Multi-energy system low-carbon optimization operation strategy considering electricity-to-ammonia technology

Abstract

The invention belongs to the technical field of new energy, and provides a multi-energy system low-carbon optimization operation strategy considering an electricity-to-ammonia technology. The multi-energy system low-carbon optimization operation strategy comprises the following steps: 1) constructing an energy conversion equipment model; comprising the steps of constructing an electricity-to-ammonia equipment model, constructing a combined heat and power generation unit model and constructing an electric heating model; 2) constructing a generalized energy storage model; comprising the steps of constructing an electric heating energy storage model, constructing an ammonia fuel cell model and constructing a flexible load model; according to the method, coal-fired ammonia doping is carried out on the cogeneration unit, part of ammonia energy is used for replacing coal combustion, system carbon emission is reduced, a regulation and control strategy among multi-energy systems is provided according to respective equipment model characteristics, then multi-index benefits including operation cost, renewable energy utilization rate and system carbon emission are constructed, and comprehensive benefits of the system regulation and control process are evaluated.

Description

Technical Field

[0001] The present invention belongs to the field of new energy technology and proposes a low-carbon optimized operation strategy for a multi-energy system considering power-to-ammonia technology. Background Art

[0002] Constructing a multi-energy system with electric and thermal energy flow as the core provides a feasible path for promoting wind and solar power consumption and low-carbon operation. At present, some parts of my country have abundant wind and solar resources, and many places have developed large-scale ammonia use scenarios, focusing on promoting the demonstration application of green hydrogen and synthetic ammonia industries. However, the participation of multiple energy sources and energy storage makes the system structure more complex, thereby affecting the safety, stability and economic operation of the system. Therefore, the formulation of a strategy that adapts to the low-carbon coordinated operation of the multi-energy system has attracted much attention. To this end, the present invention proposes a low-carbon optimization operation strategy for a multi-energy system considering the power-to-ammonia technology. First, an energy conversion model containing cogeneration units, power-to-ammonia equipment, and electric heating equipment is constructed. Secondly, the participation of generalized energy storage including electric thermal storage, ammonia fuel cells, and flexible loads is considered. The coordination between the energy conversion model and generalized energy storage in the multi-energy system is studied and a control strategy is proposed. Finally, a multi-index benefit including operating costs, renewable energy utilization rate, and system carbon emissions is constructed. The power of each device in the system under the multi-objective function is solved by an algorithm and a multi-scenario comparative analysis is performed to verify the effectiveness of the strategy proposed in the present invention for the low-carbon optimization operation of the multi-energy system. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to propose a low-carbon optimized operation strategy for a multi-energy system taking into account the power-to-ammonia technology, which is scientific, reasonable, efficient and practical.

[0004] A low-carbon optimization operation strategy for a multi-energy system considering power-to-ammonia technology, which includes the following: Energy conversion equipment model construction

[0005] Step 1: Construct the power-to-ammonia (P2A) equipment model. P2A is a measure to achieve power-to-ammonia conversion by using hydrogen energy to further synthesize ammonia based on the production of hydrogen through water electrolysis. The power-to-ammonia equipment model is mainly as follows:

[0006]

[0007] Where: PR P2A t is the heat released during the electro-ammonia conversion process, α P2A is the P2A heat generation ratio, β is the heat power released by generating unit ammonia, m P2A t is the mass of ammonia produced, η P2A is the unit energy consumption for generating ammonia, P P2A,PT t 、P P2A,PV t 、P PTt 、P PV t The wind power and photovoltaic power consumed to generate ammonia and the actual wind power and photovoltaic power supply, x PT 、x PV 、x P2A is the unit energy consumption cost coefficient of wind power, photovoltaic power and electricity-to-ammonia conversion, M P2A The operating cost of electricity-to-ammonia conversion.

[0008] Step 2: Build a combined heat and power (CHP) model

[0009] Extraction steam CHP has certain advantages in improving energy efficiency, reducing environmental pollution, improving heating quality, and increasing power supply. Its model is as follows:

[0010]

[0011] Where PCHPt is the electrical power of CHP at time t, PRCHPt is the thermal power of CHP at time t, g CHP is the change value of PCHPt when PRCHPt decreases, e1 is the cogeneration power supply constant, x 1 CHP 、x 2 CHP 、x 3 CHP is the CHP power supply cost coefficient, M 1 CHP Cost of combined heat and power generation.

[0012] The ammonia generated by electricity-to-ammonia conversion is used to replace part of the coal in the combined heat and power generation process based on the ammonia-coal heat ratio, thereby reducing the amount of coal burned and lowering the carbon emissions of the system. The main model is as follows:

[0013]

[0014] Where m c t 、m NH3 t is the coal consumption and ammonia consumption of cogeneration, y 1 CHP 、y 2 CHP 、y 3 CHP , e2 is the coal consumption coefficient of cogeneration, x c is the unit coal price, κ is the ammonia-coal mixed combustion ratio during ammonia-blended combustion, H NH3 、H c is the lower calorific value of ammonia and coal, M CHP The operating cost of combined heat and power generation;

[0015] Step 3: Build an Electric Heating (EB) Model

[0016]

[0017] Where PR EB t is the EB thermal power, P EB t is the EB electric power, β EB is the EB thermoelectric efficiency, x EB is the EB cost coefficient, M EB is the EB cost;

[0018] Construction of generalized energy storage model

[0019] Step 1: Build an electric thermal energy storage model

[0020]

[0021] Where, P EN t 、P EN,in t 、P EN,ou t P is the storage capacity, charging and discharging power of the electrothermal energy storage at time t; EN,min t 、P EN,max t 、P EN,in,max t 、P EN,out,max t is the lower and upper limits of the electric thermal energy storage capacity and the upper limits of the charging and discharging power at time t; η EN in ,η EN out k is the efficiency of charging and discharging electric thermal energy storage; EN in 、k EN out It is the criterion for charging and discharging of electric thermal energy storage. When k is 1, it is in the working process, and when it is 0, it is in the non-working process. EN is the EN cost coefficient, M EN the cost of storing energy for electric heat;

[0022] Step 2: Build an ammonia fuel cell model

[0023]

[0024] Where, P FC t is the power supply of the ammonia fuel cell at time t, η FC Battery energy efficiency; m FC,NH3 tis the amount of ammonia energy consumed by the battery at time t, x FC is the battery cost coefficient, M FC For the cost of batteries.

[0025] Step 3: Flexible load

[0026] (1) Transferable load

[0027]

[0028] Where, P ZB t 、P ZA t 、P Z min 、P Z max x is the lower limit and upper limit of power and load transferability before and after load transfer, Z is the load transfer cost coefficient, M Z Cost of transferable loads;

[0029] (2) Load reduction

[0030]

[0031] Where, P XB t 、P XA t is the power before and after load reduction, μ is the load reduction rate, ξ t To determine whether the load is in a curtailable state, it takes 0 or 1, S max is the maximum number of times the load can be reduced, x X is the load reduction cost coefficient, M X Cost of transferable loads;

[0032] Based on energy conversion equipment and a generalized energy storage model, a control strategy is proposed for the low-carbon operation of multi-energy systems: when there is a surplus of wind and solar energy in the system, the above model is used to perform electricity-ammonia conversion to store excess wind and solar resources; when the wind and solar energy supply in the system is in short supply, the above model is used to perform ammonia-electricity conversion to release the stored ammonia energy for energy supply. At the same time, cogeneration can also be used to replace coal powder combustion with a certain amount of ammonia energy, thereby reducing the carbon emissions of system operation and achieving low-carbon operation.

[0033] Construction of multi-index benefit model

[0034] Step 1: Operating costs C1

[0035] C1=M P2A +M CHP +M EB +M EN +MFC +M Z +M X

[0036] Step 2: Renewable energy utilization rate C2

[0037]

[0038] Where, P L t 、P CHP t 、P FC t is the load, CHP and ammonia fuel cell rate at time t;

[0039] Step 3: System carbon emissions C3

[0040]

[0041] Where, Ω CHP ,Ω D is the carbon emission coefficient of cogeneration and upper power grid, f CHP is the coal consumption for cogeneration, P D t is the power supply of the upper power grid at time t;

[0042] Solve using algorithms

[0043] Step 1: Use the algorithm to solve the system regulation of energy conversion equipment and generalized energy storage in different scenarios.

[0044] Step 2: Select the power of each device model under the lowest system carbon emissions in each scenario, compare and analyze the 24-hour fluctuation of system power under different scenarios, and verify that the proposed strategy can effectively improve the low-carbon operation of the multi-energy system.

[0045] Through the above design scheme, the present invention can bring the following beneficial effects: first, establish an energy conversion equipment model (including electricity-to-ammonia equipment, cogeneration units, and electric heating) and a generalized energy storage model (electric thermal storage, ammonia fuel cells, and flexible loads) in a multi-energy system, wherein the cogeneration unit is burned with coal and ammonia, and part of the ammonia energy is used to replace coal combustion to reduce the system's carbon emissions, and a control strategy between multi-energy systems is proposed based on the characteristics of each equipment model. Then, a multi-indicator benefit including operating costs, renewable energy utilization rate, and system carbon emissions is constructed to evaluate the comprehensive benefits of the system control process. Finally, the output power of each equipment model under different scenarios is simulated to form a 24-hour power fluctuation graph and a comparative analysis is performed to verify the effectiveness and feasibility of the strategy proposed in the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0047] Figure 1 This is a flow chart of a low-carbon optimized operation strategy for a multi-energy system considering power-to-ammonia technology according to the present invention;

[0048] Figure 2 This is a framework diagram of a multi-energy system with a low-carbon optimized operation strategy considering the power-to-ammonia technology of the present invention;

[0049] Figure 3 This is a wind-solar and load power curve diagram of a low-carbon optimized operation strategy for a multi-energy system considering power-to-ammonia technology in the present invention;

[0050] Figure 4 This is a 24-hour power fluctuation diagram of the system when the low-carbon optimized operation strategy of the multi-energy system considering the power-to-ammonia technology does not consider the participation of energy storage and flexible load;

[0051] Figure 5 This is a 24-hour power fluctuation diagram of the system when considering the low-carbon optimization operation strategy of a multi-energy system taking into account the power-to-ammonia technology of the present invention and the participation of energy storage and flexible load. DETAILED DESCRIPTION

[0052] The present invention proposes a low-carbon optimization operation strategy for a multi-energy system considering the power-to-ammonia technology, combined with Figures 1 to 5 , including the following steps:

[0053] 1. Construct a multi-energy system framework model. Figure 2 The following description will be given using the system framework diagram as an example.

[0054] 2. Energy conversion equipment model

[0055] (1) Power-to-ammonia equipment (P2A)

[0056]

[0057] Where: PR P2A t is the heat released during the electro-ammonia conversion process, α P2A is the P2A heat generation ratio, β is the heat power released by generating unit ammonia, m P2A t is the mass of ammonia produced, η P2A is the unit energy consumption for generating ammonia, P P2A,PT t 、P P2A,PV t 、P PT t 、P PV t The wind power and photovoltaic power consumed to generate ammonia and the actual wind power and photovoltaic power supply, x PT 、xPV 、x P2A is the unit energy consumption cost coefficient of wind power, photovoltaic power and electricity-to-ammonia conversion, M P2A The operating cost of electricity-to-ammonia conversion.

[0058] (2) Combined heat and power (CHP)

[0059]

[0060] Where PCHPt is the electrical power of CHP at time t, PRCHPt is the thermal power of CHP at time t, g CHP is the change value of PCHPt when PRCHPt decreases, e1 is the cogeneration power supply constant, x 1 CHP 、x 2 CHP 、x 3 CHP is the CHP power supply cost coefficient, M 1 CHP Cost of combined heat and power generation.

[0061] The ammonia generated by electricity-to-ammonia conversion is used to replace part of the coal in the combined heat and power generation process based on the ammonia-coal heat ratio, thereby reducing the amount of coal burned and lowering the carbon emissions of the system. The main model is as follows:

[0062]

[0063] Where m c t 、m NH3 t is the coal consumption and ammonia consumption of cogeneration, y 1 CHP 、y 2 CHP 、y 3 CHP , e2 is the coal consumption coefficient of cogeneration, x c is the unit coal price, κ is the ammonia-coal mixed combustion ratio during ammonia-blended combustion, H NH3 、H c is the lower calorific value of ammonia and coal, M CHP The operating cost of combined heat and power generation;

[0064] (3) Electric heating (EB)

[0065]

[0066] Where PR EB t is the EB thermal power, P EB t is the EB electric power, β EB is the EB thermoelectric efficiency, xEB is the EB cost coefficient, M EB is the EB cost;

[0067] 3. Generalized Energy Storage Model

[0068] (1) Electric thermal energy storage

[0069]

[0070] Where PEN t 、P EN,in t 、P EN,ou t P is the storage capacity, charging and discharging power of the electrothermal energy storage at time t; EN,min t 、P EN ,max t 、P EN,in,max t 、P EN,out,max t is the lower and upper limits of the electric thermal energy storage capacity and the upper limits of the charging and discharging power at time t; η EN in ,η EN out k is the efficiency of charging and discharging electric thermal energy storage; EN in 、k EN out It is the criterion for charging and discharging of electric thermal energy storage. When k is 1, it is in the working process, and when it is 0, it is in the non-working process. EN is the EN cost coefficient, M EN the cost of storing energy for electric heat;

[0071] (2) Ammonia fuel cells

[0072]

[0073] Where, P FC t is the power supply of the ammonia fuel cell at time t, η FC Battery energy efficiency; m FC,NH3 t is the amount of ammonia energy consumed by the battery at time t, x FC is the battery cost coefficient, M FC For the cost of batteries.

[0074] (3) Flexible load

[0075] 1) Transferable load

[0076]

[0077] Where, P ZB t 、P ZA t 、P Z min 、P Z max x is the lower limit and upper limit of power and load transferability before and after load transfer, Z is the load transfer cost coefficient, M Z Cost of transferable loads;

[0078] 2) Load reduction

[0079]

[0080] Where, P XB t 、P XA t is the power before and after load reduction, μ is the load reduction rate, ξ t To determine whether the load is in a curtailable state, it takes 0 or 1, S max is the maximum number of times the load can be reduced, x X is the load reduction cost coefficient, M X Cost of transferable loads;

[0081] Based on energy conversion equipment and a generalized energy storage model, a control strategy is proposed for the low-carbon operation of multi-energy systems: when there is a surplus of wind and solar energy in the system, the above model is used to perform electricity-ammonia conversion to store excess wind and solar resources; when the wind and solar energy supply in the system is in short supply, the above model is used to perform ammonia-electricity conversion to release the stored ammonia energy for energy supply. At the same time, cogeneration can also be used to replace coal powder combustion with a certain amount of ammonia energy, thereby reducing the carbon emissions of system operation and achieving low-carbon operation.

[0082] 4. Multi-index benefits

[0083] (1) Operating expenses C1

[0084] C1=M P2A +M CHP +M EB +M EN +M FC +M Z +M X

[0085] (2) Renewable energy utilization rate C2

[0086]

[0087] Where, P L t 、P CHPt 、P FC t is the load, CHP and ammonia fuel cell rate at time t;

[0088] (3) System carbon emissions C3

[0089]

[0090] Where, Ω CHP ,Ω D is the carbon emission coefficient of cogeneration and upper power grid, f CHP is the coal consumption for cogeneration, P D t is the power supply of the upper power grid at time t;

[0091] 5. Model calculation process

[0092] See attached flow chart Figure 1 As shown, the steps are as follows:

[0093] ① Determine the grid structure model of the multi-energy system (including electrical and thermal energy systems);

[0094] ② Establish energy conversion equipment models (including electricity-to-ammonia equipment, cogeneration units, and electric heating) and generalized energy storage models (electrical thermal energy storage, ammonia fuel cells, and flexible loads);

[0095] ③ Construct a multi-index benefit model including operating costs, renewable energy utilization rate, and system carbon emissions to comprehensively evaluate the coordinated regulation of the system by energy conversion equipment and generalized energy storage;

[0096] The algorithm is used to solve the system regulation of energy conversion equipment and generalized energy storage in different scenarios, and the model power of each device under the lowest system carbon emissions in each scenario is selected to compare and analyze the 24-hour fluctuation of system power in different scenarios, verifying that the proposed strategy can effectively improve the low-carbon operation of the multi-energy system.

[0097] In-depth analysis Figures 4-5 The experimental results show that:

[0098] From 10 PM to 6 AM, system power consumption is low. Wind power output is high, but wind and solar power absorption is limited, resulting in significant waste of wind power. To alleviate this problem, P2A technology has been introduced. It converts and stores excess wind power into ammonia energy, effectively improving the system's wind and solar power absorption capacity. During peak demand periods from 8 AM to 4 PM, when wind power supply decreases and photovoltaic power increases, P2A equipment absorbs the system's excess wind and solar power, stabilizing the supply while also balancing system supply and demand by appropriately reducing peak load. From 5 PM to 10 PM, another peak demand period, when wind power supply increases, P2A equipment continues to operate, converting electricity into ammonia energy. This also requires adjusting the corresponding power load to enhance wind and solar power utilization. Furthermore, the ammonia stored in P2A can be converted into electricity at any time using an ammonia fuel cell, synergizing with the CHP system to reduce the energy burden on the system. The participation and regulation of energy conversion equipment and generalized energy storage enables the large-scale penetration of low-carbon wind and solar resources in multi-energy systems, promoting the low-carbon operation of the system. At the same time, the regulation of energy storage and flexible loads also improves the flexibility of system operation to a certain extent.

[0099] The calculation conditions and the like in the embodiments of the present invention are only used to further illustrate the present invention and are not exhaustive and do not constitute a limitation on the scope of protection of the claims. A person skilled in the art can conceive of other substantially equivalent alternatives based on the inspiration gained from the examples of the present invention without creative work, and all of them are within the scope of protection of the present invention.

Claims

1. A low-carbon optimization operation strategy for a multi-energy system considering power-to-ammonia technology, characterized by: The following steps are involved: 1) Construct energy conversion equipment models, including power-to-ammonia equipment models, combined heat and power unit models, and electric heating models; 2) Construct a generalized energy storage model, including an electric thermal energy storage model, an ammonia fuel cell model, and a flexible load model; 3) Construct a multi-index benefit model; 4) The algorithm is used to solve the system regulation of energy conversion equipment and generalized energy storage in different scenarios, and the model power of each device under the lowest system carbon emissions in each scenario is selected to compare and analyze the 24-hour fluctuation of system power in different scenarios to verify that the proposed strategy can effectively improve the low-carbon operation of the multi-energy system.

2. The low-carbon optimized operation strategy for a multi-energy system considering power-to-ammonia technology according to claim 1 is characterized in that: Building an energy conversion device model includes the following steps: Step 1: Build a model of the power-to-ammonia equipment The model of the electric-to-ammonia conversion equipment is as follows: Where: PR P2A t is the heat released during the electro-ammonia conversion process, α P2A is the P2A heat generation ratio, β is the heat power released by generating unit ammonia, m P2A t is the mass of ammonia produced, η P2A is the unit energy consumption for generating ammonia, P P2A,PT t 、P P2A,PV t 、P PT t 、P PV t The wind power and photovoltaic power consumed to generate ammonia and the actual wind power and photovoltaic power supply, x PT 、x PV 、x P2A is the unit energy consumption cost coefficient of wind power, photovoltaic power and electricity-to-ammonia conversion, M P2A The operating cost of electricity-to-ammonia conversion; Step 2: Build a cogeneration unit model The model is as follows: Where PCHPt is the electrical power of CHP at time t, PRCHPt is the thermal power of CHP at time t, g CHP is the change value of PCHPt when PRCHPt decreases, e1 is the cogeneration power supply constant, x 1 CHP 、x 2 CHP 、x 3 CHP is the CHP power supply cost coefficient, M 1 CHP Cost of combined heat and power generation; Ammonia generated by electricity-to-ammonia conversion is used to replace part of the coal in the combined heat and power generation process based on the ammonia-coal heat ratio, thereby reducing the amount of coal burned and lowering the carbon emissions of the system. The main model is as follows: Where m c t 、m NH3 t is the coal consumption and ammonia consumption of cogeneration, y 1 CHP 、y 2 CHP 、y 3 CHP , e2 is the coal consumption coefficient of cogeneration, x c is the unit coal price, κ is the ammonia-coal mixed combustion ratio during ammonia-blended combustion, H NH3 、H c is the lower calorific value of ammonia and coal, M CHP The operating cost of combined heat and power generation; Step 3: Build an electric heating model Where PR EB t is the EB thermal power, P EB t is the EB electric power, β EB is the EB thermoelectric efficiency, x EB is the EB cost coefficient, M EB is the EB cost.

3. The low-carbon optimized operation strategy for a multi-energy system considering power-to-ammonia technology according to claim 1 is characterized in that: The construction of the generalized energy storage model comprises the following steps: Step 1: Build an electric thermal energy storage model Where, P EN t 、P EN,in t 、P EN,ou t P is the storage capacity, charging and discharging power of the electrothermal energy storage at time t; EN,min t 、P EN,max t 、P EN ,in,max t 、P EN,out,max t The lower and upper limits of the electric thermal energy storage capacity and the upper limits of the charging and discharging power at time t; η EN in ,η EN out k is the efficiency of charging and discharging electric thermal energy storage; EN in 、k EN out is the criterion for charging and discharging of electric thermal energy storage. When k is 1, it is in the working process, and when it is 0, it is in the non-working process. xEN is the EN cost coefficient, and MEN is the cost of electric thermal energy storage. Step 2: Build an ammonia fuel cell model Where, P FC t is the power supply of the ammonia fuel cell at time t, η FC Battery energy efficiency; m FC,NH3 t is the amount of ammonia energy consumed by the battery at time t, x FC is the battery cost coefficient, M FC The cost of the battery; Step 3: Build a flexible load model (1) Transferable load Where, P ZB t 、P ZA t 、P Z min 、P Z max x is the lower limit and upper limit of power and load transferability before and after load transfer, Z is the load transfer cost coefficient, M Z Cost of transferable loads; (2) Load reduction Where, P XB t 、P XA t is the power before and after load reduction, μ is the load reduction rate, ξ t To determine whether the load is in a curtailable state, it takes 0 or 1, S max is the maximum number of times the load can be reduced, x X is the load reduction cost coefficient, M X Cost of transferable loads; Based on energy conversion equipment and a generalized energy storage model, a control strategy is proposed for the low-carbon operation of multi-energy systems: when there is a surplus of wind and solar energy in the system, the above model is used to convert electricity into ammonia and store the excess wind and solar resources; When the system's wind and solar energy supply is in short supply, the above model is used to convert ammonia into electricity, releasing the stored ammonia energy for energy supply. At the same time, cogeneration is used to replace coal powder combustion with a certain amount of ammonia energy, reducing the system's operating carbon emissions and achieving low-carbon operation.

4. The low-carbon optimized operation strategy for a multi-energy system considering power-to-ammonia technology according to claim 1 is characterized in that: The construction of the multi-index benefit model comprises the following steps: Step 1: Operating costs C1 C1=M P2A +M CHP +M EB +M EN +M FC +Μ Z +M X Step 2: Renewable energy utilization rate C2 Where, P L t 、P CHP t 、P FC t is the load, CHP and ammonia fuel cell rate at time t; Step 3: System carbon emissions C3 Where, Ω CHP ,Ω D is the carbon emission coefficient of cogeneration and upper power grid, f CHP is the coal consumption for cogeneration, P D t is the power supply of the upper power grid at time t.

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