Integrated energy system low-carbon scheduling method and system considering P2G and CCS

Abstract

The invention discloses an integrated energy system low-carbon scheduling method and system considering P2G and CCS, and belongs to the technical field of power generation scheduling, and the method comprises the steps: building a mathematical model of integrated energy system equipment, building a CCP combined operation mode model, combining CHP, P2G and CCS, and converting electric energy into natural gas through P2G by a CHP unit at an electric load trough, and achieving thermoelectric decoupling; the method comprises the following steps: establishing an optimal scheduling model, and when the integrated energy system is optimized, establishing an objective function with the lowest total cost, including the unit operation cost of a CHP unit, a P2G and a CCS, the wind curtailment and light curtailment penalty cost and the carbon transaction cost in a CCP combined operation mode. According to the method, the output range of the CHP unit is expanded, the adjusting capacity of the CHP unit is enhanced, then the wind power absorption capacity of the system is improved, carbon emission of the system is effectively reduced, economic benefits are improved, and meanwhile the problem of high cost after CCS is added to a coal-fired unit can be effectively solved through the established CCP combined operation mode.

Description

Technical Field

[0001] This invention relates to the field of power generation dispatching technology, specifically to a low-carbon dispatching method and system for an integrated energy system that considers P2G and CCS. Background Technology

[0002] Integrated energy systems are multi-energy coupled systems containing electricity, heat, and natural gas. Compared to traditional energy systems, they offer greater flexibility in regulation. Through coordinated control of various energy systems, system energy efficiency can be improved while reducing carbon emissions. Coal-fired units in integrated energy systems produce significant amounts of carbon dioxide. While CCS (Carbon Dioxide Separation System) can achieve a carbon dioxide capture rate of over 90%, its current capture cost is relatively high. Power-to-gas (P2G) technology, introduced by Germany, is another effective way to reduce carbon dioxide emissions. This technology converts carbon dioxide into methane to provide energy. Therefore, combining CCS and P2G technologies to utilize captured carbon dioxide can significantly improve and reduce carbon emissions, while simultaneously improving energy efficiency. P2G technology has a strong capacity for renewable energy absorption, making its rational application in integrated energy systems of great significance. However, current research mainly focuses on the joint optimization of P2G and wind power, with less research on the joint optimization of P2G equipment and coal-fired units. At the same time, the high investment and construction costs of CCS mean that, given the current average price in the domestic carbon trading market, the economic benefits of adding CCS to coal-fired and gas-fired units are relatively low. Summary of the Invention

[0003] In view of the above-mentioned problems, the present invention is proposed.

[0004] Therefore, the objective of this invention is to provide a low-carbon dispatching method for integrated energy systems that considers P2G and CCS. Starting from the supply side of the integrated energy system, this invention analyzes the operating characteristics of combined heat and power (CHP), power-to-gas (P2G), and carbon capture systems (CCS), proposes a joint operation mode of CHP-CCS-P2G (CCP), analyzes the regulation capacity of the CHP units under the joint operation mode from the perspectives of operating characteristics, carbon emissions, operating costs, and constraints, establishes a day-ahead low-carbon dispatching model for integrated energy systems that considers carbon trading under the CCP joint operation mode, and verifies the effectiveness of the proposed method through numerical simulation.

[0005] To address the aforementioned technical problems, this invention provides the following technical solution: a low-carbon dispatching method for an integrated energy system considering P2G and CCS, comprising the following steps: A mathematical model of the integrated energy system equipment is established, which includes a combined heat and power (CHP) unit, power-to-gas (P2G) converter, carbon capture device, micro gas turbine, and energy storage. A CCP joint operation mode model is established, which combines CHP, P2G, and CCS. During periods of low electricity load, the CHP unit converts electricity into natural gas via P2G, achieving heat and power decoupling. An optimization scheduling model is established, which establishes an objective function that minimizes the total cost when optimizing the integrated energy system. This includes the unit operating costs of CHP, P2G, and CCS under the CCP joint operation mode, the cost of wind and solar curtailment penalties, and the cost of carbon trading.

[0006] As a preferred embodiment of the low-carbon dispatching method for an integrated energy system considering P2G and CCS as described in this invention, the mathematical model for establishing the integrated energy system equipment includes: Establish an electrothermal output characteristic model for a combined heat and power unit; Establish a P2G mathematical model, including the first process and the second process. The first process is the generation of hydrogen, and the second process is the synthesis of methane. Consider that the P2G equipment needs to consume carbon dioxide when generating methane, and calculate the carbon consumption during the operation of the P2G. Establish a mathematical model for CCS and calculate the electrical energy required by each device during the absorption, desorption, and compression of carbon dioxide in CCS.

[0007] As a preferred embodiment of the low-carbon dispatching method for an integrated energy system considering P2G and CCS as described in this invention, the mathematical model for establishing the integrated energy system equipment further includes: Establish a mathematical model for the gas turbine: in, Let be the electrical power consumed by the gas turbine at time t. This represents the gas power consumed by the gas turbine at time t. For the operating efficiency of gas turbines, The heat power consumed by the gas turbine at time t. For the loss coefficient of the gas turbine, The heating coefficient of the gas turbine, For the preheating recovery rate of the gas turbine; Establish a mathematical model for energy storage, considering only thermal and electrical storage units: Where x represents the energy category, BS represents a battery, and GS represents a gas storage tank. and Let be the energy stored by energy storage device x during time periods t and t+1, respectively. and Let x be the charging and discharging power of the energy storage device during time period t. ≥0, ≤0, For energy storage devices with capacity x, and This refers to the charging and discharging efficiency of energy storage device x, where Δt is the time interval. and These are the state parameters for charging and discharging, respectively; =1 indicates that the energy storage device performs a charging operation during time period t. =1 indicates that the energy storage device x performs an energy release operation.

[0008] As a preferred embodiment of the integrated energy system low-carbon dispatching method considering P2G and CCS described in this invention, the establishment of the CCP joint operation mode model includes, In the CCP joint operation mode, the CHP unit provides power to the P2G and CCS equipment, and the remaining power is set as the grid power of the CHP unit. Set the power output range of the CHP units under the CCP joint operation mode, and set the power output of the CHP units within the power output range of the CHP units. By converting the grid power of the CHP unit, the grid power output range of the CHP unit under the CCP joint operation mode can be obtained; Calculate the power constraints of the P2G equipment and the power constraints of the established CCS mathematical model when obtaining power. Substitute the power constraints of the P2G equipment and the power constraints of the CCS mathematical model when obtaining power into the grid power output range of the CHP unit to obtain the grid power output range of the CHP unit under the CCP joint operation mode. Calculate the thermal power output range of the CHP unit under the CCP joint operation mode, and substitute it into the established electro-thermal output characteristic model of the cogeneration unit to obtain the electro-thermal output relationship of the CHP unit under the CCP joint operation mode. Since the electrical energy consumed by P2G and CCS all comes from the thermal power unit, the combined output constraint of P2G and CCS is calculated, and the electrical-thermal output relationship of the CHP unit is substituted into it to obtain the electrical-thermal output coupling characteristics of the CHP unit under the CCP joint operation mode.

[0009] As a preferred embodiment of the low-carbon dispatching method for a comprehensive energy system considering P2G and CCS as described in this invention, the establishment of the CCP joint operation mode model further includes constructing an electric-heat-gas output characteristic diagram under the CCP mode by using the grid power output range of the CHP unit under the CCP joint operation mode, the thermal power output range of the CHP unit under the CCP joint operation mode, and the electric-thermal output coupling characteristics of the CHP unit under the CCP joint operation mode. Substituting the established P2G mathematical model into the power constraints of the P2G device, the range constraints of the P2G output qi power are obtained. Under the CCP joint operation mode, the CHP unit realizes the conversion between multiple forms of energy such as electricity, gas and heat, and strengthens the coupling relationship of the integrated energy system; when and At that time, the Qi Gong output by P2G is at its maximum value; when At that time, the Qigong output of P2G is at its minimum value; in, This refers to the on-grid power of the CHP unit under the CCP joint operation mode. and To constrain the upper and lower limits of the on-grid power of CHP units under the CCP joint operation mode, H is the minimum output electrothermal conversion coefficient of the CHP unit. CHP,t Let be the thermal power output of the CHP unit at time t. The electrothermal conversion coefficient of the CHP unit. To set a lower limit constraint on the thermal power of the CHP unit under the CCP joint operation mode. This represents the upper limit of the operating power of P2G devices. This represents the upper limit of the CCS operating power. Substituting the P2G mathematical model and the CCS mathematical model into the electrical-thermal output relationship of the CHP unit under the CCP joint operation mode, the coupling relationship of CHP, P2G and CCS under the CCP joint operation mode is obtained.

[0010] As a preferred embodiment of the low-carbon scheduling method for an integrated energy system considering P2G and CCS as described in this invention, the optimized scheduling model includes: prediction data, constraints, and a minimum objective function. The forecast data includes forecast data for wind power, solar power, and load demand; The constraints include output and ramp rate constraints for the CHP unit, micro gas turbine, and electric chiller under CCP joint operation mode, satisfying the constraint condition of constant power balance. When optimizing the integrated energy system, the minimum objective function with the lowest total cost is established. The operating cost of the minimum objective function includes the operating costs of the CHP unit, P2G and CCS units, the cost of wind and solar curtailment penalties and carbon trading costs under the CCP joint operation mode. The unit operating cost is established by creating a model for the power generation cost of the thermal power unit, and a model for the operating cost of the gas turbine, including fuel costs and a gas purchase cost model. The aforementioned wind and solar curtailment penalty cost is a model for establishing the wind and solar curtailment penalty cost, including wind curtailment penalty cost and solar curtailment penalty cost; The carbon trading cost is established by modeling the carbon trading cost, allocating initial carbon emission rights to each carbon emission unit, and allowing each unit to choose to buy or sell carbon emission allowances based on its actual carbon emission situation. The objective function that minimizes operating cost is: Where C represents the total operating cost of the integrated energy system optimization scheduling model. For gas purchase costs, As a penalty for abandoning light, The penalty cost of abandoning wind power, For the fuel cost of micro gas turbines, For the operating costs of thermal power units, For the cost of carbon trading, The operating cost of the CCP joint operation mode.

[0011] As a preferred embodiment of the low-carbon scheduling method for an integrated energy system considering P2G and CCS as described in this invention, the optimized scheduling model further includes establishing the constraints. When optimizing the integrated energy system, it is necessary to satisfy the balance constraints of electricity-gas-heat power and the output constraints of each component unit, specifically including electricity power balance constraints, heat power balance constraints, gas power balance constraints, micro gas turbine constraints, and gas purchase constraints.

[0012] Another objective of this invention is to provide a low-carbon dispatching system for an integrated energy system that takes into account P2G and CCS.

[0013] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a low-carbon scheduling system for an integrated energy system considering P2G and CCS, comprising an integrated energy model module, a CCP joint operation module, and an optimized scheduling module; The integrated energy model module establishes a mathematical model of integrated energy system equipment, which mainly includes cogeneration units, power-to-gas conversion, carbon capture devices, micro gas turbines, and energy storage. The CCP joint operation module combines CHP, P2G and CCS. During periods of low electricity load, the CHP unit converts electrical energy into natural gas through P2G, achieving thermal-electric decoupling. The optimization scheduling module establishes an objective function that minimizes the total cost when optimizing the integrated energy system. This includes the unit operating costs of CHP units, P2G and CCS units, wind and solar curtailment penalty costs, and carbon trading costs under the CCP joint operation mode.

[0014] The present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, characterized in that the processor executes the computer program to implement the steps of a low-carbon scheduling method for an integrated energy system considering P2G and CCS.

[0015] The present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that, when the computer program is executed by a processor, it implements the steps of the aforementioned low-carbon scheduling method for an integrated energy system considering P2G and CCS.

[0016] The beneficial effects of this invention are as follows: This invention addresses the thermoelectric coupling characteristics of CHP units in integrated energy optimization, deeply analyzes the operation modes of P2G, CCS, and CHP, and proposes a joint low-carbon operation mode (CCP) for CHP units that includes P2G and CCS. The CCP joint operation mode decouples the strong thermoelectric coupling constraints of CHP units, expands the output range of CHP units, enhances their regulation capabilities, and thus improves the system's wind power absorption capacity.

[0017] The CCP joint optimization model established in this invention can effectively reduce the carbon emissions of the system and improve economic efficiency. At the same time, the CCP joint operation mode can effectively alleviate the high cost problem of adding CCS to coal-fired units. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of 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.

[0019] Figure 1 The present invention provides an overall flowchart of a low-carbon dispatching method for an integrated energy system considering P2G and CCS, as an embodiment of the present invention.

[0020] Figure 2 The electric-thermal output characteristics under CCP mode of a low-carbon dispatching method for an integrated energy system considering P2G and CCS are provided as an embodiment of the present invention.

[0021] Figure 3 The electric-heat-gas output characteristics under CCP mode are provided in an embodiment of the present invention for a low-carbon dispatching method for an integrated energy system that considers P2G and CCS.

[0022] Figure 4 This invention provides an integrated energy system structure that considers P2G and CCS in a low-carbon scheduling method for an integrated energy system, as an embodiment of the present invention.

[0023] Figure 5 This invention provides source-load prediction data for an integrated energy system that considers P2G and CCS in a low-carbon scheduling method for an integrated energy system, as an embodiment of the present invention.

[0024] Figure 6 This invention provides a simulation structure for an integrated energy system that considers P2G and CCS in a low-carbon scheduling method for an integrated energy system, as an embodiment of the present invention.

[0025] Figure 7 The power optimization scheduling result is provided by an embodiment of the present invention for a low-carbon scheduling method of an integrated energy system considering P2G and CCS.

[0026] Figure 8 The thermal power optimization scheduling result is provided by an embodiment of the present invention for a low-carbon scheduling method of an integrated energy system considering P2G and CCS.

[0027] Figure 9 The gas power optimization scheduling result is provided by an embodiment of the present invention for a low-carbon scheduling method of an integrated energy system considering P2G and CCS. Detailed Implementation

[0028] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and 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 should fall within the protection scope of the present invention.

[0029] Example 1, referring to Figures 1-4 This is the first embodiment of the present invention, which provides a low-carbon dispatching method for an integrated energy system considering P2G and CCS, comprising: S1: Establish a mathematical model of the integrated energy system equipment, which mainly includes cogeneration units, power-to-gas conversion, carbon capture devices, micro gas turbines, and energy storage.

[0030] Furthermore, in step S1, the mathematical model of the integrated energy system equipment consists of the following: S1-1: Establish a mathematical model for the combined heat and power (CHP) unit. The electrothermal output of the CHP unit is mutually restrictive; therefore, the specific expression of the electrothermal output characteristic equation of the CHP unit is as follows: (1) in, and These are the minimum and maximum output power of CHP, respectively. The minimum output electrothermal conversion coefficient of the CHP unit. The electrothermal conversion coefficient is the maximum output of the CHP unit. The slope is linear. This represents the minimum thermal power of the CHP unit. Let t be the thermal power output of the CHP unit at time t.

[0031] S1-2: Establish the P2G mathematical model, including the first and second processes. The first process is the generation of hydrogen gas, and the second process is the synthesis of methane. The P2G chemical reaction process is as follows: (2) in, Let be the electrical power consumed by P2G at time t. Let α be the gas power generated by P2G at time t, and α be the power conversion coefficient.

[0032] Considering that the P2G equipment consumes carbon dioxide during the chemical reaction that produces methane, the carbon consumption during P2G operation is as follows: (3) in, Let β be the amount of carbon dioxide consumed by P2G at time t, and let β be the conversion coefficient for the amount of carbon dioxide consumed by P2G to generate a unit of electrical energy.

[0033] S1-3: Establish a mathematical model for CCS and calculate the electrical energy required by each device during the absorption, desorption, and compression of carbon dioxide in the CCS process: (4) in, Let be the electrical power consumed by the CCS at time t, be the unit carbon emission of the coal-fired unit, and be the carbon capture rate of the carbon capture system.

[0034] S1-4: Establish the mathematical model of the gas turbine, which is an important electrical coupling device in an integrated energy system. The gas turbine (MT) converts fossil fuels into electrical energy by burning natural gas. The gas turbine model is shown below: in, Let be the electrical power consumed by the gas turbine at time t. This represents the gas power consumed by the gas turbine at time t. For the operating efficiency of gas turbines, The heat power consumed by the gas turbine at time t. For the loss coefficient of the gas turbine, The heating coefficient of the gas turbine, This refers to the preheating recovery rate of the gas turbine.

[0035] S1-5: Establish a mathematical model for energy storage. The application of energy storage devices in integrated energy systems can alleviate the uncertainty of wind and solar power output and the problem of stable load fluctuations. Integrated energy systems contain various forms of energy storage units. In this invention, only thermal storage and electrical storage units are considered. The mathematical model is shown below: Where x represents the energy category, BS represents a battery, and GS represents a gas storage tank. and Let be the energy stored by energy storage device x during time periods t and t+1, respectively. and Let x be the charging and discharging power of the energy storage device during time period t. ≥0, ≤0, For energy storage devices with capacity x, and This refers to the charging and discharging efficiency of energy storage device x, where Δt is the time interval. and These are the state parameters for charging and discharging, respectively; =1 indicates that the energy storage device performs a charging operation during time period t. =1 indicates that the energy storage device x performs an energy release operation.

[0036] S2: Establish a joint operation mode model of CHP-CCS-P2G (CCP), considering CHP, P2G and CCS as a whole. During periods of low electricity load, the CHP unit converts electrical energy into natural gas through P2G, achieving thermal-electric decoupling.

[0037] Furthermore, in step S2, the establishment of the CHP-CCS-P2G (CCP) joint operation mode model includes the following components: In the CCP joint operation mode, the CHP unit needs to provide power to the P2G and CCS equipment, and the rest is the on-grid power of the CHP unit, as shown in equation (10): (10) in, The electrical power output of the CHP unit. This refers to the on-grid power of the CHP unit under the CCP joint operation mode. The electrical power supplied by the CHP unit to the P2G under CCP joint operation mode. The electrical power supplied by the CHP unit to the CCS under the CCP joint operation mode.

[0038] The power output range of the CHP unit under the CCP joint operation mode is shown in equation (11): (11) The output of the CHP unit in equation (11) By converting equation (10), the power output range of the CHP unit in the CCP joint operation mode can be obtained as shown in equation (12): (12) The power constraint of P2G devices is shown in equation (13): (13) in, and These represent the lower and upper limits of the operating power of P2G devices, respectively.

[0039] The power constraints of the electrical energy required by each device in the CCS process of carbon dioxide absorption, desorption and compression are shown in equation (14): (14) in, and These represent the lower and upper limits of the CCS operating power, respectively.

[0040] Substituting equations (13) and (14) into equation (12), we can obtain the on-grid power output range of the CHP unit under the CCP joint operation mode as shown in equation (15): (15) in, and To set upper and lower limits for the on-grid power of CHP units under the CCP joint operation mode.

[0041] Under the CCP joint operation mode, the thermal power output range of the CHP unit is expressed by equation (16) as follows: (16) in, and These are the upper and lower limits of the thermal power of the CHP unit under the CCP joint operation mode.

[0042] Substituting equation (16) into equation (1), the electrical-thermal output relationship of the CHP unit under the CCP joint operation mode is shown in equation (17): (17) Since all the electrical energy consumed by P2G and CCS comes from the thermal power unit, the combined output constraint of P2G and CCS is as shown in equation (18): (18) Substituting equation (18) into equation (17), the electro-thermal coupling characteristics of the CHP unit under the CCP joint operation mode are shown in equation (19): (19) in, The electrothermal conversion coefficient of the CHP unit is given by equations (15), (16), and (19). It can be seen from equations (15), (16), and (19) that the electrothermal output range of the CHP unit under the CCP joint operation mode is... Figure 3 In this context, ABGIJ represents a region.

[0043] It can be seen that the CCP joint operation mode increases the adjustment range of the CHP unit. Under the same thermal output, considering P2G and CCS, the CHP unit can provide a smaller grid-connected output. Increasing the adjustment range of the CHP unit allows for control of the grid-connected power of the CHP unit by adjusting the operating power of the P2G equipment without changing the system's thermal output.

[0044] Substituting equation (2) into equation (13), we can obtain the range constraint of P2G output qigong as shown in equation (20): (20) in, Let P2G be the gas power output at time t. and These are the lower and upper limits of the output gas power, respectively.

[0045] Under the CCP joint operation mode, the CHP unit can realize the conversion between multiple forms of energy such as electricity, gas and heat, which strengthens the coupling relationship of the integrated energy system.

[0046] It can be seen from equations (19) and (20) that when and At that time, the Qi Gong output by P2G is at its maximum value. At that time, the Qi Gong output by P2G is at its minimum value.

[0047] Therefore, under the CCP joint operation mode, the P2G output gas power output range of the CHP unit is: Figure 3 The ABHIJ region in the middle.

[0048] Substituting equations (2)-(4) into equation (17), we obtain the coupling relationship between CHP, P2G and CCS under the CCP joint operation mode as shown in equation (21).

[0049] (twenty one) Therefore, the adjustment range of the CHP unit under the CCP joint operation mode is: Figure 3 The ABEFG-ABHIJ area is included. Under the CCP joint operation mode, the CHP unit strengthens the coupling relationship between various energy sources in the integrated energy system. Considering P2G, the electricity generated by the CHP unit can be converted into natural gas during off-peak grid periods, thereby improving the wind power absorption capacity during off-peak grid periods.

[0050] S3: Establish an optimized scheduling model. When optimizing the integrated energy system, an objective function with the lowest total cost is established. This mainly includes the operating costs of CHP units, P2G and CCS, carbon trading costs, gas turbine operating costs, wind and solar curtailment penalty costs, and gas purchase costs under the CCP joint operation mode.

[0051] Furthermore, in step S3, an optimized scheduling model is established: S3-1: The proposed integrated energy system architecture based on carbon trading is as follows: Figure 4 As shown.

[0052] The forecast data includes forecasts for wind power, solar power, and load demand.

[0053] The constraints include output and ramp rate constraints for the CHP unit, micro gas turbine, and electric chiller under CCP joint operation mode, and the constraint of constant power balance.

[0054] The operating costs of the minimum objective function include the operating costs of the generating units, the costs of wind and solar curtailment penalties, and the costs of carbon trading.

[0055] S3-2: When optimizing the integrated energy system, an objective function for minimizing total cost was established, which mainly includes the operating costs of CHP units, P2G and CCS, carbon trading costs, gas turbine operating costs, wind and solar curtailment penalty costs, and gas purchase costs under the CCP joint operation mode.

[0056] S3-2-1: Establishing a carbon trading cost model The carbon trading mechanism involves first allocating initial carbon emission rights to each carbon-emitting unit, and then each unit choosing to buy or sell carbon emission allowances based on its actual carbon emissions. In the proposed optimization model, the system's carbon emissions are the amount of carbon dioxide produced by coal-fired and gas-fired units minus the amount of carbon dioxide captured by CCS.

[0057] (twenty two) (twenty three) (twenty four) in, Let be the amount of carbon dioxide emitted by the system at time t from both coal-fired and gas-fired units. This represents the amount of carbon dioxide emitted by the CHP unit at time t under the CCP joint operation mode. This represents the amount of carbon dioxide emitted by the thermal power unit at time t. Let be the amount of carbon dioxide emitted by MT at time t. is the carbon emission factor of MT. This represents the amount of carbon dioxide emitted by the CHP unit at time t. , , The carbon emission coefficient of coal-fired power units. Let t be the amount of carbon dioxide captured by the carbon capture device at time t.

[0058] The carbon allowance for an integrated energy system consists of coal-fired and gas-fired power units, so the carbon emission allowance for an integrated energy system is represented by (25) as follows: (25) in, Let A be the carbon emission allowance of the integrated energy system at time t, and let A be the carbon emission allowance coefficient. Let t be the output of the i-th thermal power unit.

[0059] The carbon trading cost of an integrated energy system mainly consists of the expenditures or gains incurred when purchasing or selling carbon emission allowances during system operation, when there is a shortage or surplus of carbon emission rights. Therefore, the carbon trading cost is described as follows (26).

[0060] (26) in, Let ε be the cost of carbon trading, ε be the cost coefficient of carbon trading, and T be the total system operating time.

[0061] S3-2-2: Establishing a thermal power unit operating cost model: The operating cost of a thermal power unit is mainly the power generation cost, which is calculated as follows: (27) in, For the operating costs of thermal power units, , and The cost coefficient of the i-th thermal power unit, where n is the total number of thermal power units and i is the variable index.

[0062] S3-2-3: Establishing an operating cost model for gas turbines: The fuel cost of the gas turbine is calculated by (28).

[0063] (28) in, For the fuel cost of micro gas turbines, This represents the cost coefficient for micro gas turbines.

[0064] S3-2-4: Establish a penalty cost model for wind and solar power curtailment: The cost of wind curtailment penalty is expressed as follows (29).

[0065] (29) in, The penalty cost of abandoning wind power, The penalty cost coefficient for wind curtailment Let be the wind curtailment power at time t.

[0066] The cost of the light-wasting penalty is expressed by (30) as follows: (30) in, As a penalty for abandoning light, The cost coefficient for the light abandonment penalty, Let be the power of abandoned light at time t.

[0067] S3-2-5: Establish a gas purchase cost model (31) in, For gas purchase costs, For the gas purchase price, The gas load of the integrated energy system at time t. This represents the gas consumption at time t in the CPP joint operation mode.

[0068] In summary, the objective function that minimizes operating costs is described by (32) as follows.

[0069] (32) Where C represents the total operating cost of the integrated energy system optimization scheduling model. The operating cost of the CCP joint operation mode.

[0070] S3-3: Establishing Constraints When optimizing a comprehensive energy system, it is necessary to meet the balance constraints of electrical, gas, and heat power, as well as the output constraints of each component unit, as follows: S3-3-1: Power Balance Constraints The power balance constraints that the integrated energy system needs to satisfy during optimal scheduling are shown in equation (33): (33) in, Let BS represent the electrical load of the integrated energy system at time t, and GS represent the gas storage tank. Let be the power of the photovoltaic system at time t. Let be the power of the wind power at time t. Let be the charging power of the energy storage at time t. Let be the discharge power of the stored energy at time t. Let be the electrical power of the gas turbine at time t.

[0071] S3-3-2: Thermal Power Balance The heat and power balance constraints that the integrated energy system needs to satisfy during optimal scheduling are shown in equation (34): (34) in, Let t be the heat load of the integrated energy system at time t.

[0072] S3-3-3: Gas Power Balance The gas power balance constraint that the integrated energy system needs to satisfy during the optimal scheduling period is shown in equation (35): (35) in, Let t be the gas purchase power of the integrated energy system at time t.

[0073] S3-3-4: Constraints on Micro Gas Turbines The output power and ramp rate constraints of the micro gas turbine are represented by (36): (36) In the formula: and These represent the upper and lower limits of the output power of a micro gas turbine, respectively. Let be the output power of the gas turbine at time t-1. and These represent the lower and upper limits of the ramp slope output by the micro gas turbine, respectively.

[0074] S3-3-5: Gas Purchase Constraints The power consumption constraint for the integrated energy system under gas purchase conditions is shown in equation (37): (37) in, and The maximum and minimum values ​​of the gas purchase power are respectively.

[0075] Example 2, refer to Figure 5 and Figure 9 This is the second embodiment of the present invention, which provides a low-carbon scheduling method for an integrated energy system that considers P2G and CCS. To verify the beneficial effects of the present invention, scientific demonstration is carried out through experiments.

[0076] ① The parameters for the calculation example include the predicted data for electrical load, heat load, gas load, and wind and solar power, such as... Figure 5 As shown.

[0077] This paper adopts an improved IEEE-30 node power grid, a 6-node heat network, and a 7-node gas network as the integrated energy system architecture, as shown in the figure. Figure 6 As shown.

[0078] G1 and G3 are thermal power units, and G2 is a combined heat and power (CHP) unit connected to the P2G and CCS for flexible operation as proposed in this paper. Grid nodes 23 and 25 are connected to wind power and photovoltaic power, respectively. Gas grid node 7 is connected to the natural gas source, node 5 is connected to the P2G, and node 3 is connected to the gas turbine. The parameters of the thermal power units and CHP units are shown in Table 1. The input parameters of the scheduling model are shown in Table 2.

[0079] Table 1 Unit Operating Parameters

[0080] Table 2 Input parameters of the scheduling model

[0081] ② Optimize scheduling results.

[0082] The optimized scheduling results of the integrated energy system under the CCP joint operation mode are as follows: Figures 7-9 As shown. On the grid side, the electricity load demand is met by wind power, photovoltaic power, thermal power units, combined heat and power units, gas turbines, and energy storage batteries; on the gas grid side, the gas load and gas turbine demand are met by P2G and gas sources; on the heating grid side, the heat load demand is met by combined heat and power units and gas turbines.

[0083] During peak wind power output hours at night, when electrical load is low, the CHP units' heat-driven operation severely impacts their ability to absorb wind power. For example... Figure 7 and 8 It can be seen that the CCP joint operation mode proposed in this paper can convert the electricity generated by the CHP unit into natural gas, expand the regulation range of the CHP unit, reduce the grid-connected electricity of the CHP unit, and provide space for wind power consumption.

[0084] ③ To further verify the effectiveness of the CCP joint operation mode proposed in this paper in the low-carbon scheduling of the system.

[0085] This paper uses the following four models to verify the advantages of the CCP joint operation mode in terms of system economy and carbon emissions.

[0086] Model 1: P2G and CCS are not considered in the simulation model.

[0087] Model 2: The simulation model considers CHP units with CCS.

[0088] Model 3: The simulation model considers CHP units with P2G.

[0089] Model 4: The simulation model considers a joint optimization model including P2G and CCS.

[0090] The operating costs of different model systems are shown in Table 3. A comparison of Model 1 and Model 2 shows that considering CCS increases the total system cost by 179,157. This is because the daily operating cost of CCS is 264,142 yuan, but the revenue from carbon trading is 15,250 yuan after adding CCS. Currently, with the domestic carbon trading price at 50 yuan / ton, adding CCS to coal-fired power units will significantly increase the system's operating costs.

[0091] By comparing Model 1 and Model 3, it can be seen that the total cost of the system is reduced by 24,863 yuan after considering P2G. This is because the electricity of P2G comes from the CHP unit. Considering P2G reduces the gas purchase cost of the system, as well as the curtailment costs of wind and solar power.

[0092] By comparing Model 3 and Model 4, it can be seen that adding P2G equipment to carbon capture power plants can further reduce the operating costs of the system. This is because, considering the flexible operation mode proposed in this paper, the carbon capture cost of P2G can be reduced, which is consistent with the carbon capture cost of CCS.

[0093] Table 3 Operating Costs of Different Model Systems

[0094] Table 4 shows the wind and solar power integration and carbon emissions for different models. It can be seen that the flexible operation mode proposed in this paper increases wind power integration capacity by 20.34% and photovoltaic integration capacity by 19.85% compared with the model without considering P2G and CCS, while reducing carbon emissions by 1021.87t.

[0095] Table 4 Comparison of optimization effects of different models

[0096] Example 3 is the third embodiment of the present invention, which differs from the previous two embodiments in that: If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0097] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0098] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0099] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0100] Example 4 is the fourth embodiment of the present invention. This embodiment provides a low-carbon scheduling system for an integrated energy system that considers P2G and CCS, including an integrated energy model module, a CCP joint operation module, and an optimized scheduling module. The integrated energy model module establishes a mathematical model of integrated energy system equipment, which mainly includes combined heat and power units, power-to-gas conversion, carbon capture devices, micro gas turbines, and energy storage. The CCP joint operation module combines CHP, P2G and CCS. During periods of low electricity load, the CHP unit converts electrical energy into natural gas through P2G, achieving thermal-electric decoupling. The optimization scheduling module establishes an objective function that minimizes the total cost when optimizing the integrated energy system. This includes the unit operating costs of CHP units, P2G and CCS units, wind and solar curtailment penalty costs, and carbon trading costs under the CCP joint operation mode.

[0101] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A low-carbon dispatching method for an integrated energy system considering P2G and CCS, characterized in that: include, A mathematical model of integrated energy system equipment is established, wherein the integrated energy system equipment includes a combined heat and power unit, a power-to-gas converter, a carbon capture device, a micro gas turbine, and energy storage. Establish a CCP joint operation mode model to combine CHP, P2G and CCS. When the power load is low, the CHP unit converts electricity into natural gas through P2G to achieve thermal-electric decoupling. An optimized scheduling model is established. When optimizing the integrated energy system, an objective function with the lowest total cost is established, which includes the unit operating costs of CHP units, P2G and CCS units, wind and solar curtailment penalty costs and carbon trading costs under the CCP joint operation mode.

2. The low-carbon dispatching method for an integrated energy system considering P2G and CCS as described in claim 1, characterized in that: The mathematical model for establishing the integrated energy system equipment includes, Establish an electrothermal output characteristic model for a combined heat and power unit; Establish a P2G mathematical model, including the first process and the second process. The first process is the generation of hydrogen, and the second process is the synthesis of methane. Consider that the P2G equipment needs to consume carbon dioxide when generating methane, and calculate the carbon consumption during the operation of the P2G. Establish a mathematical model for CCS and calculate the electrical energy required by each device during the absorption, desorption, and compression of carbon dioxide in CCS.

3. A low-carbon dispatching method for an integrated energy system considering P2G and CCS as described in claim 2, characterized in that: The mathematical model for establishing integrated energy system equipment also includes Establish a mathematical model for the gas turbine: in, Let be the electrical power consumed by the gas turbine at time t. This represents the gas power consumed by the gas turbine at time t. For the operating efficiency of gas turbines, The heat power consumed by the gas turbine at time t. For the loss coefficient of the gas turbine, The heating coefficient of the gas turbine, For the preheating recovery rate of the gas turbine; Establish a mathematical model for energy storage, considering only thermal and electrical storage units: Where x represents the energy category, BS represents a battery, and GS represents a gas storage tank. and Let be the energy stored by energy storage device x during time periods t and t+1, respectively. and Let x be the charging and discharging power of the energy storage device during time period t. ≥0, ≤0, For energy storage devices with capacity x, and This refers to the charging and discharging efficiency of energy storage device x, where Δt is the time interval. and These are the state parameters for charging and discharging, respectively; =1 indicates that the energy storage device performs a charging operation during time period t. =1 indicates that the energy storage device x performs an energy release operation.

4. A low-carbon dispatching method for an integrated energy system considering P2G and CCS as described in claim 3, characterized in that: The establishment of the CCP joint operation mode model includes, In the CCP joint operation mode, the CHP unit provides power to the P2G and CCS equipment, and the remaining power is set as the grid power of the CHP unit. Set the power output range of the CHP units under the CCP joint operation mode, and set the power output of the CHP units within the power output range of the CHP units. By converting the grid power of the CHP unit, the grid power output range of the CHP unit under the CCP joint operation mode can be obtained; Calculate the power constraints of the P2G equipment and the power constraints of the established CCS mathematical model when obtaining power. Substitute the power constraints of the P2G equipment and the power constraints of the CCS mathematical model when obtaining power into the grid power output range of the CHP unit to obtain the grid power output range of the CHP unit under the CCP joint operation mode. Calculate the thermal power output range of the CHP unit under the CCP joint operation mode, and substitute it into the established electro-thermal output characteristic model of the cogeneration unit to obtain the electro-thermal output relationship of the CHP unit under the CCP joint operation mode. Since the electrical energy consumed by P2G and CCS all comes from the thermal power unit, the combined output constraint of P2G and CCS is calculated, and the electrical-thermal output relationship of the CHP unit is substituted into the calculation to obtain the electrical-thermal output coupling characteristics of the CHP unit under the CCP joint operation mode.

5. A low-carbon dispatching method for an integrated energy system considering P2G and CCS as described in claim 4, characterized in that: The establishment of the CCP joint operation mode model also includes constructing an electric-heat-gas output characteristic diagram under the CCP mode by using the grid power output range of the CHP unit under the CCP joint operation mode, the thermal power output range of the CHP unit under the CCP joint operation mode, and the electric-thermal output coupling characteristics of the CHP unit under the CCP joint operation mode. Substituting the established P2G mathematical model into the power constraints of the P2G device, the range constraints of the P2G output qi power are obtained. Under the CCP joint operation mode, the CHP unit realizes the conversion between multiple forms of energy such as electricity, gas and heat, and strengthens the coupling relationship of the integrated energy system; when and At that time, the Qi Gong output by P2G is at its maximum value; when At that time, the Qigong output of P2G is at its minimum value; in, This refers to the on-grid power of the CHP unit under the CCP joint operation mode. and To constrain the upper and lower limits of the on-grid power of CHP units under the CCP joint operation mode, H is the minimum output electrothermal conversion coefficient of the CHP unit. CHP,t Let be the thermal power output of the CHP unit at time t. The electrothermal conversion coefficient of the CHP unit. To set a lower limit constraint on the thermal power of the CHP unit under the CCP joint operation mode. This represents the upper limit of the operating power of P2G devices. This represents the upper limit of the CCS operating power. Substituting the P2G mathematical model and the CCS mathematical model into the electrical-thermal output relationship of the CHP unit under the CCP joint operation mode, the coupling relationship of CHP, P2G and CCS under the CCP joint operation mode is obtained.

6. A low-carbon dispatching method for an integrated energy system considering P2G and CCS as described in claim 4, characterized in that: The optimized scheduling model includes predicted data, constraints, and a minimum objective function; The forecast data includes forecast data for wind power, solar power, and load demand; The constraints include output and ramp rate constraints for the CHP unit, micro gas turbine, and electric chiller under CCP joint operation mode, satisfying the constraint condition of constant power balance. When optimizing the integrated energy system, the minimum objective function with the lowest total cost is established. The operating cost of the minimum objective function includes the operating costs of the CHP unit, P2G and CCS units, the cost of wind and solar curtailment penalties and carbon trading costs under the CCP joint operation mode. The unit operating cost is established by creating a model for the power generation cost of the thermal power unit, and a model for the operating cost of the gas turbine, including fuel costs and a gas purchase cost model. The aforementioned wind and solar curtailment penalty cost is a model for establishing the wind and solar curtailment penalty cost, including wind curtailment penalty cost and solar curtailment penalty cost; The carbon trading cost is established by modeling the carbon trading cost, allocating initial carbon emission rights to each carbon emission unit, and allowing each unit to choose to buy or sell carbon emission allowances based on its actual carbon emission situation. The objective function that minimizes operating cost is: Where C represents the total operating cost of the integrated energy system optimization scheduling model. For gas purchase costs, As a penalty for abandoning light, The penalty cost of abandoning wind power, For the fuel cost of micro gas turbines, For the operating costs of thermal power units, For the cost of carbon trading, The operating cost of the CCP joint operation mode.

7. A low-carbon dispatching method for an integrated energy system considering P2G and CCS as described in claim 4, characterized in that: The optimization scheduling model also includes establishing the constraints, which require satisfying the balance constraints of electricity-gas-heat power and the output constraints of each component unit when optimizing the integrated energy system. Specifically, these constraints include electricity power balance constraints, heat power balance constraints, gas power balance constraints, micro gas turbine constraints, and gas purchase constraints.

8. A low-carbon dispatching system for an integrated energy system considering P2G and CCS, employing the low-carbon dispatching method for an integrated energy system considering P2G and CCS as described in any one of claims 1 to 7, characterized in that, include: Integrated energy model module, CCP joint operation module, and optimized scheduling module; The integrated energy model module establishes a mathematical model of integrated energy system equipment, which mainly includes cogeneration units, power-to-gas conversion, carbon capture devices, micro gas turbines, and energy storage. The CCP joint operation module combines CHP, P2G and CCS. During periods of low electricity load, the CHP unit converts electrical energy into natural gas through P2G, achieving thermal-electric decoupling. The optimization scheduling module establishes an objective function that minimizes the total cost when optimizing the integrated energy system. This includes the unit operating costs of CHP units, P2G and CCS units, wind and solar curtailment penalty costs, and carbon trading costs under the CCP joint operation mode.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of a low-carbon scheduling method for an integrated energy system considering P2G and CCS as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of a low-carbon scheduling method for an integrated energy system considering P2G and CCS as described in any one of claims 1 to 7.

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