[0004] Chinese Patent CN114049004B discloses a stochastic planning method, system, and device for the capacity of an electric hydrogen energy station. This invention considers the uncertainties of the electric hydrogen energy system and the degradation mechanism of reversible solid oxide batteries (SOBs), planning the capacity of the SOBs and hydrogen storage tanks in the electric hydrogen energy station to minimize the overall system cost. However, it only considers the impact of SOB degradation on its lifespan and modifies the SOB's operation and maintenance cost function, without considering the impact of SOB degradation on its performance. Chinese Patent CN118826078A discloses a capacity planning method, system, device, and medium for microgrid energy storage devices. This invention establishes a multi-state transition operation model for reversible SOBs, including power generation, electrolysis, hot standby, and shutdown states, and considers the thermal effects of reversible SOBs in fuel cell mode. It combines the reversible SOB model and a bi-level capacity planning model for energy storage devices to set constraints and solve for the planned capacity of the energy storage devices. However, its constraints on reversible solid oxide batteries consider the efficiency of fuel cells and electrolyzers as constant values, which cannot accurately reflect the impact of reversible solid oxide battery load changes on system capacity planning. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a comprehensive energy system capacity planning method and system. The capacity planning process considers the dynamic changes in the efficiency of reversible solid oxide batteries with their load, which helps improve the accuracy of capacity optimization and economic analysis of system components.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] On one hand, this invention provides a comprehensive energy system capacity planning method based on reversible solid oxide batteries, comprising: constructing a reversible solid oxide battery power generation / hydrogen production system model and calculating the system efficiency corresponding to the working load of the electrolyzer and fuel cell; constructing a comprehensive energy system model based on the reversible solid oxide battery; establishing a mixed-integer linear programming model of the comprehensive energy system model, wherein the objective function of the mixed-integer linear programming model is the total thermoelectric cost of the system, and the constraints include energy balance, mass balance, full-condition constraints of the reversible solid oxide battery, and constraints of each component; wherein the component conversion efficiency constraint of the reversible solid oxide battery adopts the calculated system efficiency corresponding to the working load of the electrolyzer and fuel cell; inputting renewable energy output time-series data, user demand time-series data, and component technical and economic parameters; solving the objective function under the constraints, and outputting the optimal capacity configuration of each component of the comprehensive energy system and the scenario operation optimization results at different times on typical days.

[0008] Furthermore, the reversible solid oxide battery power generation / hydrogen production system model is as follows: In SOFC mode, hydrogen is introduced into the system via a fuel pump, heated to the stack inlet temperature, and then introduced into the fuel electrode of the stack; air is introduced into the system via a fan, heated to the stack inlet temperature, and then introduced into the oxygen electrode of the stack. Part of the air undergoes an electrochemical reaction with the hydrogen at the fuel electrode inside the stack; the other part carries away the heat generated by the electrochemical reaction and irreversible losses within the stack, thus controlling the stack temperature. In SOEC mode, water is introduced into the system via a fuel pump and initially heated into steam. To maintain a reducing atmosphere during stack operation, hydrogen and water vapor are mixed via a mixer, heated to the stack inlet temperature, and then introduced into the stack; air is introduced into the system via a fan, heated to the stack operating temperature, and then introduced into the stack. This air carries away the oxygen generated by the electrochemical reaction within the stack and controls the stack temperature, either by providing heat for the electrochemical reaction in an endothermic state or by carrying away the heat generated by irreversible losses within the stack in an exothermic state.

[0009] Furthermore, the system efficiency calculation formula under SOFC / SOEC mode is as follows: ; ; in, For system efficiency in SOFC mode, For system efficiency under SOEC mode, Power generation of the fuel cell stack in SOFC mode For fuel pump power consumption in SOFC mode, For the power consumption of the wind turbine in SOFC mode, The power consumption of the electric heater in SOFC mode. This refers to the heat of hydrogen at the stack in SOFC mode. For the heat generated by the fuel cell stack in SOEC mode, For hydrogen production power consumption of fuel cell stacks in SOEC mode, For fuel pump power consumption in SOEC mode, For the power consumption of the wind turbine in SOEC mode, The power consumption for electric heating in SOEC mode.

[0010] Furthermore, calculating the system efficiency corresponding to the working load of the electrolyzer and fuel cell includes: determining the operating mode of the RSOC system, setting parameters such as current density, stack inlet and outlet temperatures, and fuel utilization rate, and obtaining the system mass flow and energy flow based on Aspen Plus simulation; establishing an optimization model in MATLAB software, obtaining the model simulation results through interaction with Aspen Plus, performing system process integration analysis on all energy flows based on the pinch analysis method, achieving maximum system heat recovery, obtaining the overall system combination curve and minimum heat source or heat sink requirement, calculating the system efficiency, determining the optimal operating temperature and fuel utilization rate of the system under different current densities, and obtaining the optimal system efficiency under different current densities.

[0011] Furthermore, the total thermoelectric cost of the system includes the initial investment cost of components, the replacement cost of components, and the operating cost; the initial investment cost of the components includes the initial investment cost of the reversible solid oxide battery system, photovoltaic, hydrogen storage tank, lithium battery, and electric heater; the replacement cost comes from the replacement cost of the reversible solid oxide battery stack and lithium battery; and the operating cost is the system's electricity purchase cost.

[0012] The 20-year cost of the integrated energy system is expressed by the formula:

[0013] ;

[0014] ;

[0015] in, Indicates the overall cost of the energy system; This indicates the initial investment cost of each component in an integrated energy system; This indicates the replacement cost of reversible solid oxide batteries; This indicates the cost of replacing lithium batteries; Indicates a typical day; Indicates the number of typical days selected; Indicates the number of times a typical day d occurs; Indicates time; This represents the operating cost at time t on a typical day d; This represents the investment cost of component g; This indicates the installed capacity of component g.

[0016] Furthermore, the constraint on energy balance is expressed by the following formula:

[0017] ;

[0018] ;

[0019] in, This represents the user-side power demand at time t on the d-th typical day; This represents the amount of electricity purchased by the power grid at time t on the d-th typical day; This represents the photovoltaic power generation at time t on the d-th typical day; This represents the fuel cell power generation at time t on the d-th typical day; This represents the discharge amount of the lithium battery at time t on the d-th typical day; This represents the amount of electricity sold by the power grid at time t on the d-th typical day; This represents the lithium battery charge at time t on the d-th typical day; This represents the power consumption of the electrolytic cell at time t on the d-th typical day; This represents the power consumption of the electric heater at time t on the d-th typical day; This represents the user-side thermal demand at time t on the d-th typical day; This indicates the thermal efficiency of electric heating.

[0020] Furthermore, the constraint on mass balance is expressed by the following formula:

[0021] ;

[0022] in, This represents the amount of hydrogen stored in the hydrogen storage tank at time t on the d-th typical day; This represents the amount of hydrogen stored in the hydrogen storage tank at time t-1 on the d-th typical day; This represents the amount of hydrogen produced by the electrolyzer at time t on the d-th typical day; This represents the hydrogen consumption of the fuel cell at time t on the d-th typical day.

[0023] Furthermore, the full-condition constraints of reversible solid oxide batteries include: operating state constraints of reversible solid oxide batteries, unit load change rate constraints of reversible solid oxide batteries, and component conversion efficiency constraints of reversible solid oxide batteries.

[0024] The operating state constraint of the reversible solid oxide battery is that the stack can only operate in one state of fuel cell or electrolyzer at any given time.

[0025] The unit's load change rate constraint is expressed by the following formula:

[0026] ;

[0027] ;

[0028] in, This represents the fuel cell power generation at time t-1 on the d-th typical day; This represents the power consumption of the electrolytic cell at time t-1 on the d-th typical day; This indicates the installed capacity in the reversible solid oxide battery power generation mode; This indicates the installed capacity in the reversible solid oxide battery hydrogen production mode;

[0029] The component conversion efficiency constraint of the reversible solid oxide battery is expressed by the following formula:

[0030] ;

[0031] ;

[0032] Where Δt represents time; This represents the system efficiency corresponding to the fuel cell workload at time t on the d-th typical day; This represents the system efficiency corresponding to the working load of the electrolytic cell at time t on the d-th typical day.

[0033] Furthermore, the constraints of each component include:

[0034] The state-of-charge constraint of a lithium battery can be expressed by the following formula:

[0035] ;

[0036] in, This represents the state of charge of the lithium battery at time t on the d-th typical day;

[0037] The constraint on the proportion of electricity purchased from the grid to the user's electricity demand is expressed by the formula:

[0038] ;

[0039] in, This represents the user-side power demand at time t on the d-th typical day. This represents the amount of electricity purchased by the power grid at time t on the d-th typical day;

[0040] The constraints on the hydrogen storage capacity and energy storage capacity of hydrogen storage tanks and lithium batteries are expressed by the following formula:

[0041] ;

[0042] ;

[0043] in, This indicates the amount of hydrogen stored in the hydrogen storage tank at time 0 on the d-th typical day; This indicates the amount of hydrogen stored in the hydrogen storage tank at 24:00 on the d-th typical day; This indicates the mass of hydrogen input to the hydrogen storage tank at time 0 on the d-th typical day; This indicates the mass of hydrogen output from the hydrogen storage tank at time 0 on the d-th typical day; This represents the lithium battery's energy storage capacity at time 0 on the d-th typical day; This represents the lithium battery's energy storage capacity at 24:00 on the d-th typical day. This represents the lithium battery charge at time 0 on the d-th typical day; This represents the discharge amount of the lithium battery at time 0 on the d-th typical day.

[0044] On the other hand, the present invention provides an integrated energy system based on solid oxide batteries. This integrated energy system is planned using the aforementioned capacity planning method and includes: a residential module, which serves as the energy consumer side of the system and requires a stable and suitable supply of electricity and heat; a photovoltaic power generation module, used to convert solar energy into electrical energy to provide the necessary power to the residential module and the electric heater module. When photovoltaic output is excessive, it can be stored through a lithium battery module, a reversible solid oxide battery module, or sold to the grid module; a reversible solid oxide battery module, used to convert electrical energy into chemical energy. In electrolysis mode, it uses excess electricity to produce hydrogen for storage, and in fuel cell mode, it uses the stored hydrogen to generate electricity. The reversible solid oxide battery can operate in fuel cell mode, electrolysis mode, and hot standby mode; a hydrogen storage module, used to store hydrogen produced by the reversible solid oxide battery module in electrolysis mode; a lithium battery module, used to store excess electricity and put into operation when the system requires a rapid change in load rate; an electric heater module, used to provide heat to the residential module; and a grid module, used to purchase electricity to supply power to the residential module when the system output is insufficient, and to sell electricity to the residential module when the system generates excess power and the energy storage reaches its limit.

[0045] The beneficial effects of the technical solution provided by the embodiments of the present invention include: fully considering the theoretical optimal working performance of reversible solid oxide batteries under all operating conditions, and considering the dynamic change of reversible solid oxide battery efficiency with its load during the capacity planning process, which is conducive to improving the accuracy of capacity optimization and economic analysis of system components. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a flowchart of the integrated energy system capacity planning method provided in Embodiment 1 of the present invention;

[0048] Figure 2 This is a model of the reversible solid oxide battery power generation system provided in Embodiment 1 of the present invention;

[0049] Figure 3This is a model of the reversible solid oxide battery hydrogen production system provided in Embodiment 1 of the present invention;

[0050] Figure 4 This is a schematic diagram of a comprehensive energy system based on a reversible solid oxide battery provided in Embodiment 1 of the present invention. Detailed Implementation

[0051] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] It should be noted that in this invention, "RSOC" stands for reversible solid oxide cell; "SOFC" stands for solid oxide fuel cell, and SOFC mode is fuel cell mode; "SOEC" stands for solid oxide electrolysis cell, and SOEC mode is electrolysis mode.

[0054] Example 1

[0055] This invention provides a method for integrated energy system capacity planning, such as... Figure 1As shown, the method, based on reversible solid oxide batteries, includes: constructing a reversible solid oxide battery power generation / hydrogen production system model and calculating the system efficiency corresponding to the working load of the electrolyzer and fuel cell; constructing a comprehensive energy system model based on reversible solid oxide batteries; establishing a mixed-integer linear programming model for the comprehensive energy system model, wherein the objective function of the mixed-integer linear programming model is the total thermoelectric cost of the system, and the constraints include energy balance, mass balance, full-condition constraints of the reversible solid oxide battery, and constraints of each component; wherein the component conversion efficiency constraint of the reversible solid oxide battery adopts the calculated system efficiency corresponding to the working load of the electrolyzer and fuel cell; inputting renewable energy output time-series data, user demand time-series data, and component technical and economic parameters; solving the objective function under the constraints, and outputting the optimal capacity configuration of each component of the comprehensive energy system and the scenario operation optimization results at different times on each typical day.

[0056] like Figure 2 As shown, the reversible solid oxide battery power generation system model is as follows: In SOFC mode, hydrogen is introduced into the system through a fuel pump, heated to the inlet temperature of the fuel cell stack, and then introduced into the fuel electrode of the fuel cell stack; air is introduced into the system through a fan, heated to the inlet temperature of the fuel cell stack, and then introduced into the oxygen electrode of the fuel cell stack. Part of the air undergoes an electrochemical reaction with the hydrogen in the fuel electrode inside the fuel cell stack; the other part carries away the heat generated by the electrochemical reaction and irreversible losses inside the fuel cell stack, thereby controlling the temperature of the fuel cell stack.

[0057] like Figure 3 As shown, the model of the reversible solid oxide battery hydrogen production system is as follows: In SOEC mode, water is initially heated into steam after being introduced into the system by a fuel pump. In order to maintain a reducing atmosphere during the operation of the stack, hydrogen and water vapor are mixed by a mixer and heated to the stack inlet temperature before being introduced into the stack. Air is introduced into the system by a fan, heated to the stack operating temperature, and then introduced into the stack. On the one hand, it carries away the oxygen produced by the electrochemical reaction in the stack, and on the other hand, it controls the stack temperature, supplementing heat for the electrochemical reaction in an endothermic state or carrying away the heat generated by irreversible loss in the stack in an exothermic state.

[0058] System efficiency is a key indicator for evaluating and optimizing system operation. The system efficiency calculation formula under SOFC / SOEC mode is as follows:

[0059] ;

[0060] ;

[0061] in, For system efficiency in SOFC mode, For system efficiency under SOEC mode, Power generation of the fuel cell stack in SOFC mode For fuel pump power consumption in SOFC mode, For the power consumption of the wind turbine in SOFC mode, The power consumption of the electric heater in SOFC mode. This refers to the heat of hydrogen at the stack in SOFC mode. For the heat generated by the fuel cell stack in SOEC mode, For hydrogen production power consumption of fuel cell stacks in SOEC mode, For fuel pump power consumption in SOEC mode, For the power consumption of the wind turbine in SOEC mode, The power consumption for electric heating in SOEC mode.

[0062] Calculating the system efficiency corresponding to the working load of the electrolyzer and fuel cell includes: determining the operating mode of the RSOC system, setting parameters such as current density, stack inlet and outlet temperatures, and fuel utilization rate, and obtaining the system mass flow and energy flow based on Aspen Plus simulation; establishing an optimization model in MATLAB software, obtaining the model simulation results through interaction with Aspen Plus, performing system process integration analysis on all energy flows based on the pinch analysis method, achieving maximum system heat recovery, obtaining the overall system curve and minimum heat source or heat sink requirement, calculating the system efficiency, determining the optimal operating temperature and fuel utilization rate of the system under different current densities, and obtaining the optimal system efficiency under different current densities.

[0063] In this embodiment of the invention, the Aspen Plus simulation software's built-in modules are used for modeling. The fuel pump, wind turbine, and electric heater are constructed by fitting actual measurements. The operating parameters and constraints of the RSOC stack in SOFC (SOEC) mode are shown in Table 1.

[0064] Table 1 Solid oxide stack parameters

[0065]

[0066] The total thermoelectric cost of the system includes the initial investment cost of components, the replacement cost of components, and the operating cost. The initial investment cost of the components includes the initial investment cost of the reversible solid oxide battery system, photovoltaic, hydrogen storage tank, lithium battery, and electric heater. The replacement cost comes from the replacement cost of the reversible solid oxide battery stack and the lithium battery. The operating cost is the system's electricity purchase cost.

[0067] The 20-year cost of the integrated energy system is expressed by the formula:

[0068] ;

[0069] ;

[0070] in, Indicates the overall cost of the energy system; This indicates the initial investment cost of each component in an integrated energy system; This indicates the replacement cost of reversible solid oxide batteries; This indicates the cost of replacing lithium batteries; Indicates a typical day; Indicates the number of typical days selected; Indicates the number of times a typical day d occurs; Indicates time; This represents the operating cost at time t on a typical day d; This represents the investment cost of component g; This indicates the installed capacity of component g.

[0071] The energy balance constraint is expressed by the following formula:

[0072] ;

[0073] ;

[0074] in, This represents the user-side power demand at time t on the d-th typical day; This represents the amount of electricity purchased by the power grid at time t on the d-th typical day; This represents the photovoltaic power generation at time t on the d-th typical day; This represents the fuel cell power generation at time t on the d-th typical day; This represents the discharge amount of the lithium battery at time t on the d-th typical day; This represents the amount of electricity sold by the power grid at time t on the d-th typical day; This represents the lithium battery charge at time t on the d-th typical day; This represents the power consumption of the electrolytic cell at time t on the d-th typical day; This represents the power consumption of the electric heater at time t on the d-th typical day; This represents the user-side thermal demand at time t on the d-th typical day; This indicates the thermal efficiency of electric heating.

[0075] The constraint on mass balance is expressed by the following formula:

[0076] ;

[0077] in, This represents the amount of hydrogen stored in the hydrogen storage tank at time t on the d-th typical day; This represents the amount of hydrogen stored in the hydrogen storage tank at time t-1 on the d-th typical day; This represents the amount of hydrogen produced by the electrolyzer at time t on the d-th typical day; This represents the hydrogen consumption of the fuel cell at time t on the d-th typical day.

[0078] The full-condition constraints of reversible solid oxide batteries include: operating state constraints of reversible solid oxide batteries, unit load change rate constraints of reversible solid oxide batteries, and component conversion efficiency constraints of reversible solid oxide batteries.

[0079] The operating state constraint of the reversible solid oxide battery is that the stack can only operate in one state of fuel cell or electrolyzer at any given time.

[0080] The unit's load change rate constraint is expressed by the following formula:

[0081] ;

[0082] ;

[0083] in, This represents the fuel cell power generation at time t-1 on the d-th typical day; This represents the power consumption of the electrolytic cell at time t-1 on the d-th typical day; This indicates the installed capacity in the reversible solid oxide battery power generation mode; This indicates the installed capacity in the reversible solid oxide battery hydrogen production mode;

[0084] The component conversion efficiency constraint of the reversible solid oxide battery is expressed by the following formula:

[0085] ;

[0086] ;

[0087] Where Δt represents time; This represents the system efficiency corresponding to the fuel cell workload at time t on the d-th typical day; This represents the system efficiency corresponding to the working load of the electrolytic cell at time t on the d-th typical day.

[0088] The constraints of each component include:

[0089] The state-of-charge constraint of a lithium battery can be expressed by the following formula:

[0090] ;

[0091] in, This represents the state of charge of the lithium battery at time t on the d-th typical day;

[0092] The constraint on the proportion of electricity purchased from the grid to the user's electricity demand is expressed by the formula:

[0093] ;

[0094] in, This represents the user-side power demand at time t on the d-th typical day. This represents the amount of electricity purchased by the power grid at time t on the d-th typical day;

[0095] The constraints on the hydrogen storage capacity and energy storage capacity of hydrogen storage tanks and lithium batteries are expressed by the following formula:

[0096] ;

[0097] ;

[0098] in, This indicates the amount of hydrogen stored in the hydrogen storage tank at time 0 on the d-th typical day; This indicates the amount of hydrogen stored in the hydrogen storage tank at 24:00 on the d-th typical day; This indicates the mass of hydrogen input to the hydrogen storage tank at time 0 on the d-th typical day; This indicates the mass of hydrogen output from the hydrogen storage tank at time 0 on the d-th typical day; This represents the lithium battery's energy storage capacity at time 0 on the d-th typical day; This represents the lithium battery's energy storage capacity at 24:00 on the d-th typical day. This represents the lithium battery charge at time 0 on the d-th typical day; This represents the discharge amount of the lithium battery at time 0 on the d-th typical day.

[0099] In the steps of solving the integrated energy system under the aforementioned constraints, the objective function is specifically solved using the CPLEX solver.

[0100] The following example, using a residential building, verifies the effectiveness of the proposed integrated energy system capacity planning method based on solid oxide batteries by comparing different definitions of efficiency for reversible solid oxide battery systems:

[0101] The efficiency, lifespan, and investment cost of each component in the system are shown in Table 2.

[0102] Table 2 Technical and Economic Parameter Settings

[0103]

[0104] The efficiency (%) of the RSOC stack in SOFC mode and the efficiency (%) in SOEC mode adopt the dynamic change of the efficiency of the reversible solid oxide cell with its load proposed in this application.

[0105] The capacity configuration of each device obtained by solving the capacity planning method described above is shown in Table 2.

[0106] Table 2 Optimal Component Capacity

[0107]

[0108] The investment costs of each piece of equipment are shown in Table 3.

[0109] Table 3. Cost corresponding to optimal component capacity

[0110]

[0111] The above calculations show that the technical solution proposed in this invention can improve the system's economic efficiency.

[0112] Example 2

[0113] This embodiment provides a comprehensive energy system based on solid oxide batteries. The comprehensive energy system is planned using the capacity planning method described in Embodiment 1, as follows: Figure 4 As shown, it includes:

[0114] Residential modules, as the energy consumers of the system, need to be provided with stable and appropriate electricity and heat;

[0115] Photovoltaic power generation modules are used to convert solar energy into electrical energy to provide the power required by residential modules and electric heater modules. When there is excess photovoltaic output, it can be stored through lithium battery modules, reversible solid oxide battery modules or sold to grid modules.

[0116] The reversible solid oxide battery module is used to convert electrical energy into chemical energy. In electrolysis mode, it uses excess electricity to produce hydrogen for storage, and in fuel cell mode, it uses the stored hydrogen to generate electricity. The reversible solid oxide battery can operate in fuel cell mode, electrolysis mode, and hot standby mode.

[0117] The hydrogen storage module is used to store hydrogen produced in the electrolysis mode of the reversible solid oxide battery module.

[0118] Lithium-ion battery modules are used to store excess power and are put into operation when the system requires a rapid change in load rate;

[0119] Electric heater module, used to provide heat to residential modules;

[0120] The grid module is used to purchase electricity from residential modules when the system output is insufficient, and to sell electricity to residential modules when the system generates excess power and the energy storage reaches its limit.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A comprehensive energy system capacity planning method, the method being based on a reversible solid oxide battery, characterized in that, include: A model of a reversible solid oxide battery power generation / hydrogen production system was constructed, and the system efficiency corresponding to the working load of the electrolyzer and fuel cell was calculated. Construct a comprehensive energy system model based on reversible solid oxide batteries; A mixed-integer linear programming model is established for the integrated energy system model. The objective function of the mixed-integer linear programming model is the total thermoelectric cost of the system. The constraints include energy balance, mass balance, full-condition constraints of the reversible solid oxide battery, and constraints of each component. The component conversion efficiency constraint of the reversible solid oxide battery adopts the system efficiency corresponding to the working load of the electrolyzer and fuel cell obtained by calculation. Input renewable energy output time-series data, user demand time-series data, and component technical and economic parameters; Solve the objective function under constraints, and output the optimal capacity configuration of each component of the integrated energy system and the scenario operation optimization results at different times of each typical day.

2. The capacity planning method according to claim 1, characterized in that, The model of the reversible solid oxide battery power generation / hydrogen production system is as follows: In SOFC mode, hydrogen is introduced into the system via a fuel pump, heated to the inlet temperature of the fuel cell stack, and then introduced into the fuel electrode of the fuel cell stack. Air is introduced into the system via a blower, heated to the inlet temperature of the fuel cell stack, and then introduced into the oxygen electrode of the fuel cell stack. Part of the air undergoes an electrochemical reaction with the hydrogen at the fuel electrode inside the fuel cell stack, while the other part carries away the heat generated by the electrochemical reaction and irreversible losses inside the fuel cell stack, thus controlling the fuel cell stack temperature. In SOEC mode, water is initially heated into steam after being pumped into the system. To maintain a reducing atmosphere during the operation of the fuel cell stack, hydrogen and water vapor are mixed by a mixer and heated to the stack inlet temperature before being introduced into the stack. Air is introduced into the system by a blower, heated to the stack operating temperature, and then introduced into the stack. This process removes oxygen generated by the electrochemical reaction within the stack and controls the stack temperature. In an endothermic state, it provides heat to the electrochemical reaction, or in an exothermic state, it removes heat generated by irreversible losses within the stack.

3. The capacity planning method according to claim 2, characterized in that, The system efficiency calculation formula under SOFC / SOEC mode is as follows: ； ； in, For system efficiency in SOFC mode, For system efficiency under SOEC mode, This refers to the power output of the fuel cell stack in SOFC mode. For fuel pump power consumption in SOFC mode, For the power consumption of the wind turbine in SOFC mode, The power consumption of the electric heater in SOFC mode. This refers to the heat of hydrogen at the stack in SOFC mode. For the heat generated by the fuel cell stack in SOEC mode, For hydrogen production power consumption of fuel cell stacks in SOEC mode, For fuel pump power consumption in SOEC mode, For the power consumption of the wind turbine in SOEC mode, This refers to the power consumption of electric heating in SOEC mode.

4. The capacity planning method according to claim 3, characterized in that, The calculation of system efficiency corresponding to the workload of the electrolyzer and fuel cell includes: The operating mode of the RSOC system was determined, and parameters such as current density, stack inlet and outlet temperatures, and fuel utilization rate were set. The system mass flow and energy flow were obtained based on Aspen Plus simulation. An optimization model was established in MATLAB software. The simulation results were obtained by interacting with Aspen Plus. Based on the pinch analysis method, the system process integration analysis of all energy flows was carried out to achieve maximum heat recovery of the system. The overall system combination curve and minimum heat source or heat sink requirements were obtained and the system efficiency was calculated. The optimal operating temperature and fuel utilization rate of the system under different current densities were determined, and the optimal efficiency of the system under different current densities was obtained.

5. The capacity planning method according to claim 1, characterized in that, The total thermoelectric cost of the system includes the initial investment cost of components, the replacement cost of components, and the operating cost. The initial investment cost of the components includes the initial investment cost of the reversible solid oxide battery system, photovoltaic, hydrogen storage tank, lithium battery, and electric heater. The replacement cost comes from the replacement cost of the reversible solid oxide battery stack and the lithium battery. The operating cost is the system's electricity purchase cost. The 20-year cost of the integrated energy system is expressed by the formula: ； ； in, Indicates the overall cost of the energy system; This indicates the initial investment cost of each component in an integrated energy system; This indicates the replacement cost of reversible solid oxide batteries; This indicates the cost of replacing lithium batteries; Indicates a typical day; Indicates the number of typical days selected; Indicates the number of times a typical day d occurs; Indicates time; This represents the operating cost at time t on a typical day d; This represents the investment cost of component g; This indicates the installed capacity of component g.

6. The capacity planning method according to claim 1, characterized in that, The energy balance constraint is expressed by the following formula: ； ； in, This represents the user-side power demand at time t on the d-th typical day; This represents the amount of electricity purchased by the power grid at time t on the d-th typical day; This represents the photovoltaic power generation at time t on the d-th typical day; This represents the fuel cell power generation at time t on the d-th typical day; This represents the discharge amount of the lithium battery at time t on the d-th typical day; This represents the amount of electricity sold by the power grid at time t on the d-th typical day; This represents the lithium battery charge at time t on the d-th typical day; This represents the power consumption of the electrolytic cell at time t on the d-th typical day; This represents the power consumption of the electric heater at time t on the d-th typical day; This represents the user-side thermal demand at time t on the d-th typical day; This indicates the thermal efficiency of electric heating.

7. The capacity planning method according to claim 1, characterized in that, The constraint on mass balance is expressed by the following formula: ； in, This represents the amount of hydrogen stored in the hydrogen storage tank at time t on the d-th typical day; This represents the amount of hydrogen stored in the hydrogen storage tank at time t-1 on the d-th typical day; This represents the amount of hydrogen produced by the electrolyzer at time t on the d-th typical day; This represents the hydrogen consumption of the fuel cell at time t on the d-th typical day.

8. The capacity planning method according to claim 1, characterized in that, The full-condition constraints of reversible solid oxide batteries include: operating state constraints of reversible solid oxide batteries, unit load change rate constraints of reversible solid oxide batteries, and component conversion efficiency constraints of reversible solid oxide batteries. The operating state constraint of the reversible solid oxide battery is that the stack can only operate in one state of fuel cell or electrolyzer at any given time. The unit's load change rate constraint is expressed by the following formula: ； ； in, This represents the fuel cell power generation at time t-1 on the d-th typical day; This represents the power consumption of the electrolytic cell at time t-1 on the d-th typical day; This indicates the installed capacity in the reversible solid oxide battery power generation mode; This indicates the installed capacity in the reversible solid oxide battery hydrogen production mode; The component conversion efficiency constraint of the reversible solid oxide battery is expressed by the following formula: ； ； Where Δt represents time; This represents the system efficiency corresponding to the fuel cell workload at time t on the d-th typical day; This represents the system efficiency corresponding to the working load of the electrolytic cell at time t on the d-th typical day.

9. The capacity planning method according to claim 1, characterized in that, The constraints of each component include: The state-of-charge constraint of a lithium battery can be expressed by the following formula: ； in, This represents the state of charge of the lithium battery at time t on the d-th typical day; The constraint on the proportion of electricity purchased from the grid to the user's electricity demand is expressed by the formula: ； in, This represents the user-side power demand at time t on the d-th typical day. This represents the amount of electricity purchased by the power grid at time t on the d-th typical day; The constraints on the hydrogen storage capacity and energy storage capacity of hydrogen storage tanks and lithium batteries are expressed by the following formula: ； ； in, This indicates the amount of hydrogen stored in the hydrogen storage tank at time 0 on the d-th typical day; This indicates the amount of hydrogen stored in the hydrogen storage tank at 24:00 on the d-th typical day; This indicates the mass of hydrogen input to the hydrogen storage tank at time 0 on the d-th typical day; This indicates the mass of hydrogen output from the hydrogen storage tank at time 0 on the d-th typical day; This represents the lithium battery's energy storage capacity at time 0 on the d-th typical day; This represents the lithium battery's energy storage capacity at 24:00 on the d-th typical day. This represents the lithium battery charge at time 0 on the d-th typical day; This represents the discharge amount of the lithium battery at time 0 on the d-th typical day.

10. A comprehensive energy system based on solid oxide batteries, characterized in that, The integrated energy system is planned using any one of the capacity planning methods described in claims 1-9, and includes: Residential modules, as the energy consumers of the system, need to be provided with stable and appropriate electricity and heat; Photovoltaic power generation modules are used to convert solar energy into electrical energy to provide the power required by residential modules and electric heater modules. When there is excess photovoltaic output, it can be stored through lithium battery modules, reversible solid oxide battery modules or sold to grid modules. The reversible solid oxide battery module is used to convert electrical energy into chemical energy. In electrolysis mode, it uses excess electricity to produce hydrogen for storage, and in fuel cell mode, it uses the stored hydrogen to generate electricity. The reversible solid oxide battery can operate in fuel cell mode, electrolysis mode, and hot standby mode. The hydrogen storage module is used to store hydrogen produced in the electrolysis mode of the reversible solid oxide battery module. Lithium-ion battery modules are used to store excess power and are put into operation when the system requires a rapid change in load rate; Electric heater module, used to provide heat to residential modules; The grid module is used to purchase electricity from residential modules when the system output is insufficient, and to sell electricity to residential modules when the system generates excess power and the energy storage reaches its limit.

Images