Closing mines and developing renewable energy methods

Abstract

This disclosure provides a method for developing renewable energy in closed mines, including: calculating the wind and solar capacity coefficient of the closed mine unit; assessing the wind and solar power generation potential of the closed mine unit; designing grid-connected lines for wind and solar power generation in the closed mine unit based on grid partitioning; designing a power generation dispatch layer; and constructing a power system model that includes the closed mine unit to minimize construction and operation costs.

Description

Technical Field

[0001] This disclosure relates to the fields of new energy development and smart grid technology, and in particular to a method for developing renewable energy from closed mines. Background Technology

[0002] As the world's largest energy consumer and carbon emitter, my country faces increasing pressure to adjust its energy structure and reduce carbon emissions, making the vigorous development of renewable energy an urgent task. Meanwhile, as of 2024, mining operations had occupied and damaged approximately 54 million mu (about 3.6 million hectares) of land nationwide. Therefore, it is necessary and pressing to transform and develop closed mines into renewable energy sources. Summary of the Invention

[0003] In view of this, in order to at least partially solve at least one of the aforementioned technical problems, this disclosure provides a method for developing renewable energy in closed mines.

[0004] To achieve the above objectives, the technical solution disclosed herein is as follows:

[0005] According to embodiments of this disclosure, a method for developing renewable energy in closed mines is provided, comprising: calculating the wind and solar capacity coefficient of the closed mine unit; assessing the wind and solar power generation potential of the closed mine unit; designing grid-connected lines for wind and solar power generation in the closed mine unit based on grid partitioning; designing a power generation dispatch layer; and constructing a power system model including the closed mine unit to minimize construction and operation costs.

[0006] According to embodiments of this disclosure, calculating the wind and solar capacity coefficient of a closed mine unit includes calculating the wind power capacity coefficient of the closed mine unit and calculating the photovoltaic power generation capacity coefficient of the closed mine unit.

[0007] According to embodiments of this disclosure, assessing the wind and solar power generation potential of a closed mine unit includes assessing the wind power generation potential of the closed mine unit; and assessing the photovoltaic power generation potential of the closed mine unit.

[0008] According to embodiments of this disclosure, the grid-based design of wind and solar power grid connection lines for closed mining units includes: dividing wind and solar power unit grids based on geographical latitude and longitude information; designating closed mining units within each wind and solar power unit grid as closed mining units and connecting them to the nearest substation in the province via branch lines; and connecting the substation to the nearest major node in the same province via trunk lines, while ensuring the shortest total distance for wind and solar power grid connection.

[0009] According to embodiments of this disclosure, the central point of each county or district is used as the spatial location of the substation, all prefecture-level cities and above in the urban agglomeration are positioned as load centers, and the central point of the load center in space is used as the main node of the power grid.

[0010] According to embodiments of this disclosure, the power generation dispatch layer is designed to rationally allocate annual power demand to various types of generator units on the supply side based on a heuristic dispatch sequence, using hours as the time scale. Fixed generator units are located in the first layer of the power generation dispatch layer, while generator units in closed mining units are located in the second layer.

[0011] According to embodiments of this disclosure, when constructing a power system model that includes closed mining units, an objective function is established with the goal of minimizing construction and operation costs. The constraints of the objective function include supply and demand balance constraints, wind and solar power generation constraints, stationary unit power supply constraints, wind and solar grid connection line constraints, inter-provincial transmission line constraints, reserve capacity requirements, ramp-up capacity constraints, and energy storage operation constraints.

[0012] According to embodiments of this disclosure, the method for developing renewable energy in closed mines further includes calculating the cost of wind and solar power generation in the closed mine unit and calculating the cost of leveled connection of branch lines. Attached Figure Description

[0013] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0014] Figure 1 This is a schematic diagram illustrating the working principle of a photovoltaic-pumped storage power station in an abandoned mine.

[0015] Figure 2 This is a flowchart of a method for developing renewable energy from closed mines, according to an embodiment of this disclosure.

[0016] Figure 3 This is a schematic diagram illustrating the technical process and principle of a method for developing renewable energy from closed mines, as described in this disclosure. Detailed Implementation

[0017] This disclosure provides a method for developing renewable energy in closed mines, using wind power and photovoltaic power generation as the main renewable energy power generation technologies. It innovatively combines the resource endowment conditions and geographical spatial characteristics of closed mines with the planning of new energy power systems, thereby achieving spatial site selection and capacity configuration optimization for renewable energy development in closed mines.

[0018] Research and practice abroad combining mine closures with renewable energy have achieved relatively mature progress. For example, the Ruhr mining region in Germany has already achieved continuous wind power generation projects. Meanwhile, domestic scholar Zhang Zhenqi believes that the application of photovoltaic power generation technology in abandoned mine tailings dams has certain feasibility, and points out from an economic perspective that photovoltaic power generation systems are an effective choice for the sustainable development of abandoned mining areas. However, there are relatively few domestic scholars researching the site selection for renewable energy development in closed mines. Existing technologies are generally based on a single closed mine, combining pumped storage with photovoltaic power generation. Photovoltaic arrays transmit solar power generated through a confluence of current to a nearby pumped storage power station. When there are few electrical devices and the grid load is low, the transformer pumps water from the lower reservoir to the upper reservoir, storing this low-energy flow as the potential energy of the water. When the number of electrical devices increases and the grid load rises, the water is released from the upper reservoir to maintain grid stability. The workflow and principle are as follows: Figure 1 As shown. However, the above-mentioned existing technology still has the following drawbacks:

[0019] 1. There is limited research in China on the site selection for renewable energy development in closed mines, and most of it remains at the theoretical stage without specific experimental evidence.

[0020] 2. Current research is mainly limited to the level of individual mines, focusing on feasibility analysis, suitability evaluation and physical utilization potential assessment of specific mines. The research methods used are highly context-dependent, resulting in insufficient universality and generalizability of the research results.

[0021] 3. Existing research has limited coverage of integrating multiple closed mines on a large scale into the overall planning of new energy power networks from the perspective of the overall energy system. In particular, there are research gaps in key aspects such as capacity configuration and spatial layout optimization of multi-generation complementary power generation layers.

[0022] 4. Existing studies have given little consideration to the accurate matching of supply capacity and demand response in time and space after the development and grid connection of renewable energy from closed mines, and have not included closed mines as an important source of renewable energy power generation in the planning of future new energy power systems.

[0023] Therefore, this disclosure provides a method for developing renewable energy in closed mines, which uses wind power and photovoltaic power generation as the main renewable energy power generation technologies. It innovatively combines the resource endowment conditions and geographical spatial characteristics of closed mines with the planning of new energy power systems, thereby achieving spatial site selection and capacity configuration optimization for renewable energy development in closed mines.

[0024] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0025] In the embodiments disclosed herein, such as Figure 2 and Figure 3 As shown, a method for developing renewable energy in a closed mine is provided, including the following operations S1-S5:

[0026] S1: Calculate the wind and solar capacity coefficient of the closed mine unit;

[0027] S2: Assess the wind and solar power generation potential of closed mining units;

[0028] S3: Based on grid partitioning design, shut down the wind and solar power grid connection lines of the mining unit;

[0029] S4: Design of the power generation dispatch layer; and

[0030] S5: Construct a power system model that includes closed mining units to minimize construction and operating costs.

[0031] According to embodiments of this disclosure, calculating the wind and solar capacity coefficient of a closed mine unit includes calculating the wind power capacity coefficient of the closed mine unit and calculating the photovoltaic power generation capacity coefficient of the closed mine unit.

[0032] Regarding the calculation of wind power capacity factor: Based on hourly-scale wind speed simulation data in both east-west and north-south directions, the wind power capacity factor of the closed mine unit is calculated according to the following formula. First, Equation 1 is used to synthesize the wind speed data in both directions.

[0033] (1);

[0034] (2);

[0035] Next, Equation 2 was used to calculate the real-time wind speed data at the height of the wind turbine hub. and These represent the wind speeds at the target altitude and the original altitude, respectively. and These represent the target height and the original height, respectively. The conversion factor varies depending on the geographical location. Subsequently, the real-time power of the wind turbine is inferred from the wind speed, as shown in Equation 3.

[0036] (3);

[0037] (4);

[0038] In the formula, This indicates the real-time power of the fan. This indicates the rated power of the fan. Indicates real-time wind speed. , and These represent the cut-in wind speed, rated wind speed, and cut-out wind speed of the wind turbine, respectively. Finally, using Formula 4, the ratio of the wind turbine's real-time power to its rated power is calculated as the capacity factor for closed-mine wind power generation. .

[0039] Regarding the calculation of photovoltaic power generation capacity factor: Based on the solar radiation data at the unit scale of the closed mine, the hourly photovoltaic power generation capacity factor of the closed mine for 8760 hours throughout the year is calculated using Equation 5.

[0040] (5);

[0041] In the formula, and These represent the conditions under which the photovoltaic module operates at the calculated time and under standard experimental conditions (photovoltaic module temperature is 25℃, solar radiation is 1000W / m²). 2 The solar energy conversion efficiency (at an air quality of 1.5 AM) is calculated. This paper assumes that the conversion efficiency of the photovoltaic module remains constant as the amount of solar radiation changes, i.e. and The ratio is always 1. This indicates the power loss during the photovoltaic module's power generation process. and These represent the calculated shading effect coefficient and temperature effect coefficient, respectively.

[0042] According to embodiments of this disclosure, assessing the wind and solar power generation potential of a closed mine unit includes assessing the wind power potential of the closed mine unit and assessing the photovoltaic power generation potential of the closed mine unit.

[0043] Regarding wind power potential assessment: First, based on the inherent characteristics of closed mines, a suitability evaluation index system for wind power development and utilization in closed mines is constructed. This system assesses the suitability of wind power development in closed mines nationwide, classifying them into those suitable for wind power development and those unsuitable. The evaluation index system is shown in Table 1.

[0044] Table 1. Evaluation Index System for the Suitability of Wind Power Development in Closed Mines

[0045]

[0046] Next, for closed mining units suitable for wind power development, their physical potential for wind power development was calculated using Formula 6:

[0047] (6);

[0048] In the formula This indicates the potential for maximum installed capacity of wind power generation from closed mining land resources. This indicates the area of ​​the closed mine. This indicates the installed capacity of wind power per unit area.

[0049] Regarding the assessment of photovoltaic power generation potential: Similarly, a suitability evaluation index system for the development and utilization of photovoltaic power generation in closed mines is constructed to constrain the suitability of deploying photovoltaic power generation projects in closed mines. The evaluation index system is shown in Table 2.

[0050] Table 2. Suitability Evaluation Index System for Photovoltaic Power Generation Development in Closed Mines

[0051]

[0052] Assuming photovoltaic (PV) power generation adopts a fixed tilt installation mode, it is necessary to calculate the PV module installation factor for a closed mine unit. The PV installation factor refers to the effective PV panel area factor per unit land area, and the specific calculation formula is as follows:

[0053] (7);

[0054] In the formula, This refers to the photovoltaic installation factor. Finally, the photovoltaic installation capacity potential is calculated according to Formula 8:

[0055] (9);

[0056] In the formula, This indicates the maximum installed capacity potential of the photovoltaic power generation projects located in the closed mines; This indicates the power generation per unit area of ​​a photovoltaic panel.

[0057] According to embodiments of this disclosure, the design for shutting down grid-connected wind and solar power generation lines in mining units based on grid partitioning includes:

[0058] Wind and solar power generation unit grids are divided based on geographical latitude and longitude information;

[0059] Each wind and solar power generation unit grid includes units with closed mines, and these units are connected to the nearest substation in their respective provinces via branch lines; and

[0060] Under the principle of ensuring the shortest total distance for wind and solar power grid connection, the substation is connected to the nearest major node in the same province via trunk lines.

[0061] According to the embodiments of this disclosure, the center point of each county or district is used as the spatial location of the substation, all prefecture-level cities and above in the urban agglomeration are positioned as load centers, and the center point of the load center in space is used as the main node of the power grid.

[0062] Specifically, each wind and solar power generation unit grid (including ordinary spatial grid units and closed mine units) is first connected to the nearest substation in its province via branch lines. Then, under the principle of minimizing the total grid connection distance for wind and solar power generation, the substation is connected to the nearest major node in the same province via trunk lines (the center point of each county or district in China is used as the spatial location of the substation in the model, all prefecture-level cities and above in the urban agglomeration are positioned as load centers, and the center point of the load center in space is used as the major node of the future power grid).

[0063] According to embodiments of this disclosure, the power generation dispatch layer is designed to rationally allocate annual power demand to various types of generator units on the supply side based on a heuristic dispatch sequence, using hours as the time scale. Fixed generating units are located in the first layer of the power generation dispatch layer, while generator units in closed mining units are located in the second layer.

[0064] Specifically, based on a heuristic scheduling sequence, annual electricity demand is rationally allocated to various types of generating units on the supply side on an hourly time scale, as shown in Table 3 below. Based on the electricity demand of each province and the generation of the first layer G1 (fixed generation layer, with priority power use, a mandatory operating layer) of the model's generation scheduling layer, the existing power gap in each province is calculated, and then the power generation of the second layer G2 to the fifth layer G5 is used to gradually fill the power gap. Renewable energy generation from closed mines is placed in the second layer of the model; this layer is also called the variable energy generation layer.

[0065] Table 4 Power Generation Layer Scheduling Sequence

[0066]

[0067] According to embodiments of this disclosure, when constructing a power system model that includes closed mining units, an objective function is established with the goal of minimizing construction and operation costs. The constraints of the objective function include supply and demand balance constraints, wind and solar power generation constraints, stationary unit power supply constraints, wind and solar grid connection line constraints, inter-provincial transmission line constraints, reserve capacity requirements, ramp-up capacity constraints, and energy storage operation constraints.

[0068] Regarding the construction of the objective function: The established objective function is to minimize the construction and operation costs of a new energy power system that couples with the development of renewable energy from closed mines, based on existing infrastructure and fixed installed capacity. (Setting...) Represents a set of provinces; This indicates the provinces involved in the nine major clean energy bases. A subset of; This refers to a collection of renewable energy power generation technologies (ordinary onshore wind power, ordinary photovoltaic power generation, offshore wind power, photovoltaic power generation in closed mines, and wind power in closed mines). Indicates province Renewable energy power generation technology The set of grid cells that can be utilized; Indicates province Zhonghe Substation Connected renewable energy generation technologies The set of grid cells that can be utilized; Indicates province Renewable energy power generation technology A set of potentially usable closed mining units; Indicates province Zhongyu Substation Connected renewable energy generation technologies A set of potentially usable closed mining units; Represents a collection of substations; Represents a set of load centers; This refers to a collection of energy storage technologies (pumped hydro storage and lithium-ion battery chemical energy storage). Represents a collection of power generation layers; Represents a set of time slices. Provinces representing the nine major clean energy bases New energy technologies The installed capacity plan is in GW. Indicates power generation layer The unit ramp-up cost, expressed in yuan / kW; Indicates power generation layer The unit downhill cost, in yuan / kW; Indicates power generation layer The unit standby cost, expressed in yuan / kW; Indicates power generation layer The unit fuel cost, expressed in yuan / kW; Indicates power generation layer The unit variable operation and maintenance cost is expressed in yuan / kW; Indicates energy storage technology The cost of capital, expressed in yuan / kW; Indicates energy storage technology Fixed operation and maintenance costs, in yuan / kW yr; Indicates energy storage technology Variable operation and maintenance costs, in yuan / kWh; Indicates province and Fixed investment in power transmission lines between them, in yuan / kW; Indicates province and Variable investment in power transmission lines between them, in yuan / kW km; Indicates province Power generation layer In time slice Maximum capacity, in GW; Indicates province Renewable energy power generation technology The possible use of the first The maximum installed capacity potential of each grid cell, in GW; Indicates province renewable energy technology The possible use of the first The maximum installed capacity potential of a closed mining unit, in GW; Indicates province and The transmission capacity of existing power transmission lines between them, in GW; Indicates province The maximum installed capacity of future pumped storage hydroelectric power, in GW; Indicates province Installed pumped storage capacity, in GW; Indicates province The maximum operating capacity of coal-fired combined heat and power plants, in GW; Indicates province Power generation layer At any moment The hourly capacity factor is used to represent the time. Indicates province No. Renewable energy generation technology for individual grid units At any moment The capacity factor is used to represent; Indicates province No. Renewable energy generation technology for closed mining units At any moment The capacity factor is used to represent; Indicates province No. Renewable energy generation technology for individual grid units The annual average capacity coefficient is used to represent this. Indicates province No. Renewable energy generation technology for closed mining units The annual average capacity coefficient is used to represent this. Indicates province No. Photovoltaic module installation coefficient for a closed mining unit; Represents renewable energy power generation technology The area occupied per unit of installed capacity, expressed in GW / km². 2 ; Indicates province No. The area of ​​a closed mine, in km² 2 ; Indicates province No. Renewable energy technology for individual grid units The levelized cost of the branch line connected to the substation, in yuan / kWh; Indicates province No. Renewable energy technology for closed mining units The levelized cost of the branch line connected to the substation, in yuan / kWh; Indicates province and The distance between inter-provincial transport routes, in km; Indicates province No. The distance between each grid cell and the substation, in km; Indicates province No. The distance between a closed mining unit and a substation, in km; Indicates province substation Distance to the load center, in km; Indicates province At any moment Electricity demand, in GW; Indicates province At any moment The net electricity demand remaining after deducting the supply required for L1 to operate, in GW; Indicates province No. Renewable energy generation technology for individual grid units It is expressed as the ratio of installed capacity to maximum potential installed capacity; Indicates province No. Renewable energy generation technology for closed mining units It is expressed as the ratio of installed capacity to maximum potential installed capacity; Indicates province No. Renewable energy generation technology for individual grid units The levelized cost of electricity, expressed in yuan / kWh; Indicates province No. Renewable energy generation technology for closed mining units The levelized cost of electricity, expressed in yuan / kWh; Indicates energy storage technology The investment recovery coefficient; Indicates province and The investment recovery coefficient of inter-provincial transmission lines; This represents the investment recovery factor of the grid-connected branch line; This indicates the investment recovery coefficient of the grid-connected trunk line; Indicates power generation layer The maximum gradeability is represented by; Indicates power generation layer The maximum downhill slope is represented by; Indicates energy storage technology The charging efficiency is expressed as follows; Indicates energy storage technology The discharge efficiency is expressed as follows; This indicates the minimum transmission efficiency of a coal-fired combined heat and power (CHP) system if it were to be put into operation during periods when it is not required to operate. Indicates energy storage technology The self-discharge rate is expressed as... The reserve capacity demand rate represents the electrical load. This represents the reserve capacity demand rate for renewable energy generation technologies. Indicates energy storage technology The duration of , in hours; This indicates the capital investment cost of grid-connected lines, expressed in yuan / kW. km; This indicates the transmission loss rate of branch and trunk lines connected to the wind and solar grid, expressed in % / km. Indicates province and Energy loss rate of inter-provincial transmission lines, expressed in % / km; Indicates power generation layer Energy loss rate expressed using CCS technology. Indicates province No. Each grid unit develops renewable energy technologies The capacity represents the proportion of the maximum potential. Indicates province No. One closed mine develops renewable energy technologies The capacity represents the proportion of the maximum potential. Indicates connecting provinces The Middle Renewable energy generation technology for individual grid units With substation The capacity of the branch lines, in GW; Indicates connecting provinces The Middle Renewable energy generation technology for closed mining units With substation The capacity of the branch lines, in GW; Indicates connecting provinces medium substation With load center The capacity of the trunk line, in GW; Indicates province and The capacity of inter-provincial transmission lines, in GW; Indicates province Medium energy storage technology Capacity, in GW; Indicates province Renewable energy power generation technology At any moment The electricity generated (summed by grid cells and closed mine cells) is measured in GW. Indicates province China Power Technology (Power generation layers L2-L4 and renewable energy power generation technologies) at time The electricity generated is transmitted to other provinces, measured in GW; Indicates province At any moment Delivered to provinces The amount of electricity in the system is measured in gigabytes (GW). Indicates province China Power Technology At any moment Storage to energy storage technology The amount of electricity in the system is measured in gigabytes (GW). Indicates province Medium energy storage technology At any moment The energy released is measured in gigabytes (GW). Indicates the cutoff time. ,province Storage technology The total energy in the system, expressed in GWh; Indicates province Medium energy storage technology At any moment The provided reserve capacity is in GW; Indicates province Middle power generation layer At any moment The provided reserve capacity is in GW; Indicates province Middle power generation layer At any moment The load provided is in GW; Indicates province Middle power generation layer At any moment The hourly ramp capacity, in GW; Indicates province Middle power generation layer At any moment The hourly ramp capacity, in GW; This represents a binary variable used to determine the province during non-essential operating periods. Coal-fired power generation technology in the L3 layer is constantly evolving. Is it running? Indicates province substations in China With load center Total annual power transmission volume, in GWh; Indicates province medium substation Levelized cost of trunk lines connected to load centers, in yuan / kW; Indicates province power generation layer At any moment The power generation capacity is expressed in GW. The specific formula for calculating the objective function is as follows:

[0069] (9);

[0070] In this embodiment of the disclosure, combined with Figure 3As shown, the circuit system model including closed mine units is a bottom-up, multi-scale fusion model. Its objective is to minimize the overall construction and operation costs of China's power system. At the spatial unit scale, it combines wind and solar renewable energy generation technologies at the grid unit and closed mine unit scales with traditional power generation technologies at the provincial / regional scale. These technologies include coal-fired combined heat and power (CHP), nuclear power, biomass power generation (BECCS), hydropower, and natural gas power generation (natural gas + CCS). These technologies collectively meet the hourly operational constraints of the power system, including supply-demand balance constraints, reserve capacity constraints, and ramp-up constraints. Based on this, the model optimizes the dispatching and operation of traditional power generation technologies on the supply side, inter-provincial power transmission, and the capacity construction, expansion, dispatching, and spatial layout of renewable energy generation technologies at the spatial grid and closed mine units. This aims to obtain the optimal development potential configuration and spatial layout planning for renewable energy from closed mines in China under the carbon neutrality target. Constraints may include, for example, the following:

[0071] ① Supply and demand balance constraints:

[0072] The electricity demand of each province in each time slot should equal the total electricity supply. The specific formula is as follows:

[0073] (10);

[0074] ②Constraints on wind and solar power generation:

[0075] The power generation utilization of each renewable energy technology at any given moment should be less than or equal to the maximum power generation capacity that the installed capacity of that technology can provide at that moment.

[0076] (11);

[0077] The total area occupied by wind power and photovoltaic power generation cannot exceed the total area of ​​the mining area. The specific constraint function is as follows:

[0078] (12);

[0079] The wind and solar installed capacity of the nine major clean energy bases is subject to constraints, requiring that the wind and solar installed capacity of each province involved in the nine major clean energy bases be greater than or equal to the national wind and solar power deployment plan for these provinces, as shown in Formula 13:

[0080] (13);

[0081] ③ Power supply constraints for fixed units:

[0082] For stationary generating units, the amount of electricity they provide during a time slot should be less than or equal to the maximum transmission capacity of that time slot.

[0083] (14);

[0084] In addition, coal-fired combined heat and power units must meet their minimum output power requirements if they need to be put into operation to meet electricity demand during non-essential operating periods.

[0085] (15);

[0086] (16);

[0087] ④ Constraints on wind and solar grid connection lines:

[0088] The installed capacity of each branch line should be greater than or equal to the maximum power generation of the renewable energy installed capacity of the grid unit or closed mine unit connected to the substation, as shown in the following formula:

[0089] (17);

[0090] (18);

[0091] For the trunk line connecting the substation and the load center during the wind and solar grid connection process, its installed capacity should be greater than or equal to the maximum power transmitted to it by the substation.

[0092] (19);

[0093] ⑤ Constraints on inter-provincial transmission lines:

[0094] At the same time, from the province arrive The sum of the power transmission volume in the two provinces and the power transmission volume in the opposite direction should be less than or equal to the installed capacity of the inter-provincial transmission line between the two provinces. Furthermore, inter-provincial transmission lines connecting the same province should have the same installed capacity regardless of the transmission direction. The specific constraint functions are as follows:

[0095] (20);

[0096] (twenty one);

[0097] For two provinces that already have inter-provincial power transmission lines, the future capacity of their inter-provincial transmission lines should be greater than or equal to the existing installed capacity.

[0098] (twenty two);

[0099] ⑥ Backup capacity requirements:

[0100] Each province must ensure that the sum of all its power sources not only covers its electricity demand but also meets the requirements determined by the capacity marginal factor. The determined reserve capacity. Specific reserve capacity constraints are as follows:

[0101] (twenty three);

[0102] The reserve capacity provided by stationary generating units and energy storage units must be greater than or equal to the wind and solar power supply multiplied by a reserve factor. The reserve capacity constraints for renewable energy units are as follows:

[0103] (twenty four);

[0104] ⑦ Climbing capacity constraint:

[0105] To extend the service life of generating units and reduce power system operating costs, the output variation of stationary generating units over two consecutive time periods is affected by the ramp rate. The limitations are as follows:

[0106] (25);

[0107] (26);

[0108] ⑧ Constraints on energy storage operation:

[0109] The energy storage system is required to store the same amount of energy at the start of the time slice as it stores the energy at the end of the time slice. The specific constraint function is shown below:

[0110] (27);

[0111] The total energy stored by an energy storage system in a time slice is a function of the energy stored in the system during that time slice and the charging / discharging schedule during that time slice. Furthermore, the energy stored in an energy storage system cannot exceed its capacity and storage duration limits. The specific constraint functions are as follows:

[0112] (28);

[0113] (29);

[0114] For any province and any energy storage technology, the amount of discharge at any given moment plus the reserve capacity minus the amount of charging should be less than or equal to its specified capacity.

[0115] (30);

[0116] (31);

[0117] (32);

[0118] Furthermore, at any given moment, the sum of the energy storage system's discharge and the provided reserve capacity should be less than or equal to the total energy stored in the energy storage system at the previous moment. The specific constraint function is as follows:

[0119] (33);

[0120] Based on the existing pumped storage capacity and future pumped storage capacity plans of each province, this model sets the upper and lower limits of the pumped storage capacity for each province using Formula 34:

[0121] (34);

[0122] According to embodiments of this disclosure, the method for developing renewable energy in closed mines further includes calculating the cost of wind and solar power generation in the closed mine unit and calculating the cost of leveling connection of branch lines.

[0123] In this embodiment, a power generation cost model is used to determine the levelized cost of electricity (LCOE) for wind and solar power in each spatial grid unit and closed mine unit, using the wind and solar power generation capacity coefficients of each grid unit and closed mine unit, as well as the corresponding capital investment and operation and maintenance costs, as key parameters. Regarding the calculation of branch line costs for closed mine units: the levelized connection cost of the branch line is calculated based on the transmitted power of the branch line connecting the power generation unit and the substation. Firstly, the capital recovery coefficient is used... Convert the initial investment into an annuity, as shown in Formula 35:

[0124] (35);

[0125] In the formula, This is the actual weighted average cost of capital. This represents the required capital recovery period for the wind and solar project. Next, the levelized cost of the branch lines for each power generation unit is calculated using Equation 36:

[0126] (36);

[0127] In the formula, This represents the capital investment per unit capacity of a transmission line; Average annual capacity factor for wind and solar power generation in each grid cell and closed mine cell; This refers to the loss rate of power transmission lines; It refers to the distance of the branch line connecting the power generation unit and the substation, and 8760 refers to a total of 8760 hours throughout the year.

[0128] The embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. It should be noted that implementations not illustrated or described in the drawings or the main text of the specification are forms known to those skilled in the art and are not described in detail. Furthermore, the definitions of the various elements and methods described above are not limited to the specific structures, shapes, or methods mentioned in the embodiments, and those skilled in the art can easily modify or substitute them.

[0129] Furthermore, unless specifically described or required to occur in a specific order, the order of the above steps is not limited to those listed above and can be varied or rearranged according to the desired design. Moreover, the above embodiments can be used in combination with each other or with other embodiments based on design and reliability considerations; that is, technical features from different embodiments can be freely combined to form more embodiments.

[0130] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A method for developing renewable energy from closed mines, comprising: Calculate the wind and solar capacity coefficients of the closed mining unit, including calculating the wind power capacity coefficient and the photovoltaic power generation capacity coefficient of the closed mining unit; Assess the wind and solar power potential of closed mining units, including assessing the wind power potential and the solar power potential of closed mining units; The grid-based design of wind and solar power grid connection lines for closed mining units includes dividing wind and solar power unit grids based on geographical latitude and longitude information; identifying closed mines within each wind and solar power unit grid as closed mining units and connecting them to the nearest substation in the province via branch lines; and connecting the substation to the nearest major node in the same province via trunk lines while ensuring the shortest total distance for wind and solar power grid connection. The design of the power generation dispatch layer includes allocating annual electricity demand to various types of generating units on the supply side based on a heuristic dispatch sequence, using hours as the time scale. The first layer of the power generation dispatch layer comprises fixed generating units, including nuclear power units, BECCS units, and mandatory CHP-CCS units. Generating units in closed mining units are located in the second layer, which also includes conventional wind and solar power units and offshore wind power units. The third layer includes hydropower units, the fourth layer includes all CHP-CCS units except those mandatory in the first layer, and the fifth layer includes natural gas CCS units. Based on the electricity demand of each province and the power generation of the first layer of the model power generation dispatch layer, the power gap in each province is calculated, and the power gap is gradually filled using the power generation from the second to the fifth layers. as well as A power system model incorporating closed mining units is constructed with the goal of minimizing construction and operation costs. The objective function is established with constraints including supply and demand balance constraints, wind and solar power generation constraints, stationary unit power supply constraints, wind and solar grid connection line constraints, inter-provincial transmission line constraints, reserve capacity demand, ramp-up capacity constraints, and energy storage operation constraints.

2. According to the method for developing renewable energy in closed mines as described in claim 1, the central point of each county or district is used as the spatial location of the substation, all prefecture-level cities and above in the urban agglomeration are positioned as load centers, and the central point of the load center in space is used as the main node of the power grid.

3. The method for developing renewable energy in closed mines according to claim 1 further includes calculating the cost of wind and solar power generation in the closed mine unit and calculating the cost of leveling connection of branch lines.

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