Large-scale hybrid energy storage optimization method and device considering thermal power transformation of Carnot cell

Abstract

The invention relates to a large-scale hybrid energy storage optimization method and device considering thermal power transformation of a Carnot battery, and the method comprises the steps: building a hybrid energy storage planning and operation integrated model considering green certificate-carbon transaction with the maximum net income as the purpose, and then building a hybrid energy storage planning and operation integrated model considering green certificate-carbon transaction with the maximum daily net income as the purpose. Solving through the hybrid energy storage planning and operation integrated model to obtain hybrid energy storage candidate schemes in multiple groups of typical scenes; the method achieves the optimal configuration of the electric heating hybrid energy storage of the new energy base of the Sagomean district, comprehensively considers the randomness, volatility, intermittency and extreme weather conditions of the new energy output, achieves the optimal configuration of the electric heating hybrid energy storage of the new energy base of the Sagomean district, achieves the optimal configuration of the electric heating hybrid energy storage of the new energy base of the Sagomean district district, and achieves the optimal configuration of the electric heating hybrid energy storage of the new energy base of the Sagomean district district. The method is closer to the actual situation of the Saggohm new energy base, certain calculation precision is reserved, meanwhile, the model solving difficulty is greatly reduced, and the calculation efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of energy system configuration technology, specifically to a large-scale hybrid energy storage optimization method and device that considers the conversion of thermal power plants into Carnot batteries. Background Technology

[0002] With the large-scale development and utilization of the Shagohuang renewable energy base, the issue of renewable energy consumption has become increasingly urgent, placing higher demands on the power system's ability to flexibly adjust resources. Energy storage, with its technical characteristics of "power support and power transfer," helps improve renewable energy consumption capacity and system support capabilities, and is an important technical means for large-scale grid connection of renewable energy. Typically, a single type of energy storage technology is insufficient to meet the diverse application scenarios of ensuring safety, supply, and promoting consumption, while hybrid energy storage, by coupling different energy storage technologies, effectively compensates for the shortcomings of a single type of energy storage.

[0003] Currently, the Shagohuang New Energy Base generally adopts an integrated development model of wind, solar, thermal, and energy storage. Besides supporting coal-fired power plants, some coal-fired power units in the surrounding area are nearing their design life, presenting potential for retrofitting with Carnot batteries. Carnot batteries are a new type of large-scale energy storage system based on thermodynamic cycling and thermal storage technology. They can convert surplus green electricity into thermal energy stored in molten salt, and then convert the thermal energy back into electrical energy for reuse when needed. They have advantages such as low susceptibility to geographical and environmental factors and large energy storage capacity. Retrofitting decommissioned thermal power plants with molten salt Carnot batteries can fully utilize the remaining value of the thermal power units and provide inertial support for the weak power grid structure of the sending-end system, expanding the application scenarios of molten salt thermal storage in the Shagohuang New Energy Base.

[0004] However, there is currently little research on the application of Carnot batteries in the Shagohuang new energy base, and the technical characteristics of Carnot batteries in decommissioned thermal power units are still incomplete. Furthermore, current methods for configuring hybrid electrothermal energy storage in the Shagohuang new energy base mostly employ typical daily or weekly scenario analysis, which fails to fully account for the randomness, fluctuations, intermittency, and impact of extreme weather on new energy output. Moreover, the simulation process involves large amounts of data and long simulation times throughout the year. Therefore, there is currently no efficient and accurate optimization method for the hybrid electrothermal energy storage configuration in the Shagohuang new energy base considering the conversion of decommissioned thermal power units into Carnot batteries. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this application provides a large-scale hybrid energy storage optimization method and apparatus that considers the conversion of thermal power plants into Carnot batteries, specifically adopting the following technical solution:

[0006] A method for optimizing large-scale hybrid energy storage considering the conversion of coal-fired power plants into Carnot batteries is provided for optimizing the configuration of electrochemical energy storage and molten salt thermal energy storage capacity in a hybrid energy storage system, wherein the molten salt thermal energy storage is configured using Carnot batteries converted from coal-fired power plants. The method includes the following steps:

[0007] The wind and solar power curves and power transmission curves for each period of the year were obtained, and the structural composition and energy flow relationship of the Carnot batteries converted from thermal power plants were also obtained.

[0008] A characteristic model of a Carnot battery retrofitted from a thermal power plant is constructed based on its structural composition and energy flow relationship.

[0009] Based on the goal of maximizing net profit, a hybrid energy storage planning and operation integrated model is constructed by combining the characteristic model of the Carnot battery in the thermal power plant conversion.

[0010] Select typical scenarios for different wind and solar power output based on the wind and solar power curves and power transmission curves for different periods throughout the year;

[0011] With the aim of maximizing daily net income under equal annual values, and combining different typical wind and solar power output scenarios, the integrated model of hybrid energy storage planning and operation is solved to obtain energy storage configuration strategies under different typical wind and solar power output scenarios.

[0012] With the aim of maximizing the net annual return under the equivalent annual value, we conduct a full-year time-series production simulation of energy storage configuration strategies under different typical wind and solar power output scenarios to obtain the optimal energy storage configuration strategy.

[0013] Optionally: The net revenue of the hybrid energy storage system in each time period in the integrated planning and operation model of hybrid energy storage is obtained by calculating the comprehensive revenue, investment cost and operating cost of the hybrid energy storage system in the corresponding time period;

[0014] The comprehensive revenue of the hybrid energy storage system is obtained by calculating the electricity sales revenue and green certificate trading revenue for the corresponding time period; the investment cost of the hybrid energy storage system is obtained by calculating the investment costs of wind power generation, photovoltaic power generation, thermal power units, electrochemical energy storage and molten salt Carnot batteries for the corresponding time period under the equivalent annual value; the operating cost of the hybrid energy storage system is obtained by calculating the fuel cost of thermal power units, carbon trading cost, renewable energy curtailment penalty and main grid power purchase cost for the corresponding time period.

[0015] Optionally: The integrated planning and operation model of the hybrid energy storage needs to meet the first constraint condition, which includes the rated power and rated capacity constraints of the electrothermal hybrid energy storage, power balance constraints, new energy operation constraints, thermal power unit operation constraints, electrochemical energy storage operation constraints, and external DC transmission operation constraints.

[0016] Optionally: The steps for solving the integrated planning and operation model of hybrid energy storage, with the aim of maximizing daily net income under equal annual values ​​and in combination with typical scenarios of different wind and solar power output, include:

[0017] For the selected typical wind and solar power output scenarios, the corresponding wind and solar power curves and power transmission curves for the typical wind and solar power output scenarios are obtained respectively.

[0018] With the goal of maximizing daily net profit, a hybrid integer linear programming approach is used to solve the integrated model of hybrid energy storage planning and operation, and output the corresponding energy storage configuration strategy for typical wind and solar power output scenarios.

[0019] Optionally: The step of conducting year-round time-series production simulation of energy storage configuration strategies under different typical wind and solar power output scenarios with the aim of maximizing annual net income under the equivalent annual value includes:

[0020] Obtain energy storage configuration strategies under typical scenarios of different wind and solar power outputs; and divide the entire year into several time series lengths according to a preset step size;

[0021] For different typical scenarios of wind and solar power output, the integrated model of hybrid energy storage planning and operation under different time series is solved sequentially according to the time series length to obtain the net benefits of different time series under the current energy storage configuration strategy.

[0022] The net income from different time periods is summed to obtain the annual net income corresponding to the current energy storage configuration strategy;

[0023] For different energy storage configuration strategies, the energy storage configuration strategy with the highest annual net return is selected.

[0024] Optional: When conducting year-round time-series production simulations for energy storage configuration strategies under different typical wind and solar power output scenarios, a second constraint must be met. The second constraint includes:

[0025] The change in power output at the end of the previous time sequence and the change in power output at the beginning of the next time sequence must meet the allowable ramp rate range of the adjacent time sequence.

[0026] The operating state of electrochemical energy storage and molten salt thermal energy storage at the end of the previous time series is the same as the operating state at the beginning of the next time series.

[0027] Optionally: The step of constructing a characteristic model of molten salt thermal energy storage based on the structural composition and energy flow relationship of a Carnot battery converted from a thermal power plant includes:

[0028] The structural composition and energy flow relationship of the modified Carnot battery for thermal power plants are analyzed. The modified Carnot battery for thermal power plants includes at least a heat pump cycle unit, a molten salt thermal storage unit, and a steam generation unit.

[0029] Based on the structural composition analysis of the Carnot battery in the thermal power plant renovation, a corresponding cost model is obtained;

[0030] The corresponding operating model is obtained based on the energy flow relationship of the Carnot battery conversion in the thermal power plant.

[0031] The characteristic model of the Carnot battery converted from thermal power plant is obtained based on the cost model and the operation model.

[0032] Optional: The cost model must satisfy a third constraint, which includes:

[0033] The rated power of the heat pump cycle unit is calculated by the rated power of the molten salt thermal storage unit and the coefficient of performance of the heat pump cycle unit.

[0034] The rated power of the steam generating unit is the same as the rated power of the molten salt thermal storage unit.

[0035] Optionally: The running model must satisfy a fourth constraint, which includes:

[0036] The thermal storage power of the molten salt thermal storage unit is calculated by the charging power of the Carnot battery converted from thermal power plant and the heating coefficient of the heat pump cycle unit, and the charging power of the Carnot battery converted from thermal power plant does not exceed the rated power of the heat pump cycle unit.

[0037] The energy state of the molten salt thermal storage unit in the current period is calculated by its energy state in the previous period, the charging and discharging power, the charging and discharging efficiency and the heat loss rate.

[0038] The charging and discharging processes of the molten salt thermal storage unit cannot be carried out simultaneously, and the energy state of the molten salt thermal storage unit does not exceed the corresponding upper and lower limits. The charging power or discharging power of the molten salt thermal storage unit does not exceed the maximum charging power or maximum discharging power under the corresponding state.

[0039] The discharge power of the modified Carnot battery in the thermal power plant does not exceed the heat release power of the molten salt thermal storage unit.

[0040] The charging and discharging power of the modified Carnot battery is equal to the difference between the discharging power and the charging power of the modified Carnot battery.

[0041] Furthermore, this application also discloses a large-scale hybrid energy storage optimization device considering the conversion of coal-fired power plants into Carnot batteries, used to optimize the configuration of electrochemical energy storage and molten salt thermal storage capacity in a hybrid energy storage system, wherein the molten salt thermal storage is configured using coal-fired power plants converted into Carnot batteries. The device includes:

[0042] The parameter acquisition module is used to acquire the wind and solar power curves and power transmission curves for each period of the year, and to acquire the structural composition and energy flow relationship of the Carnot batteries converted from thermal power plants.

[0043] The Carnot Battery Characteristic Building Module is used to construct characteristic models of Carnot batteries converted from thermal power plants based on their structural composition and energy flow relationships.

[0044] The energy storage model building module is used to build an integrated model for hybrid energy storage planning and operation based on the characteristics of the Carnot battery converted from thermal power plants, with the goal of maximizing net profit.

[0045] The scenario selection module is used to select typical scenarios with different wind and solar power output based on the wind and solar power curves and power transmission curves for different periods of the year.

[0046] The energy storage strategy generation module aims to maximize the daily net income under the equal annual value, and solves the integrated model of hybrid energy storage planning and operation in combination with different typical wind and solar power output scenarios to obtain energy storage configuration strategies under different typical wind and solar power output scenarios.

[0047] The energy storage strategy optimization module is used to simulate the energy storage configuration strategy throughout the year under different typical wind and solar power output scenarios with the aim of maximizing the annual net income under the equal annual value, and obtain the optimal energy storage configuration strategy.

[0048] Beneficial effects

[0049] The technical solution of this application achieves the following beneficial effects:

[0050] (1) The hybrid energy storage optimization method of this application aims to maximize net income. It establishes an integrated model for hybrid energy storage planning and operation that takes into account green certificate-carbon trading. First, with the goal of maximizing daily net income, the integrated model for hybrid energy storage planning and operation is used to obtain multiple hybrid energy storage candidate schemes under typical scenarios. Then, with the goal of maximizing annual net income, the annual time-series production simulation of each energy storage candidate scheme is performed to select the best energy storage configuration scheme. This method realizes the optimized configuration of electric and thermal hybrid energy storage in the Shagohuang New Energy Base. It fully considers the randomness, volatility, intermittency and extreme weather conditions of new energy output, and is closer to the actual situation of the Shagohuang New Energy Base. It retains a certain degree of calculation accuracy while greatly reducing the difficulty of model solving and improving calculation efficiency.

[0051] (2) The hybrid energy storage optimization method of this application adopts the Carnot battery configuration of decommissioned thermal power plants to form molten salt thermal storage, which can be combined with electrochemical energy storage to effectively support the power transmission from the Shagohuang new energy base. By utilizing the advantages of large capacity, low cost and long discharge time of the Carnot batteries converted from decommissioned thermal power plants, it complements electrochemical energy storage to a certain extent, realizes the comprehensive utilization of multiple energy sources, effectively improves the flexibility of the power system, and significantly increases the utilization rate of new energy in the base and the proportion of renewable energy in the transmission channels. Attached Figure Description

[0052] Figure 1 This is a flowchart of a large-scale hybrid energy storage optimization method that considers the conversion of thermal power plants into Carnot batteries, as described in this application.

[0053] Figure 2This is a schematic diagram of the structure of the Shagohuang New Energy Base, which includes a decommissioned thermal power plant converted into a Carnot battery, as described in this application embodiment.

[0054] Figure 3 This is a schematic diagram of the molten salt Carnot battery power generation system based on the retrofitting of decommissioned thermal power plants in this application embodiment.

[0055] Figure 4 This is a diagram showing the energy flow relationship during discharge of molten salt energy storage formed by the Carnot battery configuration in the embodiment of this application.

[0056] Figure 5 This is a flowchart illustrating the process of simulating and solving the annual time-series production based on time dimension decomposition in this application embodiment.

[0057] Figure 6 This is a power balance diagram of the Shagohuang New Energy Base under a typical spring week scenario in this application embodiment.

[0058] Figure 7 This is a power balance diagram of the Shagohuang New Energy Base under a typical summer week scenario in this application embodiment.

[0059] Figure 8 This is a graph showing the operation curves of the electrothermal hybrid energy storage under typical weekly scenarios in spring and summer in the embodiments of this application.

[0060] Figure 9 This is a schematic diagram of the hybrid energy storage optimization device in the embodiments of this application.

[0061] Figure 10 This is a structural diagram of an electronic device according to an embodiment of this application. Detailed Implementation

[0062] The present application will now be further described with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application and should not be construed as limiting the scope of protection of the present application. It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present application.

[0063] Under the "dual carbon" goal, large-scale wind and solar power bases, focusing on desert, Gobi, and arid regions, have become the main battleground for my country's new energy development. With the large-scale development and utilization of new energy bases in these areas, the problem of new energy consumption has become increasingly prominent. Energy storage, with its technical characteristics of "power support and power transfer," helps improve the capacity for new energy consumption and system support, and is an important technical means for large-scale grid connection of new energy. Therefore, how to rationally plan energy storage capacity in new energy bases in desert and Gobi regions to ensure the safe, stable, economical, and efficient operation of these bases has become an urgent problem to be solved.

[0064] like Figure 1As shown, this embodiment specifically discloses a large-scale hybrid energy storage optimization method considering the conversion of thermal power plants into Carnot batteries. This method is used in the Shagohuang New Energy Base, such as... Figure 2 The diagram shows the structural structure of the Shagohuang New Energy Base system, which includes a converted Carnot battery from a decommissioned thermal power plant. Located at the end of the power grid and connected to the main grid, this system primarily consists of wind power, photovoltaic power, thermal power, electrochemical energy storage, and molten salt thermal energy storage. Power is transmitted to other regions via ultra-high-voltage transmission channels. The energy from electrochemical energy storage and molten salt thermal energy storage is solely provided by surplus electricity from the new energy plants; off-peak electricity from the grid and thermal power generation are not considered for storage. Furthermore, neither type of storage can be charged or discharged simultaneously. When the Shagohuang New Energy Base experiences peak wind and solar power generation, the surplus electricity can be absorbed and stored through electrochemical energy storage and molten salt thermal energy storage, promoting the utilization of new energy sources. When wind and solar power output is low, electrochemical energy storage and molten salt thermal energy storage work together to release energy and meet power transmission needs. In the event of extreme weather conditions such as high temperatures, cold waves, or sandstorms, causing a significant short-term reduction in wind and solar power output, the base will purchase electricity from the local grid to meet power transmission needs. In this case, the main grid will provide emergency power support.

[0065] The large-scale hybrid energy storage optimization method in this embodiment can optimize the configuration of electrochemical energy storage and molten salt thermal energy storage capacity in the hybrid energy storage system within the base. The molten salt thermal energy storage utilizes molten salt Carnot batteries configured from decommissioned thermal power plants. Specifically, the method includes the following steps:

[0066] First, obtain the relevant parameters:

[0067] Specifically, this embodiment acquires wind and solar power curves and power transmission curves for each time period throughout the year, and obtains the structural composition and energy flow relationship of the Carnot cells converted from thermal power plants. The wind and solar power curves reflect the changes in output power of wind and solar power generation over time, showing the power output of wind and solar power at different times. The power transmission curve reflects the changes in power transmission capacity or quantity over time when electricity is transmitted from the generation end, providing a clear view of power transmission at different times. Both are important bases for power system planning, scheduling, and trading.

[0068] In detail, the wind and solar power curves mentioned above in this embodiment can be obtained by analyzing the historical power data and related meteorological data collected throughout the year through a data analysis model to obtain the annual 8760h wind and solar power curves; while the power transmission curves are obtained by fitting based on the power balance by analyzing the power source at the sending end, the load at the receiving end, and the power grid transmission capacity.

[0069] More specifically, traditional thermal power units generally consist of a boiler, a steam turbine, and a generator. In this embodiment, the thermal power unit is converted into a Carnot battery by using a heat pump cycle unit and a molten salt thermal storage unit to replace the boiler combustion system, while retaining the original power generation cycle system, i.e., the steam generation unit. This allows the thermal power unit to be converted into a molten salt Carnot battery. For example... Figure 3 As shown, the Carnot battery based on the conversion of decommissioned thermal power plants can be divided into three parts: heat pump cycle unit, molten salt thermal storage unit, and steam generation unit. The heat pump cycle unit consists of equipment such as motor, expander, compressor, heat source heat exchanger, regenerator, and cold source heat exchanger. The molten salt thermal storage unit adopts a dual-tank molten salt thermal storage system based on high-temperature molten salt tank and low-temperature molten salt tank. The steam generation unit retains the original steam turbine, generator, condenser, and other equipment.

[0070] During the charging process, the waste electricity from renewable energy sources drives the compressor to adiabatically compress the circulating working fluid to a high-temperature, high-pressure state. This high-temperature, high-pressure working fluid then exchanges heat with molten salt in a heat source heat exchanger, becoming a medium-temperature, high-pressure working fluid, with its heat stored in a high-temperature molten salt tank. The medium-temperature, high-pressure working fluid then exchanges heat with the working fluid at the outlet of a cold source heat exchanger via a regenerator, becoming a low-temperature, high-pressure working fluid. It then enters an expander to perform work, becoming a low-temperature, low-pressure working fluid. After exchanging heat with the cold source heat exchanger, the temperature of the low-temperature, low-pressure working fluid rises, and it enters the regenerator for further heating, becoming a medium-temperature, low-pressure working fluid. Finally, it re-enters the compressor, becoming a high-temperature, high-pressure working fluid, and begins the next cycle. The waste electricity from renewable energy sources is ultimately converted into thermal energy stored in molten salt, achieving energy storage.

[0071] During the discharge process, the molten salt heat exchange process in the high-temperature molten salt storage tank is divided into two parts. One part of the molten salt enters the superheater and exchanges heat with steam from the evaporator. The steam is further heated to the main steam temperature and enters the high-pressure steam system. The other part of the molten salt enters the reheat superheater and exchanges heat with steam extracted from the high-pressure steam system. After the steam temperature rises, it enters the medium- and low-pressure steam system, converting the thermal energy of the steam into the mechanical energy of the rotor and ultimately outputting electrical energy. After the heat exchange, the two parts of molten salt merge and pass through the evaporator and preheater to exchange heat with low-temperature steam before returning to the low-temperature molten salt storage tank. Since the energy of the Carnot battery comes from the waste electricity of new energy sources, and the final form of energy utilization is also electrical energy, the charging and discharging processes cannot be carried out simultaneously.

[0072] Subsequently, a characteristic model for converting thermal power plants into Carnot batteries was constructed:

[0073] This embodiment constructs a characteristic model of a Carnot battery converted from a thermal power plant based on its structural composition and energy flow relationship.

[0074] Specifically, the Carnot battery converted from a thermal power plant includes at least a heat pump cycle unit, a molten salt thermal storage unit, and a steam generation unit; and its energy flow relationship is as follows: Figure 4As shown, the input energy of the heat pump cycle unit comes from the abandoned electricity of new energy sources, and the output energy is stored in the molten salt thermal storage unit through the heat source heat exchanger; while the output energy of the molten salt thermal storage unit is converted into the input energy of the steam generation unit through the steam heat exchange between the superheater and the evaporator.

[0075] Subsequently, based on the structural composition analysis of the Carnot battery in the thermal power plant conversion, the corresponding cost model is obtained, which can be expressed as:

[0076]

[0077] Where C CB Cost of modifying Carnot batteries; This indicates the unit power cost of the heat pump equipment; This indicates the unit capacity cost of the molten salt thermal storage unit; This indicates the unit power cost of the steam generating unit; Indicates the rated power of the heat pump equipment; Indicates the rated capacity of the molten salt thermal storage unit; This indicates the rated power of the steam generating unit.

[0078] It should be noted that the rated power of the heat pump cycle unit in this embodiment is calculated using the rated power of the molten salt thermal storage unit and the coefficient of performance (COP) of the heat pump cycle unit; and the rated power of the steam generating unit is the same as the rated power of the molten salt thermal storage unit. That is, the following relationship is satisfied:

[0079]

[0080] in The rated power of the molten salt thermal storage unit is indicated; the coefficient of performance (COP) of the heat pump cycle unit is defined as the ratio of the heat output of the heat pump cycle unit to the electrical energy consumed.

[0081] Subsequently, the corresponding operating model is obtained based on the energy flow relationship of the Carnot battery converted from the thermal power plant. The following settings can be made when constructing the operating model: 1) Ignore the pressure drop of the pipeline and heat exchanger; 2) All links in the cycle process reach a steady state; 3) The compressor and expander are adiabatic during operation; 4) The isentropic efficiency and mechanical efficiency of the compressor and expander are constant.

[0082] Specifically, in this embodiment, the input energy of the heat pump cycle unit comes from the abandoned power of new energy sources, and the output energy is stored in the molten salt thermal storage unit through a heat source heat exchanger. Therefore, the following relationship must be satisfied: the thermal storage power of the molten salt thermal storage unit is calculated using the charging power of the converted Carnot battery and the heating coefficient of the heat pump cycle unit, and the charging power of the converted Carnot battery does not exceed the rated power of the heat pump cycle unit; that is:

[0083]

[0084] In the above formula This represents the thermal storage power of the molten salt thermal storage unit during time period t; This represents the charging power of the Carnot battery converted from a thermal power plant during time period t.

[0085] In this embodiment, the energy state of the molten salt thermal storage unit in the current period is calculated based on its energy state in the previous period, the charge / discharge power, the charge / discharge efficiency, and the heat loss rate; its energy balance model can be expressed as:

[0086]

[0087] In the above formula, E tes,t and E tes,t-1 These represent the energy states of the molten salt thermal storage unit during time period t and time period t-1, respectively. This indicates the self-heating rate of the molten salt thermal storage unit; This represents the heat release power of the molten salt thermal storage unit during time period t; and Δt represents the heat charging and heat release efficiency of the molten salt thermal storage unit, respectively; Δt represents the time interval.

[0088] Furthermore, the charging and discharging processes of the molten salt thermal storage unit cannot occur simultaneously, and the energy and charging / discharging power of the molten salt thermal storage unit are subject to certain limitations: the energy state of the molten salt thermal storage unit does not exceed the corresponding upper and lower limits, and the charging or discharging power of the molten salt thermal storage unit does not exceed the maximum charging or discharging power under the corresponding state; that is:

[0089]

[0090] In the above formula and These represent the lower and upper limits of the energy state of the molten salt thermal storage unit, respectively; and P represents the energy state at the initial and final moments, respectively. tes,t This represents the heat charge / discharge power of the molten salt thermal storage unit during time period t; This represents the heat release state of the molten salt thermal storage unit during time period t, and is a 0-1 variable; This represents the charging state of the molten salt thermal storage unit during time period t, and is a 0-1 variable.

[0091] Furthermore, in this embodiment, thermal energy is converted into electrical energy through the steam generating unit. Therefore, during the energy conversion process of the steam generating unit, the following must be satisfied: the discharge power of the Carnot battery converted from thermal power plant does not exceed the heat release power of the molten salt thermal storage unit; that is:

[0092]

[0093] In the above formula η represents the discharge power of the molten salt Carnot cell during time period t; g K represents thermoelectric conversion efficiency. p This indicates the plant's power consumption rate.

[0094] Furthermore, to standardize the description of the charging and discharging power of Carnot batteries converted from thermal power plants, it must satisfy the following condition: the charging and discharging power of the Carnot battery converted from thermal power plants is equal to the difference between the discharging power and the charging power of the Carnot battery converted from thermal power plants. That is:

[0095]

[0096] In the above formula, P cb,t This represents the charging and discharging power of the Carnot battery during time period t.

[0097] By combining the above conditions, an operational model for the conversion of thermal power plants into Carnot batteries can be constructed.

[0098] Finally, by combining the cost model and the operation model, the characteristic model of the thermal power plant converted into a Carnot battery can be obtained.

[0099] Furthermore, an integrated model for hybrid energy storage planning and operation will be constructed:

[0100] This embodiment aims to maximize net profit and constructs an integrated model for hybrid energy storage planning and operation by combining the characteristic model of thermal power plant conversion to Carnot batteries.

[0101] Specifically, in the integrated planning and operation model of hybrid energy storage described in this embodiment, the net revenue of the hybrid energy storage system for each time period is obtained by calculating the comprehensive revenue, investment cost, and operating cost of the hybrid energy storage system for the corresponding time period, and can be expressed as:

[0102] maxG t =R t -I cost,t -O cost,t ;

[0103] Among them G t R represents the net income of the base during time period t; t This represents the base's overall revenue during time period t; I cost,t This represents the investment cost of the base during time period t; O cost,t This represents the operating cost of the base during time period t.

[0104] The annual comprehensive revenue of the Shagohuang New Energy Base consists of electricity sales revenue and green certificate revenue. Therefore, the comprehensive revenue of the hybrid energy storage system is obtained by calculating the electricity sales revenue and green certificate trading revenue for the corresponding time period, i.e.:

[0105]

[0106] In the above formula, R t R represents the base's overall revenue during time period t; es,t λ represents the electricity sales revenue of the base during time period t; es Indicates the electricity price; P dc,t This represents the DC power transmitted during time period t.

[0107] Furthermore, green certificate trading applies to the on-grid electricity generated by renewable energy power generation projects such as wind power and solar power. Power generation companies certify their environmental rights generated during the production process in the form of green certificates, and then trade them through market mechanisms to obtain revenue. Therefore, the formula for calculating the revenue from green certificate trading is as follows:

[0108] R gct,t =λ gct (P wp,t +P pv,t )Δt;

[0109] In the above formula, R gct,t λ represents the green certificate trading revenue of renewable energy in time period t; gct Indicates the price of the green certificate; P wp,t and P pv,t These represent the actual output of wind power and photovoltaic power generation during time period t, respectively.

[0110] The investment cost of the hybrid energy storage system is obtained by calculating the investment costs of wind power, photovoltaic power, thermal power units, electrochemical energy storage, and molten salt Carnot batteries for the corresponding time period under the same annual value. In this embodiment, the daily investment cost of the hybrid energy storage system is used for calculation, and the calculation formula is as follows:

[0111] C inv,t =C wp,t +C pv,t +C g,t +C bat,t +C cb,t ;

[0112] In the above formula, C inv,t C represents the investment cost of the base in time period t, based on the annual value of the base; wp,t C pv,t C g,t C bat,t C cb,t These represent the investment costs of wind power generation, photovoltaic power generation, thermal power units, electrochemical energy storage, and Carnot batteries used in the retrofitting of thermal power plants, respectively, during time period t.

[0113] Furthermore, since the operating cost of the Shagohuang New Energy Base consists of the fuel cost of thermal power units, carbon trading costs, new energy curtailment penalties, and the cost of purchasing electricity from the main grid during extreme weather, the operating cost of the hybrid energy storage system in this embodiment is obtained by calculating the fuel cost of thermal power units, carbon trading costs, new energy curtailment penalties, and the cost of purchasing electricity from the main grid for the corresponding time period. Its operating cost can be calculated using the following formula:

[0114]

[0115] In the above formula, C op,t C represents the base operating cost during time period t; coal,t C represents the fuel cost of a thermal power unit during time period t; cet,t C represents the carbon trading cost of thermal power units in time period t; cur,t C represents the penalty fee for abandoned renewable energy at the base during time period t; grid,t λ represents the cost of purchasing electricity from the local power grid under extreme weather conditions during time period t; coal P represents the price per unit of standard coal. g,t Indicates the output of the thermal power unit during time period t; η coal Indicates the pulverized coal combustion efficiency in the boiler; Q coal Indicates the calorific value of pulverized coal combustion; λ wp and λ pv These represent the unit wind curtailment and solar curtailment penalty coefficients, respectively. and λ represents the power of wind and solar power curtailment during time period t, respectively; grid This indicates the price of electricity purchased from the local power grid under extreme weather conditions; P grid,t This indicates the emergency support power of the main network during time period t.

[0116] Carbon trading products mainly consist of carbon emission allowances and nationally certified voluntary emission reductions. Carbon emission allowances are based on initial quotas and circulate among power generation companies through the purchase or sale of carbon emission rights. This embodiment uses the industry benchmark method to calculate the initial carbon emission allowances, and the carbon emission trading of thermal power units can be calculated according to the following formula:

[0117] C cet,t =λ cet (D ace,t -D ini,t );

[0118] In the above formula, λ cet D represents the carbon trading price coefficient; ace,t D represents the actual carbon emissions of a thermal power unit during time period t; ini,t This represents the initial carbon emission allowance for thermal power units during time period t.

[0119] Furthermore, the initial carbon emission allowance and actual carbon emissions of thermal power units can be calculated using the following formula:

[0120]

[0121] In the above formula, P g,t This indicates the output of the thermal power unit during time period t; B e The F1 value represents the power generation baseline value for the unit's category; F1 represents the correction factor for the unit's cooling method; F f Indicates the unit's peak-shaving correction factor; A cei This indicates the actual carbon emission intensity of the unit.

[0122] In addition, the integrated planning and operation model of hybrid energy storage described in this embodiment also needs to meet some constraints, including rated power and rated capacity constraints of electrothermal hybrid energy storage, power balance constraints, new energy operation constraints, thermal power unit operation constraints, electrochemical energy storage operation constraints, and external DC transmission operation constraints.

[0123] Furthermore, the integrated planning and operation model for hybrid energy storage must meet the rated power and rated capacity constraints of the electrothermal hybrid energy storage, that is, the rated power and rated capacity of electrochemical energy storage and molten salt thermal energy storage in the Shagohuang New Energy Base must meet certain limitations:

[0124]

[0125] In the above formula and These represent the maximum rated power of electrochemical energy storage and molten salt thermal energy storage, respectively; N bat and N tes These represent the charge / discharge durations for electrochemical energy storage and molten salt thermal energy storage, respectively.

[0126] Furthermore, the integrated planning and operation model for hybrid energy storage needs to satisfy power balance constraints. The power balance equation for the Shagohuang New Energy Base is shown below:

[0127] P wp,t +P pv,t +P g,t +P bat,t +P cb,t +P grid,t =P dc,t ;

[0128] In the above formula, P bat,t This represents the charging and discharging power of the electrochemical energy storage during time period t.

[0129] Furthermore, the integrated planning and operation model for hybrid energy storage must meet the constraints of new energy operation, namely, the wind and solar power of the Shagohuang new energy base must meet the following constraints:

[0130]

[0131] In the above formula, δ wp,t and δ pv,t These represent the theoretical normalized output of wind power and photovoltaic power generation during time period t, respectively.

[0132] The utilization rate of new energy sources must meet the following constraints:

[0133]

[0134] In the above formula, ε represents the utilization rate of new energy sources; T represents the number of time periods within the operating cycle.

[0135] Furthermore, the integrated planning and operation model for hybrid energy storage must meet the operational constraints of thermal power units, namely, the output and ramp rate of the thermal power units must meet the following constraints:

[0136]

[0137] In the above formula Indicates the rated power of the thermal power unit; P represents the minimum technical output of a thermal power unit. g,t+1 This indicates the power output of the thermal power unit during the time period t+1; Indicates the rate of load reduction of thermal power units; This indicates the rate of increase in power output of the thermal power unit.

[0138] Furthermore, the integrated planning and operation model for hybrid energy storage needs to meet the operational constraints of electrochemical energy storage. In this case, the energy balance model for electrochemical energy storage is shown in the following equation:

[0139]

[0140] In the above formula, E bat,t E represents the energy state of electrochemical energy storage at time t; bat,t-1 This indicates the energy state of electrochemical energy storage at time t-1; These represent the charging power and discharging power of the electrochemical energy storage during time period t, respectively. Indicates the self-discharge rate of electrochemical energy storage; Indicates energy storage charging efficiency; This indicates the energy storage and discharge efficiency.

[0141] The electrochemical energy storage charging and discharging processes cannot occur simultaneously, therefore its energy and charging / discharging power are subject to certain limitations.

[0142]

[0143] In the above formula and These represent the minimum and maximum energy states of electrochemical energy storage, respectively. and These represent the energy states at the initial and final moments of electrochemical energy storage, respectively. This represents the discharge state of the energy storage during time period t, and is a 0-1 variable; This represents the charging state of energy storage during time period t, and is a 0-1 variable.

[0144] Furthermore, the integrated planning and operation model for hybrid energy storage needs to meet the constraints of DC power transmission, namely, the renewable energy power transmitted from the Shagohuang New Energy Base to the DC transmission channel needs to meet the following constraints:

[0145]

[0146] In the above formula, ζ represents the proportion of renewable energy power transmitted through external channels.

[0147] The next step is to select typical scenarios:

[0148] This embodiment selects different typical wind and solar power output scenarios based on the wind and solar power curves and power transmission curves for different periods throughout the year. It should be noted that the data volume for the wind and solar power curves and power transmission curves throughout the year is extremely large, leading to long model computation times. This embodiment first selects some typical wind and solar power output scenarios, potentially choosing the most representative wind and solar power output and power transmission modes from massive amounts of data. This simplifies the continuous and complex annual operation into several sets of typical scenarios, using these typical scenarios to represent a class of similar operating conditions. While maintaining a certain level of accuracy, this significantly improves computational efficiency, achieving a balance between accuracy and efficiency.

[0149] Next, we will conduct the initial planning of the energy storage configuration strategy:

[0150] This embodiment first aims to maximize daily net revenue under equal annual values, and then solves the integrated planning and operation model of hybrid energy storage in combination with typical wind and solar power output scenarios to obtain energy storage configuration strategies under different typical wind and solar power output scenarios. It should be understood that the ultimate goal of the method in this embodiment is to obtain an energy storage configuration scheme that maximizes annual revenue. However, due to the long time span of the annual data and the large number of variables to be optimized, the model is difficult to solve directly. Therefore, this embodiment first selects some representative typical wind and solar power output scenarios, and uses the wind and solar power curves and power transmission curves under the corresponding scenarios, combined with the maximization of daily revenue, to obtain an initial energy storage scheme.

[0151] Specifically, this embodiment obtains the wind and solar power curves and power transmission curves for the selected typical wind and solar power output scenarios. By selecting typical scenarios, the long-term annual problem is broken down into a short-term daily problem, which greatly reduces the amount of data processing and the solution dimensions of the variables to be optimized, enabling the model to achieve efficient solution within a reasonable time.

[0152] Finally, with the goal of maximizing daily net profit, the integrated model of hybrid energy storage planning and operation is solved using mixed integer linear programming to output energy storage configuration strategies for typical wind and solar power output scenarios. This allows for the formation of multiple sets of energy storage configuration schemes for typical wind and solar power output scenarios as candidate schemes.

[0153] Finally, a full-year time-series production simulation was conducted:

[0154] This embodiment aims to maximize annual net income under equal annual values. It conducts year-round time-series production simulations of energy storage configuration strategies under different typical wind and solar power output scenarios to obtain the optimal energy storage configuration strategy. The specific steps are as follows:

[0155] Obtain energy storage configuration strategies under typical scenarios of different wind and solar power outputs; and divide the entire year into several time series lengths according to a preset step size;

[0156] For different typical scenarios of wind and solar power output, the integrated model of hybrid energy storage planning and operation under different time series is solved sequentially according to the time series length to obtain the net benefits of different time series under the current energy storage configuration strategy.

[0157] The net income from different time periods is summed to obtain the annual net income corresponding to the current energy storage configuration strategy;

[0158] For different energy storage configuration strategies, the energy storage configuration strategy with the highest annual net return is selected.

[0159] It should be noted that after obtaining candidate energy storage solutions based on different typical scenarios maximizing daily returns, further production simulations are needed to comprehensively and accurately evaluate the long-term benefits of each solution, with annual returns as the objective. By simulating the operation of each candidate energy storage solution under specific conditions throughout the year, the annual returns of each solution are calculated. This approach allows consideration of the significant seasonal variations in wind and solar power output, the overall trend of the electricity market throughout the year, and the impact of long-term equipment wear and tear on returns. This enables the selection of energy storage configurations with superior annual returns that better meet long-term operational needs, ensuring that the selected solutions maximize benefits in the long run.

[0160] In addition, it should be noted that, such as Figure 5 As shown, in this embodiment, during the annual time-series production simulation, due to the large amount of data throughout the year, the 8760 hours of the year can be decomposed into several shorter sub-periods. By increasing the coupling constraints between the preceding and following sub-periods, the integrated model of electric and thermal hybrid energy storage planning and operation for each sub-period is solved sequentially, forming a complete 8760-hour time-series production simulation result. By appropriately decomposing the time dimension of the whole year, the difficulty of solving the model is greatly reduced at the cost of sacrificing a small amount of computational accuracy.

[0161] Furthermore, when this embodiment performs year-round time-series production simulation for energy storage configuration strategies under different typical wind and solar power output scenarios, it needs to meet the operational constraints of thermal power units and hybrid electric-thermal energy storage:

[0162] The change in power output at the end of the previous time sequence and at the beginning of the next time sequence must meet the allowable ramp rate range of the adjacent time sequence, that is:

[0163]

[0164] In the above formula This indicates the power output of the thermal power unit at the end of time sequence n-1; This indicates the power output of the thermal power unit at the beginning of time sequence n.

[0165] The operating state at the end of the previous time series and the operating state at the beginning of the next time series for electrochemical energy storage and molten salt thermal storage are the same, that is:

[0166]

[0167] In the above formula These represent the energy states of the electrochemical energy storage and the molten salt Carnot battery at the end of time series n-1, respectively. denoted as electrochemical energy storage and molten salt Carnot battery at the initial time n, respectively.

[0168] Furthermore, it should be noted that in this embodiment, due to the nonlinear constraints involving the multiplication of 0-1 variables and continuous variables in the charging and discharging constraints of electrochemical energy storage and molten salt Carnot batteries, this paper transforms the nonlinear constraints into linear constraints and uses the YALMIP toolkit on the Matlab platform to call the CPLEX mathematical optimization solver for solving.

[0169] Furthermore, this embodiment takes a new energy base project as an example for analysis. The project has a planned total installed capacity of 16 million kilowatts, including 4 million kilowatts of wind power, 8 million kilowatts of photovoltaic power, and 4 million kilowatts of supporting coal-fired power. A certain scale of energy storage is also configured. Two subcritical 600,000-kilowatt units around the base are nearing the end of their service life and can be converted into molten salt Carnot batteries. The wind and solar curtailment cost is set at 300 yuan / MWh, the grid purchase price is 1,000 yuan / MWh, the unit standard coal price is 800 yuan / t, the green certificate price is 100 yuan / MWh, the carbon trading price is 90 yuan / t, the power generation benchmark value is 0.7910 tCO2 / MWh, the unit cooling method correction coefficient is 1, the unit load output coefficient is 0.55, the actual carbon emission intensity of the unit is 0.9 tCO2 / MWh, the pulverized coal combustion efficiency is 0.89, the pulverized coal combustion calorific value is 29.31 MJ / kg, the wind and solar utilization rate is 91%, and the renewable energy power generation accounts for 50%. The dual-tank molten salt thermal energy storage system uses solar salt, with a heat pump cycle pressure ratio of 3, an isentropic efficiency of 0.9 for the compressor and expander, and a mechanical efficiency of 1. The compressor outlet temperature is 589℃, the cold source inlet temperature is 67℃, and the molten salt inlet and outlet temperatures are 290℃ and 560℃, respectively. The plant power consumption rate is 6%. The electrochemical energy storage and molten salt Carnot battery have a service life of 10 years.

[0170] This embodiment sets up three sets of schemes for comparative analysis of key indicators such as annual net income, new energy utilization rate, and proportion of renewable energy power generation in a certain new energy base. Scheme 1: The new energy base is not equipped with any energy storage; Scheme 2: The new energy base is only equipped with electrochemical energy storage; Scheme 3: The new energy base is equipped with electrochemical energy storage and molten salt Carnot batteries converted from decommissioned thermal power plants, i.e., an electrothermal hybrid energy storage scheme. Through the time-series production simulation method of 8760 hours per year, the energy storage configuration results of the Shagohuang new energy base for each scheme are shown in Table 1.

[0171] Table 1

[0172]

[0173]

[0174] As shown in Table 1, Scheme 3 is the preferred option. With 556MW / 2224MWh of electrochemical energy storage and 2800MW / 16800MWh of molten salt energy storage, the new energy base can achieve a maximum annual net income of 3.628 billion yuan, with annual electricity sales revenue and green certificate revenue of 13.192 billion yuan and 2.625 billion yuan respectively, of which green certificate revenue accounts for 16.6% of the total revenue. Although Scheme 1 has the lowest annual investment cost, it results in a severe deficiency in the system's flexible adjustment capability. Compared with Scheme 1, although the annual investment cost of Scheme 3 increases by 1.169 billion yuan, the annual operating cost decreases by 1.187 billion yuan, and the annual net income increases by 277 million yuan, an increase of 8.27%. Scheme 2 requires an additional 777 million yuan in annual investment in electrochemical energy storage, which somewhat improves the problem of insufficient resources for flexible system adjustment. Scheme 2 increases the new energy utilization rate by 4.78 percentage points compared to Scheme 1, and the proportion of renewable energy in the power transmission channel increases by 2.5 percentage points. Option 3, with its hybrid electric-thermal energy storage, can further improve the utilization rate of new energy sources and the proportion of renewable energy in the transmission channel. Compared to Option 2, the utilization rate of new energy sources is increased by 4.64 percentage points, and the proportion of renewable energy in the power transmission channel is increased by 1.38 percentage points. Based on an average utilization of 5,500 hours for the DC transmission channel, the channel will transmit 44 billion kWh of electricity annually. Option 3 can transmit 1.7 billion kWh and 600 million kWh more renewable energy annually than Options 1 and 2, respectively. Furthermore, the annual carbon emission costs of thermal power units under the above options are not significantly different, meaning that the energy storage configuration options for the Shagohuang new energy base have a relatively small impact on the carbon emissions of thermal power units.

[0175] For the hybrid electric-thermal energy storage configuration scheme of Scheme 3, the operation was analyzed under typical weekly scenarios in spring, summer, autumn and winter. The power balance and operation curves of the hybrid electric-thermal energy storage at the Shagohuang New Energy Base under typical weekly scenarios in spring and summer are shown below. Figures 6 to 8 As shown. According to Figure 6 and Figure 8It can be seen that in a typical spring week scenario, from 8:00 AM to 9:00 AM on the first day, photovoltaic power generation is at its peak, while thermal power units reach their minimum technical output for deep peak shaving. Electrochemical energy storage and molten salt Carnot batteries absorb surplus renewable energy through electricity and heat storage, respectively, avoiding large-scale power curtailment. By 10:00 AM, the power transmission capacity rapidly increases, exceeding 6 million kilowatts. Due to the higher cycle efficiency of electrochemical energy storage compared to molten salt Carnot batteries, electrochemical energy storage releases energy first. From 10:00 AM to 5:00 PM, thermal power units increase their output to meet the power transmission demand together with new energy sources. Electrochemical energy storage and molten salt Carnot batteries do not discharge to release energy, and electrothermal hybrid energy storage is in a static state. This is because from 6:00 PM to 8:00 PM, due to the lack of light at night, the power generation capacity of new energy sources decreases, and the power supply weakens. Even after thermal power units increase their output to 4 million kilowatts, they still cannot meet the power transmission demand. Therefore, electrochemical energy storage and molten salt Carnot batteries must discharge during the evening peak period to play their peak role. If they discharge in advance, it will be difficult to meet the power transmission curve requirements by relying solely on the power generation capacity of the base. It will be necessary to purchase power from the main grid urgently or reduce DC power. Therefore, electrothermal hybrid energy storage cannot discharge during the period from 10:00 AM to 5:00 PM and can only rely on the thermal power units for regulation. From 1:00 AM to 6:00 AM on the second day, wind power generation was at its peak, and from 8:00 AM to 9:00 AM, photovoltaic power generation gradually increased. Thermal power units underwent deep peak shaving for up to 9 hours, while electrochemical energy storage and molten salt Carnot batteries entered continuous charging mode. Due to insufficient photovoltaic output at midday, electrochemical energy storage and molten salt Carnot batteries started discharging. At 9:00 AM on the third day, the base experienced a certain scale of power curtailment. The reason for this curtailment was that the power generation of new energy sources far exceeded the charging power of electrochemical energy storage and molten salt Carnot batteries, and the thermal power units also reached their minimum output limit. The system had no other means to absorb new energy, thus resulting in a certain scale of power curtailment. From 1 p.m. to 8 p.m., the Shagohuang New Energy Base encountered extreme weather, experiencing eight consecutive hours of poor wind and solar power. The thermal power units quickly increased their output to reach their peak performance, achieving a maximum technical output of 4 million kilowatts. As the output of photovoltaic power generation began to decrease in the afternoon, electrochemical energy storage and molten salt energy storage started their discharge mode to meet the power demand, and by 4 p.m., all the power had been exhausted. At this point, the base had to purchase high-priced electricity from the main grid to meet the power transmission demand for five hours during the evening peak period.

[0176] according to Figure 7 and Figure 8It is evident that during typical summer weeks, the base experienced multiple instances of power supply falling short of demand. On the first, sixth, and seventh days, during the midday and evening peak hours, it purchased high-priced electricity from the main grid to meet the power needs of the receiving areas. On the third and fourth days, abundant wind and solar resources led to a surge in renewable energy generation, resulting in the base maintaining a high output level. This resulted in two consecutive days of wind and solar power curtailment, with thermal power units operating at minimum technical output for extended periods. Electrochemical energy storage and molten salt Carnot batteries maximized the absorption of renewable energy, leading to a significant increase in curtailment. During the midday peak on the fifth day, the hybrid electrothermal energy storage continuously discharged to meet the power transmission curve requirements. Electrochemical energy storage discharged continuously for 4 hours, and the molten salt Carnot battery discharged continuously for 6 hours, verifying that the base's hybrid electrothermal energy storage can complement both long and short-cycle cycles, contributing to a high proportion of renewable energy transmission.

[0177] Furthermore, to analyze the impact of the time series length of the time-series production simulation on the hybrid energy storage configuration of the Shagohuang New Energy Base, this embodiment designs two sets of calculation examples for comparison with the results of the annual 8760-hour production simulation of Scheme 3. Calculation example 1 uses wind and solar data from four typical days in spring, summer, autumn, and winter, with a time series length of 4 days; calculation example 2 uses wind and solar data from four typical weeks in spring, summer, autumn, and winter, with a time series length of 4 weeks. The time-series production simulation results of the Shagohuang New Energy Base under different time series lengths are shown in Table 2.

[0178] Table 2

[0179]

[0180] According to the calculation results in Table 2, compared with Scheme 3, the annual operating costs of the bases in Examples 1 and 2 decreased by 34% and 15.4% respectively, the net income of the bases increased by 49% and decreased by 5% respectively, the utilization rate of new energy increased by 16.86 percentage points and 16.99 percentage points respectively, and the proportion of renewable energy power generation in the transmission channels increased by 11.8 percentage points and decreased by 0.05 percentage points respectively. These results indicate that considering the time series length has a significant impact on the planned operation of the base, the shorter the time series length of the time-series production simulation, the greater the calculation error. Typical daily and weekly scenarios cannot fully reflect the randomness, volatility, and intermittency of new energy output. In particular, the desert and Gobi regions often face extreme weather such as high temperatures and sandstorms, which will seriously affect the accuracy of the calculation results of key indicators such as the annual net income of the base, the utilization rate of new energy, and the proportion of renewable energy power generation in the transmission channels. Therefore, an 8760-hour time-series production simulation method is adopted throughout the year to fully consider various extreme weather changes and truly reflect the actual operation of the new energy base in the desert and Gobi regions.

[0181] Furthermore, considering that the charging and discharging duration of the electrothermal hybrid energy storage system has a certain impact on the energy storage planning and operation results of the Shagohuang New Energy Base, this embodiment also designed two sets of calculation examples to compare and analyze the impact of the charging and discharging duration of the electrothermal hybrid energy storage system. Calculation example 3: The base is equipped with only 2400MW / 4800MWh of electrochemical energy storage, i.e., the electrochemical energy storage charges and discharges for 2 hours. Calculation example 4: The base is equipped with 556MW / 2224MWh of electrochemical energy storage and 2100MW / 16800MWh of molten salt energy storage, with the molten salt energy storage charging and discharging for 8 hours. The simulation results of the annual 8760h time-series production of the Shagohuang New Energy Base under different electrothermal hybrid energy storage charging and discharging durations are shown in Table 3.

[0182] Table 3

[0183]

[0184] According to the results in Table 3, compared to Scheme 2, which only includes electrochemical energy storage, in terms of economics, the annual investment cost of Scheme 3 increases by 155 million yuan, while the annual net income decreases by 40 million yuan. In terms of new energy consumption, the utilization rate of new energy and the proportion of renewable energy power in the transmission channel increase by 0.51 and 0.27 percentage points, respectively. These results indicate that when the base is equipped with a rated electrochemical energy storage capacity of 4800MWh, the investment entity of the Shagohuang New Energy Base should configure electrochemical energy storage with a rated power of 1200MW and a duration of 4 hours, which is more economical than that with a rated power of 2400MW and a duration of 2 hours. This is because the investment cost of electrochemical energy storage consists of power cost and capacity cost. An increase in rated power leads to a significant increase in power cost, while the revenue from electricity sales mainly depends on the amount of electricity sold, so the change in revenue is not significant. From the perspective of the investment entity, electrochemical energy storage with a smaller rated power and a longer charging / discharging time should be configured. On the other hand, electrochemical energy storage with a larger rated power can better play its role in peak shaving and deep regulation, realizing peak shaving and valley filling of the system and promoting the consumption of new energy. From the perspective of system consumption, electrochemical energy storage with a larger rated power and shorter charge and discharge time should be configured. Similarly, compared with the above scheme 3, which is equipped with a hybrid electrothermal energy storage, the annual net profit of the calculation example 4 base increases by 0.32 billion yuan, while the new energy utilization rate and the proportion of renewable energy in the channel decrease by 0.49 and 0.18 percentage points, respectively. Carnot batteries and electrochemical energy storage show the same trend in terms of economics and new energy consumption. In addition, in terms of ensuring system safety, Carnot batteries with a larger rated power can provide more inertia support for the system, making full use of the residual value of stranded assets such as decommissioned coal-fired power turbines and generators.

[0185] Further, such as Figure 9As shown, this application also discloses a large-scale hybrid energy storage optimization device considering the conversion of thermal power plants into Carnot batteries, used to optimize the configuration of electrochemical energy storage and molten salt thermal storage capacity in a hybrid energy storage system, wherein the molten salt thermal storage is configured using a converted thermal power plant Carnot battery. The device includes:

[0186] The parameter acquisition module is used to acquire the wind and solar power curves and power transmission curves for each period of the year, and to acquire the structural composition and energy flow relationship of the Carnot batteries converted from thermal power plants.

[0187] The Carnot Battery Characteristic Building Module is used to construct characteristic models of Carnot batteries converted from thermal power plants based on their structural composition and energy flow relationships.

[0188] The energy storage model building module is used to build an integrated model for hybrid energy storage planning and operation based on the characteristics of the Carnot battery converted from thermal power plants, with the goal of maximizing net profit.

[0189] The scenario selection module is used to select typical scenarios with different wind and solar power output based on the wind and solar power curves and power transmission curves for different periods of the year.

[0190] The energy storage strategy generation module aims to maximize the daily net income under the equal annual value, and solves the integrated model of hybrid energy storage planning and operation in combination with different typical wind and solar power output scenarios to obtain energy storage configuration strategies under different typical wind and solar power output scenarios.

[0191] The energy storage strategy optimization module is used to simulate the energy storage configuration strategy throughout the year under different typical wind and solar power output scenarios with the aim of maximizing the annual net income under the equal annual value, and obtain the optimal energy storage configuration strategy.

[0192] The apparatus provided in this application embodiment can achieve... Figure 1 To avoid repetition, the various processes implemented in the method embodiments will not be described again here.

[0193] like Figure 10 As shown in the illustration, this application also provides an electronic device, including a processor and a memory, and a program or instructions stored in the memory and executable on the processor, which, when executed by the processor, implement as follows: Figure 1 The various processes of the method embodiments shown are all capable of achieving the same technical effect, and will not be described again here to avoid repetition.

[0194] This application embodiment also provides a readable storage medium storing a program or instructions that, when executed by a processor, implement the above-described functionality. Figure 1 The various processes described in the embodiments of the method described herein can achieve the same technical effect, and will not be repeated here to avoid repetition.

[0195] This application also provides a computer program product, including computer instructions, which, when executed by a processor, implement the above-described... Figure 1 The various processes described in the embodiments of the method described herein can achieve the same technical effect, and will not be repeated here to avoid repetition.

[0196] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for optimizing large-scale hybrid energy storage considering the conversion of thermal power plants into Carnot batteries, used to optimize the configuration of electrochemical energy storage and molten salt thermal storage capacity in a hybrid energy storage system, wherein the molten salt thermal storage is configured using Carnot batteries converted from thermal power plants, characterized in that, The steps include: The wind and solar power curves and power transmission curves for each period of the year were obtained, and the structural composition and energy flow relationship of the Carnot batteries converted from thermal power plants were also obtained. A characteristic model of a Carnot battery retrofitted from a thermal power plant is constructed based on its structural composition and energy flow relationship. Based on the goal of maximizing net profit, a hybrid energy storage planning and operation integrated model is constructed by combining the characteristic model of the Carnot battery in the thermal power plant conversion. Select typical scenarios for different wind and solar power output based on the wind and solar power curves and power transmission curves for different periods throughout the year; With the aim of maximizing daily net income under equal annual values, and combining different typical wind and solar power output scenarios, the integrated model of hybrid energy storage planning and operation is solved to obtain energy storage configuration strategies under different typical wind and solar power output scenarios. With the aim of maximizing the net annual return under the equivalent annual value, we conduct a full-year time-series production simulation of energy storage configuration strategies under different typical wind and solar power output scenarios to obtain the optimal energy storage configuration strategy.

2. The large-scale hybrid energy storage optimization method according to claim 1, characterized in that, In the integrated planning and operation model of hybrid energy storage, the net income of the hybrid energy storage system in each time period is obtained by calculating the comprehensive income, investment cost and operating cost of the hybrid energy storage system in the corresponding time period. The comprehensive revenue of the hybrid energy storage system is obtained by calculating the electricity sales revenue and green certificate trading revenue for the corresponding time period; the investment cost of the hybrid energy storage system is obtained by calculating the investment costs of wind power generation, photovoltaic power generation, thermal power units, electrochemical energy storage and molten salt Carnot batteries for the corresponding time period under the equivalent annual value; the operating cost of the hybrid energy storage system is obtained by calculating the fuel cost of thermal power units, carbon trading cost, renewable energy curtailment penalty and main grid power purchase cost for the corresponding time period.

3. The large-scale hybrid energy storage optimization method according to claim 2, characterized in that, The integrated planning and operation model for hybrid energy storage must meet the first constraint condition, which includes the rated power and rated capacity constraints of the electrothermal hybrid energy storage, power balance constraints, new energy operation constraints, thermal power unit operation constraints, electrochemical energy storage operation constraints, and external DC transmission operation constraints.

4. The large-scale hybrid energy storage optimization method according to claim 1, characterized in that, The steps for solving the integrated planning and operation model of hybrid energy storage, with the aim of maximizing daily net income under equal annual values ​​and in combination with typical scenarios of different wind and solar power output, include: For the selected typical wind and solar power output scenarios, the corresponding wind and solar power curves and power transmission curves for the typical wind and solar power output scenarios are obtained respectively. With the goal of maximizing daily net profit, a hybrid integer linear programming approach is used to solve the integrated model of hybrid energy storage planning and operation, and output the corresponding energy storage configuration strategy for typical wind and solar power output scenarios.

5. The large-scale hybrid energy storage optimization method according to claim 1, characterized in that, The steps for conducting year-round time-series production simulation of energy storage configuration strategies under different typical wind and solar power output scenarios, with the aim of maximizing annual net income under equivalent annual values, include: Obtain energy storage configuration strategies under typical scenarios of different wind and solar power outputs; The entire year is divided into several time series lengths according to a preset step size; For different typical scenarios of wind and solar power output, the integrated model of hybrid energy storage planning and operation under different time series is solved sequentially according to the time series length to obtain the net benefits of different time series under the current energy storage configuration strategy. The net income from different time periods is summed to obtain the annual net income corresponding to the current energy storage configuration strategy; For different energy storage configuration strategies, the energy storage configuration strategy with the highest annual net return is selected.

6. The large-scale hybrid energy storage optimization method according to claim 5, characterized in that, When conducting year-round time-series production simulations for energy storage configuration strategies under different typical wind and solar power output scenarios, a second constraint must be met. The second constraint includes: The change in power output at the end of the previous time sequence and the change in power output at the beginning of the next time sequence must meet the allowable ramp rate range of the adjacent time sequence. The operating state of electrochemical energy storage and molten salt thermal energy storage at the end of the previous time series is the same as the operating state at the beginning of the next time series.

7. The large-scale hybrid energy storage optimization method according to claim 1, characterized in that, The steps for constructing a characteristic model of molten salt thermal energy storage based on the structural composition and energy flow relationship of a Carnot battery converted from a thermal power plant include: The structural composition and energy flow relationship of the modified Carnot battery for thermal power plants are analyzed. The modified Carnot battery for thermal power plants includes at least a heat pump cycle unit, a molten salt thermal storage unit, and a steam generation unit. Based on the structural composition analysis of the Carnot battery in the thermal power plant renovation, a corresponding cost model is obtained; The corresponding operating model is obtained based on the energy flow relationship of the Carnot battery conversion in the thermal power plant. The characteristic model of the Carnot battery converted from thermal power plant is obtained based on the cost model and the operation model.

8. The large-scale hybrid energy storage optimization method according to claim 7, characterized in that, The cost model must satisfy a third constraint, which includes: The rated power of the heat pump cycle unit is calculated by the rated power of the molten salt thermal storage unit and the coefficient of performance of the heat pump cycle unit. The rated power of the steam generating unit is the same as the rated power of the molten salt thermal storage unit.

9. The large-scale hybrid energy storage optimization method according to claim 7, characterized in that, The operating model must satisfy a fourth constraint, which includes: The thermal storage power of the molten salt thermal storage unit is calculated by the charging power of the Carnot battery converted from thermal power plant and the heating coefficient of the heat pump cycle unit, and the charging power of the Carnot battery converted from thermal power plant does not exceed the rated power of the heat pump cycle unit. The energy state of the molten salt thermal storage unit in the current period is calculated by its energy state in the previous period, the charging and discharging power, the charging and discharging efficiency and the heat loss rate. The charging and discharging processes of the molten salt thermal storage unit cannot be carried out simultaneously, and the energy state of the molten salt thermal storage unit does not exceed the corresponding upper and lower limits. The charging power or discharging power of the molten salt thermal storage unit does not exceed the maximum charging power or maximum discharging power under the corresponding state. The discharge power of the modified Carnot battery in the thermal power plant does not exceed the heat release power of the molten salt thermal storage unit. The charging and discharging power of the modified Carnot battery is equal to the difference between the discharging power and the charging power of the modified Carnot battery.

10. A large-scale hybrid energy storage optimization device considering the conversion of thermal power plants into Carnot batteries, used for optimizing the configuration of electrochemical energy storage and molten salt thermal storage capacity in a hybrid energy storage system, wherein the molten salt thermal storage is configured using Carnot batteries converted from thermal power plants, characterized in that, The device comprises: The parameter acquisition module is used to acquire the wind and solar power curves and power transmission curves for each period of the year, and to acquire the structural composition and energy flow relationship of the Carnot batteries converted from thermal power plants. The Carnot Battery Characteristic Building Module is used to construct characteristic models of Carnot batteries converted from thermal power plants based on their structural composition and energy flow relationships. The energy storage model building module is used to build an integrated model for hybrid energy storage planning and operation based on the characteristics of the Carnot battery converted from thermal power plants, with the goal of maximizing net profit. The scenario selection module is used to select typical scenarios with different wind and solar power output based on the wind and solar power curves and power transmission curves for different periods of the year. The energy storage strategy generation module aims to maximize the daily net income under the equal annual value, and solves the integrated model of hybrid energy storage planning and operation in combination with different typical wind and solar power output scenarios to obtain energy storage configuration strategies under different typical wind and solar power output scenarios. The energy storage strategy optimization module is used to simulate the energy storage configuration strategy throughout the year under different typical wind and solar power output scenarios with the aim of maximizing the annual net income under the equal annual value, and obtain the optimal energy storage configuration strategy.

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