A source-load-storage low-carbon scheduling method for coordinated operation of carbon capture and hydrogen energy storage

Abstract

The application provides a source-load-storage low-carbon scheduling method for coordinated operation of carbon capture and hydrogen energy storage, and belongs to the technical field of power systems. Firstly, the operation mechanism of the source-load-storage three sides is analyzed. Secondly, a source-grid-load coordinated operation structure framework is constructed, and the operation structure framework is shown in the drawings. In view of the deficiencies in the operation of the carbon capture unit and the hydrogen energy storage system under the rotating reserve demand, the coordinated operation characteristics of the two are researched. Finally, a source-load-storage low-carbon economic scheduling model for the coordinated operation of the carbon capture unit and the hydrogen energy storage system is established with the optimal system comprehensive cost as the target. The system uncertainty is described by using a fuzzy membership function, and the system rotating reserve demand is determined. The model is verified through an example simulation, and the verification shows that the model can significantly improve the new energy consumption level under the premise of taking into account the economy and low carbon of the system operation.

Description

Technical Field

[0001] This invention belongs to the field of power system technology, and in particular relates to a source-load-storage low-carbon dispatching method that coordinates carbon capture and hydrogen energy storage. Background Technology

[0002] With the construction of new power systems, new requirements are being placed on carbon emissions in the power industry. Replacing traditional high-carbon emission power generation equipment with low-carbon emission equipment is an important means of achieving energy transition. Among these, renewable energy plays an increasingly important role in the energy transition of new power systems. However, the randomness and volatility of renewable energy output lead to difficulties in renewable energy consumption and high pressure on spinning reserves. Therefore, fully coordinating dispatchable resources of power generation, load, and storage to achieve renewable energy consumption is particularly important for the low-carbon operation of the power system.

[0003] On the source side, although conventional thermal power units emit significant carbon, other regulation equipment cannot currently completely replace them. Carbon capture units (CCUs), as a transitional device between source-side thermal power generation and renewable energy generation, can effectively reduce the high carbon emissions of current source-side thermal power units. Furthermore, compared to conventional thermal power units, CCUs have faster response times and a wider regulation range, making them more suitable for system spinning reserve tasks.

[0004] In terms of energy storage, hydrogen energy storage, as a new form of energy storage, has advantages such as large storage capacity and clean and pollution-free operation. When combined with wind power to form a wind-hydrogen co-generation system, it can effectively reduce the problem of wind curtailment.

[0005] On the load side, the introduction of demand response mechanisms can improve the flexibility of load-side resource adjustment and fully leverage the advantages of the load side. Guiding user electricity consumption behavior through price signals can alleviate the adjustment pressure on the source side and energy storage devices, and improve the capacity for renewable energy absorption during off-peak periods.

[0006] Currently, there is some research on the participation of carbon capture units or hydrogen energy storage systems in the low-carbon economic dispatch of power systems. However, in existing technologies, carbon capture units, as the main facilities for system spinning reserve, cannot fully utilize their advantages. Furthermore, hydrogen energy storage development is still in its early stages. Due to the capacity limitations of energy storage devices, hydrogen energy storage systems cannot independently meet the control needs of the power system, whether providing spinning reserve or energy time-shifting. Exploring various utilization forms of hydrogen energy storage and its coupling relationships with other power generation equipment is a problem that urgently needs to be solved for the rapid development of hydrogen energy.

[0007] In summary, to address the challenges of renewable energy consumption and the high pressure on spinning reserves, a new approach is urgently needed to analyze the operational mechanism of energy sources, loads, and storage, and to study the coordinated operational characteristics of these three aspects in order to achieve low-carbon dispatch. Summary of the Invention

[0008] The technical problem to be solved by this invention is to provide a source-load-storage low-carbon dispatching method that coordinates carbon capture and hydrogen energy storage, so as to solve the problems of difficulty in new energy consumption and insufficient spinning reserve capacity caused by large-scale grid connection of new energy during the construction of new power systems.

[0009] A low-carbon dispatching method for coordinated operation of carbon capture and hydrogen energy storage, comprising the following steps, which are performed sequentially. Step 1: Analyze the operation mechanism of the source, load, and storage sides. On the source side, the traditional thermal power unit is retrofitted for low carbonization, and a diversion device and solution storage device are installed to form a carbon capture unit under a comprehensive and flexible operation mode. On the storage side, a hydrogen energy storage system is adopted, and the energy time-shifting characteristics and equivalent spinning reserve characteristics of hydrogen energy storage are combined to realize the consumption of new energy. On the load side, a demand response mechanism is introduced to realize the interaction between source and load. Step 2: Combine carbon capture with the time-shifting characteristics of hydrogen energy storage in Step 1. The carbon capture unit improves the capacity for renewable energy consumption during off-peak hours through the storage tank, alleviating the peak-shaving pressure on the hydrogen energy storage system. When the carbon capture unit reaches its lower output limit during off-peak hours and there is still power curtailment, the hydrogen energy storage system consumes the remaining power and replaces the high-cost carbon capture unit output with energy storage output during peak hours. By combining carbon capture with the equivalent spinning reserve characteristics of hydrogen energy storage in step one, the carbon capture unit's reserve capacity is reduced during off-peak hours after the hydrogen energy storage system assumes the system's spinning reserve, thereby increasing the carbon capture unit's adjustment range. Step 3: Based on the method of coordinating carbon capture and hydrogen energy storage in Step 2, establish a source-load-storage low-carbon economic dispatch model and model constraints, adjust the rotating reserve capacity of the carbon capture unit, so that the carbon capture unit operates with a lower net output and performs low-carbon dispatch.

[0010] The carbon capture unit model after the source-side thermal power unit modification in step one is as follows: (3) In the formula: U c,t For carbon capture units t Start / stop status during specific time periods; , The standby capacity for the upper and lower rotation of the carbon capture unit; The standby time for rotation is set to 10 minutes. for t Net output of thermal power units during the period; , These are the upper and lower limits of the output power, respectively. , These represent the uphill and downhill ramp rates of the carbon capture unit, respectively.

[0011] The hydrogen energy storage system in step one includes an electrolyzer, a hydrogen storage tank, and a fuel cell; The output model of the hydrogen energy storage system is shown below: (4) In the formula: 、 for t Input and output power of the electrolytic cell during the time period; For electrolytic cell efficiency; for t Energy stored in time-limited hydrogen storage tanks; , for t Time-of-use fuel cell input and output power; For fuel cell efficiency.

[0012] The energy time-shifting characteristic of hydrogen storage in step one is that when the output of new energy sources is high and the load demand is low, the surplus wind power is input into the electrolyzer as hydrogen production power, and the generated hydrogen is stored in the hydrogen storage tank; when the output of new energy sources is low and the load demand is high, the hydrogen in the hydrogen storage tank is input into the fuel cell and converted into electrical energy to generate electricity and connect to the grid, thus realizing energy time shifting.

[0013] The equivalent rotating standby characteristic of hydrogen energy storage in step one, considering the equivalent rotating constraint of the electrolyzer, is as follows: (5) In the formula: , Electrolytic cells t The up-and-down rotational reserve capacity provided during the time period; This refers to the rated capacity of the electrolytic cell; This is the upper limit of the hydrogen storage tank's capacity; This indicates the start / stop status of the electrolytic cell equipment; a value of 1 indicates the equipment is started, and a value of 0 indicates the equipment is stopped. In the fuel cell startup state, the equivalent spinning reserve constraint is: (6) The equivalent spinning reserve constraint is as follows when the fuel cell is shut down: (7) In the formula: , fuel cells t The up-and-down rotational reserve capacity provided during the time period; This refers to the rated capacity of the fuel cell; This is the lower limit of the hydrogen storage tank capacity; This indicates the start / stop status of the fuel cell equipment.

[0014] The method for introducing a demand response mechanism on the load side in step one to facilitate source-load interaction is as follows: Demand response shifts the load by changing users' electricity consumption patterns, without changing the total load before and after the shift; (8) In the formula: This is the predicted load value; For demand response t Load size during a given time period.

[0015] The adjustment range of the carbon capture unit under the standby requirement in step two is as follows: (9).

[0016] The third step, the source-load-storage low-carbon economic dispatch model, aims to optimize the overall cost of the power system. The objective function is: (10) In the formula: F The overall cost of the power system; F p The cost of generating electricity from thermal power units; F o Costs associated with the start-up and shutdown of thermal power units; F v Cost of solution loss; F y For carbon trading costs; F s For the operation and maintenance costs of hydrogen energy storage; F b For backup costs; F q Cost of electricity loss.

[0017] The variables of the objective function of the source-load-storage low-carbon economic dispatch model are: 1) Power generation cost of thermal power units: (11) In the formula: T is the scheduling period; n This refers to the number of thermal power units. P Hi,t For thermal power units t Power generation during a given period; a i , b i , c i For the first i The power generation cost coefficient of a thermal power unit; 2) Start-up and shutdown costs of thermal power units: (12) In the formula: U i,t For the firsti Taiwan thermal power units t Start / stop status during specific time periods; S g,i For the first i Start-up and shutdown costs of the Taiwanese generator unit; 3) Solution loss cost: (13) In the formula: K s This represents the cost coefficient for ethanolamine solution; This is the solution running loss coefficient; E Jc,t For carbon capture units t The amount of CO2 captured during a given time period; 4) Carbon trading costs: (14) In the formula: c tj For carbon trading prices; This represents the total carbon emissions of the system. For carbon trading quotas; 5) Hydrogen energy storage operation and maintenance costs: The operation and maintenance costs of hydrogen energy storage are determined by the electrolyzer and fuel cell, while the operation and maintenance costs of the hydrogen storage tank are assumed to be zero. (15) In the formula: c el This is the unit operation and maintenance cost coefficient for the electrolytic cell; c fc This refers to the unit operation and maintenance cost coefficient for fuel cells. 6) Spinning reserve cost: The system spinning reserve cost is shown in formula (16). Hydrogen storage utilizes wind power curtailment to produce hydrogen, and its spinning reserve cost is less than that of thermal power units. The electrolyzer reserve cost is approximately replaced by operation and maintenance costs. (16) In the formula: N m To provide a suite of rotating standby equipment, including conventional thermal power units, carbon capture units, and hydrogen energy storage systems; , For the first k Rotational reserve cost coefficients for similar equipment; , They are respectively t Time period k The up and down rotational reserve capacity provided by this type of equipment; 7) Cost of electricity loss: Energy losses include wind power curtailment losses and energy losses caused by the conversion efficiency of hydrogen energy storage systems during the process of absorbing wind curtailment. Both types of energy losses are measured together using the penalty cost of new energy wind curtailment. (17) (18) In the formula: , , They are respectively t Forecasted wind power, actual grid-connected power, and wind curtailment power for the specified time period; c w This represents the cost coefficient for wind curtailment penalties. The constraints of the source-load-storage low-carbon economic dispatch model in step three are as follows: 1) Power balance constraints: (19) In the formula: P Ji,t For the first i Net output power of the thermal power unit; For demand response t Load size during different time periods; 2) Operating constraints of thermal power units: (20) In the formula: , The first i Upper and lower limits of the output power of thermal power units in Taiwan; 3) Constraints of carbon capture power plants: The carbon capture unit's ability to capture carbon dioxide means that the carbon capture grid connection power is affected by the capture energy consumption. The mathematical model for the carbon capture unit under a comprehensive flexible operation mode is shown below: (twenty one) In the formula: P Hc,t for t Power generation output of the carbon capture unit during a given period; P B,t Energy consumption for carbon capture; P r,t For carbon capture units t Energy consumption during different time periods; E c,t For carbon capture units t The amount of CO2 captured during a given time period; E v,t for t The amount of CO2 supplied by the storage tank during a given period; V ca,t fort The time-slot storage tank provides the required volume of solution for carbon dioxide; M V and M CO2 These are the molar masses of the ethanolamine solution and carbon dioxide, respectively. This refers to the regeneration tower's analytical value; ρ v This refers to the concentration of the alkanolamine solution. The density of the alkanolamine solution; 4) Constraints of hydrogen energy storage systems: (twenty two) In the formula: E hs,0 , E hs,T This represents the amount of hydrogen stored in the hydrogen storage tank at the initial and final moments. for t Maximum input power of the electrolytic cell during the time period; for t Maximum output power of fuel cell during a given time period; 6) Constraints on new energy output: (twenty three) 7) System uncertainty constraints: The output of wind power and the output of the load are uncertain. The system reserves a certain amount of spinning reserve capacity to cope with the uncertainty of wind power output and load output. The size of the reserved spinning reserve capacity is defined by the magnitude of the error in renewable energy output and the error in load. The uncertainty of the system can be described by a triangular fuzzy membership function. (twenty four) In the formula: H Membership function; S 1 is the lower limit of the parameter. S 2 represents historical statistical data; S 3 is the upper limit of the parameter; The triangular fuzzy membership degree used is only used to determine the spin-around reserve capacity in the system spin-around reserve constraints; The prediction errors of wind power and load are used as fuzzy parameters to describe the uncertainty of their respective outputs. The fuzzy parameter model is as follows: (25) In the formula: , This represents a fuzzy representation of the prediction errors for wind power and load. , , , This is the proportionality coefficient for wind power output and load demand forecasting errors; 8) Rotational spare constraint: Thermal power unit standby constraints: (26) (27) In the formula: , For the first i The rotating reserve capacity of the thermal power units; , The first i The rate of ascent and descent of the thermal power unit; 9) System standby constraints: The rotational spare constraints under the triangular fuzzy parameters are converted into sharp equivalence classes. (28) (29) In the formula: Cr {} represents the confidence expression; a To satisfy the confidence level of the system's rotational standby constraint.

[0018] Through the above design scheme, the present invention can bring the following beneficial effects: 1. By analyzing the operating mechanisms of the source, load, and storage sides, and fully exploring the advantages of carbon capture units, hydrogen energy storage systems, and demand response to improve the dispatch flexibility of the power system, the potential for renewable energy consumption in the system can be effectively enhanced, and the pressure on the system's spinning reserve can be reduced.

[0019] 2. Exploring multiple utilization pathways of hydrogen energy storage systems, besides energy time-shifting, is an important means to realize the development of hydrogen energy. This patent utilizes the equivalent rotating reserve characteristics of the hydrogen energy storage system to compensate to some extent for the low energy conversion efficiency caused by energy time-shifting in hydrogen energy storage.

[0020] 3. By examining the limitations and advantages of carbon capture units and hydrogen energy storage systems during operation, this study explores the coordinated operation characteristics of carbon capture units and hydrogen energy storage systems. Analysis reveals that coordinated operation can reduce the spinning reserve capacity of carbon capture units, allow carbon capture units to operate with lower net output, increase the grid-connected capacity of new energy sources, reduce energy loss during energy time-shifting in hydrogen energy storage, and improve energy utilization efficiency. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a schematic diagram of a carbon capture unit in the source-load-storage low-carbon scheduling method for coordinated operation of carbon capture and hydrogen energy storage according to the present invention.

[0022] Figure 2This is a schematic diagram of the hydrogen energy storage operation principle of the source-load-storage low-carbon scheduling method for coordinated operation of carbon capture and hydrogen energy storage according to the present invention.

[0023] Figure 3 This is a structural diagram of the source-load-storage low-carbon scheduling method for coordinated operation of carbon capture and hydrogen energy storage according to the present invention.

[0024] Figure 4 This is a diagram showing the adjustment range of the carbon capture unit under the rotating reserve requirement of the source-load-storage low-carbon dispatching method for coordinated operation of carbon capture and hydrogen energy storage according to the present invention.

[0025] Figure 5 This is an improved IEEE-30 node wiring diagram for a specific implementation of the source-load-storage low-carbon scheduling method for coordinated operation of carbon capture and hydrogen energy storage according to the present invention.

[0026] Figure 6 The diagrams for the power generation and net output of carbon capture units in scenarios 2 and 3 of the specific implementation of the source-load-storage low-carbon dispatching method for coordinated operation of carbon capture and hydrogen energy storage of the present invention are shown.

[0027] Figure 7 The following is a scenario 3 rotating reserve allocation diagram of the source-load-storage low-carbon scheduling method for coordinated operation of carbon capture and hydrogen energy storage according to the present invention.

[0028] Figure 8 The following is a scenario 4 rotating reserve allocation diagram of the source-load-storage low-carbon scheduling method for coordinated operation of carbon capture and hydrogen energy storage according to the present invention. Detailed Implementation

[0029] A low-carbon dispatching method for coordinating carbon capture and hydrogen energy storage, based on the analysis of the operating mechanisms of the three sides of source, load, and storage, such as... Figure 3 As shown, the source side involves low-carbon retrofitting of traditional thermal power units, and the installation of diversion devices and solution storage devices to form a carbon capture unit operating under a comprehensive and flexible mode. A schematic diagram of the carbon capture unit operating under this comprehensive and flexible mode is shown below. Figure 1 As shown, CO2 generated by conventional thermal power plants enters the absorption tower via a flue gas bypass, where it combines with a solution and is stored in a rich solution storage tank. During periods of low load, the rich solution is sent to a regeneration tower to separate CO2, which is then compressed and sealed by a compressor. During operation, the flue gas bypass device controls the real-time carbon capture rate, and the storage device enables decoupled operation of power generation and carbon capture.

[0030] Hydrogen energy storage systems include equipment such as electrolyzers, hydrogen storage tanks, and fuel cells, but the capacity of each individual device is limited. Their operating mechanism is as follows: Figure 2 As shown, therefore, various devices should be considered as a whole for low-carbon economic dispatch of the power system. During operation, hydrogen energy storage systems can improve the utilization rate of new energy sources, thereby reducing carbon emissions. The pathways for new energy consumption through hydrogen energy storage systems are divided into two aspects: 1) Considering the time-shifting characteristics of hydrogen energy storage. The time-shifting characteristics of hydrogen energy storage proposed in this patent are the same as those of traditional energy storage. When the output of new energy sources is high and the load demand is low, the surplus wind power is input into the electrolyzer as hydrogen production power, and the generated hydrogen is stored in the hydrogen storage tank. When the output of new energy sources is low and the load demand is high, the hydrogen in the hydrogen storage tank is input into the fuel cell and converted into electricity to generate electricity for grid connection, thus realizing energy time shifting.

[0031] 2) Consider the equivalent spinning reserve characteristics of hydrogen energy storage. Hydrogen energy storage systems have a fast response speed and can provide upper and lower spinning reserves by flexibly adjusting output, thereby reducing the spinning reserve capacity of thermal power units. Thermal power units can then operate at a lower net output, increasing the grid-connected capacity of new energy sources.

[0032] While hydrogen energy storage systems can leverage energy time-shift characteristics to facilitate renewable energy integration, this process suffers from energy losses, resulting in low energy utilization efficiency and unsatisfactory renewable energy integration. Therefore, considering the equivalent spinning reserve characteristics of hydrogen energy storage systems can, to some extent, compensate for this deficiency in energy conversion efficiency.

[0033] Load-side regulation resources cannot be ignored. The introduction of demand response mechanisms can improve the flexibility of load-side resource regulation, fully leverage the advantages of the load side, and achieve interaction between "source" and "load". Price-based demand response changes load behavior by guiding electricity prices, increasing load during off-peak periods to improve the absorption of new energy sources, and reducing load during peak periods to lower generation costs. Dispatch plans are formulated on a one-hour time scale during the day-ahead phase.

[0034] A low-carbon economic dispatch model is established based on the research of the three-sided operation characteristics of source, load, and storage. The research includes: On the source side, conventional thermal power units and carbon capture units (CCUs) retrofitted for low-carbon operation capture carbon dioxide, reducing carbon emissions from these units. On the load side, a demand response mechanism guides user electricity consumption patterns, increasing load demand during off-peak periods. Wind power is coupled with a hydrogen storage system, utilizing surplus wind power to produce hydrogen, improving wind power integration. Spinning reserve demand is shifted from being provided by thermal power units to being jointly provided by hydrogen storage systems and thermal power units.

[0035] The load-side demand response mechanism, in coordination with the source-side carbon capture units and hydrogen energy storage system, can move from "source following load" to "source-load-storage interaction," jointly ensuring the low-carbon and economical operation of the power system.

[0036] Both carbon capture units and hydrogen energy storage systems can be used for energy time-shifting and serve as partial spinning backups for the system. Therefore, it is necessary to conduct in-depth research on the limitations of their operation and their complementary advantages.

[0037] 1) The time-shifting characteristics of carbon capture and hydrogen energy storage are combined.

[0038] Due to the anti-peak-shaving characteristics of wind power, wind curtailment levels are high during off-peak hours, leading to insufficient renewable energy absorption capacity when considering carbon capture units alone. Furthermore, carbon capture units operate at high output during peak periods; although energy consumption limits can reduce carbon capture energy consumption during peak hours, load demand keeps power generation costs high. Considering only the time-shifting characteristics of hydrogen storage, significant energy is lost during energy conversion, resulting in low renewable energy utilization and unsatisfactory wind curtailment absorption.

[0039] The above analysis shows that, considering the coordinated operation of carbon capture units and hydrogen energy storage systems based on their energy time-shift characteristics, their advantages can be complemented. ① Carbon capture units improve the capacity for renewable energy absorption during off-peak hours through their storage tanks, alleviating the peak-shaving pressure on the hydrogen energy storage system. ② When the carbon capture unit reaches its lower output limit during off-peak hours and still experiences power curtailment, the hydrogen energy storage system can absorb the surplus energy and replace the high-cost output of the carbon capture unit with energy storage output during peak hours, improving the economic efficiency of the power system operation.

[0040] 2) The carbon capture and hydrogen storage are combined with the equivalent rotating reserve characteristics.

[0041] Assuming that carbon capture energy consumption changes linearly with the increase in power generation output of the carbon capture unit, carbon capture energy consumption is highest during off-peak hours and lowest during peak hours, thus ensuring the maximum adjustment range of the carbon capture unit.

[0042] Adjustment range of carbon capture unit under rotating standby requirements: (9).

[0043] like Figure 4 As shown, Figure 4 middle, , These represent the maximum and minimum energy consumption for carbon capture. , These are respectively the upper and lower rotating reserve capacity of the carbon capture unit after the hydrogen energy storage unit assumes rotating reserve. , , These represent the net output adjustment ranges for conventional thermal power units, carbon capture units, and carbon capture units considering the equivalent spinning reserve characteristics of hydrogen storage, respectively.

[0044] As shown in the above formula, under spinning reserve requirements, the net output adjustment range of source-side carbon capture units is limited, failing to fully leverage the advantages of carbon capture. Furthermore, high output during peak periods leads to high power generation costs. Hydrogen storage systems can share the spinning reserve capacity of carbon capture units. Therefore, the adjustment range of carbon capture units is related to the size of the spinning reserve capacity undertaken by hydrogen storage. After the hydrogen storage system assumes the system's spinning reserve, the reserve capacity of carbon capture units decreases during off-peak periods, thus increasing the adjustment range of carbon capture units.

[0045] Example: A simulation based on an improved IEEE-30 node system is used as an example. The system includes four thermal power units, of which unit G1 is a carbon capture unit retrofitted for low-carbon operation. The other three thermal power units are conventional thermal power units with high carbon emissions. The installed capacity of wind power is 200MW. The system structure framework is as follows: Figure 5 As shown, the scheduling model is a mixed-integer linear programming problem. The model is solved in MATLAB using the commercial optimization software GUROBI, which is accessed via YALMIP.

[0046] To verify the effectiveness of the scheduling model proposed in this paper, the following five scenarios are established: Scenario 1: Carbon capture units, hydrogen energy storage systems, and load-side demand response are not considered.

[0047] Scenario 2: Introduce a carbon capture unit based on Scenario 1.

[0048] Scenario 3: Introduce a hydrogen energy storage system based on Scenario 2, but only consider the energy time shift characteristics of hydrogen energy storage.

[0049] Scenario 4: Based on Scenario 3, consider the equivalent spinning reserve characteristics of hydrogen energy storage.

[0050] Scenario 5: Introduce load-side demand response based on Scenario 4.

[0051] Five operational scenarios were simulated, and the cost comparison is shown in Table 1.

[0052] Table 1. Cost Comparison in Different Scenarios

[0053] As shown in Table 1, without considering carbon capture units and hydrogen energy storage systems, the standby cost, carbon emissions, and wind power curtailment in Scenario 1 remain at a high level, resulting in insufficient low-carbon and economical operation of the power system.

[0054] Compared to Scenario 1, Scenario 2, with its low-carbon retrofitted carbon capture units, offers significant advantages in carbon emissions, renewable energy integration, and total system cost. Carbon capture units can capture and store CO2 generated by thermal power units, reducing carbon emissions by 1420 tons. Compared to traditional thermal power units, carbon capture units have a wider output adjustment range, operating at lower net output during off-peak periods, reducing energy loss costs and increasing renewable energy grid connection capacity.

[0055] Scenario 3 introduces a hydrogen energy storage system, but only considers the energy time-shift characteristics of the hydrogen energy storage system. Compared with Scenario 2, Scenario 3 shows that the system's power loss cost and overall cost are reduced, with the power loss cost reduced by 66.08%.

[0056] Scenario 4 considers the equivalent spinning reserve characteristics of hydrogen energy storage based on Scenario 3. Compared with thermal power units, the hydrogen energy storage system in Scenario 4 has a lower reserve cost. Compared with the first three scenarios, the reserve cost is significantly reduced, with a reduction of RMB 80,656 compared to Scenario 3, and a reduction of RMB 94,303 in the overall cost.

[0057] Scenario 5 builds upon Scenario 4 by introducing demand response on the load side, improving the system's dispatchability. With demand response implemented, some conventional thermal power units shut down during peak periods, resulting in a power generation deficit that is absorbed by carbon capture units. Carbon emissions are reduced by 107 tons compared to Scenario 4. The total system cost is also reduced.

[0058] 1) Coordinating the carbon capture unit with the time-shifting characteristics of hydrogen energy storage capacity When the system lacks carbon capture units and hydrogen energy storage systems, the regulation capacity of conventional thermal power units is limited, the capacity for renewable energy absorption is weak, and a large amount of wind curtailment occurs. The energy time-shift characteristics of carbon capture units combined with hydrogen energy storage systems can improve the grid-connected power of renewable energy and the economic efficiency of power system operation. The power generation and net power output curves of the carbon capture units in scenarios 2 and 3 are shown below. Figure 6 As shown.

[0059] In Scenario 2, carbon capture energy consumption is high during the periods of 1:00-8:00 and 20:00-24:00, resulting in lower net output power for carbon capture units. While the amount of renewable energy fed into the grid increases, wind curtailment still occurs during off-peak hours. The unused wind power in Scenario 2 is transferred to peak periods for consumption in Scenario 3 through the time-shifting characteristics of the hydrogen energy storage system. Figure 6 It can be seen that during the period from 10:00 to 19:00, the time-shifting characteristics of hydrogen energy storage reduce the power output and net output power of the carbon capture unit in scenario 3, thereby improving the system's wind power absorption level.

[0060] 2) The carbon capture unit is combined with the hydrogen storage unit to achieve the equivalent spinning reserve characteristic. Scenario 3 and Scenario 4 rotating reserve allocation plan as follows Figure 7 and Figure 8 As shown in Scenario 3, during off-peak hours, the carbon capture unit (CCU) outputs less, but has sufficient capacity to provide spinning reserve for the system. However, bearing all the spinning reserve capacity limits the space for renewable energy grid connection, making it difficult to absorb wind power. During peak hours, due to the energy consumption limitations of carbon capture, the carbon capture unit consumes less energy to capture carbon dioxide, and can independently meet the system's spinning reserve requirements.

[0061] In Scenario 4, fuel cells account for 18.18% of the upper spinning reserve capacity, while electrolyzers and fuel cells account for 84.75% and 4.89% of the lower spinning reserve capacity, respectively. Due to capacity limitations, electrolyzers and fuel cells cannot fully handle the system's spinning reserve and must cooperate with carbon capture units (CCUs). The remaining spinning reserve demand is met by the CCUs. Compared to Scenario 3, the CCUs operate with a lower net output, resulting in increased wind power grid connection during off-peak hours.

[0062] The above examples are illustrative demonstrations of the proposed patent and are not intended to limit the proposed scheduling method. The source-load-storage low-carbon economic scheduling method proposed in this patent, which considers the coordinated operation of carbon capture units and hydrogen energy storage systems, has a wide range of applicability. For those skilled in the field of power systems, other variations or modifications can be made based on the above description, and such variations or modifications are still within the protection scope of this invention.

Claims

1. A low-carbon dispatching method for source-load-storage that coordinates carbon capture and hydrogen energy storage, characterized by: The steps are as follows, and the steps are performed in sequence. Step 1: Analyze the operation mechanism of the source, load, and storage sides. On the source side, the traditional thermal power unit is retrofitted for low carbonization, and a diversion device and solution storage device are installed to form a carbon capture unit under a comprehensive and flexible operation mode. On the storage side, a hydrogen energy storage system is adopted, and the energy time-shifting characteristics and equivalent spinning reserve characteristics of hydrogen energy storage are combined to realize the consumption of new energy. On the load side, a demand response mechanism is introduced to realize the interaction between source and load. Step 2: Combine carbon capture with the time-shifting characteristics of hydrogen energy storage in Step 1. The carbon capture unit improves the capacity for renewable energy consumption during off-peak hours through the storage tank, alleviating the peak-shaving pressure on the hydrogen energy storage system. When the carbon capture unit reaches its lower output limit during off-peak hours and there is still power curtailment, the hydrogen energy storage system consumes the remaining power and replaces the high-cost carbon capture unit output with energy storage output during peak hours. By combining carbon capture with the equivalent spinning reserve characteristics of hydrogen energy storage in step one, the carbon capture unit's reserve capacity is reduced during off-peak hours after the hydrogen energy storage system assumes the system's spinning reserve, thereby increasing the carbon capture unit's adjustment range. Step 3: Based on the method of coordinating carbon capture and hydrogen energy storage in Step 2, establish a source-load-storage low-carbon economic dispatch model and model constraints, adjust the rotating reserve capacity of the carbon capture unit, so that the carbon capture unit operates with a lower net output and performs low-carbon dispatch. The carbon capture unit model after the source-side thermal power unit modification in step one is as follows: (3) In the formula: U c,t For carbon capture units t Start / stop status during specific time periods; , The standby capacity for the upper and lower rotation of the carbon capture unit; The standby time for rotation is set to 10 minutes. for t Net output of thermal power units during the period; , These are the upper and lower limits of the output power, respectively. , These represent the uphill and downhill ramp rates of the carbon capture unit, respectively. The hydrogen energy storage system in step one includes an electrolyzer, a hydrogen storage tank, and a fuel cell; The output model of the hydrogen energy storage system is shown below: (4) In the formula: 、 for t Input and output power of the electrolytic cell during the time period; For electrolytic cell efficiency; for t Energy stored in time-limited hydrogen storage tanks; , for t Time-of-use fuel cell input and output power; For fuel cell efficiency; The equivalent rotating standby characteristic of hydrogen energy storage in step one, considering the equivalent rotating constraint of the electrolyzer, is as follows: (5) In the formula: , Electrolytic cells t The up-and-down rotational reserve capacity provided during the time period; This refers to the rated capacity of the electrolytic cell; This is the upper limit of the hydrogen storage tank's capacity; This indicates the start / stop status of the electrolytic cell equipment; a value of 1 indicates the equipment is started, and a value of 0 indicates the equipment is stopped. In the fuel cell startup state, the equivalent spinning reserve constraint is: (6) The equivalent spinning reserve constraint is as follows when the fuel cell is shut down: (7) In the formula: , fuel cells t The up-and-down rotational reserve capacity provided during the time period; This refers to the rated capacity of the fuel cell; This is the lower limit of the hydrogen storage tank capacity; This indicates the start / stop status of the fuel cell equipment. The third step, the source-load-storage low-carbon economic dispatch model, aims to optimize the overall cost of the power system. The objective function is: (10) In the formula: F The overall cost of the power system; F p The cost of generating electricity from thermal power units; F o Costs associated with the start-up and shutdown of thermal power units; F v Cost of solution loss; F y For carbon trading costs; F s For the operation and maintenance costs of hydrogen energy storage; F b For backup costs; F q Cost of electricity loss; The variables of the objective function of the source-load-storage low-carbon economic dispatch model are: 1) Power generation cost of thermal power units: (11) In the formula: T is the scheduling period; n This refers to the number of thermal power units. P Hi,t For thermal power units t Power generation during a given period; a i , b i , c i For the first i The power generation cost coefficient of a thermal power unit; 2) Start-up and shutdown costs of thermal power units: (12) In the formula: U i,t For the first i Taiwan thermal power units t Start / stop status during specific time periods; S g,i For the first i Start-up and shutdown costs of the Taiwanese generator unit; 3) Solution loss cost: (13) In the formula: K s This represents the cost coefficient for ethanolamine solution; This is the solution running loss coefficient; E Jc,t For carbon capture units t The amount of CO2 captured during a given time period; 4) Carbon trading costs: (14) In the formula: c tj For carbon trading prices; This represents the total carbon emissions of the system. For carbon trading quotas; 5) Hydrogen energy storage operation and maintenance costs: The operation and maintenance costs of hydrogen energy storage are determined by the electrolyzer and fuel cell, while the operation and maintenance costs of the hydrogen storage tank are assumed to be zero. (15) In the formula: c el This is the unit operation and maintenance cost coefficient for the electrolytic cell; c fc This refers to the unit operation and maintenance cost coefficient for fuel cells. 6) Spinning reserve cost: The system spinning reserve cost is shown in formula (16). Hydrogen storage utilizes wind power curtailment to produce hydrogen, and its spinning reserve cost is less than that of thermal power units. The electrolyzer reserve cost is approximately replaced by operation and maintenance costs. (16) In the formula: N m To provide a suite of rotating standby equipment, including conventional thermal power units, carbon capture units, and hydrogen energy storage systems; , For the first k Rotational reserve cost coefficients for similar equipment; , They are respectively t Time period k The up and down rotational reserve capacity provided by this type of equipment; 7) Cost of electricity loss: Energy losses include wind power curtailment losses and energy losses caused by the conversion efficiency of hydrogen energy storage systems during the process of absorbing wind curtailment. Both types of energy losses are measured together using the penalty cost of new energy wind curtailment. (17) (18) In the formula: , , They are respectively t Forecasted wind power, actual grid-connected power, and wind curtailment power for the specified time period; c w This represents the cost coefficient for wind curtailment penalties. The constraints of the source-load-storage low-carbon economic dispatch model in step three are as follows: 1) Power balance constraints: (19) In the formula: P Ji,t For the first i Net output power of the thermal power unit; For demand response t Load size during different time periods; 2) Operating constraints of thermal power units: (20) In the formula: , The first i Upper and lower limits of the output power of thermal power units in Taiwan; 3) Constraints of carbon capture power plants: The carbon capture unit's ability to capture carbon dioxide means that the carbon capture grid connection power is affected by the capture energy consumption. The mathematical model for the carbon capture unit under a comprehensive flexible operation mode is shown below: (21) In the formula: P Hc,t for t Power generation output of the carbon capture unit during a given period; P B,t Energy consumption for carbon capture; P r,t For carbon capture units t Energy consumption during different time periods; E c,t For carbon capture units t The amount of CO2 captured during a given time period; E v,t for t The amount of CO2 supplied by the storage tank during a given period; V ca,t for t The time-slot storage tank provides the required volume of solution for carbon dioxide; M V and M CO2 These are the molar masses of the ethanolamine solution and carbon dioxide, respectively. This refers to the regeneration tower's analytical value; ρ v This refers to the concentration of the alkanolamine solution. The density of the alkanolamine solution; 4) Constraints of hydrogen energy storage systems: (22) In the formula: E hs,0 , E hs,T This represents the amount of hydrogen stored in the hydrogen storage tank at the initial and final moments. for t Maximum input power of the electrolytic cell during the time period; for t Maximum output power of fuel cell during a given time period; 6) Constraints on new energy output: (23) 7) System uncertainty constraints: The output of wind power and the output of the load are uncertain. The system reserves a certain amount of spinning reserve capacity to cope with the uncertainty of wind power output and load output. The size of the reserved spinning reserve capacity is defined by the magnitude of the error in renewable energy output and the error in load. The uncertainty of the system can be described by a triangular fuzzy membership function. (24) In the formula: H Membership function; S 1 is the lower limit of the parameter. S 2 represents historical statistical data; S 3 is the upper limit of the parameter; The triangular fuzzy membership degree used is only used to determine the spin-around reserve capacity in the system spin-around reserve constraints; The prediction errors of wind power and load are used as fuzzy parameters to describe the uncertainty of their respective outputs. The fuzzy parameter model is as follows: (25) In the formula: , This represents a fuzzy representation of the prediction errors for wind power and load. , , , This is the proportionality coefficient for wind power output and load demand forecasting errors; 8) Rotational spare constraint: Thermal power unit standby constraints: (26) (27) In the formula: , For the first i The rotating reserve capacity of the thermal power units; , The first i The rate of ascent and descent of the thermal power unit; 9) System standby constraints: The rotational spare constraints under the triangular fuzzy parameters are converted into sharp equivalence classes. (28) (29) In the formula: Cr {} represents the confidence expression; a To satisfy the confidence level of the system's rotational standby constraint.

2. The source-load-storage low-carbon dispatching method for coordinated operation of carbon capture and hydrogen energy storage according to claim 1, characterized in that: The energy time-shifting characteristic of hydrogen storage in step one is that when the output of new energy sources is high and the load demand is low, the surplus wind power is input into the electrolyzer as hydrogen production power, and the generated hydrogen is stored in the hydrogen storage tank; when the output of new energy sources is low and the load demand is high, the hydrogen in the hydrogen storage tank is input into the fuel cell and converted into electrical energy to generate electricity and connect to the grid, thus realizing energy time shifting.

3. The source-load-storage low-carbon dispatching method for coordinated operation of carbon capture and hydrogen energy storage according to claim 1, characterized in that: The method for introducing a demand response mechanism on the load side in step one to facilitate source-load interaction is as follows: Demand response shifts the load by changing users' electricity consumption patterns, without changing the total load before and after the shift; (8) In the formula: This is the predicted load value; For demand response t Load size during a given time period.

4. The source-load-storage low-carbon dispatching method for coordinated operation of carbon capture and hydrogen energy storage according to claim 1, characterized in that: The adjustment range of the carbon capture unit under the standby requirement in step two is as follows: (9)。

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