Double-layer optimization method and system for hydrogen-ammonia comprehensive energy system considering multi-energy network coupling

Abstract

The invention relates to the technical field of comprehensive energy system optimization, and particularly discloses a hydrogen-ammonia comprehensive energy system double-layer optimization method and system considering multi-energy network coupling, and the method comprises the steps: constructing a hydrogen-ammonia comprehensive energy system model, taking a hydrogen-ammonia comprehensive energy system operator as a leader, taking a hydrogen-ammonia comprehensive energy system as a follower, and carrying out the optimization of the hydrogen-ammonia comprehensive energy system; an upper-layer leader establishes an upper-layer comprehensive energy operator objective function by making transaction prices of five energy sources, namely electricity, heat, gas, hydrogen and cold, and by taking the purpose of maximizing own income in the transaction process with the user and the energy supply side; a lower-layer follower formulates an output plan of each type of unit according to the energy price formulated by the upper layer, and a lower-layer hydrogen-ammonia comprehensive energy system objective function is constructed with the purpose of maximizing the own income; solving the upper and lower layer objective functions to obtain the optimal output of each type of unit; according to the invention, the scheduling of the system is stimulated by using a stepped green certificate-carbon transaction mechanism to realize low carbon and economization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of integrated energy system optimization, and particularly relates to a hydrogen-ammonia integrated energy system double-layer optimization method and system considering multi-energy network coupling. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] Current integrated energy system research mainly focuses on the collaborative optimization of traditional energy forms such as electricity, heat, and gas. A few advanced systems attempt to include hydrogen energy carriers, but the integration of ammonia energy as a zero-carbon fuel and energy storage medium is still in the experimental stage. In terms of energy transmission and distribution networks, existing models generally use simplified topological structures (such as a 10-node electric-thermal combined network), and have not established a multi-scale coupled network architecture that considers power grid flow constraints, heat and cold network transmission delays, and gas and hydrogen network pressure dynamics. Load-side management focuses on electricity and heat demand response, while price elasticity regulation of gas, hydrogen, and cold loads has not yet formed a systematic solution, making it difficult to smooth the multi-energy flow chain disturbance when high volatility renewable energy is connected.

[0004] Existing carbon reduction technologies rely too much on basic carbon trading mechanisms, making it difficult to achieve three-dimensional coordination of carbon capture (source-side unit emission reduction), step-by-step green certificate-carbon trading (policy incentive dispatch), and load-side carbon flow tracking (node carbon potential assessment), resulting in a lack of closed-loop optimization chain for source-grid-load carbon reduction resources, significantly weakening the effectiveness of system-level carbon reduction. In addition, existing carbon flow operations mostly focus on calculating the node carbon potential and carbon emissions of the electric and thermal load sides along with the power grid and heat network, and few studies involve carbon flow operation and carbon potential analysis of electric-thermal-gas networks.

[0005] In addition, existing unit collaborative optimization often focuses on optimal unit operation under fixed time-of-use energy prices, making it difficult to coordinate the interests of upstream energy suppliers and park operators, and the solution process is prone to local optimization, resulting in loss of interest. SUMMARY

[0006] To solve the above problems, the present application provides a hydrogen-ammonia comprehensive energy system double-layer optimization method and system considering multi-energy grid coupling, integrates renewable energy such as wind power, photovoltaic, photo-thermal, hydrogen energy, ammonia energy and the like as clean electricity or heat source, introduces combined heat and power units, ammonia production devices and ammonia fuel cells, electrolytic cell hydrogen production, methanation devices, photo-thermal steam turbines, electricity, heat, gas, hydrogen, cold or ammonia energy storage, and multi-type energy conversion and storage equipment such as compressed air refrigeration, to meet multi-unit and load demand; a step green certificate-carbon trading mechanism is used to encourage the dispatch of the system to be more low-carbon, the carbon flow calculation theory is used to quantify the carbon reduction contribution of the carbon reduction means to the load side; a master-slave game framework is adopted, the upper layer solves the global profit optimization of the hydrogen-ammonia comprehensive energy operator by a projection optimization algorithm, and the lower layer calls a Gurobi solver to realize low-carbon economic dispatch of the hydrogen-ammonia comprehensive energy system.

[0007] In some embodiments, the following technical solutions are adopted: A hydrogen-ammonia comprehensive energy system double-layer optimization method considering multi-energy grid coupling, comprising: A hydrogen-ammonia comprehensive energy system model is constructed, the hydrogen-ammonia comprehensive energy system model comprising wind turbine generators, photovoltaic, photo-thermal units, combined heat and power units, gas boilers, electricity, heat, gas, hydrogen, cold and ammonia energy storage systems, ammonia fuel cells, methanation natural gas production, carbon capture and storage devices, electric refrigeration equipment, hydrogen electrolytic cells and electric ammonia production equipment; A step green certificate-carbon trading mechanism is established to guide the hydrogen-ammonia comprehensive energy system to operate in the direction of reducing carbon emissions; five types of loads, i.e., cold, heat, electricity, gas and hydrogen, are considered, and price incentive demand response is used to stimulate the five types of loads to complete reduction, substitution and transfer; six energy flows, i.e., cold, heat, electricity, gas, hydrogen and ammonia, are considered, and carbon flow operation of the power system, heat network and gas network is performed respectively; The hydrogen-ammonia comprehensive energy system operator is taken as a leader and the hydrogen-ammonia comprehensive energy system is taken as a follower, the upper layer leader sets the transaction prices of five types of energy, i.e., electricity, heat, gas, hydrogen and cold, to maximize its own benefits in the process of transaction with users and energy supply sides, and an upper layer comprehensive energy operator target function is constructed; the lower layer follower sets the output plans of each type of unit according to the energy prices set by the upper layer to maximize its own benefits, and a lower layer hydrogen-ammonia comprehensive energy system target function is constructed; The upper and lower layer target functions are solved to obtain optimal outputs of each type of unit.

[0008] In other embodiments, the following technical solutions are adopted: A hydrogen-ammonia comprehensive energy system double-layer optimization system considering multi-energy grid coupling, comprising: A model construction module is configured to construct a hydrogen-ammonia integrated energy system model, the hydrogen-ammonia integrated energy system model comprising a wind turbine, a photovoltaic, a solar-thermal unit, a combined heat and power unit, a gas boiler, an electricity, heat, gas, hydrogen, cold and ammonia energy storage system, an ammonia fuel cell, a methanation natural gas production device, a carbon capture and storage device, an electric refrigeration device, a hydrogen electrolyzer and an electric ammonia production device. A carbon flow calculation module is configured to guide the hydrogen-ammonia integrated energy system to operate in the direction of reducing carbon emissions by establishing a stepped green certificate-carbon trading mechanism; considering five types of loads of cold, heat, electricity, gas and hydrogen, using price incentive demand response to stimulate the five types of loads to complete reduction, substitution and transfer; and considering six energy flows of cold, heat, electricity, gas, hydrogen and ammonia, respectively performing carbon flow operation of a power system, a heat network and a gas network. A target function construction module is configured to take the hydrogen-ammonia integrated energy system operator as a leader and the hydrogen-ammonia integrated energy system as a follower, the upper leader formulates trading prices of five types of energy of electricity, heat, gas, hydrogen and cold to maximize its own benefits in the process of trading with users and energy supply sides, and constructs an upper integrated energy operator target function; and the lower follower formulates output plans of each type of unit according to the energy prices formulated by the upper layer to maximize its own benefits, and constructs a lower hydrogen-ammonia integrated energy system target function. An optimization solution module is configured to solve the upper and lower target functions to obtain optimal outputs of each type of unit.

[0009] In some other embodiments, the following technical solutions are adopted: A terminal device comprises a processor and a memory, the processor is used to implement instructions, and the memory is used to store a plurality of instructions, the instructions are suitable for being loaded and executed by the processor to implement the hydrogen-ammonia integrated energy system double-layer optimization method considering multi-energy network coupling.

[0010] In some other embodiments, the following technical solutions are adopted: A computer readable storage medium stores a plurality of instructions, the instructions are suitable for being loaded and executed by a processor of a terminal device to implement the hydrogen-ammonia integrated energy system double-layer optimization method considering multi-energy network coupling.

[0011] Compared with the prior art, the hydrogen-ammonia integrated energy system double-layer optimization method considering multi-energy network coupling has the following beneficial effects: (1) The present application is oriented to an industrial park, fully considers the output characteristics of renewable energy such as wind power, photovoltaic power, and photothermal power, and realizes the mutual conversion among electricity, heat, gas, cold, hydrogen, and ammonia on the basis of electricity by introducing facilities such as a combined cooling, heating, and power device, a hydrogen electrolysis tank, electric ammonia, an ammonia fuel cell, electric refrigeration, hydrogen methanation, electricity, heat, gas, hydrogen, ammonia, and cold energy storage equipment, and a gas boiler, realizes the efficient collaboration of multiple energies, reduces the dependence on the superior energy network, improves the consumption rate of new energy, and reduces carbon emissions.

[0012] (2) The present application introduces a carbon capture unit on the power generation side to reduce the carbon emissions of the generator unit, and uses harmful greenhouse gas CO2 as the input energy of the hydrogen methanation equipment to realize the clean conversion of carbon; a step-by-step green certificate-carbon trading strategy is introduced in the scheduling of the hydrogen-ammonia comprehensive energy system, which promotes the scheduling results to develop in the low-carbon direction by combining the clean properties of green certificate trading and the punishment characteristics of carbon trading.

[0013] (3) The present application designs a 33-node electricity-6-node heat-6-node gas-6-node hydrogen-4-node cold network (33E-6H-6G-6Hy-4C) system, which realizes the coupling and collaboration among various energies while fully considering the dynamic energy flow and time delay characteristics of various energy networks; a carbon flow operation framework of the electricity-heat-gas network is introduced, so that the carbon reduction means can take effect on the load side, and the subsequent carbon emission reduction evaluation and node carbon potential demand response can be added; then, an integrated demand response strategy is introduced to meet the energy reduction and time shift of the five demand loads of electricity, heat, gas, cold, and hydrogen, and further to suppress the influence of large load fluctuation on the integrated energy system.

[0014] (4) The present application uses master-slave game as the optimization framework of the multi-energy industrial park, establishes a double-layer collaborative scheduling model, introduces an integrated energy operator to realize the upper energy network management, and the lower layer is a hydrogen-ammonia integrated energy system; the upper leader aims to maximize its own income in the process of trading with users and energy supply side by formulating the trading prices of five kinds of energy of electricity, heat, gas, hydrogen, and cold, and the lower follower formulates the output plans of various types of units according to the energy prices formulated by the upper layer to maximize its own income.

[0015] At the same time, a projection optimization algorithm is used to solve the multi-dimensional strong nonlinear problem of the upper operator, which solves the problem that the existing heuristic algorithm is easy to fall into local optimum.

[0016] Other features and advantages of the additional aspects of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1A flow chart of a double-layer optimization method of a hydrogen-ammonia comprehensive energy system considering multi-energy network coupling in an embodiment of the present application; Figure 2 A schematic diagram of a hydrogen-ammonia comprehensive energy system collaborative operation architecture in an embodiment of the present application; Figure 3 A schematic diagram of an E33-H6-G6-Hy6-C4 energy network coupling topology in an embodiment of the present application; Figure 4 A schematic diagram of a hydrogen-ammonia comprehensive energy system master-slave game architecture in an embodiment of the present application; Figure 5 A double-layer joint solution flow chart of a projection optimization algorithm-Gurobi solver in an embodiment of the present application. DETAILED DESCRIPTION

[0018] It should be noted that the following detailed description is illustrative only and is intended to provide further description of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0019] It should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a presence of a feature, step, operation, device, component, and / or a combination thereof.

[0020] Embodiment one In one or more embodiments, a double-layer optimization method of a hydrogen-ammonia comprehensive energy system considering multi-energy network coupling is disclosed, which combines Figure 1 , and specifically includes the following processes: S101: Construct a hydrogen-ammonia comprehensive energy system model, which includes wind turbines, photovoltaic, photothermal units, combined heat and power units, gas boilers, electricity, heat, gas, hydrogen, cold and ammonia energy storage systems, ammonia fuel cells, methanation natural gas, carbon capture and storage devices, electric refrigeration equipment, hydrogen electrolysis cells and electric ammonia production equipment.

[0021] In this embodiment, a multi-energy complementary comprehensive energy system containing cold, heat, electricity, gas, hydrogen and ammonia is constructed for the multi-type energy demand characteristics of an industrial park. The system integrates renewable energy such as wind power, photovoltaic, photothermal, hydrogen energy and ammonia energy as clean power or heat source, introduces multi-type energy conversion and storage equipment such as combined heat and power units, ammonia production devices and ammonia fuel cells, electrolysis cells for hydrogen production, methanation devices, photothermal steam turbines, electricity, heat, gas, hydrogen, cold and ammonia energy storage and compressed air refrigeration, etc., to meet the multi-unit and load demand.

[0022] Specifically, in combination with Figure 2 The hydrogen-ammonia comprehensive energy system includes six kinds of energy, namely electricity, heat, gas, hydrogen, cold and ammonia, is driven by three kinds of renewable energy, namely photovoltaic, wind power and photo-thermal, and considers the demand response of electricity, heat, gas, hydrogen and cold load to reduce the influence of excessive load fluctuation on the system.

[0023] The hydrogen-ammonia comprehensive energy system includes combined heat and power (CCHP), gas boiler (GB), electricity, heat, gas, hydrogen, cold and ammonia energy storage, ammonia fuel cell, methane natural gas, carbon capture and storage, electric refrigeration, hydrogen electrolyzer and ammonia production by electricity. The CCHP unit includes a gas turbine, waste heat recovery, heat refrigeration device, which can convert natural gas into electricity, heat and cold. The GB can convert natural gas into heat energy. The carbon capture and storage device is used to modify the CCHP and GB to absorb part of their carbon emissions, and cooperate with the hydrogen produced by the electrolyzer to convert waste carbon dioxide into clean methane fuel to supply the gas load, CCHP and GB. Part of the electricity is converted into ammonia energy by the ammonia production device, which is used to supply the ammonia fuel cell for power generation to realize time shift of electricity and meet the demand of electricity load. In addition, the byproduct heat generated by ammonia production is connected to the heat network to participate in the circulation of heat energy. The cold load is supplied by the CCHP, compressed air refrigeration equipment and cold storage tank. In order to further reduce the carbon emissions of the source side device, the gas turbine in the CCHP and the GB are modified to hydrogen combustion. Under the condition of supplying the same combustion heat value, part of the carbon emissions is reduced.

[0024] It should be noted that the interaction between the hydrogen-ammonia comprehensive energy system and the upper electricity, heat and gas network is mutual. Since hydrogen energy is converted from excess electricity, there is almost no surplus, so there is only hydrogen purchase from the upper hydrogen network, and no hydrogen sales link. In addition, since the cold load demand in the region is usually less than the electricity, heat and gas load, there is no purchase and sale link of the upper cold network. Ammonia energy acts as a transfer link between electricity, hydrogen and heat, and plays a role in stabilizing the fluctuation of electricity and heat load, so there is no upper ammonia supplier and ammonia load.

[0025] The regional industrial comprehensive energy system of the embodiment can realize efficient cooperation of multiple energies, reduce dependence on the upper energy network, improve the consumption rate of new energy, and reduce carbon emissions.

[0026] In the embodiment, the model of the hydrogen-ammonia comprehensive energy system is established as follows: The energy production, conversion and low-carbonization equipment of the hydrogen-ammonia comprehensive energy system includes wind turbine, photovoltaic, photothermal unit, CCHP, GB, electricity, heat, gas, hydrogen, cold and ammonia energy storage, ammonia fuel cell, methanation natural gas, hydrogen electrolyzer, carbon capture and storage, electric refrigeration, etc.

[0027] (1) Photovoltaic power generation model: The output of the photovoltaic generator mainly depends on the radiation intensity of the sun, and the output power can be modeled as: (1) wherein, η is the photoelectric conversion efficiency of the photovoltaic, A is the area of the photovoltaic panel, I is the illumination intensity.

[0028] (2) Wind power generation model: The output of the photovoltaic generator mainly depends on the radiation intensity of the sun, and the output power can be modeled as: (2) wherein, ρ represents the comprehensive air density, Cp is the wind energy utilization coefficient, A is the swept wind area, v is the wind speed, , and represent the cut-in, cut-out and rated wind speed respectively.

[0029] (3) Photothermal power generation model: Photothermal power generation mainly utilizes a mirror field to collect solar thermal energy. In the embodiment, part of the thermal energy is converted into a heat network, and the other part of the thermal energy is used to cooperate with a steam turbine to generate electricity. The output thermal power can be modeled as: (3) (4) (5) wherein, η represents the thermal-electric conversion efficiency of the steam turbine, Q represents the thermal power allocated by the photothermal power station to the steam turbine, Q represents the heat provided by the heat network to the steam turbine, Q represents the total heat received by the photothermal power station, Q represents the heat supplied by the photothermal power station to the heat network, η represents the photothermal conversion efficiency, A represents the area of the photothermal mirror field.

[0030] (4) CCHP model: The CCHP unit includes a gas turbine, a waste heat recovery, and an absorption refrigeration three modules, which can be modeled as: (6) (7) (8) where, represents the power generation, is the power generation efficiency, is the natural gas consumption, is the total waste heat power, is the heating ratio, is the cooling ratio, is the refrigeration coefficient, is the output cold power.

[0031] (5) GB model: The GB unit can convert natural gas into heat to input into the heat network or supply heat load, and output heat power which can be modeled as: (9) where, represents the low calorific value of natural gas, represents the consumption of natural gas, represents the boiler thermal efficiency.

[0032] (6) Electricity, heat, gas, hydrogen, cold and ammonia energy storage: The energy storage device needs to meet the SOC constraint, the charge-discharge mutual exclusion constraint, the power constraint and the electric quantity constraint, aiming to provide flexible power buffer for the integrated energy system, which can be modeled as: (10) (11) (12) (13) (14) where, S represents the set of energy storage systems, which is composed of electric energy storage elec, thermal energy storage therm, gas energy storage gas, hydrogen energy storage hydro, cold energy storage cool and ammonia energy storage ammonia; and respectively represent the state of charge and discharge, and respectively represent the charge and discharge power of the energy storage set, and represent the upper limit of the charge and discharge of the energy storage set, is the energy of the energy storage set, and represent the upper and lower bounds of the energy of the energy storage set, respectively, and represent the charging and discharging efficiency of the energy storage set, respectively, is the self-discharge rate.

[0033] (7) Hydrogen production by electrolysis: The electrolyzer can convert electrical energy into hydrogen energy, which is modeled as: (15) where, is the hydrogen production, is the electrolyzer efficiency, is the electricity consumption of the electrolyzer, is the electrical-to-hydrogen conversion factor of hydrogen.

[0034] (8) Ammonia production and ammonia fuel cell: The air separation ammonia production device can use the separated nitrogen in the air and the hydrogen produced by the hydrogen electrolyzer to produce ammonia, and the ammonia fuel cell can use the produced ammonia to produce electrical energy. For air separation ammonia production, this process can be modeled as: (16) (17) (18) where, represents the electricity consumption of ammonia production, represents the electricity consumption rate of nitrogen production, represents the molar mass of ammonia, and represent the upper and lower bounds of the electricity consumption of ammonia production, respectively, represents the efficiency of ammonia production. represents the consumption of nitrogen, represents the consumption of hydrogen, and represent the molar mass of nitrogen and hydrogen, respectively, represents the production of ammonia.

[0035] The ammonia fuel cell can be modeled as: (19) (20) (21) where, is the power generation of the ammonia fuel cell, is the heat generated by ammonia production, and respectively represent the efficiency of ammonia fuel cell and ammonia production, is the mass power conversion factor of ammonia, represents the consumed mass of ammonia, and respectively represent the upper and lower limit of ammonia fuel cell power production.

[0036] (9) Carbon capture and storage device: Carbon capture and storage device can retrofit specific units to capture the carbon dioxide emitted by these units through flue gas diversion, shower capture, etc. and store it in the solution storage for hydrogen methanation equipment, which is modeled as: (22) (23) where, represents the power generation or heat production of the unit retrofitted by carbon capture, including CCHP, GB; represents the flue gas diversion ratio, represents the efficiency of the absorption tower, represents the energy consumption coefficient of the absorption tower, and respectively represent the operating energy consumption and fixed energy consumption of the carbon capture plant, is the total energy consumption of the carbon capture plant, and represent the lean liquid volume and rich liquid volume, and the subscripts in and out represent the input liquid and output liquid, and respectively represent the captured and regenerated CO2, represents the CO2 absorption coefficient of the alcohol amine solution, is the density of CO2.

[0037] (10) Methanation to produce natural gas: Methanation can convert hydrogen and carbon dioxide into natural gas, and the volume of CO2 consumed by this process is the same as the volume of methane produced, which is modeled as: (24) where, is the volume of natural gas produced, is the amount of hydrogen consumed, and respectively represent the calorific value of hydrogen and natural gas, represents the density of natural gas, is the efficiency of the reactor.

[0038] (11) Electric refrigeration: Electric refrigerators produce cold by consuming electricity, which is modeled as: (25) (26) wherein, and are the upper limit of the input electric power and the refrigeration coefficient of the electric refrigerator, respectively, is the output cold power, is the input electric power. (12) Hydrogen-doped combustion: In this embodiment, the gas turbine and the GB are modified to hydrogen-doped combustion, with a ratio of 0-20% dynamic hydrogen-doping, which is modeled as: (27) wherein, Ω mix is the set of units for hydrogen-doped combustion, which includes the CHP and the GB, is the input power of the mixed gas, and represent the volume power conversion coefficients of hydrogen and natural gas, respectively, represents the hydrogen-doping ratio of the unit, and are the electric and thermal efficiencies of the units in the set, respectively, is the density of hydrogen, and are the gas consumption and hydrogen consumption of the units in the set, respectively.

[0039] S102: By establishing a stepped green certificate-carbon trading mechanism, guide the hydrogen-ammonia integrated energy system to run in the direction of reducing carbon emissions; considering the five types of loads of cold, heat, electricity, gas and hydrogen, use price incentive demand response to stimulate five types of loads to complete reduction, substitution and transfer; considering the six energy flows of cold, heat, electricity, gas, hydrogen and ammonia, respectively, the carbon flow calculation of the power system, heat network and gas network is carried out.

[0040] In this embodiment, by establishing a stepped green certificate-carbon trading mechanism, guide the hydrogen-ammonia integrated energy system to run in the direction of reducing carbon emissions, as follows: The stepped carbon trading market can guide the hydrogen-ammonia integrated energy system to run in the direction of reducing carbon emissions by implementing rewards and penalties on carbon emissions within a certain range.

[0041] This embodiment uses the baseline method to allocate the carbon quota of the hydrogen-ammonia integrated energy system, and the modeling of carbon trading is as follows: (28) wherein, represents the carbon quota of the hydrogen-ammonia integrated energy system, Carbon emission quota obtained by representing all carbon emission units (gas turbine, GB), Carbon quota coefficient of elements in all carbon emission unit sets, The power generation of these units.

[0042] Since the gas turbine and GB in this embodiment are carbon capture modified, the actual carbon emission of the system can be represented as: (29) Where, Represent the total carbon emission of the system, Represent the carbon emission generated by external power purchase, Represent the carbon emission generated by the system itself, Represent the carbon emission captured by the carbon capture unit, Represent the carbon emission intensity of external power purchase.

[0043] Therefore, the carbon emission right of the hydrogen-ammonia integrated energy system can be calculated as: (30) The stepped carbon trading cost is represented as: (31) Where, Represent the base price of carbon trading, Represent the price increase, Represent the length of the carbon emission interval.

[0044] Similar to the stepped carbon emission mechanism, one green certificate represents 1MWh of renewable energy on-grid power, so the green certificate held by the hydrogen-ammonia integrated energy system is modeled as: (32) (33) Where, Green certificate quota, Represent the green certificate quota coefficient, Electric load, The actual number of green certificates obtained by the hydrogen-ammonia integrated energy system, Represent the power generation of the gas turbine of the photothermal power station; 、 Represent the power generation of photovoltaic and wind power respectively.

[0045] Therefore, the tradable green certificate is: (34) The cost of the step ladder green certificate is similar to the cost of carbon trading, which is not described here. The green certificate mechanism can supplement the excess carbon emission rights by offsetting part of the carbon emissions. The step ladder green certificate-carbon trading mechanism is modeled as: (35) (36) wherein, is the carbon emissions offset by the green certificate, and represent the carbon emissions of coal-fired and new energy power supply, respectively, represents the carbon emission rights of the green certificate combined with carbon trading.

[0046] Substitute in the above formula for in the step ladder carbon trading mechanism, and the step ladder green certificate-carbon trading mechanism can be obtained.

[0047] In this embodiment, five types of loads, cold, heat, electricity, gas and hydrogen, are considered, and price incentive type demand response is used to stimulate five types of loads to complete reduction, substitution and transfer. Specifically, Electricity, heat and cold can be substituted for each other within a certain range, and gas and hydrogen can be substituted for each other within a certain range. In addition, five types of loads can be reduced and time-shifted within a certain range, which is modeled as: (37) (38) (39) (40) (41) wherein, , , , and represent the electricity, heat, cold, gas and hydrogen loads after demand response, respectively, and the subscript base represents the corresponding base load, , , , , represent the electricity, heat, cold, gas and hydrogen load transfer amounts, respectively, , , , , represent the electricity, heat, cold, gas and hydrogen load reduction amounts, respectively, , , , 、 、 、 、 respectively represent the replaceable amount of electric load to thermal load, electric load to cold load, thermal load to electric load, thermal load to cold load, cold load to electric load, cold load to thermal load, gas load to hydrogen load and hydrogen load to gas load.

[0048] The constraints of each load under integrated demand response are as follows: (42) (43) (44) (45) (46) (47) wherein, and represent the upper limit and lower limit of the electric load transfer amount, represents the upper limit of the electric load that can be cut, and respectively represent the upper limit of the transferable amount of electric load and hydrogen load, and the remaining loads are the same, which will not be repeated here.

[0049] In this embodiment, considering the cold, heat, electricity, gas, hydrogen and ammonia six kinds of energy flow, the carbon flow operation of the power system, the heat network and the gas network is carried out respectively, specifically: 1. First, establish the E33-H6-G6-Hy6-C4 energy network coupling topology.

[0050] The hydrogen-ammonia integrated energy system in this embodiment considers six kinds of energy flow, including cold, heat, electricity, gas, hydrogen and ammonia. The power grid uses the IEEE33 node topology based on direct current flow, the heat network uses the 6-node heating network considering the time delay characteristics and hot water backflow, the gas network uses the Belgium 6-node gas network considering gas pressure and gas flow direction, the cold network is modeled as 4 nodes, and the hydrogen network and the gas network are similar, modeled as 6 nodes. Figure 3As shown, the power grid contains 2 wind power, 2 photovoltaic, ammonia fuel cell, P2A, electric energy storage, solar thermal, CCS, upper power grid, electric refrigeration (ISA) and other power generation or power consumption devices, the heat grid contains heat storage tank, waste heat recovery device in CCHP, upper heat grid, GB and other heat generation devices, the gas grid contains upper gas grid, methanation device, gas storage tank and other devices, the hydrogen grid contains upper hydrogen grid, electrolytic tank, hydrogen storage tank and other devices, and the cold grid contains absorption refrigeration in CCHP, ISA and other devices. In the E33-H6-G6-Hy6-C4 energy grid coupling topology, the CCHP is the key hub connecting the electric-thermal-gas-cold grid, the hydrogen grid can supply hydrogen to the methanation device in the gas grid, the heat grid can supply the steam turbine equipped in the CSP in the power grid, the CSP and ammonia plant in the power grid can supply heat to the heat grid, and the ISA in the power grid is not only an electric load but also an input cooling equipment of the cold grid. The collaborative operation and close coupling of these devices enable the hydrogen-ammonia integrated energy system to realize multi-energy utilization and low-carbon operation.

[0051] (1) Power network modeling: The power network proposed in this embodiment only considers direct current flow, i.e., only considers active power and phase angle, as follows: (48) wherein, and represent the phase angles of nodes i and j , respectively, represents the flow between nodes i and j , and represent the minimum and maximum values of the flow between nodes i and j , and represent the minimum and maximum values of the phase angle of node i , represents the phase angle of the reference node, represents the impedance between node i and node j .

[0052] (2) Cold and heat network modeling: The cold and heat networks proposed in this embodiment take into account temperature loss, and both networks use the temperature drop and temperature rise model of the water supply pipeline, as follows: (49) wherein, and represent the inlet and outlet temperatures of the pipeline i in the cold and heat networks, respectively, represents the ambient temperature, representative of the pipe heat transfer coefficient, representative of the pipe i length, representative of the pipe mass coefficient, representative of the mass of water in the pipe.

[0053] In the cold and heat networks, the mixed temperature of the cold and hot water in the pipe is modeled as: (50) (51) (52) (53) where, and are the mixed water temperature at the node k of the inlet and return pipes, and represent the inlet and return water temperature of the pipe i , and represent the inlet and return flow rate of the pipe i , and represent the outlet temperature of the inlet and return pipe i .

[0054] The relationship between the heat source, heat load, and water temperature in the heat network is as follows: (54) (55) where, is the specific heat capacity of water, and are the water flow rate into the heat load node and out of the heat source node, represents the heat load, and represent the unit heat consumption of the system and the heat generation of the heat source, which will be explained in detail below.

[0055] The relationship between the cold source, cold load, and water temperature in the cold network is similar to that in the heat network, and will not be repeated here.

[0056] (3) Gas and hydrogen network modeling: The principles of the natural gas network and hydrogen network mentioned in this embodiment are similar, and the relationship between the gas flow rate and the node gas pressure in the constraints is as follows: (56) (57) (58) in, For gas and hydrogen network nodes i and j The gas flow rate in the pipeline between The direction of airflow in the gas and hydrogen grids. It refers to air pressure; min and max are the lower and upper limits, respectively.

[0057] 2. Calculation of carbon flow in electricity, heat, and gas networks: To evaluate proposed carbon reduction strategies such as carbon capture and storage-methanation and tiered green certificates-carbon trading on the load side, this embodiment establishes a carbon flow calculation model under energy grid coupling. Since the hydrogen and cooling grids do not generate carbon emissions, the carbon flow calculation only considers the electricity, heat, and gas grids. Specifically, it fully considers the output characteristics of various energy production and conversion equipment in the dynamic operation of the hydrogen-ammonia integrated energy system, and takes into account load changes under integrated demand response. Through the definition and calculation of nodal carbon potential, along with the power flow of the electricity, heat, and gas grids, it calculates the carbon potential and load carbon emissions of each node in the coupled energy grid, fully visualizing the carbon flow of the coupled energy grid at every moment to efficiently quantify the carbon reduction effect and provide a foundation for subsequent nodal carbon potential demand response.

[0058] (1) Calculation of carbon flow in power system: In the IEEE 33-bus power system, the carbon potential of each node is determined by the active power injection from the generators and transmission lines connected to that node. This process is modeled as follows: (59) in, For nodes n A collection of connected generator sets. For generator h carbon emission intensity, For the unit h active power, and Representing the inflow nodes of the power system n The carbon flow rate and power of the branch; This represents the set of branches from which power flows into node n.

[0059] In a power grid, the node carbon potential vector of units that generate carbon emissions. It is represented as: (60) in, e N Representing the i The carbon potential of a node that generates carbon emissions.

[0060] The nodal carbon potential vector of all nodes It is represented as: (61) in, The active flux matrix, This is the transpose of the branch power flow distribution matrix. Inject power flow matrix into the unit.

[0061] (2) Calculation of carbon flow in heating network: Similar to an electric power system, in the 6-node heat network system used in this embodiment, the carbon potential of each node is determined by the amount of heat power injected from the heating units and heat pipes connected to that node. This process is modeled as follows: (62) in, For nodes n A collection of interconnected thermal power units. For hotspot units h carbon emission intensity, For the unit h active power, and These represent the inflow nodes in the heating network. n The carbon flow rate and thermal power of the branch pipes; This represents the set of pipe branches through which hot water flows into node n.

[0062] In a heating network, the node carbon potential vector of units that generate carbon emissions. It is represented as: (63) in, e N Representing the i The node carbon potential of a thermal power unit that generates carbon emissions.

[0063] The nodal carbon potential vector of all nodes It is represented as: (64) in, The active flux matrix, This is the transpose of the heat network power flow distribution matrix. Injecting a power flow matrix into the thermal power unit.

[0064] (3) Calculation of carbon flow in the gas network: In a 6-node gas supply system, the carbon potential of each gas network node is determined by the gas source and gas flow rate connected to that node, expressed as: (65) where, is the set of pipes connected to node g , g is the set of all pipes flowing into node p , is the set of gas sources connected to node g , w is the set of gas sources , w is the carbon intensity of gas source , are the gas flow rates of pipe p and gas source w , and represent the carbon flow rate and gas power of branch pipes flowing into node n in the gas network.

[0065] In the gas network, different gas sources have different carbon intensities, and the node carbon potential vector of node is represented as: (66) where, represents the carbon intensity of the gas source, G represents the number of gas sources that produce carbon emissions.

[0066] The node carbon potential vector of all nodes in the gas network is represented as: (67) where, is the active power flow matrix of the gas network, is the transpose of the gas network power flow distribution matrix, is the gas source injection power flow matrix.

[0067] This embodiment introduces carbon capture units on the source side to capture carbon emissions from source-side units in terms of carbon emission reduction, and combines a methanation device to produce clean methane. Hydrogen is used for combustion in gas turbines and gas boilers to reduce part of the carbon emissions. A step green certificate-carbon trading mechanism is used to encourage the dispatch of the system to be more low-carbon. Carbon flow calculation theory is used to quantify the contribution of carbon reduction means to load side.

[0068] This embodiment designs a 33-node electricity-6-node heat-6-node gas-6-node hydrogen-4-node cold network (33E-6H-6G-6Hy-4C) system, which fully considers the dynamic energy flow and time delay characteristics of various energy networks, and realizes the coupling and cooperation between various types of energy; The carbon flow operation framework of the electricity-heat-gas network is introduced, which makes the carbon reduction means effective at the load side, and facilitates the subsequent carbon emission reduction evaluation and the addition of node carbon potential demand response. Price incentive demand response is introduced at the load side, which uses the time-shiftable and reducible characteristics of the load to reduce the impact of source-load mismatch between the five types of energy, i.e. electricity, heat, gas, hydrogen and cold, on the system.

[0069] S103: The hydrogen-ammonia integrated energy system operator is taken as the leader, and the hydrogen-ammonia integrated energy system is taken as the follower. The upper leader sets the transaction prices of electricity, heat, gas, hydrogen and cold to maximize its own benefits in the process of trading with users and energy supply sides, and constructs an upper integrated energy operator objective function. The lower follower sets the output plans of various types of units according to the energy prices set by the upper layer to maximize its own benefits, and constructs a lower hydrogen-ammonia integrated energy system objective function.

[0070] This embodiment proposes a hydrogen-ammonia integrated energy system double-layer collaborative scheduling model based on master-slave game. The hydrogen-ammonia integrated energy system operator is taken as the leader, and the hydrogen-ammonia integrated energy system is taken as the follower to solve the decision variables of each party when pursuing their own maximum benefits. The upper leader aims to maximize its own benefits in the process of trading with users and energy supply sides by setting the transaction prices of electricity, heat, gas, hydrogen and cold, and the lower follower sets the output plans of various types of units according to the energy prices set by the upper layer to maximize its own benefits. In addition, in the solving process of the lower layer, in addition to the carbon capture and transformation of source-side units to achieve the purpose of carbon reduction, the influence of multi-element energy flow transformation and utilization such as ladder carbon trading, green certificate and hydrogen-ammonia on the carbon reduction potential of the hydrogen-ammonia integrated energy system will be quantitatively evaluated. Finally, the carbon emission flow and node carbon potential of the load side of the multi-energy coupled energy network are calculated according to the real-time carbon flow of the electricity-heat-gas network, so as to quantify the effect of various carbon reduction means from the perspective of the load side.

[0071] (1) Upper integrated energy operator objective function: Objective function of hydrogen-ammonia integrated energy operator Mainly includes energy selling revenue , energy purchasing cost , interaction cost with superior energy , wherein the superior energy network includes electricity, heat, gas and hydrogen network, and the specific expression is as follows: (68) The energy selling revenue is modeled as: (69) where, , , , and represent the revenue of electricity, heat, gas, hydrogen, and cold energy sales, , , , and represent the electricity, heat, gas, hydrogen, and cold load after demand response, , , , and represent the electricity, heat, gas, hydrogen, and cold energy sales price set by the upper-level integrated energy operator, , , and represent the set of electricity, heat, gas, and hydrogen-consuming devices in the hydrogen-ammonia integrated energy system.

[0072] The integrated energy operator proposed in this embodiment includes the interaction costs of electricity, heat, gas, and hydrogen. It is worth mentioning that the interaction of hydrogen only includes the purchase of hydrogen interaction cost. This is because the hydrogen-ammonia integrated energy system needs a large amount of hydrogen energy as the energy conversion medium of the heterogeneous energy flow system, so the sale of hydrogen is ignored, and the supply of cold energy completely relies on the self-consistency of the system, so the interaction with the upper-level cold network is ignored. The energy interaction cost with the upper-level energy network is modeled as: (70) where, , , and are the interaction costs with the upper-level power grid, the upper-level heat grid, the upper-level gas grid, and the hydrogen seller, and represent the time-of-use electricity price and the on-grid electricity price, and represent the upper and lower limits of the heat price, and represent the upper and lower limits of the gas price, represents the upper limit of the hydrogen price; and represent the electricity power purchased and sold to the upper-level power grid, and represent the heat power purchased and sold to the upper-level heat grid, and represent the natural gas volume purchased and sold to the upper-level gas grid, represents the hydrogen mass purchased from the hydrogen seller.

[0073] The energy purchasing cost of the upper-level operator to the hydrogen-ammonia integrated energy system includes five energy forms of electricity, heat, gas, hydrogen, and cold, which are modeled as: (71) wherein, , , , and represent the set of power generation, heat generation, gas source, hydrogen production, and refrigeration devices in the hydrogen-ammonia integrated energy system, , , , and represent the purchase prices of electricity, heat, gas, hydrogen, and cold energy from the upper-level energy operator to the lower-level hydrogen-ammonia integrated energy system.

[0074] The set of various energy production and consumption devices in the hydrogen-ammonia integrated energy system is represented as: (72) wherein, is the photovoltaic power generation power, is the wind power generation power, it is worth noting that in the power grid topology in the present patent, photovoltaic and wind power have two stations respectively, which will not be repeated here; is the power generation power of the solar thermal power station, which is composed of the power generation power obtained by the heat supply of the heat network to the gas turbine and the power generation power obtained by the direct heat supply of the solar thermal power station to the gas turbine, is the power generation power of the CCHP unit, is the discharge power of the electric energy storage, is the power generation power of the ammonia fuel cell; is the discharge power of the electric energy storage, represents the energy consumption of the carbon capture plant, is the energy consumption of the electrolytic cell, represents the energy consumption of ammonia production, represents the power consumption of the electric refrigeration unit; , , , and represent the heat power of CCHP, GB, heat discharge of heat energy storage, heat production of ammonia production, and heat power delivered to the heat network by CSP, respectively; , and represent the heat power of heat discharge of heat energy storage, heat for absorption refrigeration, and heat power delivered to the steam turbine in the CSP station by the heat network, respectively; represents the volume of natural gas produced by hydrogen methanation; and respectively represent the hydrogen consumption volume of the gas engine unit in CCHP and GB; and respectively represent the hydrogen release volume of the hydrogen storage tank and the hydrogen production volume of the electrolytic tank; , , and respectively represent the hydrogen blending volume of GB and CCHP, the hydrogen charging volume of the hydrogen storage tank, and the hydrogen consumption volume of the ammonia production unit; and respectively represent the carbon dioxide production volume of the CCHP unit and the GB unit; , , and respectively represent the carbon dioxide sequestration volume in the carbon capture and sequestration unit, the carbon dioxide consumption volume of the methanation device, the carbon dioxide capture volume of the carbon capture unit, and the carbon dioxide release volume; , and respectively represent the cooling power of the electric refrigeration, the absorption refrigeration, and the cold storage energy; represents the cooling charging power of the cold storage tank.

[0075] (2) Lower hydrogen-ammonia integrated energy system objective function: The collaborative operation of each unit in the hydrogen-ammonia integrated energy system belongs to the lower interest community, and the objective function is expressed as follows: (73) (74) wherein, represents the energy selling cost of the lower hydrogen-ammonia integrated energy system, , , , and respectively represent the energy purchasing cost of the lower hydrogen-ammonia integrated energy system to the upper energy operator, represents the energy selling income of the lower energy system to the upper operator, i.e., the energy purchasing cost of the upper operator; represents the operation and maintenance cost of the lower system, represents the step green certificate-carbon trading cost.

[0076] The operation and maintenance cost expression of ES is as follows: (75) wherein, , and respectively represent the operation and maintenance costs of the power generation, heat generation, and energy storage equipment, , and The operation and maintenance cost coefficients of the three respectively, wherein the equipment needing operation and maintenance of electric energy includes wind power, photovoltaic, steam turbine of photothermal power station, ammonia fuel cell, gas turbine in CCHP, hydrogen electrolyzer; the equipment needing maintenance of heat energy includes waste heat recovery boiler in CCHP, GB; the energy storage equipment mainly includes six kinds of electric, heat, gas, cold, hydrogen and ammonia.

[0077] S104: solving the upper and lower target functions to obtain the optimal output of each type of unit.

[0078] The hydrogen-ammonia comprehensive energy system double-layer optimization operation strategy proposed in the embodiment contains two benefit subjects. The upper hydrogen-ammonia comprehensive energy system operator aims to maximize its own benefits, formulates the prices of five kinds of energy, i.e., electric, heat, gas, hydrogen and cold, to improve its energy selling revenue to users and reduce the energy purchasing cost to the lower hydrogen-ammonia comprehensive energy system. In addition, the upper energy operator needs to complete the energy interaction between the lower hydrogen-ammonia comprehensive energy system and the upper energy network, i.e., selling the excess energy to the upper energy network to obtain the revenue and supplement the system consumption in the form of purchase for the lacking energy. The patent sets the electric, heat, gas and hydrogen energy interaction with the upper energy network, wherein the electric, heat and gas are bidirectional, and the hydrogen can only be purchased from the upper hydrogen network. It is worth mentioning that the upper hydrogen-ammonia comprehensive energy operator obtains the benefits while also bears the risks of energy price changes and energy supply interruption. Especially when the lower system is short of energy supply, the upper operator needs to bear the energy purchasing cost to the upper energy network. The goal of the lower hydrogen-ammonia comprehensive energy system is to complete the multi-energy complementation and collaborative scheduling of the system on the basis of the energy buying and selling prices formulated by the upper energy operator, maximize its own benefits on the premise of meeting the energy supply and demand balance. Therefore, the game process of the two systems can be summarized as follows: on the premise of maximizing the upper revenue, the lower system follows the optimization result of the upper system to optimize its own revenue. This process is called master-slave game, and the whole process framework principle diagram is shown in Figure 4 .

[0079] In order to solve the double-layer optimization model proposed in the patent, a novel projection optimization algorithm is used to solve the multi-dimensional strong nonlinear problem of the upper operator, and the lower layer uses the Gurobi commercial solver to solve the mixed linear integer programming model. The master-slave game solving process based on the projection optimization algorithm-Gurobi solver combination proposed in the patent is shown in Figure 5 . Specifically, the initial value matrix of each dimension variable is obtained through the initialization of the projection algorithm, the scale is N p× N d, wherein N p and Nd represents the population size and dimension of the projection algorithm, respectively. Then, based on the initialized energy prices, the optimal scheduling rate of the lower-level model is calculated. This process is completed using the Gurobi solver. Subsequently, the solved scheduling results are substituted into the upper-level model to calculate the upper-level objective function. N The algorithm compares p objective functions and selects the optimal upper-level decision variable corresponding to the optimal objective function. In the next iteration, the change of the upper-level decision variable depends on the previous optimal decision variable and the algorithm's position update mechanism. This loop continues until the maximum number of iterations is reached. Notably, each iteration uses an elitist retention strategy to preserve the decision variable corresponding to the currently appearing optimal objective function, ensuring the effectiveness of the optimization. When the upper-level optimization reaches the set maximum number of iterations, the optimal upper-level objective function value is output, and the optimal upper-level decision variable is substituted into the lower-level algorithm to calculate the optimal lower-level objective function value.

[0080] Example 2 In one or more embodiments, a two-layer optimization system for a hydrogen-ammonia integrated energy system considering multi-energy grid coupling is disclosed, comprising: The model building module is configured to build a hydrogen-ammonia integrated energy system model, which includes wind turbines, photovoltaics, solar thermal power units, combined cooling, heating and power units, gas boilers, electric, heat, gas, hydrogen, cooling and ammonia energy storage systems, ammonia fuel cells, methanation to natural gas, carbon capture and storage devices, electric refrigeration equipment, hydrogen electrolyzers and electric ammonia production equipment; The carbon flow calculation module is configured to guide the hydrogen-ammonia integrated energy system toward reducing carbon emissions by establishing a tiered green certificate-carbon trading mechanism; it takes into account five types of loads: cooling, heating, electricity, gas, and hydrogen, and uses price-incentive demand response to stimulate these five types of loads to complete reduction, substitution, and transfer; it considers six energy flows: cooling, heating, electricity, gas, hydrogen, and ammonia, and performs carbon flow calculations for the power system, heating network, and gas network respectively; The objective function construction module is configured to treat the integrated hydrogen-ammonia energy system operator as the leader and the integrated hydrogen-ammonia energy system as the follower. The upper-level leader sets the trading prices of five energy sources—electricity, heat, gas, hydrogen, and cooling—aims to maximize its own profits in transactions with users and energy suppliers, thus constructing the upper-level integrated energy operator's objective function. The lower-level follower formulates the output plans of various types of units based on the energy prices set by the upper level, aiming to maximize its own profits, thus constructing the lower-level integrated hydrogen-ammonia energy system's objective function. The optimization solution module is configured to solve the objective functions of the upper and lower layers to obtain the optimal output of each type of unit.

[0081] Example 3 In one or more embodiments, a terminal device is disclosed, comprising a processor and a memory, the processor being configured to implement instructions; the memory being configured to store a plurality of instructions adapted to be loaded and executed by the processor to implement the method for hydrogen-ammonia integrated energy system double-layer optimization considering multi-energy grid coupling as described in Embodiment I.

[0082] In some other embodiments, a computer-readable storage medium is disclosed, wherein a plurality of instructions are stored, the instructions being adapted to be loaded and executed by a processor of a terminal device to implement the method for hydrogen-ammonia integrated energy system double-layer optimization considering multi-energy grid coupling as described in Embodiment I.

[0083] The above description of the specific embodiments of the present application in conjunction with the accompanying drawings is not intended to limit the scope of protection of the present application. Those skilled in the art should understand that various modifications or variations can be made to the technical solutions of the present application without departing from the scope of protection of the present application.

Claims

1. A two-layer optimization method for a hydrogen-ammonia integrated energy system considering multi-energy network coupling, characterized in that, include: Construct a hydrogen-ammonia integrated energy system model, which includes wind turbines, photovoltaics, solar thermal power units, combined cooling, heating and power units, gas boilers, electric, heat, gas, hydrogen, cooling and ammonia energy storage systems, ammonia fuel cells, methanation to natural gas production, carbon capture and storage devices, electric refrigeration equipment, hydrogen electrolyzers and electric ammonia production equipment; By establishing a tiered green certificate-carbon trading mechanism, the hydrogen-ammonia integrated energy system is guided to operate in the direction of reducing carbon emissions; taking into account five types of loads—cooling, heating, electricity, gas, and hydrogen—price-incentive demand response is used to stimulate the reduction, substitution, and transfer of these five types of loads; considering six energy flows—cooling, heating, electricity, gas, hydrogen, and ammonia—carbon flow calculations are performed for the power system, heating network, and gas network, respectively. The hydrogen-ammonia integrated energy system operator is considered the leader, and the hydrogen-ammonia integrated energy system is considered the follower. The upper-level leader sets the trading prices of five energy sources—electricity, heat, gas, hydrogen, and cooling—aiming to maximize its own profits in transactions with users and energy suppliers, thus constructing the objective function of the upper-level integrated energy operator. The lower-level followers formulate output plans for various types of units based on the energy prices set by the upper level, aiming to maximize their own profits, thus constructing the objective function of the lower-level hydrogen-ammonia integrated energy system. The objective functions of the upper and lower layers are solved to obtain the optimal output of each type of unit.

2. The two-layer optimization method for a hydrogen-ammonia integrated energy system considering multi-energy grid coupling as described in claim 1, characterized in that, The establishment of the tiered green certificate-carbon trading mechanism specifically refers to: ； ； in, Carbon emissions offset by green certificates. and These represent the carbon emissions from coal-fired power and renewable energy sources, respectively. Carbon emission rights representing green certificates in the joint carbon trading system, Represents the total carbon emissions of the system. Carbon allowances representing the hydrogen-ammonia integrated energy system It's a green certificate quota.

3. The two-layer optimization method for a hydrogen-ammonia integrated energy system considering multi-energy grid coupling as described in claim 1, characterized in that, Taking into account five types of loads—cooling, heating, electricity, gas, and hydrogen—a price-incentive-based demand response is used to stimulate the reduction, substitution, and shift of these five types of loads, specifically: ； ； ； ； ； in, , , , and These represent the electricity, heat, cooling, gas, and hydrogen loads after the demand response, respectively. The subscript "base" indicates the corresponding base load. , , , , These represent the load transfer amounts for electricity, heat, cold, gas, and hydrogen, respectively. , , , , These represent the reductions possible for electricity, heat, cooling, gas, and hydrogen loads, respectively. , , , , , , , These represent the substitutable quantities for electrical load to thermal load, electrical load to cold load, thermal load to electrical load, thermal load to cold load, cold load to electrical load, cold load to thermal load, gas load to hydrogen load, and hydrogen load to gas load, respectively.

4. The two-layer optimization method for a hydrogen-ammonia integrated energy system considering multi-energy grid coupling as described in claim 1, characterized in that, Carbon flow calculations are performed separately for the power system, heating network, and gas network, specifically as follows: Modeling is performed separately for the power grid, heating network, gas network, hydrogen network, and cold network to form a multi-energy network coupled topology; Among them, the nodal carbon potential energy vector of all nodes in the power system It is represented as: ； In the formula, The active flux matrix, This is the transpose of the branch power flow distribution matrix. Injecting a power flow matrix into the unit, The node carbon potential vector for units that generate carbon emissions; Nodal carbon potential energy vector of all nodes in the heating network It is represented as: ； In the formula, The active flux matrix, This is the transpose of the heat network power flow distribution matrix. Injecting a power flow matrix into the thermal power unit, Carbon potential vector for unit nodes that generate carbon emissions; Nodal carbon potential vector of all nodes in the gas network It is represented as: ； In the formula, This is the active flux matrix of the gas network. This is the transpose of the gas flow distribution matrix. Injecting a current matrix into the gas source, This represents the carbon potential vector for different gas source nodes.

5. The two-layer optimization method for a hydrogen-ammonia integrated energy system considering multi-energy grid coupling as described in claim 1, characterized in that, Constructing the objective function of the upper-level integrated energy operator Specifically: ； in, For energy sales revenue, For energy purchase costs, This refers to the interaction cost of higher-level energy sources.

6. The two-layer optimization method for a hydrogen-ammonia integrated energy system considering multi-energy grid coupling as described in claim 1, characterized in that, The objective function for constructing the lower-level hydrogen-ammonia integrated energy system is as follows: ； in, This represents the energy sales cost of the lower-level hydrogen-ammonia integrated energy system. This represents the energy purchase cost from the upper-level energy operator to the lower-level hydrogen-ammonia integrated energy system. This represents the revenue from selling energy to the upper-level operator of the hydrogen-ammonia integrated energy system, which is the energy purchase cost of the upper-level operator. This represents the operation and maintenance cost of the lower-level hydrogen-ammonia integrated energy system. This represents the tiered cost of green certificates and carbon trading.

7. The two-layer optimization method for a hydrogen-ammonia integrated energy system considering multi-energy grid coupling as described in claim 1, characterized in that, Solving the objective functions of the upper and lower levels yields the optimal output for each type of unit, specifically: Using a master-slave game as the optimization framework for multi-energy industrial parks, an integrated energy operator is introduced to manage the upper-level energy grid, while the lower-level system is a hydrogen-ammonia integrated energy system. The upper-level system operator acts as the leader, and the lower-level integrated energy system acts as the follower. The goal is to maximize the interests of the followers while maximizing the interests of the leader. The upper level uses a projection optimization algorithm to achieve global optimization, while the lower level uses the Gurobi commercial solver to solve a mixed linear integer programming problem. Through continuous iteration between the upper and lower levels, the ultimate goal is to maximize the interests of both the integrated energy operator and the industrial integrated energy system under the premise of low carbon emissions.

8. A two-layer optimization system for a hydrogen-ammonia integrated energy system considering multi-energy grid coupling, characterized in that, include: The model building module is configured to build a hydrogen-ammonia integrated energy system model, which includes wind turbines, photovoltaics, solar thermal power units, combined cooling, heating and power units, gas boilers, electric, heat, gas, hydrogen, cooling and ammonia energy storage systems, ammonia fuel cells, methanation to natural gas, carbon capture and storage devices, electric refrigeration equipment, hydrogen electrolyzers and electric ammonia production equipment; The carbon flow calculation module is configured to guide the hydrogen-ammonia integrated energy system toward reducing carbon emissions by establishing a tiered green certificate-carbon trading mechanism; it takes into account five types of loads: cooling, heating, electricity, gas, and hydrogen, and uses price-incentive demand response to stimulate these five types of loads to complete reduction, substitution, and transfer; it considers six energy flows: cooling, heating, electricity, gas, hydrogen, and ammonia, and performs carbon flow calculations for the power system, heating network, and gas network respectively; The objective function construction module is configured to treat the integrated hydrogen-ammonia energy system operator as the leader and the integrated hydrogen-ammonia energy system as the follower. The upper-level leader sets the trading prices of five energy sources—electricity, heat, gas, hydrogen, and cooling—aims to maximize its own profits in transactions with users and energy suppliers, thus constructing the upper-level integrated energy operator's objective function. The lower-level follower formulates the output plans of various types of units based on the energy prices set by the upper level, aiming to maximize its own profits, thus constructing the lower-level integrated hydrogen-ammonia energy system's objective function. The optimization solution module is configured to solve the objective functions of the upper and lower layers to obtain the optimal output of each type of unit.

9. A terminal device comprising a processor and a memory, the processor for implementing instructions; the memory for storing multiple instructions, characterized in that, The instructions are adapted to be loaded by a processor and executed by the processor using the two-layer optimization method for a hydrogen-ammonia integrated energy system considering multi-energy network coupling, as described in any one of claims 1-7.

10. A computer-readable storage medium storing a plurality of instructions, characterized in that, The instructions are adapted to be loaded and executed by the processor of the terminal device, and are based on the two-layer optimization method for a hydrogen-ammonia integrated energy system considering multi-energy network coupling as described in any one of claims 1-7.

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