Gravity energy storage and CCUS-P2G coupled mining area integrated energy system optimization scheduling method

Abstract

The invention discloses a mining area integrated energy system optimization scheduling method coupling gravity energy storage and CCUS-P2G. The method comprises the following steps: constructing a mining area integrated energy system architecture containing gravity energy storage and CCUS-P2G coupling; a vertical shaft type gravity energy storage device model is established, and mutual conversion between electric energy and gravitational potential energy is achieved through vertical displacement of a weight; establishing a CCUS-P2G coupling model, and synthesizing methane from carbon dioxide captured by a CCUS device and hydrogen generated by an electrolytic bath in the two-stage P2G in a methane reactor; a mixing gas turbine model is established, methane generated according to the CCUS-P2G coupling model is mixed with gas in coal bed gas in the mining area, and gas meeting the combustion concentration requirement of a gas turbine is obtained; a system optimization scheduling model considering a stepped carbon transaction mechanism is constructed, and solving is carried out on the premise that system power balance constraints are met by taking the minimum total cost of the system as an objective function. The defects that in the prior art, the utilization rate of mining area associated energy is low, waste mine resources are wasted, and a single energy system cannot give consideration to low carbon and economical efficiency at the same time are overcome to a certain extent.

Description

Technical Field

[0001] This invention relates to the field of integrated energy system and power system operation control technology, and in particular to an optimized scheduling method for an integrated energy system in a mining area that utilizes gravity energy storage constructed in abandoned mines and combines it with carbon capture and power-to-gas technology, and couples gravity energy storage with CCUS-P2G. Background Technology

[0002] Coal, as a crucial primary energy source globally, is often accompanied by the generation of significant amounts of associated energy resources during its extraction, including methane, exhaust ventilation, water inrush, and coal gangue. Statistics show that coal mines possess vast reserves of methane and water resources; however, the current extensive energy utilization and management practices prevalent in mining areas lead to the direct discharge or abandonment of these high-recovery-value associated energy resources. This not only results in severe resource waste but also pollutes the surrounding ecological environment.

[0003] To address the aforementioned issues, the concept of Integrated Mining Environment Systems (CMIES) has emerged, aiming to promote the economical and low-carbon synergy of electricity and heat energy through coordinated optimization of the mutual conversion and cascade utilization of various energy sources in mining areas. Currently, research has been conducted on the optimized scheduling of CMIES. The literature “Luo Zhao, Luo Mengshun, Shen Xin, et al. Coordinated Optimization Scheduling of Integrated Mining Environment Systems Based on Carbon Capture-Electricity-Gas Conversion [J]. Automation of Electric Power Systems, 2024, 48(03):22-30” introduces associated energy utilization and carbon capture-electricity-gas conversion coupling units into CMIES to improve the low-carbon economic efficiency of CMIES; the literature “Liang Zhe, Li Mei, Zhou Mengran. Multi-objective Optimization Scheduling of Integrated Mining Environment Systems Including P2G and Hybrid Electric Energy Storage [J]. Electric Power Automation Equipment, 2021, 41(1) 0):122-129. "Utilizing hybrid electric energy storage technology to promote wind and solar energy consumption and improve the energy utilization efficiency and economy of CMIES; the literature "Huang Hongxu, Liang Rui, Zhang Xiaotong, et al. Multi-objective configuration bi-layer optimization of coal mine integrated energy system under carbon constraints[J]. Power System Technology, 2022, 46(05):1731-1742." constructs a multi-energy complementary system based on coal gangue, coalbed methane and water inflow, optimizes the energy consumption structure of CMIES, and improves the economy of CMIES; the literature "HUANG Hongxu, LIANG Rui, LV Chaoxian, et al. Two-stage robust stochastic scheduling for energy recovery in coal mine integrated energy system[J]. Applied Energy, 2021(290):116759." promotes the utilization of associated energy in CMIES through multi-energy flow coupling. While some existing technologies have proposed operational models that consider energy resource recovery or utilize single associated energy sources (such as using heat pumps to recover mine hydrothermal energy, using catalysts to improve the conversion efficiency of low-concentration methane, and using heat pipes to extract coal gangue thermal energy), most current research focuses only on the utilization of single associated energy sources within mining areas, or fails to fully consider synergy with renewable energy sources such as wind power and photovoltaics, lacking systematic research on the comprehensive complementarity of multiple energy sources. On the other hand, mining areas typically possess abundant wind and solar resources, suitable for constructing distributed wind and solar power plants. With the high proportion of renewable energy connected to the grid, configuring energy storage systems has become crucial for ensuring grid security and promoting grid absorption. Among numerous energy storage technologies, vertical shaft gravity energy storage converted from abandoned mines has advantages such as low construction cost, high safety, and flexible site selection, making it very suitable for mining scenarios. However, current research on constructing gravity energy storage in abandoned mines within mining areas is limited, and its potential for smoothing fluctuations and peak shaving has not yet been fully explored.Furthermore, in the context of low-carbon transformation, the combination of carbon capture, utilization, and storage (CCUS) technology and power-to-gas (P2G) technology is a key means to achieve energy conservation and emission reduction. While existing research on integrated energy systems includes cases of introducing carbon trading mechanisms or CCUS-P2G technology, most focus on traditional integrated energy systems, with relatively little research specifically on integrated energy systems in mining areas. Existing solutions often fail to fully utilize the coupling of carbon trading mechanisms and CCUS-P2G technology to address the difficulties in utilizing low-concentration methane and the high carbon emissions in mining areas, and also fail to effectively tap the unique circular economy potential of mining areas.

[0004] In summary, existing mining area energy system technologies suffer from the following shortcomings: First, the utilization mode of associated energy in mining areas is singular, lacking multi-energy synergy; second, the development of idle resources such as abandoned mines is insufficient, limiting the application of gravity energy storage; and third, the coupling degree between market mechanisms (such as tiered carbon trading) and low-carbon technologies (CCUS-P2G) is insufficient, making it difficult to achieve dual optimization of system economy and low carbon emissions. Therefore, there is an urgent need for a comprehensive energy system optimization and scheduling method for mining areas that can couple gravity energy storage and CCUS-P2G technologies. Summary of the Invention

[0005] This invention provides an optimized scheduling method for integrated energy systems in mining areas that couples gravity energy storage with CCUS-P2G, aiming to overcome the shortcomings of existing technologies such as low utilization rate of associated energy in mining areas, waste of resources in abandoned mines, and the difficulty of a single energy system in achieving both low carbon emissions and economic efficiency.

[0006] The technical solution of this invention is:

[0007] According to a first aspect of the present invention, a method for optimizing the scheduling of an integrated energy system in a mining area coupled with gravity energy storage and CCUS-P2G is provided, comprising:

[0008] S1. Construct a comprehensive energy system architecture for a mining area that includes gravity energy storage and CCUS-P2G coupling; the comprehensive energy system for a mining area that includes gravity energy storage and CCUS-P2G coupling includes an energy supply unit, an energy conversion unit, an energy storage unit, and a CCUS-P2G coupling unit; wherein, the energy storage unit includes at least a gravity energy storage device established using abandoned mine shafts; the CCUS-P2G coupling unit includes a CCUS device and a two-stage P2G, wherein the CCUS device provides a carbon source for the methanation of the two-stage P2G;

[0009] S2. Establish a model of a vertical shaft-type gravity energy storage device, and realize the mutual conversion of electrical energy and gravitational potential energy through the vertical displacement of the weight;

[0010] S3. Establish a CCUS-P2G coupling model to synthesize methane in a methane reactor by combining carbon dioxide captured by the CCUS device with hydrogen generated by the electrolyzer in the two-stage P2G.

[0011] S4. Establish a blended gas turbine model, and blend the methane generated in S3 with the gas in the coalbed methane of the mining area to obtain gas that meets the combustion concentration requirements of the gas turbine.

[0012] S5: Construct a system optimization scheduling model that considers the tiered carbon trading mechanism, with the objective function of minimizing the total system cost, and solve it under the premise of satisfying the system power balance constraint.

[0013] Furthermore, the CCUS-P2G coupling model includes: a CCUS device model, an electrolyzer model, a methanation model, and an HFC model.

[0014] Furthermore, the blended gas turbine model is specifically as follows:

[0015] ;

[0016] ;

[0017] In the formula: , They are respectively The electrical and thermal power output of the gas turbine at all times; , These are the power conversion coefficient and energy loss rate of the gas turbine, respectively. This refers to the lower heating value of natural gas. This represents the maximum output power of the gas turbine. , These are the upper and lower limits of the gas turbine's ramp power, respectively; for The volume of methane produced by the methane reactor at any given time; for The volume of methane produced by the methane reactor at any given time for blending; and Divided into The volume of methane stored and released in the methane storage tank at any given time; for The volume of methane after mixing at any given time; for The volume of methane in the coalbed methane at any given time; , , for The volume fraction of methane in coalbed methane produced by the methane reactor after constant mixing; , These represent the minimum and maximum volume fractions of methane available for combustion, respectively.

[0018] Furthermore, the objective function of the system optimization scheduling model considering the tiered carbon trading mechanism is as follows:

[0019] ;

[0020] ;

[0021] in, For system energy purchase costs, To incur the cost of energy abandonment, For equipment operation and maintenance costs, For carbon sequestration costs, For carbon trading costs; for Time-based tiered carbon trading costs; This indicates the total scheduling cycle.

[0022] According to a second aspect of the present invention, a mining area integrated energy system optimization and scheduling system coupled with gravity energy storage and CCUS-P2G is provided, comprising a module of the mining area integrated energy system optimization and scheduling method coupled with gravity energy storage and CCUS-P2G as described above.

[0023] The beneficial effects of this invention are:

[0024] (1) This invention constructs a multi-energy complementary architecture for associated energy sources unique to mining areas (such as gas, exhaust gas, water inrush, and coal gangue). In particular, in terms of gas utilization, it innovatively proposes to synthesize methane from carbon dioxide captured by CCUS and hydrogen generated by P2G, and then mix it with low-concentration gas (coalbed methane) that is originally difficult to use directly in the mining area, so that it meets the combustion standards of gas turbines. This method not only solves the greenhouse effect problem caused by the direct emission of low-concentration gas, but also converts it into high-value power generation fuel, realizing the recycling of carbon and the coordinated supply of multiple energy sources.

[0025] (2) This invention utilizes the natural topographical advantages of the mining area to convert abandoned mine shafts into vertical gravity energy storage systems. Compared with traditional pumped hydro storage or chemical battery energy storage, this gravity energy storage scheme has the advantages of low construction cost, high safety, environmental friendliness, and long lifespan. By utilizing idle underground space to achieve "time shift" of electrical energy, it effectively smooths out the output fluctuations of renewable energy sources such as wind power and photovoltaics, saving land resources and providing a new path for the ecological restoration and transformation of abandoned mine shafts.

[0026] (3) By introducing a tiered carbon trading mechanism and combining it with CCUS-P2G technology, this invention strengthens the synergistic relationship between electricity and carbon emissions. Simulation results show that, compared with systems that do not use this method, the model proposed in this invention can reduce the total system cost by RMB 184,600, reduce carbon emissions by 208.73 tons, and increase the renewable energy consumption rate by 32.16% (even reaching 100%). This proves that this method can effectively alleviate the contradiction between energy supply and demand in mining areas and significantly reduce carbon emissions while ensuring economic viability.

[0027] (4) The system constructed in this invention integrates multiple energy flows, including electricity, heat, gas, hydrogen, and carbon. During peak wind and solar power output periods, gravity storage and P2G equipment can serve as loads to absorb excess electricity; during peak load periods, gravity storage releases gravitational potential energy to generate electricity, while the mixed high-concentration methane drives the gas turbine to provide electricity and heat. This multi-source complementary and source-load interactive operation mode significantly improves the ability of the mining area's integrated energy system to cope with renewable energy fluctuations and load changes, ensuring the safe and stable supply of energy. Attached Figure Description

[0028] Figure 1 This is a structural diagram of the integrated energy system (CMIES) for the mining area.

[0029] Figure 2 This is a power balance diagram for CMIES.

[0030] Figure 3 This is a thermal power balance diagram for CMIES.

[0031] Figure 4 This is a CMIES cold power balance diagram.

[0032] Figure 5 This is a diagram showing the flow distribution for CH4.

[0033] Figure 6 The graph shows the volume fraction of CH4 before and after blending.

[0034] Figure 7 This is a diagram showing the carbon flow in CMIES. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0036] Example 1: As Figures 1-7As shown, according to a first aspect of the present invention, a method for optimizing the scheduling of a comprehensive energy system in a mining area that couples gravity energy storage with CCUS-P2G is provided, comprising:

[0037] S1. Construct a comprehensive energy system architecture for a mining area that includes gravity energy storage and CCUS-P2G coupling; the comprehensive energy system for a mining area that includes gravity energy storage and CCUS-P2G coupling includes an energy supply unit, an energy conversion unit, an energy storage unit, and a CCUS-P2G coupling unit; wherein, the energy storage unit includes at least a gravity energy storage device established using abandoned mine shafts; the CCUS-P2G coupling unit includes a CCUS device and a two-stage P2G, wherein the CCUS device provides a carbon source for the methanation of the two-stage P2G;

[0038] S2. Establish a model of a vertical shaft-type gravity energy storage device, and realize the mutual conversion of electrical energy and gravitational potential energy through the vertical displacement of the weight;

[0039] S3. Establish a CCUS-P2G coupling model to synthesize methane in a methane reactor by combining carbon dioxide captured by the CCUS device with hydrogen generated by the electrolyzer in the two-stage P2G.

[0040] S4. Establish a blended gas turbine model, and blend the methane generated in S3 with the low-concentration methane in the coalbed methane of the mining area to obtain high-concentration methane that meets the combustion concentration requirements of the gas turbine.

[0041] S5: Construct a system optimization scheduling model that considers the tiered carbon trading mechanism, take the minimum total system cost as the objective function, solve the problem under the premise of satisfying the system power balance constraint, and obtain the output plan of each device.

[0042] Furthermore, the CCUS-P2G coupling model includes: a CCUS device model, an electrolyzer model, a methanation model, and an HFC model.

[0043] Furthermore, the blended gas turbine model is specifically as follows:

[0044] ;

[0045] ;

[0046] In the formula: , They are respectively The electrical and thermal power output of the gas turbine at all times; , These are the power conversion coefficient and energy loss rate of the gas turbine, respectively. This refers to the lower heating value of natural gas. This represents the maximum output power of the gas turbine. , These are the upper and lower limits of the gas turbine's ramp power, respectively; for The volume of methane produced by the methane reactor at any given time; for The volume of methane produced by the methane reactor at any given time for blending; and Divided into The volume of methane stored and released in the methane storage tank at any given time; for The volume of methane after mixing at any given time; for The volume of methane in the coalbed methane at any given time; , , for The volume fraction of methane in coalbed methane produced by the methane reactor after constant mixing; , These represent the minimum and maximum volume fractions of methane available for combustion, respectively.

[0047] Furthermore, the objective function of the system optimization scheduling model considering the tiered carbon trading mechanism is as follows:

[0048] ;

[0049] ;

[0050] Where F is the total system cost, For system energy purchase costs, To incur the cost of energy abandonment, For equipment operation and maintenance costs, For carbon sequestration costs, For carbon trading costs; for Time-based tiered carbon trading costs; This indicates the total scheduling cycle.

[0051] According to a second aspect of the present invention, a mining area integrated energy system optimization and scheduling system coupled with gravity energy storage and CCUS-P2G is provided, comprising a module of the mining area integrated energy system optimization and scheduling method coupled with gravity energy storage and CCUS-P2G as described above.

[0052] Example 2: As Figures 1-7 As shown, a method for optimizing the scheduling of a mining area integrated energy system that couples gravity energy storage with CCUS-P2G includes:

[0053] Step 1: Construct a comprehensive energy system architecture for the mining area, incorporating gravity energy storage and CCUS-P2G coupling. This comprehensive energy system includes an energy supply unit, an energy conversion unit, an energy storage unit, and a CCUS-P2G coupling unit. The energy supply unit includes wind power generation, photovoltaic power generation, an external power grid, a natural gas grid, and the supply of associated energy to the mining area. The energy conversion unit includes a ventilation air methane oxidation power generation (VMOP), a water source heat pump (WSHP), a coal gangue power generation (CGPG), a combined heat and power (CHP) unit, a gas turbine (GT), a waste heat recovery boiler (WHB), an electric chiller (EC), and an absorption chiller (AC). The energy storage unit includes a gravity energy storage device (GES) and a heat storage tank. HST). The CCUS-P2G coupling unit includes a CCUS device and a two-stage P2G system. The CCUS device includes carbon capture, carbon sequestration, and a carbon dioxide storage tank (CDST). The two-stage P2G system consists of an electrolyzer (EL), a methane reactor (MR), a hydrogen fuel cell (HFC), a hydrogen storage tank (HYST), and a methane storage tank (MST). The CCUS device provides a carbon source for the methanation of the two-stage P2G system, improving the energy utilization rate of the mining area while reducing the system's carbon emissions. Based on the characteristics of associated energy in the mining area, low-concentration methane in the coalbed methane is mixed with high-concentration methane and then supplied to the GT for power generation. Exhaust air and inrush water are supplied to VMOP and WSHP for power generation and heat production, respectively. Coal gangue combustion is used to supply CGPG for power generation and heat production. WHB recovers and utilizes the high-temperature flue gas generated by GT, VMOP, and CGPG, while AC converts waste heat power into cold power, thereby realizing the coupling, interconnection, and coordinated conversion of various heterogeneous energy sources such as associated energy, electricity, heat, and cold in the mining area.

[0054] Step 2: Based on the integrated energy system architecture of the mining area including gravity energy storage and CCUS-P2G coupling, construct models for gravity energy storage devices, CCUS-P2G coupling, blended gas turbines, waste wind oxidation power generation devices, water source heat pumps, coal gangue power generation devices, combined heat and power (CHP) devices, electric chillers, absorption chillers, waste heat recovery boilers, and energy storage equipment. The waste wind oxidation power generation devices, water source heat pumps, coal gangue power generation devices, CHP devices, electric chillers, absorption chillers, waste heat recovery boilers, and energy storage equipment can adopt commonly known models in this field.

[0055] The vertical shaft gravity energy storage device model includes an energy storage process and an energy release process, as detailed below:

[0056] During the energy storage (ascent) process, the specific force balance and energy conversion are as follows:

[0057] ;

[0058] In the formula: , These represent the traction force and power of the electric motor during the ascent process, respectively. The energy stored at time t; Let be the energy storage power at time t; , These represent the total distance traveled and the time taken during the ascent; The mass of the heavy object; The acceleration due to gravity is taken as 9.8 m / s². 2 ; The energy conversion coefficient has a value of [value missing]. ; For motor efficiency; Ascent speed; This represents the time step of the scheduling model.

[0059] During the energy release process, the gravitational potential energy of the falling object generates electrical energy through a generator. The descent process can be divided into three stages: acceleration, constant speed, and deceleration. To avoid excessive fluctuations in grid power, only the electrical energy generated by the generator during the constant speed stage is supplied to the load. The equation of motion for the falling object is as follows:

[0060] ;

[0061] In the formula: , These represent the distance traveled and the time spent during the acceleration phase; , These represent the distance traveled and the time taken during the uniform motion phase, respectively. , These represent the distance traveled and the time taken during the deceleration phase, respectively. , These represent the total distance traveled and the time taken during the descent process, respectively. , These are the accelerations during the acceleration and deceleration phases, respectively. The velocity is the constant downward velocity.

[0062] During the uniform velocity phase, the forces acting on the heavy object include its own weight and the traction force from the generator. To ensure the safety of the device, an electric motor is needed to provide traction during the acceleration and deceleration phases, and the electrical energy consumed is supplied by the system. The specific force balance is as follows:

[0063] ;

[0064] ;

[0065] In the formula, During the descent The pull of time, The mechanical work done by the traction device at each stage; This is the "process time" within the integral, used to distinguish it from the "deadline time" t, which is the result variable.

[0066] The following section describes the conversion relationship between mechanical work and electrical energy on the grid side. Considering that acceleration and deceleration times are extremely short relative to the scheduling period (e.g., 15 minutes or 1 hour), based on the principle of energy conservation, they are converted into average power or energy within the time period. The formula is as follows:

[0067] ;

[0068] In the formula: , , These represent the energy consumed during the acceleration, constant speed, and deceleration phases of the traction device, respectively. The power consumed by the electric motor in the gravity energy storage device during time period t; The power output of the generator in the gravity energy storage device during time period t; , These are the maximum power limits for energy storage and energy release, respectively. For motor efficiency; For generator efficiency; , It is a 0-1 state variable, and charging and discharging cannot occur simultaneously within the time period t; , These are the minimum and maximum adjustment heights of the gravity energy storage device GES, respectively. Let t be the height of the object at time t; , This represents the change in height of the object as it rises or falls during time interval t.

[0069] Furthermore, the CCUS-P2G coupling model includes: a CCUS device model, an electrolyzer model, a methanation model, and an HFC model.

[0070] The CCUS device model is as follows:

[0071] ;

[0072] In the formula: The electrical power consumed by the CCUS device at time t; , The basic energy consumption and operating energy consumption of the CCUS device at time t are respectively (the energy consumption of the CCUS device includes basic energy consumption and operating energy consumption. The CO2 required for the methanation reaction comes entirely from the carbon dioxide captured by the carbon capture device. Unused CO2 is transported to the carbon sequestration device or storage tank). The power consumption per unit of CO2 captured; , These represent the carbon capture and storage amounts at time t, respectively. This represents the maximum operating power consumption of CCUS; Let t be the cost of carbon sequestration at time t.

[0073] The electrolytic cell model is as follows:

[0074] ;

[0075] In the formula: , These represent the hydrogen energy output of the electrolyzer at times t and t-1, respectively. The electro-hydrogen conversion efficiency of the electrolyzer; Let t be the electrical power input to the electrolytic cell at time t; Maximum hydrogen production capacity limit of the electrolyzer; , These are the upper and lower limits of the ramp power of the electrolytic cell equipment.

[0076] The methanation model is as follows:

[0077] ;

[0078] In the formula: , These represent the methane power produced by the methane reactor at times t and t-1, respectively. The maximum power generated by the methane reactor at time t; Let be the hydrogen power input to MR at time t; Methane conversion rate; The CO2 content required for the methanation process at time t; This is a coefficient used for calculating CO2 levels. Let t be the volume of methane produced by the methane reactor at time t; , These are the upper and lower limits of the ramp-up power of the methane reactor, respectively; is the volume conversion factor for methane.

[0079] The HFC model is as follows:

[0080] ;

[0081] In the formula: , t and t-1 are the electrical power output by the HFC, respectively. Let t be the thermal power output by the HFC. , These are the conversion coefficients of electrical power and thermal power in HFC, respectively. Let t be the hydrogen power input to the HFC; This represents the maximum output power of the HFC. , These are the upper and lower limits of HFC ramp power, respectively; , These are the upper and lower limits of the HFC thermoelectric ratio, respectively.

[0082] Furthermore, the construction of the blended gas turbine model is specifically as follows:

[0083]

[0084] Assuming that the volume of the mixed gas remains constant under ideal conditions, the relevant constraints are as follows:

[0085] ;

[0086] In the formula: , These represent the electrical power and thermal power output by the gas turbine at time t, respectively. , These are the power conversion coefficient and energy loss rate of the gas turbine, respectively. This refers to the lower heating value of natural gas. This represents the maximum output power of the gas turbine. , These are the upper and lower limits of the gas turbine's ramp power, respectively; Let t be the volume of methane produced by the methane reactor at time t; Let t be the volume of methane produced by the methane reactor for blending. That is, based on the methane generated in S3); and The volume of methane stored and released from the methane storage tank at time t is divided into the volume of methane stored and released at time t. The volume of methane after mixing at time t (i.e., high-concentration methane that meets the combustion concentration requirements of the gas turbine); Let t be the volume of methane in the coalbed methane at time t (i.e., the low-concentration methane in the coalbed methane of the mining area); , , The volume fraction of methane in the coalbed methane produced by the methane reactor after mixing at time t; , These represent the minimum and maximum volume fractions of methane available for combustion, respectively.

[0087] Step 3: Based on the system energy purchase cost Energy curtailment penalty costs Equipment operation and maintenance costs Carbon sequestration costs and carbon trading costs Minimizing the sum is the optimization objective. The objective function of the system optimization scheduling model considering the tiered carbon trading mechanism is as follows:

[0088] ;

[0089] in:

[0090] ;

[0091] ;

[0092] ;

[0093] ;

[0094] ;

[0095] ;

[0096] In the formula: , Let t represent the time-of-use electricity price and gas price at time t, respectively. , These represent the electricity and gas purchases at time t, respectively. , These are the penalty coefficients for wind curtailment and solar curtailment, respectively. , These represent the power of wind and solar power curtailment at time t, respectively. , , These are the penalty coefficients for abandoned gas, insufficient ventilation, and inrush water, respectively. , , These represent the gas, exhaust air, and inrush water flow rates at time t, respectively. The operation and maintenance coefficient of energy conversion equipment i. Let i be the output power of energy conversion device i at time t, where i∈{VMOP (Vacuum-fired Power Plant),WSHP (Water Source Heat Pump),CGPG (Coal Gangue Power Plant),CHP (Cogeneration Plant),GT (Gas Turbine),WHB (Waste Heat Recovery Boiler),EC / AC (Electric / Absorption Chiller),EL (Electrolyte),MR (Methane Reactor),HFC (Hydrogen Fuel Cell),CCUS (CCUS)}. Energy conversion device refers to the unit in the system responsible for instantaneous energy form conversion. Its input and output occur at the same time and it does not have the ability to store energy across time periods. The operation and maintenance coefficient of energy storage equipment; Let be the charging power (energy storage power) of energy storage device x at time t. Let x be the energy release power of energy storage device x at time t; x∈{thermal storage tank (HST), methane storage tank (MST), carbon storage tank (CDST), hydrogen storage tank (HYST), gravity energy storage device (GES)}, and energy storage device refers to the unit in the system responsible for energy transfer across time periods; The unit price for carbon sequestration; Let t be the cost of carbon sequestration. Let t be the tiered carbon trading cost. The base price for carbon trading. As the reward coefficient, 3 The interval length is... This is the penalty coefficient; Indicates the total scheduling period; Let t be the planned carbon emissions at time t; Let t be the actual carbon emissions at time t.

[0097] The system power balance constraints include electrical power, thermal power, and cold power balance constraints; further, they also include ramp rate and upper and lower output limits constraints for each device (such as GT, CHP, VMOP, etc.).

[0098] Step 4: Model Solving and Analysis

[0099] A commercial solver was used to solve the aforementioned mixed-integer linear programming (MILP) problem. In the simulation scenario, compared to systems without gravity energy storage and without P2G, the method in this embodiment reduced the total system cost by approximately RMB 184,600 and carbon emissions by 208.73 tons. Simultaneously, the wind and solar power absorption rates were significantly improved (e.g., wind power absorption rate could reach 100%). During peak wind and solar power output periods (e.g., 10:00-16:00), the P2G equipment operates at full load to absorb surplus electricity, and the generated methane is stored in storage tanks or directly blended; gravity energy storage is used for charging (lifting heavy objects). During peak electricity prices or peak load periods, gravity energy storage discharges, and the gas turbine uses the blended high-concentration methane to generate electricity, reducing the need for external power purchases.

[0100] The following four scenarios will be analyzed:

[0101] Scenario 1: Gravity energy storage is not considered, and CCUS-P2G is not included.

[0102] Scenario 2: Consider only gravity energy storage.

[0103] Scenario 3: Consider only CCUS-P2G.

[0104] Scenario 4: Consider gravity energy storage, including CCUS-P2G.

[0105] In scenarios 1 and 2, since the system is not equipped with P2G, high-concentration methane will be purchased from an external gas network to achieve the conditions required for mixing.

[0106] As described above, the four scenarios were simulated in MATLAB, and the simulation results are shown in Table 1.

[0107] Table 1 Optimization scheduling results for each scenario

[0108]

[0109] (1) Analysis of CMIES Low-Carbon Collaborative Operation

[0110] Table 1 shows the system optimization scheduling results. Compared to Scenario 1, Scenario 2, with the addition of a gravity energy storage device, optimized the system's carbon emissions, wind and solar energy integration, and total operating costs. The total system cost decreased by RMB 14,400, and the wind and solar energy integration rates increased to 82.31% and 96.71%, respectively. This is because the gravity energy storage device stores surplus electricity during peak wind and solar power output and discharges it when the electrical load is high, thus reducing electricity purchase costs and carbon emissions. Furthermore, since the high-concentration methane required for blending in Scenarios 1 and 2 will be purchased externally, the gas purchase costs are relatively high.

[0111] Compared to Scenario 1, Scenario 3 considers the combined operation of CCUS-P2G, resulting in a total system cost reduction of RMB 135,200, a carbon emission reduction of 187.58 tons, and wind and solar energy utilization rates increased to 82.09% and 98.71%, respectively. This is because during periods of wind and solar curtailment, P2G converts electricity into H2 via an EL device. A portion of this H2 can be directly supplied to hydrogen fuel cells to generate electrical and thermal power, while the remainder can be combined with CO2 captured by the carbon capture device in a methane reactor to produce high-concentration methane. With the reduction in carbon emissions, the system's low-carbon operation leads to revenue generation through the carbon trading mechanism. Simultaneously, the system will seal off any unused CO2. Scenario 3 not only solves the problem of purchasing high-concentration methane from external sources but also promotes energy conservation and emission reduction in the mining area.

[0112] Based on Scenario 3, Scenario 4 significantly reduced system operating costs and carbon emissions to RMB 293,300 and 402.72 tons through the synergistic complementarity between gravity energy storage devices and CCUS-P2G, while achieving 100% integration of wind and solar power.

[0113] (2) Optimization of scheduling results analysis

[0114] Scenario 4 was selected to analyze the power supply, heating and cooling balance, and gas volume flow rate and volume fraction.

[0115] Depend on Figure 2 It is known that among the CMIES associated energy utilization units, VMOP has the lowest operating and environmental costs, followed by GT blending, while CGPG has relatively high costs. The system prioritizes absorbing the output of VMOP and GT, with the power supply deficit being made up by CGPG, grid purchases, and CHP. During off-peak electricity pricing, the system makes up for the power deficit through external power purchases. This period also coincides with the peak wind power generation period, and the electricity load is relatively low. Therefore, the gravity energy storage device GES stores a large amount of electricity during this time, and the P2G device converts the electricity into H2 while ensuring the system's power demand. This H2 is then combined with CO2 from carbon capture to synthesize methane, significantly improving wind energy utilization. During the peak photovoltaic power generation period, the system's electricity load reaches its peak, and at this time, peak electricity pricing applies, so no power purchases are made. To absorb more photovoltaic output, most of the electricity is supplied to the P2G device, with the gravity energy storage device storing only a small amount. During the period from 15:00 to 17:00, which is the off-peak period for wind and photovoltaic output, the gravity energy storage device releases electricity to meet the load demand.

[0116] Depend on Figure 3It can be seen that CHP, WHB, HFC, WSHP, and HST provide the system with the required heat energy. WHB absorbs the waste heat from VMOP, GT, and CGPG, supplying the majority of the system's heat energy. CHP and HFC, due to their electrothermal effects, also provide relatively stable heat energy to the system. HST stores heat during multiple periods—8:00-9:00, 16:00, and 20:00-21:00—and releases it during 1:00-2:00, 10:00-11:00, and 22:00-24:00—reducing heat waste. Figure 4 It can be seen that the EC and AC provide the cooling energy required by the system. Since the system has abundant waste heat resources, the AC absorbs the excess heat and converts it into the cooling energy required by the system, while the remaining cooling energy is provided by the EC during off-peak electricity pricing periods.

[0117] CH4 flow rate and CH4 volume fraction before and after blending Figure 5 , Figure 6 As shown, during periods of low wind and solar power output, P2G produces less CH4. The system then blends high-concentration CH4 (HCG) stored in the MST with low-concentration CH4 (LCG) in the CBM to meet GT combustion standards and ensure stable operation. During peak wind and solar power output, to absorb more renewable energy, P2G output is higher. While ensuring blending requirements are met, excess CH4 is injected into the MST for storage. The volume fraction of CH4 (MIX) after blending shows a similar trend to that of P2G output.

[0118] CMIES' carbon emissions, carbon sequestration, carbon capture, and carbon storage are as follows: Figure 7 As shown in the diagram, during the off-peak electricity pricing periods of 0:00-7:00 and 22:00-24:00, the system purchases large amounts of electricity, resulting in lower output from carbon capture units and higher carbon emissions during this time. Only CO2 needs to be stored using CDST, with no excess CO2 requiring sequestration. From 8:00-21:00, the carbon capture units supply power to the system, leading to a relative decrease in carbon emissions and an increase in carbon capture. In addition to storage using CDST, any unusable CO2 needs to be sequestrated.

[0119] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for optimizing the scheduling of a comprehensive energy system in a mining area that couples gravity energy storage with CCUS-P2G, characterized in that, include: S1. Construct a comprehensive energy system architecture for mining areas that includes gravity energy storage and CCUS-P2G coupling; The integrated energy system for mining areas, which includes gravity energy storage and CCUS-P2G coupling, comprises an energy supply unit, an energy conversion unit, an energy storage unit, and a CCUS-P2G coupling unit; wherein, the energy storage unit includes at least a gravity energy storage device established using abandoned mine shafts; The CCUS-P2G coupling unit includes a CCUS device and a two-stage P2G. The CCUS device provides a carbon source for the methanation of the two-stage P2G. S2. Establish a model of a vertical shaft-type gravity energy storage device, and realize the mutual conversion of electrical energy and gravitational potential energy through the vertical displacement of the weight; S3. Establish a CCUS-P2G coupling model to synthesize methane in a methane reactor by combining carbon dioxide captured by the CCUS device with hydrogen generated by the electrolyzer in the two-stage P2G. S4. Establish a blended gas turbine model, and blend the methane generated in S3 with the gas in the coalbed methane of the mining area to obtain gas that meets the combustion concentration requirements of the gas turbine. S5: Construct a system optimization scheduling model that considers the tiered carbon trading mechanism, with the objective function of minimizing the total system cost, and solve it under the premise of satisfying the system power balance constraint.

2. The optimized scheduling method for integrated energy systems in mining areas coupled with gravity energy storage and CCUS-P2G as described in claim 1, characterized in that, The CCUS-P2G coupling model includes: CCUS device model, electrolyzer model, methanation model, and HFC model.

3. The optimized scheduling method for integrated energy systems in mining areas coupled with gravity energy storage and CCUS-P2G as described in claim 1, characterized in that, The blended gas turbine model is specifically as follows: ； ； In the formula: , They are respectively The electrical and thermal power output of the gas turbine at all times; , These are the power conversion coefficient and energy loss rate of the gas turbine, respectively. This refers to the lower heating value of natural gas. This represents the maximum output power of the gas turbine. , These are the upper and lower limits of the gas turbine's ramp power, respectively; for The volume of methane produced by the methane reactor at any given time; for The volume of methane produced by the methane reactor at any given time for blending; and Divided into The volume of methane stored and released in the methane storage tank at any given time; for The volume of methane after mixing at any given time; for The volume of methane in the coalbed methane at any given time; , , for The volume fraction of methane in coalbed methane produced by the methane reactor after constant mixing; , These represent the minimum and maximum volume fractions of methane available for combustion, respectively.

4. The optimized scheduling method for integrated energy systems in mining areas coupled with gravity energy storage and CCUS-P2G as described in claim 1, characterized in that, The objective function of the system optimization scheduling model considering the tiered carbon trading mechanism is as follows: ； ； in, For system energy purchase costs, To incur the cost of energy abandonment, For equipment operation and maintenance costs, For carbon sequestration costs, For carbon trading costs; for Time-based tiered carbon trading costs; This indicates the total scheduling cycle.

5. A mining area integrated energy system optimization and scheduling system coupling gravity energy storage and CCUS-P2G, characterized in that, The module includes the optimized scheduling method for integrated energy systems in mining areas that combines gravity energy storage and CCUS-P2G as described in any one of claims 1-4.

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