Comprehensive energy system scheduling method considering stepped carbon transaction and carbon capture

Abstract

The invention discloses an integrated energy system scheduling method considering stepped carbon transaction and carbon capture. The method comprises the following steps: constructing a CCPP-P2G collaborative operation model according to the working principle of a carbon capture device and power-to-gas equipment; establishing a multivariate demand response model according to the transferable and replaceable characteristics of the load side; constructing a stepped carbon transaction mechanism based on the integrated energy system; based on the constructed CCPP-P2G collaborative operation model, the demand response model and the stepped carbon transaction mechanism, the energy purchase cost, the demand response compensation cost, the carbon transaction cost, the demand response compensation cost and the demand response compensation cost are constructed; the sum of the operation and maintenance cost of the system and the total operation cost of the CCPP-P2G is the minimum, and the sum of the operation and maintenance cost of the system and the total operation cost of the CCPP-P2G is the target function. And carrying out optimization solution on the low-carbon economic dispatching model of the integrated energy system considering the demand response and carbon capture under the stepped carbon transaction under the condition that the constraint condition is met. The economic and environmental benefits of the comprehensive energy system can be considered, and reference is provided for low-carbon economic operation of the comprehensive energy system.

Description

Technical Field

[0001] The present invention relates to the technical field of optimal operation of power systems, and particularly to a dispatching method for an integrated energy system considering stepped carbon trading and carbon capture. Background Art

[0002] How to ensure the sustainable supply of energy while reducing environmental pollution has always been the focus of global attention. The traditional energy system has a simple structure and a single type of energy, lacking coordinated management between different energy forms, which leads to low energy utilization efficiency of the system. The integrated energy system has been widely applied because it couples various energy conversion devices internally and can achieve complementary advantages between different energies.

[0003] In order to balance the economic and environmental benefits of the integrated energy system, many studies have introduced the carbon trading mechanism into the integrated energy system dispatching model to limit the carbon emissions of the system. However, the traditional carbon trading mechanism only adopts a fixed carbon price and cannot stimulate the emission reduction enthusiasm of energy supply enterprises. In order to further limit the carbon emissions of the integrated energy system, on the basis of the traditional carbon trading mechanism, the concept of stepped carbon trading is proposed. With the continuous development of energy utilization technologies, flexible resources on the user side of the integrated energy system are continuously explored. As a flexible regulation means of the integrated energy system, demand response can fully stimulate the flexibility of load-side resources. With the continuous development of the research on the integrated energy system, demand response has also changed from a single electrical load to a multi-flexible load demand response. On the other hand, the emergence of carbon capture technology can capture and sequester the carbon dioxide emitted by high-carbon units during operation, thereby reducing carbon emissions during system operation. Therefore, it is of great significance to develop a low-carbon economic dispatching model for an integrated energy system considering demand response and carbon capture under stepped carbon trading. Summary of the Invention

[0004] In view of the above existing problems, the present invention proposes a dispatching method for an integrated energy system considering stepped carbon trading and carbon capture. This optimization method can balance the economic and environmental benefits of the integrated energy system and provide a reference for the low-carbon economic operation of the integrated energy system.

[0005] The above object is achieved by the following technical solutions:

[0006] A dispatching method for an integrated energy system considering demand response and carbon capture under stepped carbon trading includes the following steps:

[0007] Construct a carbon capture - power to gas (CCPP - P2G) collaborative operation model;

[0008] Construct an integrated energy system architecture based on multi - demand response;

[0009] Construct a stepped carbon trading mechanism based on the integrated energy system;

[0010] Based on the constructed CCPP-P2G collaborative operation model, multi-demand response model, and stepped carbon trading mechanism, a low-carbon economic dispatch model for an integrated energy system considering demand response and carbon capture under stepped carbon trading is constructed with the objective function of minimizing the sum of the energy purchase cost, CCPP-P2G operation cost, carbon trading cost, operation and maintenance cost, and total demand response compensation cost;

[0011] Under the satisfaction of constraint conditions, the low-carbon economic dispatch model of the integrated energy system considering the stepped carbon trading mechanism and flexible load is optimized and solved.

[0012] As an optimal technical solution, the low-carbon economic dispatch model of the integrated energy system considering demand response and carbon capture under stepped carbon trading is:

[0013] minF = F buy + F C + F DR + F OM + F CP

[0014] In the formula, minF is the minimum total low-carbon economic dispatch cost of the integrated energy system considering demand response and carbon capture under stepped carbon trading; F buy is the energy purchase cost of the integrated energy system; F C is the stepped carbon trading cost of the integrated energy system; F OM is the operation and maintenance cost of the integrated energy system; F DR is the total demand response compensation cost of the integrated energy system; F CP is the CCPP-P2G collaborative operation cost;

[0015] As an optimal technical solution, the expression of the CCPP-P2G collaborative operation cost F CP of the integrated energy system is:

[0016]

[0017] In the formula, is the power generation cost of CCPP; F CS represents the carbon storage cost; F P2G is the operation cost of P2G; a3, b3, c3 are the coal consumption coefficients of thermal power units; τ t , τ t-1 are 0-1 variables representing the unit start-stop state; ρ CS is the unit carbon storage price; represents the carbon storage amount of the carbon storage device at time t; δ P2G represents the unit operation cost of P2G.

[0018] As a preferred technical solution, the energy purchase cost F of the integrated energy system buy has the following expression:

[0019]

[0020] In the formula, α e , β e , and γ g respectively represent the electricity purchase price, electricity selling price, and gas purchase price at time t; P e,buy (t), P e,sell (t), and P g,buy (t) respectively represent the electricity purchase power, electricity selling power, and gas purchase power at time t;

[0021] As a preferred technical solution, the total demand response compensation cost F of the integrated energy system DR has the following expression:

[0022]

[0023] In the formula, δ z is the transferable load compensation coefficient; δ s is the alternative load compensation coefficient;

[0024] As a preferred technical solution, the multi - type demand response model includes base load, transferable load, and alternative load;

[0025] The transferable load model is expressed as:

[0026]

[0027] In the formula, represents the transferable load value of load i participating in the demand response; is the price elasticity matrix, and e t,j is the element in the t - th row and j - th column of the price elasticity matrix; Δρ j represents the change in electricity price at time j after the demand response; represents the initial electricity price at time j, ρ j represents the electricity price at time j; P DRmin , P DRmax represent the upper and lower limits of the transferable load power;

[0028] The alternative load model is expressed as:

[0029]

[0030] In the formula, represents the alternative load value of load i after participating in the demand response; represents the alternative load value of load i participating in the demand response; εe,h is the parameter for electric heating substitution; respectively represent the energy conversion efficiencies of electric energy and thermal energy; respectively represent the minimum and maximum amounts of replaceable electric load; are respectively the minimum and maximum amounts of replaceable thermal load.

[0031] As an optimal technical solution, the stepped carbon trading cost F of the integrated energy system C has the following expression:

[0032]

[0033] In the formula, F C is the carbon trading cost; λ is the carbon trading base price; L is the length of the carbon emission interval; α represents the growth rate of the carbon price; E c represents the carbon trading volume participated by the system.

[0034] The initial carbon emission quota model is:

[0035]

[0036] In the formula, E a is the total amount of the system's initial carbon emission quota; E P , E GT , E GB respectively represent the initial carbon emission quotas of the conventional thermal power unit, gas turbine, and gas boiler; η e , η h represent the initial carbon emission right coefficients corresponding to unit electric and gas powers; P P (t) is the output electric power of the conventional thermal power unit at time t; P e,GT (t), P h,GT (t) respectively represent the output electric and thermal powers of the gas turbine at time t; P h,GB (t) represents the output thermal power of the gas boiler at time t.

[0037] The actual carbon emission model of the system is:

[0038]

[0039] Among them, E ac represents the total actual carbon emissions of the system; E P,ac , E GT.ac , E GB,ac respectively represent the carbon emissions generated by the traditional thermal power unit, gas turbine, and gas boiler during the actual output process; a1, b1, c1 are the carbon emission calculation parameters of the traditional thermal power unit; a2, b2, c2 are the carbon emission calculation parameters of the gas turbine and gas boiler; P GTGB(t) represents the equivalent output power of the gas turbine and the gas boiler.

[0040] Based on the system's initial carbon emission rights quota model and the actual carbon emission model, the carbon trading volume participated by the system is obtained as:

[0041] E c = E ac - E a

[0042] As an optimal technical solution, the integrated energy system model with carbon capture considering demand response includes: the energy supply side, energy conversion devices, energy storage equipment, and the user-side load; the energy supply side includes grid electricity, natural gas, wind turbines, photovoltaic units, and CCPP-P2G; the energy conversion devices include gas turbines, gas boilers, and power-to-gas devices; the energy storage equipment includes electrical energy storage and thermal energy storage; the user-side load consists of electrical load and thermal load, including base load and flexible load.

[0043] As an optimal technical solution, the constraint conditions include external energy purchase constraints, power balance constraints, equipment output constraints, and energy storage constraints:

[0044] The energy purchase constraint is:

[0045]

[0046] In the formula, are respectively the minimum values of the electricity purchase volume, gas purchase volume, and electricity sales volume at time t; are respectively the maximum values of the electricity that can be purchased, natural gas volume, and electricity sales volume at time t;

[0047] The power balance constraint is:

[0048]

[0049] In the formula, P e,load (t), P h,load (t), P g,load (t) respectively represent the total electrical load, thermal load, and gas load values at time t; respectively represent the discharge and charge power of the electrical energy storage device at time t; P h,GB (t), P h,CHP (t) respectively represent the natural gas power input to the gas turbine and gas boiler at time t; respectively represent the gas release and gas storage power of the gas storage device at time t;

[0050] The equipment output constraint is:

[0051] Gas turbine constraint:

[0052]

[0053] Wherein, respectively represent the gas - to - electricity and gas - to - heat efficiency of the gas turbine; respectively represent the maximum and minimum values of the gas consumption power during the operation of the gas turbine in period t; are respectively the upper and lower limits of the gas turbine ramp constraint;

[0054] Gas boiler constraint:

[0055]

[0056] Wherein, respectively represent the maximum and minimum values of the gas consumption power during the operation of the gas boiler; are respectively the upper and lower limits of the gas boiler ramp rate

[0057] CCPP - P2G operation constraint:

[0058]

[0059] Wherein, represents the upper limit of CCPP energy consumption; ΔP CC is the CCPP ramp constraint; is the upper limit of the operation power of the P2G device in period t; T on 、T off are respectively the minimum continuous operation and outage times of the unit; are respectively the continuous operation and outage times in period t - 1.

[0060] As an optimal technical solution, considering the electric and thermal energy storage devices, since their model structures are similar, the three energy storages share the same model. Taking the electric energy storage device model as an example, its model is:

[0061]

[0062] Wherein, is a 0 - 1 variable, respectively representing the charging and discharging states of the electric energy storage device; respectively represent the upper and lower limits of the charging power of the energy storage device; D ES (t) is the stored electricity of the electric energy storage device in period t; respectively represent the upper and lower limits of the stored electricity of the energy storage device; respectively represent the charging and discharging powers of the energy storage device, and the total electricity of the energy storage device remains unchanged within a dispatching period.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] A low-carbon economic dispatch method for an integrated energy system considering demand response and carbon capture under a stepped carbon trading mechanism provided by the present invention first establishes a collaborative operation model of carbon capture - power-to-gas (CCPP-P2G); then analyzes the characteristics of shiftable load and replaceable load; introduces a stepped carbon trading mechanism, and takes the carbon trading cost under the stepped carbon trading as a component of the objective function; finally, solves the problem under the conditions of meeting energy purchase constraints, power balance constraints, equipment output constraints, and energy storage constraints; this optimization method can take into account the economic and environmental benefits of the integrated energy system and provide a reference for the low-carbon economic operation of the integrated energy system. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Attached Figure 1 is a flowchart of the low-carbon economic dispatch method for an integrated energy system considering demand response and carbon capture under the stepped carbon trading mechanism provided by the present invention;

[0066] Attached Figure 2 are the predicted curves of electricity, heat loads, and new energy output of the low-carbon economic dispatch model for the integrated energy system considering stepped carbon trading and demand response provided by the present invention.

[0067] Attached Figure 3 is the electricity load output curve of the low-carbon economic dispatch model for the integrated energy system considering stepped carbon trading and demand response provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0068] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and gives detailed implementation manners and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0069] Embodiment 1

[0070] As Figure 1 shown, a low-carbon economic dispatch method for an integrated energy system considering demand response and carbon capture under a stepped carbon trading mechanism, the steps of the method are as follows:

[0071] S1. Construct a collaborative operation model of carbon capture - power-to-gas (CCPP-P2G);

[0072] S2. Construct an integrated energy system architecture based on a multi-demand response mechanism;

[0073] S3. Construct a stepped carbon trading mechanism based on the integrated energy system;

[0074] S4. Based on steps S1, S2, and S3, construct a low-carbon economic dispatch model for an integrated energy system considering demand response and carbon capture under stepped carbon trading, with the sum of the purchase energy cost, CCPP-P2G operating cost, carbon trading cost, operation and maintenance cost, and demand response compensation total cost as the objective function, as well as the corresponding constraint conditions;

[0075] S5. Under the constraint conditions of step S4, optimize and solve the low-carbon economic dispatch model for the integrated energy system considering demand response and carbon capture under stepped carbon trading.

[0076] The integrated energy system model considering flexible loads includes the energy supply side, energy conversion devices, energy storage equipment, and user-side loads. Among them, the energy supply side includes grid electricity, natural gas, wind turbines, photovoltaic units, and CCPP-P2G; the energy conversion devices include gas turbines, gas boilers, and power-to-gas devices; the energy storage equipment includes electrical energy storage and thermal energy storage; the user-side loads consist of electrical loads and thermal loads, including base loads and flexible loads. The above integrated energy system model introduces demand response to smooth the load curve fluctuations, taking into account the economic and environmental benefits of the system and achieving peak shaving and valley filling; the carbon emissions generated within the integrated energy system ultimately participate in the carbon trading market for trading.

[0077] The CCPP-P2G collaborative operation model in step S1 includes a carbon capture system and a power-to-gas equipment model. In this system, the CO2 captured by CCPP is provided to the P2G device, and the remaining CO2 flows into the carbon storage device for storage. The P2G device is used to absorb the curtailed wind and photovoltaic power to generate natural gas and supply it to the gas device. The excess natural gas will be transported to the natural gas network for trading to obtain partial benefits, thereby improving the economy of the system and the new energy consumption capacity.

[0078] The energy consumption and equivalent output power expressions of the CCPP-P2G system are as follows:

[0079]

[0080] In Equation (1), P t CP is the total energy consumption of the CCHP-P2G system at time t; P t P2G is the equipment energy consumption of the P2G at time t; P t CC is the power provided to the carbon capture system within the system at time t; P t WA , P t VA are the curtailed wind and photovoltaic power at time t, respectively; represent the fixed power and operating power of CCPP, respectively; wC It is the operating energy consumption of the CCPP capture unit for CO2.

[0081] The amount of natural gas V generated by the P2G device consuming unit power in the t period t P2G The expression is as follows:

[0082]

[0083] In formula (2), β P2G represents the conversion efficiency of P2G; H g is the calorific value of natural gas, taking 39 MJ / m 3 .

[0084] The multi - demand response model in step S2 includes base load, shiftable load, and substitutable load. Introducing the demand response model can smooth the load curve fluctuations and achieve the interactive coupling of electricity and heat. The shiftable load refers to that users can flexibly adjust the electricity consumption in each period according to their own demand response to electricity prices. Taking the time - of - use electricity price of peak, valley, and flat as a signal, it can guide users to transfer the peak - period load to the valley - period. The charging and discharging of electric vehicles are typical shiftable loads. The shiftable load model is shown as follows:

[0085]

[0086] In formula (3), in the formula, represents the shiftable load value of load i participating in the demand response; is the price elasticity matrix, e t,j is the element of the t - th row and j - th column of the price elasticity matrix; Δρ j represents the change in electricity price at the j - th moment after the demand response; represents the initial electricity price at the j - th moment, ρ j represents the electricity price at the j - th moment; P DRmin 、P DRmax represent the upper and lower limits of the shiftable load power;

[0087] The substitutable load model is expressed as:

[0088]

[0089] In formula (4), represents the substitutable load value of load i after participating in the demand response; represents the substitutable load value of load i participating in the demand response; ε e,h is the electric - heat substitution parameter; respectively represent the energy conversion efficiencies of electric energy and heat energy; respectively represent the minimum and maximum amounts of substitutable electric load; They are the minimum and maximum amounts of replaceable heat loads respectively.

[0090] The stepped carbon trading mechanism based on the integrated energy system in step S3 includes the determination of the initial carbon emission quota and the actual carbon emission quota model. The corresponding initial carbon emission right quota model is:

[0091]

[0092] In formula (5), E a is the total amount of the system's initial carbon emission right quota; E P , E GT , E GB respectively represent the initial carbon emission right quotas of the conventional thermal power unit, gas turbine, and gas boiler; η e , η h represent the initial carbon emission right coefficients corresponding to the unit electric and gas powers; P P (t) is the output electric power of the conventional thermal power unit at time t; P e,GT (t), P h,GT (t) respectively represent the output electric and thermal powers of the gas turbine at time t; P h,GB (t) represents the output thermal power of the gas boiler at time t.

[0093] The actual carbon emission model of the system is:

[0094]

[0095] In formula (6), E ac represents the total actual carbon emissions of the system; E P,ac , E GT.ac , E GB,ac respectively represent the carbon emissions generated by the traditional thermal power unit, gas turbine, and gas boiler during the actual output process; a1, b1, c1 are the carbon emission calculation parameters of the traditional thermal power unit; a2, b2, c2 are the carbon emission calculation parameters of the gas turbine and gas boiler; P GTGB (t) represents the equivalent output power of the gas turbine and gas boiler.

[0096] From the system's initial carbon emission right quota model and the actual carbon emission model, the carbon trading volume participated by the system is:

[0097] E c = E ac - E a (7)

[0098] In order to further limit the carbon emissions of the system, a stepped carbon trading mechanism is introduced and multiple trading intervals are divided. The more carbon quotas the integrated energy system purchases, the higher the carbon price in the corresponding interval. The stepped carbon trading cost F of the integrated energy systemC The expression of

[0099]

[0100] In formula (8), F C is the carbon trading cost; λ is the carbon trading base price; L is the length of the carbon emission interval; α represents the growth rate of the carbon price; E c represents the carbon trading volume participated by the system.

[0101] Under the stepped carbon trading in step S4, the low-carbon economic dispatch model of the integrated energy system considering demand response and carbon capture takes into account both the economic and environmental benefits of the system while meeting the system constraints. Therefore, the objective function is to minimize the sum of the energy purchase cost, CCPP-P2G operation cost, carbon trading cost, operation and maintenance cost, and total demand response compensation cost of the integrated energy system:

[0102] minF = F buy + F C + F DR + F OM + F CP (9)

[0103] In formula (9), minF is the minimum total low-carbon economic dispatch cost of the integrated energy system considering demand response and carbon capture under stepped carbon trading; F buy is the energy purchase cost of the integrated energy system; F C is the stepped carbon trading cost of the integrated energy system; F OM is the operation and maintenance cost of the integrated energy system; F DR is the total demand response compensation cost of the integrated energy system; F CP is the CCPP-P2G collaborative operation cost;

[0104] The CCPP-P2G collaborative operation cost F of the integrated energy system CP The expression of is:

[0105]

[0106] In formula (10), is the power generation cost of CCPP; F CS represents the carbon storage cost; F P2G is the operation cost of P2G; a3, b3, c3 are the coal consumption coefficients of thermal power units; τ t , τ t-1 are 0-1 variables representing the unit start-stop state; ρ CS is the unit carbon storage price; represents the carbon storage volume of the carbon storage device at time t; δ P2G represents the unit operation cost of P2G.

[0107] The energy purchase cost F of the integrated energy system buy The expression is as follows:

[0108]

[0109] In formula (11), α e , β e , γ g respectively represent the electricity purchase price, electricity selling price and gas purchase price in period t; P e,buy (t), P e,sell (t), P g,buy (t) respectively represent the electricity purchase power, electricity selling power and gas purchase power in period t;

[0110] The total demand response compensation cost F of the integrated energy system DR The expression is as follows:

[0111]

[0112] In formula (12), δ z is the transferable load compensation coefficient; δ s is the replaceable load compensation coefficient;

[0113] The constraint conditions of step S4 include energy purchase constraint, power balance constraint, equipment output constraint and energy storage constraint.

[0114] The described energy purchase constraint is:

[0115]

[0116] In formula (13), are respectively the minimum values of the electricity purchase quantity, gas purchase quantity and electricity selling quantity in period t; are respectively the maximum values of the electricity quantity, natural gas quantity and electricity selling quantity that can be purchased in period t;

[0117] The described power balance constraint is:

[0118]

[0119] In formula (14), P e,load (t), P h,load (t), P g,load (t) respectively represent the total electricity load, heat load and gas load values in period t; respectively represent the discharging and charging powers of the energy storage device in period t; P h,GB (t), P h,CHP (t) respectively represent the natural gas powers input to the gas turbine and gas boiler in period t; They respectively represent the gas discharge and gas storage power of the gas storage device during period t;

[0120] The equipment output constraint is as follows:

[0121] Gas turbine constraint:

[0122]

[0123] In formula (15), They respectively represent the gas-to-electricity and gas-to-heat conversion efficiencies of the gas turbine; They respectively represent the maximum and minimum values of the gas consumption power during the operation of the gas turbine in period t; They are respectively the upper and lower limits of the gas turbine ramp constraint;

[0124] Gas boiler constraint:

[0125]

[0126] In formula (16), They respectively represent the maximum and minimum values of the gas consumption power during the operation of the gas boiler; They are respectively the upper and lower limits of the gas boiler ramp rate

[0127] CCPP-P2G operation constraint:

[0128]

[0129] In formula (17), It represents the upper limit of CCPP energy consumption; ΔP CC is the CCPP ramp constraint; is the upper limit of the operation power of the P2G device in period t; T on 、T off They are respectively the minimum continuous operation and outage times of the unit; They are respectively the continuous operation and outage times in period t-1.

[0130] Considering the electric and thermal energy storage devices, since their model structures are similar, the three energy storage devices share the same model. Taking the electric energy storage device model as an example, its model is:

[0131]

[0132] In formula (18), is a 0-1 variable, which respectively represents the charging and discharging states of the electric energy storage equipment; They respectively represent the upper and lower limits of the charging power of the energy storage equipment; D ES (t) is the stored electric quantity of the electric energy storage equipment in period t; They respectively represent the upper and lower limits of the stored electric quantity of the energy storage equipment; They respectively represent the charging and discharging powers of the energy storage device, and the total power of the electricity storage device remains unchanged within a scheduling period.

[0133] The optimization solution in step S5 is based on the MATLAB platform to call the GUROBI solver to solve the mixed-integer linear programming problem reflected by the low-carbon economic dispatch model of the integrated energy system considering demand response and carbon capture under the stepped carbon trading.

[0134] In summary, the problem solved by the present invention is a mixed-integer linear programming problem. First, a carbon capture-power to gas (CCPP-P2G) collaborative operation model is constructed; then, the load characteristics of the demand side are analyzed to obtain a multi-source demand response model; a stepped carbon trading mechanism is introduced, and the carbon trading cost under the stepped carbon trading mechanism is used as a component of the objective function; finally, under the conditions of meeting the energy purchase constraint, power balance constraint, equipment output constraint and energy storage constraint, it is solved based on the MATLAB platform by calling the GUROBI solver.

[0135] Implementation verification example

[0136] Taking a certain industrial park in the south as the research object, the equipment parameters of the park are shown in Table 1, and other parameters are shown in Table 2. The predicted values of wind power output, electricity, heat and gas load demands, and the equivalent load after DR are as Figure 2 shown.

[0137] Table 1. Equipment parameters

[0138]

[0139]

[0140] Table 2. Other parameters

[0141]

[0142] To verify the rationality of the model proposed by the present invention, the following four scenarios are compared and analyzed:

[0143] Scenario 1: Under stepped carbon trading, considering demand response and not considering CCPP-P2G.

[0144] Scenario 2: Under stepped carbon trading, considering CCPP-P2G and not considering demand response.

[0145] Scenario 3: Without considering stepped carbon trading, considering CCPP-P2G and demand response.

[0146] Scenario 4: Under stepped carbon trading, considering both CCPP-P2G and demand response.

[0147] As can be seen from Table 3, since there is no participation of flexible load in Scenario 2, the total cost is 22.8% higher than that in Scenario 4, and the carbon emissions increase by 12.1%; since there is no CCPP-P2G coordinated operation in Scenario 1, its cost is much higher than that of other scenarios, and the carbon emissions also far exceed those of other scenarios; on the basis of Scenario 3, Scenario 4 adds a stepped carbon trading mechanism, which further restricts carbon emissions, and the new energy consumption rate is also higher than that of other scenarios, verifying that the proposed method can effectively improve the economic and environmental benefits of the system.

[0148] Table 3. Scheduling results of Scenarios 1-4

[0149]

[0150] To verify the effectiveness of CCPP-P2G coordinated operation, Scenarios 1 and 4 are compared and analyzed. Combining with Table 2, it can be seen that the electrical output of Scenario 1 mainly consists of grid power purchase and gas turbines, with wind power generation as a supplement. When the electricity price is in the valley period, the electricity load demand is relatively low at this time. Since the valley electricity price is less than the operating cost of new energy power generation, grid power purchase is preferred during the valley period; during the peak electricity price period, the electricity price is higher than the operating cost of new energy power generation at this time. New energy power generation is preferred first, and the insufficient part is supplemented by batteries and grid power purchase. However, since there is no CCPP-P2G coordinated operation in Scenario 1 and the electrical output provided by CCPP-P2G is lacking, in order to meet the electrical load demand, even during the peak electricity price period, grid power purchase can only be used to meet the electrical load demand, which greatly increases the total operating cost of the system. Compared with Scenario 4, the total cost of Scenario 1 increases by 171,948 ￥, and the carbon emissions increase by 45.5%. Therefore, by introducing the CCPP-P2G coordinated operation framework, capturing CO2 through CCPP can significantly reduce carbon emissions, realize the effective utilization of internal resources, and thus reduce the system operating cost.

[0151] DR is not considered in Scenario 2. The electrical output of Scenario 2 is mainly provided by CCPP, with gas turbines and wind power generation as supplements. During the peak electricity price period, the insufficient output is supplemented by CCPP. Therefore, the total operating cost has decreased significantly compared with Scenario 1. Compared with Scenario 4, the carbon emissions increase by 12.1%, and the total operating cost increases by 22.8%. Due to the lack of DR, the peak period of the electrical load in Scenario 2 is not reduced, losing the flexibility and economy of scheduling, which leads to an increase in system carbon emissions.

[0152] To verify the effectiveness of the stepped carbon trading mechanism, Scenarios 3 and 4 are compared and analyzed. Compared with Scenario 4, due to the lack of the introduction of the stepped carbon trading mechanism, the total system cost is reduced by 1.2%, but the carbon emissions increase by 12.2%. Therefore, the introduction of the stepped carbon trading mechanism can reduce system carbon emissions while ensuring system economy, taking into account the environmental and economic attributes of the system.

[0153] In summary, the present invention provides a low-carbon economic dispatch method for an integrated energy system considering demand response and carbon capture under a stepped carbon trading system. First, a collaborative operation model of carbon capture and power-to-gas (CCPP-P2G) is established; then, a demand response mechanism is introduced to analyze the transferable and substitutable characteristics on the load side; a stepped carbon trading mechanism based on the integrated energy system is established, and the carbon trading cost under the stepped carbon trading mechanism is taken as a component of the objective function; finally, under the conditions of meeting the energy purchase constraint, power balance constraint, equipment output constraint and energy storage constraint, the GUROBI solver is called based on the MATLAB platform for solution. This model can reduce the carbon emissions and the system operation cost at the same time, and significantly reduce the peak-valley difference of the electrical load, relieve the power supply pressure during the peak electricity consumption period, and provide a reference for the low-carbon economic operation of the integrated energy system.

[0154] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations according to the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. An integrated energy system scheduling method considering stepped carbon trading and carbon capture, characterized in that It includes the following steps: S1. Construct a CCPP-P2G collaborative operation cost model; S2. Construct an integrated energy system architecture based on a multi-demand response mechanism; S3. Construct a stepped carbon trading mechanism based on the integrated energy system; S4. Based on the CCPP-P2G collaborative operation model constructed in step S1, the integrated energy system architecture constructed in step S2, and the stepped carbon trading mechanism constructed in step S3, construct a low-carbon economic dispatch model of the integrated energy system considering demand response and carbon capture with the minimum sum of energy purchase cost, CCPP-P2G operation cost, carbon trading cost, system operation and maintenance cost, and demand response compensation total cost as the objective function; minF = F buy +F C +F DR +F OM +F CP where, minF is the minimum total low-carbon economic dispatch cost of the integrated energy system considering demand response and carbon capture under the stepped carbon trading; F buy is the energy purchase cost of the integrated energy system; F C is the stepped carbon trading cost of the integrated energy system; F OM is the operation and maintenance cost of the integrated energy system; F DR is the total demand response compensation cost of the integrated energy system; F CP is the CCPP-P2G collaborative operation cost; S5. Under the satisfaction of the constraint conditions, perform an optimal solution for the low-carbon economic dispatch model of the integrated energy system considering demand response and carbon capture under the stepped carbon trading constructed in step S4.

2. The integrated energy system scheduling method considering stepped carbon trading and carbon capture according to claim 1, wherein The CCPP-P2G collaborative operation cost F of the integrated energy system CP is expressed as: In the formula, is the power generation cost of CCPP; F CS represents the carbon storage cost; F P2G is the operating cost of P2G; a3, b3, c3 are the coal consumption coefficients of thermal power units; τ t , τ t-1 are 0-1 variables representing the unit start-stop state; ρ CS is the unit carbon storage price; represents the carbon storage amount of the carbon storage device at time t; δ P2G represents the unit operating cost of P2G.

3. The integrated energy system scheduling method considering stepped carbon trading and carbon capture according to claim 1, characterized in that The energy purchase cost F of the integrated energy system buy is expressed as: Where, α e , β e , γ g respectively represent the electricity purchase price, electricity selling price, and gas purchase price in the t period; P e,buy (t), P e,sell (t), P g,buy (t) respectively represent the electricity purchase power, electricity selling power, and gas purchase power in the t period.

4. A comprehensive energy system scheduling method considering stepped carbon trading and carbon capture according to claim 1, characterized in that The total demand response compensation cost F of the integrated energy system DR is expressed as: where δ z is the transferable load compensation coefficient; δ s is the substitutable load compensation coefficient; represents the transferable load value of load i participating in demand response; represents the substitutable load value of load i participating in demand response.

5. The integrated energy system scheduling method considering stepped carbon trading and carbon capture according to claim 4, characterized in that The multi-demand response model includes base load, shiftable load, and substitutable load; The shiftable load model is expressed as: In the formula, is the price elasticity matrix, and e t,j is the element in the t-th row and j-th column of the price elasticity matrix; Δρ j represents the change in electricity price at the j-th moment after demand response; represents the initial value of the electricity price at the j-th moment, and ρ j represents the electricity price at the j-th moment; P DRmin and P DRmax represent the upper and lower limits of the transferable load power; The substitutable load model is expressed as: In the formula, represents the replaceable load value after load i participates in demand response; ε e,h is the electric-heat substitution parameter; respectively represent the energy conversion efficiencies of electric energy and heat energy; respectively represent the minimum and maximum amounts of replaceable electric load; are respectively the minimum and maximum amounts of replaceable heat load.

6. A comprehensive energy system scheduling method considering stepped carbon trading and carbon capture according to claim 5, characterized in that The stepped carbon trading cost F of the integrated energy system described above C The expression is as follows: Where F C is the carbon trading cost; λ is the base price of carbon trading; L is the length of the carbon emission interval; α represents the growth rate of the carbon price; E c represents the carbon trading volume participated by the system.

7. A scheduling method for an integrated energy system considering stepped carbon trading and carbon capture according to claim 6, characterized in that The stepped carbon trading mechanism based on the integrated energy system includes the determination of the initial carbon emission quota and the calculation method of the actual carbon emission model. The initial carbon emission right quota model is: where, E a is the total initial carbon emission allowance of the system; E P , E GT , E GB respectively represent the initial carbon emission allowances of conventional thermal power units, gas turbines, and gas boilers; η e and η h represent the initial carbon emission right coefficients corresponding to unit electricity and gas power; P P (t) is the output electric power of the conventional thermal power unit at time t; P e,GT (t), P h,GT (t) represent the output electric and thermal powers of the gas turbine at time t respectively; P h,GB (t) represents the output thermal power of the gas boiler at time t. The actual carbon emission model of the system is: Among them, E ac represents the total actual carbon emissions of the system; E P,ac , E GT.ac , E GB,ac respectively represent the carbon emissions generated by traditional thermal power units, gas turbines, and gas boilers during actual power generation; a1, b1, c1 are the carbon emission calculation parameters of traditional thermal power units; a2, b2, c2 are the carbon emission calculation parameters of gas turbines and gas boilers; P GTGB (t) represents the equivalent output power of gas turbines and gas boilers. From the system initial carbon emission right quota model and the actual carbon emission model, the carbon trading volume participated by the system is obtained as: E c = E ac - E a 。 8. A comprehensive energy system scheduling method considering stepped carbon trading and carbon capture according to claim 1, characterized in that The integrated energy system model considering demand response and including carbon capture includes: energy supply side, energy conversion devices, energy storage devices, and user-side loads; the energy supply side includes grid electric energy, natural gas, wind turbine units, photovoltaic units, CCPP-P2G; the energy conversion devices include gas turbines, gas boilers, and power-to-gas devices; the energy storage devices include electrical energy storage and thermal energy storage; the user-side loads are composed of electrical loads and thermal loads, including base loads and flexible loads.

9. A comprehensive energy system scheduling method considering stepped carbon trading and carbon capture according to claim 1, characterized in that The constraint conditions in step S5 include external energy purchase constraints, power balance constraints, equipment output constraints, and energy storage constraints: The energy purchase constraint is: Wherein, are respectively the minimum values of the electricity purchase volume, gas purchase volume, and electricity sales volume in period t; are respectively the maximum values of the electricity that can be purchased, the gas volume, and the electricity sales volume in period t; The power balance constraint is: Wherein, P e,load (t), P h,load (t), P g,load (t) respectively represent the total electric load, heat load, and gas load values in the t time period; respectively represent the discharging and charging powers of the electricity storage device in the t time period; P h,GB (t), P h,CHP (t) respectively represent the natural gas powers input into the gas turbine and gas boiler in the t time period; respectively represent the gas discharging and gas storage powers of the gas storage device in the t time period; The equipment output constraint is: Gas turbine constraint: In the formula, respectively represent the gas-to-electricity and gas-to-heat conversion efficiencies of the gas turbine; respectively represent the maximum and minimum values of the gas consumption power during the operation of the gas turbine in the t period; are respectively the upper and lower limits of the gas turbine ramp constraint; Gas boiler constraint: Wherein, respectively represent the maximum and minimum gas consumption powers during the operation of the gas boiler; are respectively the upper and lower limits of the ramp rate of the gas boiler CCPP-P2G operation constraint: In the formula, represents the upper limit of CCPP energy consumption; ΔP CC is the CCPP ramping constraint; is the upper limit of the operating power of the P2G device in period t; T on and T off are the minimum continuous operation and outage times of the unit, respectively; are the continuous operation and outage times in the (t - 1) period, respectively. Considering electrical and thermal energy storage devices, since their model structures are similar, the three types of energy storage share the same model. Taking the electrical energy storage device model as an example, its model is: In the formula, is a 0-1 variable, representing the charging and discharging states of the electricity storage device respectively; represent the upper and lower limits of the charging power of the energy storage device respectively; D ES (t) is the electricity storage capacity of the electricity storage device at time t; represent the upper and lower limits of the electricity storage capacity of the energy storage device respectively; represent the charging and discharging power of the energy storage device respectively. The total electricity of the electricity storage device remains unchanged within a scheduling period.

10. According to a method for dispatching an integrated energy system considering stepped carbon trading and carbon capture as claimed in claim 1, in step S5, under the satisfaction of the constraint conditions, the optimal solution of the model is based on the MATLAB platform to call the GUROBI solver to solve the mixed-integer linear programming problem reflected by the low-carbon economic dispatch model of the integrated energy system considering demand response and carbon capture under the stepped carbon trading.

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