Natural gas and compressed air collaborative energy storage system and method for multiple types of underground spaces

Abstract

The invention discloses a natural gas and compressed air collaborative energy storage system and method for multi-type underground spaces. According to the system, first underground gas storage spaces and second underground gas storage spaces are distributed at intervals; the outlet end of the compressor is connected with the upper end of the first compressed air injection well through a heat exchanger cold side channel. The first air pump is connected with the upper end of the first compressed air recovery well and connected with the inlet end of the expansion machine through a heat exchanger hot side channel. The outlet end of the natural gas compressor connected with the overground gas storage is connected with the natural gas injection well I through an electric control valve; a gas inlet of the overground gas storage is connected with the upper end of the first natural gas recovery well through a second gas pump. The turbine generator is connected with the overground gas storage through a third gas pump and meanwhile connected with the heat exchanger. The method comprises the following steps: in an energy excess period, adopting a strategy of preferentially compressing air energy storage or preferentially compressing natural gas energy storage or alternately storing the compressed air energy storage and the natural gas energy storage at intervals, and in an energy shortage period, adopting a strategy of preferentially generating power or preferentially supplying gas or generating power and simultaneously utilizing natural gas for afterburning and improving efficiency. According to the invention, efficient utilization of energy can be realized.

Description

Technical Field

[0001] This invention belongs to the field of large-scale energy storage and power grid peak shaving technology, specifically a natural gas and compressed air co-storage energy system and method for multiple types of underground spaces. Background Technology

[0002] With the increasing proportion of renewable energy, the volatility of the power grid is intensifying. Compressed air energy storage (CAES) and natural gas storage are two mainstream large-scale energy storage technologies, but they are usually operated independently. Due to national policy initiatives and accelerated urbanization, my country's natural gas consumption has surged, with huge peak-to-valley differences and a natural gas import dependency exceeding 70%. Underground gas storage is the most effective and economical means to ensure gas supply security and address peak-shaving needs, serving as a "buffer" and "stabilizer" to ensure stable absorption of imported resources and cope with sudden interruptions in international gas supplies. my country has the world's largest installed capacity for wind and solar power, but its intermittency and volatility pose challenges to grid stability, urgently requiring large-scale, long-duration energy storage to smooth output and fill peak and valley loads. Energy storage is a key technological support for building a new power system based on new energy sources. Compared to pumped hydro storage, which is limited by geographical conditions, and electrochemical energy storage, which has limited capacity and duration, CAES has advantages such as large scale, long lifespan, and low cost, making it an important development direction. Meanwhile, as a clean energy equipment, CAES is one of the key technological pathways to achieve the goal of "carbon peaking and carbon neutrality".

[0003] Traditional CAES (Cyclic Emission System) relies on specific geological structures (such as salt caverns) and consumes natural gas fuel during power generation, resulting in carbon emissions and high fuel costs. Natural gas storage facilities are primarily used for seasonal peak shaving and cannot directly respond to daily power fluctuations; their vast space and pressure resources remain idle during non-gas extraction periods. Existing technologies mostly target the utilization of single types of underground space. Therefore, there is an urgent need for a new solution to integrate various heterogeneous underground spaces into a unified, efficient, and collaborative energy management platform. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a natural gas and compressed air synergistic energy storage system and method for multiple types of underground spaces. This system has a reasonable structure, low investment cost, and ideal synergistic performance. It can achieve efficient energy utilization and coordinated operation of multiple energy sources, effectively solving the problems of uneven spatial and temporal energy distribution, insufficient system flexibility, and dependence on external fuels. The method is simple to implement, low in cost, highly reliable, and has ideal safety. It can comprehensively utilize various underground spaces such as abandoned oil and gas reservoirs, salt caverns, aquifers, and abandoned mines for natural gas and compressed air energy storage, and can achieve synergistic and complementary gas-electric operation.

[0005] To achieve the above objectives, the present invention provides a multi-type underground space natural gas and compressed air co-storage energy device, including an underground gas storage space I, an underground gas storage space II, an injection-production well network I, and a surface gas-electric co-storage unit. The underground gas storage space one and the underground gas storage space two are distributed alternately and have different space types; The injection-production well network includes a compressed air injection well, a compressed air production well, a natural gas injection well, and a natural gas production well. The compressed air injection well and the compressed air production well are distributed alternately, with their lower ends extending into an underground gas storage space and their upper ends extending above the ground. The natural gas injection well and the natural gas production well are also distributed alternately, with their lower ends extending into an underground gas storage space and their upper ends extending above the ground. The ground-based gas-electric co-generation unit includes an electric motor, an air compressor, a heat exchanger, an expander, a generator, a natural gas compressor, an above-ground gas storage tank, a turbine generator, and an intelligent control terminal. The air compressor is coaxially connected to the electric motor; the inlet end of the cold side channel of the heat exchanger is connected to the outlet end of the air compressor via a pipeline, and the outlet end of the cold side channel of the heat exchanger is connected to the upper end of the first compressed air injection well; the inlet end of the hot side channel of the heat exchanger is connected to the upper end of the first compressed air extraction well via an air pump; the inlet end of the expander is connected to the outlet end of the hot side channel of the heat exchanger via a pipeline; the generator is coaxially connected to the expander; the outlet end of the natural gas compressor is connected to the inlet end of the electronically controlled valve, and the outlet end of the electronically controlled valve is connected to the upper end of the first natural gas injection well; the outlet of the above-ground gas storage is connected to the inlet end of the natural gas compressor via a pipeline, and its inlet is connected to the upper end of the first natural gas extraction well via an air pump; the inlet end of the turbine generator is connected to the outlet of the above-ground gas storage via an air pump, and the turbine generator is connected to the heat exchanger via a heat exchange pipeline. The intelligent control terminal is connected to air pump one, air pump two, air pump three, electric control valve, generator and turbine generator respectively.

[0006] As a preferred option, it also includes three underground gas storage spaces and two injection-production well networks; The second injection-production well network includes a second compressed air injection well, a second compressed air production well, a second natural gas injection well, and a second natural gas production well. The second compressed air injection well, the second compressed air production well, the second natural gas injection well, and the second natural gas production well are distributed alternately, and the lower ends of all four extend into the underground gas storage space three, while the upper ends of all four extend above the ground. Meanwhile, the upper end of compressed air injection well 2 is connected to the outlet end of the cold side channel of the heat exchanger, and the upper end of compressed air production well 2 is connected to the inlet end of the hot side channel of the heat exchanger through air pump 4; the upper end of natural gas injection well 2 is connected to the outlet end of the electric control valve, and the upper end of natural gas production well 2 is connected to the air inlet of the above-ground gas storage through air pump 5; among them, air pump 4 and air pump 5 are both connected to the intelligent control terminal.

[0007] As a preferred option, the first underground gas storage space is a salt cavern or a partially abandoned mine; the second underground gas storage space is an aquifer or a depleted oil and gas reservoir.

[0008] As a preferred option, the third underground gas storage space is a partially intact depleted oil and gas reservoir.

[0009] In this invention, by simultaneously setting up two underground gas storage spaces, one space can be used for storing compressed air, and the other space can be used for storing natural gas. Furthermore, one compressed air injection well and one gas extraction well are set up for underground gas storage space one, and one natural gas injection well and one gas extraction well are set up for underground gas storage space two. This facilitates independent injection and extraction operations for compressed air and natural gas. The upper end of compressed air injection well one is connected to the outlet end of the cold side channel of a heat exchanger on the ground. Simultaneously, the inlet end of the cold side channel of the heat exchanger is connected to the outlet end of an air compressor via a pipeline. This allows not only the air compressor to compress air from the external environment and inject it into underground gas storage space one, but also the simultaneous recovery and storage of heat generated during air compression using the heat exchanger for use in subsequent gas extraction processes. The upper end of compressed air extraction well one is connected to the inlet of the hot-side channel of the heat exchanger via air pump one. This allows air pump one to extract compressed air and output it to the expander via the hot-side channel of the heat exchanger. The heat collected during the previous injection process is used to heat the extracted compressed air, significantly increasing its volume and creating a high-temperature, high-pressure gas. This gas then efficiently drives the expander to power a generator for high-efficiency power generation. A natural gas compressor connected to the above-ground gas storage facility is connected to natural gas injection well one via an electronically controlled valve. This allows the compressor to compress natural gas from the above-ground storage facility and inject it into underground storage space two. The air inlet of the above-ground gas storage facility is connected to the upper end of natural gas extraction well one via air pump two. This allows air pump two to extract natural gas and inject it into the above-ground storage facility. A turbine generator is connected to the above-ground gas storage facility via air pump three. This allows air pump three to extract natural gas from the above-ground storage facility and supply it to the turbine generator for combustion and power generation. By connecting the turbine generator and the heat exchanger through heat exchange pipelines, heat can be recovered through the heat exchanger during the turbine generator's combustion and power generation process, thereby facilitating more efficient heating of the extracted compressed air.

[0010] The system has a reasonable structure, low cost, and ideal collaborative performance. It can achieve efficient energy utilization and coordinated operation of multiple energy sources, effectively solving the problems of uneven spatial and temporal distribution of energy, insufficient system flexibility, and dependence on external fuel.

[0011] This invention also provides a method for co-storing natural gas and compressed air in multiple types of underground spaces, employing a co-storing device for natural gas and compressed air in multiple types of underground spaces, comprising the following steps: Step 1: Based on geological exploration, well logging, and pressure testing data, establish a digital profile for each candidate underground space; Step 2: Based on the multi-objective optimization algorithm, the functions are allocated, and underground gas storage space 1 is designated as the main energy storage space, underground gas storage space 2 as the main gas storage space, and underground gas storage space 3 as a composite space, forming a distributed and collaborative layout scheme. Step 3: Based on the distributed collaborative deployment scheme and the current energy usage status, prioritize and execute multi-mode collaborative operation; S1: If the current period is one of energy surplus and the grid has an urgent need for peak regulation, then control the air compressor to start working and carry out compressed air energy storage operations; S2: If the current period is a period of energy surplus and the gas price is lower than the set price lower limit threshold or natural gas needs to be stored for winter, then control the natural gas compressor to start working and carry out natural gas energy storage operations; S3: If the current period is a period of energy surplus and under normal usage conditions, adopt the intermittent mode to alternately execute S1 and S2 for a set time period; S4: If the current period is one of energy shortage and the power grid has a huge gap, and the electricity price is higher than the set price limit threshold, then control air pump one to start working and release compressed air for power generation; at the same time, control air pump three to start working and start the fuel co-generation mode. S5: If the current period is a period of energy shortage and the demand for gas for residential or industrial use is urgent, natural gas will be released first to supply gas, and gas will be drawn from the above-ground gas storage and fed into the natural gas supply pipeline network. S6: If the current period is an energy shortage period and the demand for electricity and gas is tight, then S4 and S5 will be executed simultaneously, and the execution duration of S4 and S5 will be dynamically adjusted through the intelligent control terminal. Step 4: Cross-cycle energy management; In summer, surplus energy is used to power the second gas pump, extracting natural gas from the second underground gas storage space and injecting it into the above-ground gas storage to prepare gas for winter heating. At the same time, surplus energy is used to power the electric motor, which compresses air and stores it in the first underground gas storage space through the air compressor. As a preferred option, the compressed air energy storage operation in step S1 of step three is performed as follows: The control motor starts working, drives the air compressor to compress the air in the environment in multiple stages, and outputs the compressed air to the cold side channel of the heat exchanger. The heat exchanger recovers and stores the heat, and then the cooled high-pressure air is injected through compressed air injection well one and stored in underground gas storage space one. When the pressure in underground gas storage space one reaches the upper limit threshold one, the cooled air is injected through compressed air injection well two and stored in underground gas storage space three.

[0012] As a preferred option, in step S2 of step three, the natural gas energy storage operation is performed as follows: The natural gas storage operation process is as follows: the natural gas compressor is started to pressurize the natural gas discharged from the above-ground gas storage tank to meet the injection pressure conditions, and then the pressurized natural gas is injected into the underground gas storage space 2 through the natural gas injection well 1 and stored in the underground gas storage space 2; when the pressure in the underground gas storage space 2 reaches the upper limit threshold 2, the pressurized natural gas is injected into the underground gas storage space 3 through the natural gas injection well 2.

[0013] As a preferred embodiment, in step S4 of step three, the process of releasing compressed air to generate electricity is as follows: Once the control air pump starts working, compressed air is extracted through the compressed air extraction well and output to the hot side channel of the heat exchanger. The heat exchanger heats the compressed air, thereby increasing its volume and energy. The compressed air is then sent to the expander, where the heated compressed air drives the expander to power the generator for electricity generation. The fuel co-processing mode is as follows: The fuel co-generation mode is as follows: the control gas pump starts working, extracts part of the natural gas from the above-ground gas storage and transports it to the turbine generator, and generates electricity through combustion.

[0014] To ensure a stable supply of natural gas, in step S5 of step three, when the amount of natural gas in the underground gas storage facility is lower than the set lower limit threshold 1, a natural gas replenishment operation is initiated. The natural gas replenishment process is as follows: control gas pump 2 to start working, extract natural gas from underground gas storage space 2 through natural gas extraction well 1, and transport it to the above-ground gas storage facility until the amount of natural gas in underground gas storage space 2 is lower than the set lower limit threshold 2, or the amount of natural gas in the above-ground gas storage facility is higher than the set upper limit threshold 1, then stop; when the amount of natural gas in underground gas storage space 2 is lower than the set lower limit threshold 2, and the amount of natural gas in the above-ground gas storage facility is lower than the set upper limit threshold 1, control gas pump 5 to start working, extract natural gas from underground gas storage space 3 through natural gas extraction well 2, and transport it to the above-ground gas storage facility until the amount of natural gas in underground gas storage space 2 is lower than the set lower limit threshold 3, or the amount of natural gas in the above-ground gas storage facility is higher than the set upper limit threshold 1, then stop. As a preferred option, in step one, the digital profile includes volume, maximum pressure, sealing performance, permeability, injection-production response characteristics, and geographical location.

[0015] This invention proposes a method for the coordinated energy storage of natural gas and compressed air in multiple types of underground spaces. First, a digital archive is established through underground space exploration to assess resources and allocate functions. This allows for the quantification of gas storage capacity in each underground space using parameters such as volume and pressure, and the prediction of gas leakage risks based on sealing and permeability data, thus preventing safety accidents caused by geological defects. Simultaneously, geographical location information can reduce transportation costs, prioritizing reservoirs near pipelines or power plants. Furthermore, differentiated allocation of underground gas storage spaces based on geological characteristics ensures stability and reliability during energy storage. Next, the priority of electricity and natural gas resource usage is determined based on the current energy consumption situation. During periods of energy surplus, a strategy of prioritizing compressed air energy storage, prioritizing compressed natural gas energy storage, or alternating between the two is adopted. During periods of energy shortage, a strategy of prioritizing power generation, prioritizing gas supply, or using stored natural gas for supplementary combustion and efficiency enhancement while generating electricity is adopted. This enables scientific cross-cycle energy management, maximizing the efficient use of both electricity and gas resources. Furthermore, by simultaneously activating the fuel co-generation mode during the release of compressed air for power generation, power generation efficiency and output power can be significantly improved.

[0016] This invention constructs a distributed underground energy storage system that deeply integrates natural gas storage and compressed air energy storage to address the problems of uneven spatial and temporal energy distribution, insufficient system flexibility, and dependence on external fuels. This aims to improve energy utilization efficiency, ensure system operational flexibility and reliability, and maximize overall benefits. Compared with existing technologies, this invention has the following advantages: 1. Resource integration and cost reduction: It makes full use of various abandoned or natural underground spaces, which greatly reduces the investment cost of building gas storage facilities and CAES power plants separately.

[0017] 2. Synergistic Effect: Achieving a synergistic effect of "1+1>2". Natural gas storage provides CAES power plants with efficient and low-cost on-site fuel, significantly improving power generation efficiency; the rapid response characteristics of CAES power plants provide additional power peak-shaving means for the natural gas supply system.

[0018] 3. Extreme reliability: A multi-backup and linkage system of "new energy - electricity - fuel" has been formed, which significantly improves the resilience, reliability and security of the regional energy system.

[0019] 4. Intelligence and Efficiency: Through core operating strategies, the system solves the problem of optimal scheduling under multiple energy sources and multiple objectives, making the overall operating economy of the composite system far exceed the sum of the independent operation of each part.

[0020] This method is simple to implement, low in cost, highly reliable, and has ideal safety. It can comprehensively utilize various underground spaces such as abandoned oil and gas reservoirs, salt caverns, aquifers, and abandoned mines for natural gas storage and compressed air energy storage, and can achieve coordinated and complementary operation of gas and electricity. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the system portion of the present invention; Figure 2 This is a schematic diagram of the ground-based gas-electric coordinating unit in this invention; Figure 3 This is a schematic diagram of compressed air energy storage during periods of energy surplus in the method of this invention; Figure 4 This is a schematic diagram of natural gas storage during the energy surplus period in the method of this invention; Figure 5 This is a schematic diagram illustrating the coordinated operation of compressed air energy storage and natural gas storage during periods of energy surplus in the method of this invention. Figure 6 This is a schematic diagram of compressed air release during periods of energy shortage in the method of this invention; Figure 7 This is a schematic diagram of natural gas extraction during periods of energy shortage in the method of this invention; Figure 8 This is a schematic diagram illustrating the coordinated operation of compressed air release and natural gas extraction during periods of energy shortage in the method of this invention. In the diagram: 1. Surface gas-electric co-location unit; 2. Underground gas storage space one; 3. Underground gas storage space two; 4. Underground gas storage space three; 5. Compressed air injection well one; 6. Compressed air extraction well one; 7. Natural gas injection well one; 8. Natural gas extraction well one; 9. Electric motor; 10. Air compressor; 11. Heat exchanger; 12. Expander; 13. Generator; 14. Electrically controlled valve; 15. Natural gas compressor; 16. Surface gas storage tank; 17. Turbine generator; 18. Intelligent control terminal; 19. Compressed air injection well two; 20. Compressed air extraction well two; 21. Natural gas injection well two; 22. Natural gas extraction well two. Detailed Implementation

[0022] The invention will now be further described with reference to the accompanying drawings.

[0023] like Figures 1 to 8 As shown, the present invention provides a multi-type underground space natural gas and compressed air co-storage energy device, including an underground gas storage space 1 2, an underground gas storage space 2 3, an injection and production well network 1 and a surface gas-electric co-storage unit 1; The underground gas storage space 1 and underground gas storage space 2 are distributed alternately and have different space types. The injection-production well network includes compressed air injection well 5, compressed air production well 6, natural gas injection well 7, and natural gas production well 8. The compressed air injection well 5 and compressed air production well 6 are distributed alternately, with their lower ends extending into the underground gas storage space 2 and their upper ends extending above the ground. The natural gas injection well 7 and natural gas production well 8 are distributed alternately, with their lower ends extending into the underground gas storage space 3 and their upper ends extending above the ground. The ground gas-electric co-operation unit 1 includes an electric motor 9, an air compressor 10, a heat exchanger 11, an expander 12, a generator 13, a natural gas compressor 15, an above-ground gas storage tank 16, a turbine generator 17, and an intelligent control terminal 18. The air compressor 10 is coaxially connected to the motor 9; the inlet end of the cold side channel of the heat exchanger 11 is connected to the outlet end of the air compressor 10 via a pipeline, and the outlet end of the cold side channel of the heat exchanger 11 is connected to the upper end of the compressed air injection well 5; the inlet end of the hot side channel of the heat exchanger 11 is connected to the upper end of the compressed air sampling well 6 via an air pump; the inlet end of the expander 12 is connected to the outlet end of the hot side channel of the heat exchanger 11 via a pipeline; the generator 13 is coaxially connected to the expander 12. The outlet end of the natural gas compressor 15 is connected to the inlet end of the electronically controlled valve 14, and the outlet end of the electronically controlled valve 14 is connected to the upper end of the natural gas injection well 7. The outlet of the above-ground gas storage 16 is connected to the inlet end of the natural gas compressor 15 through a pipeline, and its inlet is connected to the upper end of the natural gas extraction well 8 through a second gas pump. The inlet end of the turbine generator 17 is connected to the outlet of the above-ground gas storage 16 through a third gas pump. At the same time, the turbine generator 17 is connected to the heat exchanger 11 through a heat exchange pipeline. The intelligent control terminal 18 is connected to air pump 1, air pump 2, air pump 3, electric control valve 14, generator 13 and turbine generator 17 respectively.

[0024] As a preferred option, it also includes underground gas storage space 3-4 and injection-production well network 2; The second injection-production well network includes compressed air injection well 29, compressed air production well 20, natural gas injection well 21, and natural gas production well 22. These wells are distributed alternately, with their lower ends extending into the underground gas storage space 3 4, and their upper ends extending above ground level. When all four wells exist simultaneously, a central isolation zone can be provided within the underground gas storage space 3 4 to divide it into an air storage space and a natural gas storage space, facilitating independent zoned storage of air and natural gas. Meanwhile, the upper end of compressed air injection well 219 is connected to the outlet end of the cold side channel of heat exchanger 11, and the upper end of compressed air production well 20 is connected to the inlet end of the hot side channel of heat exchanger 11 through air pump 4; the upper end of natural gas injection well 21 is connected to the outlet end of electric control valve 14, and the upper end of natural gas production well 22 is connected to the air inlet of above-ground gas storage 16 through air pump 5; wherein, air pump 4 and air pump 5 are both connected to intelligent control terminal 18.

[0025] As a preferred embodiment, the underground gas storage space 2 is a salt cavern or a partially abandoned mine; the underground gas storage space 3 is an aquifer or a depleted oil and gas reservoir.

[0026] As a preferred option, the underground gas storage space 34 is a partially intact depleted oil and gas reservoir.

[0027] In this invention, by simultaneously setting up two underground gas storage spaces, one space can be used for storing compressed air, and the other space can be used for storing natural gas. Furthermore, one compressed air injection well and one gas extraction well are set up for underground gas storage space one, and one natural gas injection well and one gas extraction well are set up for underground gas storage space two. This facilitates independent injection and extraction operations for compressed air and natural gas. The upper end of compressed air injection well one is connected to the outlet end of the cold side channel of a heat exchanger on the ground. Simultaneously, the inlet end of the cold side channel of the heat exchanger is connected to the outlet end of an air compressor via a pipeline. This allows not only the air compressor to compress air from the external environment and inject it into underground gas storage space one, but also the simultaneous recovery and storage of heat generated during air compression using the heat exchanger for use in subsequent gas extraction processes. The upper end of compressed air extraction well one is connected to the inlet of the hot-side channel of the heat exchanger via air pump one. This allows air pump one to extract compressed air and output it to the expander via the hot-side channel of the heat exchanger. The heat collected during the previous injection process is used to heat the extracted compressed air, significantly increasing its volume and creating a high-temperature, high-pressure gas. This gas then efficiently drives the expander to power a generator for high-efficiency power generation. A natural gas compressor connected to the above-ground gas storage facility is connected to natural gas injection well one via an electronically controlled valve. This allows the compressor to compress natural gas from the above-ground storage facility and inject it into underground storage space two. The air inlet of the above-ground gas storage facility is connected to the upper end of natural gas extraction well one via air pump two. This allows air pump two to extract natural gas and inject it into the above-ground storage facility. A turbine generator is connected to the above-ground gas storage facility via air pump three. This allows air pump three to extract natural gas from the above-ground storage facility and supply it to the turbine generator for combustion and power generation. By connecting the turbine generator and the heat exchanger through heat exchange pipelines, heat can be recovered through the heat exchanger during the turbine generator's combustion and power generation process, thereby facilitating more efficient heating of the extracted compressed air.

[0028] The system has a reasonable structure, low cost, and ideal collaborative performance. It can achieve efficient energy utilization and coordinated operation of multiple energy sources, effectively solving the problems of uneven spatial and temporal distribution of energy, insufficient system flexibility, and dependence on external fuel.

[0029] This invention also provides a method for co-storing natural gas and compressed air in multiple types of underground spaces, employing a co-storing device for natural gas and compressed air in multiple types of underground spaces, comprising the following steps: Step 1: Preparation, such as Figure 1 As shown, a digital archive is established for each candidate underground space based on geological exploration, well logging, and pressure testing data; Step 2: Evaluation and Functional Allocation; Based on a multi-objective optimization algorithm, functional allocation is performed, with underground gas storage space 1-2 as the main energy storage space, underground gas storage space 2-3 as the main gas storage space, and underground gas storage space 3-4 as a composite space, forming the optimal distributed and coordinated layout scheme. Step 3: Based on the distributed collaborative deployment scheme and the current energy usage status, prioritize and execute multi-mode collaborative operation; S1: If the current period is a period of energy surplus and the grid has an urgent need for peak regulation (such as a predicted peak the next day), then control the air compressor 10 to start working in order to prioritize compressed air energy storage operations; S2: If the current period is a period of energy surplus and the gas price is lower than the set price lower limit threshold or natural gas needs to be stored for winter, control the natural gas compressor 14 to start working in order to prioritize natural gas energy storage operations; S3: If the current period is one of energy surplus and the system is operating under normal conditions, an intermittent alternation mode is adopted, with S1 and S2 executed alternately over a set time period (preferably 2 hours). This balances the grid load and simultaneously stores both types of energy, achieving "gas-electricity dual storage," as shown below. Figure 5 As shown; S4: If the current period is one of energy shortage and the power grid has a huge gap, and the electricity price is higher than the set price limit threshold, then control the air pump one to start working, so as to release compressed air for power generation; at the same time, control the air pump three to start working, and start the fuel co-generation mode. S5: If the current period is a period of energy shortage and the demand for gas for residential or industrial use is urgent, natural gas will be released first for gas supply, and gas will be drawn from the above-ground gas storage 16 and fed into the natural gas supply pipeline network. S6: If the current period is an energy shortage period and the demand for electricity and gas is tight, then S4 and S5 will be executed simultaneously, and the execution duration of S4 and S5 will be dynamically adjusted through the intelligent control terminal 18. Step 4: Cross-cycle energy management; In summer, surplus energy is used to power the second gas pump, extracting natural gas from the second underground gas storage space 3 and injecting it into the above-ground gas storage 16 to prepare gas for winter heating. At the same time, surplus energy is used to power the electric motor 9, which compresses air through the air compressor 10 and stores it in the first underground gas storage space 2. Preferably, in extreme cases, the stored natural gas can be regarded as a "strategic reserve fuel" for the entire energy system, ensuring long-term, high-power output of the CAES power plant and enhancing regional energy security; As a preferred option, the compressed air energy storage operation in step S1 of step three is performed as follows: like Figure 2 , Figure 3As shown, the control motor 9 starts working, driving the air compressor 10 to compress the air in the environment in multiple stages (the temperature of the air will rise sharply after compression), and outputs the compressed air to the cold side channel of the heat exchanger 11. The heat exchanger 11 recovers heat and stores it. This process realizes the cooling operation of the high-pressure air. The cooled high-pressure air is then injected into the underground gas storage space 2 through the compressed air injection well 5. When the pressure in the underground gas storage space 2 reaches the upper limit threshold 1, the cooled air is injected into the underground gas storage space 4 through the compressed air injection well 2.

[0030] As a preferred option, in step S2 of step three, the natural gas energy storage operation is performed as follows: The natural gas energy storage operation process is as follows: Figure 2 , Figure 4 As shown, the natural gas compressor 15 is started to pressurize the natural gas discharged from the above-ground gas storage 16 to meet the injection pressure conditions. The pressurized natural gas is then injected into the underground gas storage space 3 through the natural gas injection well 7. When the pressure in the underground gas storage space 3 reaches the upper limit threshold 2, the pressurized natural gas is injected into the underground gas storage space 4 through the natural gas injection well 21.

[0031] As a preferred embodiment, in step S4 of step three, the process of releasing compressed air to generate electricity is as follows: like Figure 2 , Figure 6 As shown, once the air pump is started, compressed air is extracted through the compressed air extraction well 6 and output to the hot side channel of the heat exchanger 11. The heat exchanger 11 heats the compressed air, thereby increasing its volume and energy. The compressed air is then sent to the expander 12, and the heated compressed air drives the expander 12 to drive the generator 13 to generate electricity. The fuel co-processing mode is as follows: The fuel co-generation mode is as follows: the control gas pump starts working, extracts part of the natural gas from the above-ground gas storage 16 and transports it to the turbine generator 17, and generates electricity through combustion. In this way, it can be transformed from non-supplementary combustion CAES to supplementary combustion CAES, and the power generation and efficiency can be increased by more than 30%.

[0032] To ensure a stable supply of natural gas, in step S5 of step three, when the amount of natural gas in the ground gas storage 16 falls below a set lower limit threshold, a natural gas replenishment operation is initiated. The natural gas replenishment process is as follows: Figure 2 , Figure 7As shown, the control pump 2 starts working, extracting natural gas from underground gas storage space 3 through natural gas extraction well 8 and transporting it to the above-ground gas storage 16, until the amount of natural gas in underground gas storage space 3 is lower than the set lower limit threshold 2, or the amount of natural gas in above-ground gas storage 16 is higher than the set upper limit threshold 1; when the amount of natural gas in underground gas storage space 3 is lower than the set lower limit threshold 2, and the amount of natural gas in above-ground gas storage 16 is lower than the set upper limit threshold 1, the control pump 5 starts working, extracting natural gas from underground gas storage space 4 through natural gas extraction well 22 and transporting it to the above-ground gas storage 6, until the amount of natural gas in underground gas storage space 3 is lower than the set lower limit threshold 3, or the amount of natural gas in above-ground gas storage 16 is higher than the set upper limit threshold 1; As a preferred option, in step one, the digital profile includes volume, maximum pressure, sealing performance, permeability, injection-production response characteristics, and geographical location.

[0033] This invention proposes a method for the coordinated energy storage of natural gas and compressed air in multiple types of underground spaces. First, a digital archive is established through underground space exploration to assess resources and allocate functions. This allows for the quantification of gas storage capacity in each underground space using parameters such as volume and pressure, and the prediction of gas leakage risks based on sealing and permeability data, thus preventing safety accidents caused by geological defects. Simultaneously, geographical location information can reduce transportation costs, prioritizing reservoirs near pipelines or power plants. Furthermore, differentiated allocation of underground gas storage spaces based on geological characteristics ensures stability and reliability during energy storage. Next, the priority of electricity and natural gas resource usage is determined based on the current energy consumption situation. During periods of energy surplus, a strategy of prioritizing compressed air energy storage, prioritizing compressed natural gas energy storage, or alternating between the two is adopted. During periods of energy shortage, a strategy of prioritizing power generation, prioritizing gas supply, or using stored natural gas for supplementary combustion and efficiency enhancement while generating electricity is adopted. This enables scientific cross-cycle energy management, maximizing the efficient use of both electricity and gas resources. Furthermore, by simultaneously activating the fuel co-generation mode during the release of compressed air for power generation, power generation efficiency and output power can be significantly improved.

[0034] This invention constructs a distributed underground energy storage system that deeply integrates natural gas storage and compressed air energy storage to address the problems of uneven spatial and temporal energy distribution, insufficient system flexibility, and dependence on external fuels. This aims to improve energy utilization efficiency, ensure system operational flexibility and reliability, and maximize overall benefits. Compared with existing technologies, this invention has the following advantages: 1. Resource integration and cost reduction: It makes full use of various abandoned or natural underground spaces, which greatly reduces the investment cost of building gas storage facilities and CAES power plants separately.

[0035] 2. Synergistic Effect: Achieving a synergistic effect of "1+1>2". Natural gas storage provides CAES power plants with efficient and low-cost on-site fuel, significantly improving power generation efficiency; the rapid response characteristics of CAES power plants provide additional power peak-shaving means for the natural gas supply system.

[0036] 3. Extreme reliability: A multi-backup and linkage system of "new energy - electricity - fuel" has been formed, which significantly improves the resilience, reliability and security of the regional energy system.

[0037] 4. Intelligence and Efficiency: Through core operating strategies, the system solves the problem of optimal scheduling under multiple energy sources and multiple objectives, making the overall operating economy of the composite system far exceed the sum of the independent operation of each part.

[0038] This method is simple to implement, low in cost, highly reliable, and has ideal safety. It can comprehensively utilize various underground spaces such as abandoned oil and gas reservoirs, salt caverns, aquifers, and abandoned mines for natural gas storage and compressed air energy storage, and can achieve coordinated and complementary operation of gas and electricity.

Claims

1. A multi-type underground space natural gas and compressed air co-storage energy device, comprising an underground gas storage space (2), characterized in that, It also includes underground gas storage space 2 (3), injection and production well network 1 and surface gas-electricity co-operation unit (1); The underground gas storage space one (2) and the underground gas storage space two (3) are distributed alternately and have different space types; The injection and production well network includes compressed air injection well one (5), compressed air production well one (6), natural gas injection well one (7) and natural gas production well one (8); the compressed air injection well one (5) and compressed air production well one (6) are distributed alternately, with their lower ends extending into underground gas storage space one (2) and their upper ends extending above the ground; the natural gas injection well one (7) and natural gas production well one (8) are distributed alternately, with their lower ends extending into underground gas storage space two (3) and their upper ends extending above the ground; The ground gas-electric co-operation unit (1) includes an electric motor (9), an air compressor (10), a heat exchanger (11), an expander (12), a generator (13), a natural gas compressor (15), an above-ground gas storage tank (16), a turbine generator (17), and an intelligent control terminal (18). The air compressor (10) is coaxially connected to the motor (9); the inlet end of the cold side channel of the heat exchanger (11) is connected to the outlet end of the air compressor (10) through a pipeline, and the outlet end of the cold side channel of the heat exchanger (11) is connected to the upper end of the compressed air injection well (5); the inlet end of the hot side channel of the heat exchanger (11) is connected to the upper end of the compressed air extraction well (6) through an air pump; the inlet end of the expander (12) is connected to the outlet end of the hot side channel of the heat exchanger (11) through a pipeline; the generator (13) is coaxially connected to the expander (12). The outlet of the natural gas compressor (15) is connected to the inlet of the electric control valve (14), and the outlet of the electric control valve (14) is connected to the upper end of the natural gas injection well (7). The outlet of the above-ground gas storage (16) is connected to the inlet of the natural gas compressor (15) through a pipeline, and its inlet is connected to the upper end of the natural gas extraction well (8) through a second gas pump. The inlet of the turbine generator (17) is connected to the outlet of the above-ground gas storage (16) through a third gas pump. At the same time, the turbine generator (17) is connected to the heat exchanger (11) through a heat exchange pipeline. The intelligent control terminal (18) is connected to air pump one, air pump two, air pump three, electric control valve (14), generator (13) and turbine generator (17), respectively.

2. The natural gas and compressed air co-storage energy storage device for multiple types of underground spaces according to claim 1, characterized in that, It also includes underground gas storage space three (4) and injection-production well network two; The second injection and production well network includes a second compressed air injection well (19), a second compressed air production well (20), a second natural gas injection well (21), and a second natural gas production well (22). The second compressed air injection well (19), the second compressed air production well (20), the second natural gas injection well (21), and the second natural gas production well (22) are distributed alternately, and the lower ends of all four extend into the third underground gas storage space (4), and the upper ends of all four extend above the ground. Meanwhile, the upper end of compressed air injection well 2 (19) is connected to the outlet end of the cold side channel of heat exchanger (11), and the upper end of compressed air production well 2 (20) is connected to the inlet end of the hot side channel of heat exchanger (11) through air pump 4; the upper end of natural gas injection well 2 (21) is connected to the outlet end of electric control valve (14), and the upper end of natural gas production well 2 (22) is connected to the air inlet of above-ground gas storage tank (16) through air pump 5; among them, air pump 4 and air pump 5 are both connected to intelligent control terminal (18).

3. A multi-type underground space natural gas and compressed air co-storage energy device according to claim 1 or 2, characterized in that, The first underground gas storage space (2) is a salt cavern or a partially abandoned mine; the second underground gas storage space (3) is an aquifer or a depleted oil and gas reservoir.

4. A natural gas and compressed air co-storage energy storage device for multiple types of underground spaces according to claim 3, characterized in that, The underground gas storage space three (4) is a partially intact depleted oil and gas reservoir.

5. A method for co-storing natural gas and compressed air in multi-type underground spaces, employing a co-storing natural gas and compressed air device for multi-type underground spaces as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Step 1: Based on geological exploration, well logging, and pressure testing data, establish a digital profile for each candidate underground space; Step 2: Based on the multi-objective optimization algorithm, the functions are allocated, and the underground gas storage space 1 (2) is used as the main energy storage space, the underground gas storage space 2 (3) is used as the main gas storage space, and the underground gas storage space 3 (4) is used as the composite space to form a distributed collaborative layout scheme. Step 3: Based on the distributed collaborative deployment scheme and the current energy usage status, prioritize and execute multi-mode collaborative operation; S1: If the current period is a period of energy surplus and the demand for grid peak regulation is urgent, then control the air compressor (10) to start working and carry out compressed air energy storage operation; S2: If the current period is an energy surplus period and the gas price is lower than the set price lower limit threshold or natural gas needs to be stored for winter, then control the natural gas compressor (14) to start working and carry out natural gas energy storage operations; S3: If the current period is a period of energy surplus and under normal usage conditions, adopt the intermittent mode to alternately execute S1 and S2 for a set time period; S4: If the current period is one of energy shortage and the power grid has a huge gap, and the electricity price is higher than the set price limit threshold, then control air pump one to start working and release compressed air for power generation; at the same time, control air pump three to start working and start the fuel co-generation mode. S5: If the current period is a period of energy shortage and the demand for gas for residential or industrial use is urgent, natural gas will be released first for gas supply, and gas will be drawn from the above-ground gas storage (16) and fed into the natural gas supply pipeline network. S6: If the current period is an energy shortage period and the demand for electricity and gas is tight, then S4 and S5 will be executed simultaneously, and the execution time of S4 and S5 will be dynamically adjusted through the intelligent control terminal (18). Step 4: Cross-cycle energy management; In summer, surplus energy is used to power the second gas pump, and natural gas in the second underground gas storage space (3) is extracted and injected into the above-ground gas storage (16) to prepare gas for winter heating. At the same time, surplus energy is used to power the electric motor (9), and air is compressed and stored in the first underground gas storage space (2) through the air compressor (10).

6. The natural gas and compressed air co-storage system for multiple types of underground spaces according to claim 5, characterized in that, In step S1 of step three, the compressed air energy storage operation is performed as follows: The control motor (9) starts working and drives the air compressor (10) to compress the air in the environment in multiple stages. The compressed air is output to the cold side channel of the heat exchanger (11). The heat exchanger (11) recovers heat and stores it. The cooled high-pressure air is injected through the compressed air injection well one (5) and stored in the underground gas storage space one (2). When the pressure in the underground gas storage space one (2) reaches the upper limit threshold one, the cooled air is injected through the compressed air injection well two (19) and stored in the underground gas storage space three (4).

7. The natural gas and compressed air co-storage system for multiple types of underground spaces according to claim 5, characterized in that, In step S2 of step three, the natural gas energy storage operation is carried out as follows: The natural gas storage operation process is as follows: the natural gas compressor (15) is started to pressurize the natural gas discharged from the above-ground gas storage (16) to meet the injection pressure conditions, and then the pressurized natural gas is injected through the first natural gas injection well (7) and stored in the second underground gas storage space (3); when the pressure in the second underground gas storage space (3) reaches the upper limit threshold 2, the pressurized natural gas is injected through the second natural gas injection well (21) and stored in the third underground gas storage space (4).

8. The natural gas and compressed air co-storage system for multiple types of underground spaces according to claim 5, characterized in that, In step S4 of step three, the process of releasing compressed air to generate electricity is as follows: Once the control air pump starts working, compressed air is extracted through the compressed air extraction well (6) and output to the hot side channel of the heat exchanger (11). The heat exchanger (11) heats the compressed air, thereby increasing the volume and energy of the compressed air. It is then transported to the expander (12). The heated compressed air drives the expander (12) to drive the generator (13) to generate electricity. The fuel co-processing mode is as follows: The fuel co-processing mode is as follows: the control gas pump starts working, extracts part of the natural gas from the above-ground gas storage (16) and transports it to the turbine generator (17) to generate electricity through combustion.

9. A method for co-storage of natural gas and compressed air in multi-type underground spaces according to claim 5, characterized in that, In step S5 of step three, when the amount of natural gas in the underground gas storage (16) is lower than the set lower limit threshold one, the natural gas replenishment operation is started. The natural gas replenishment process is as follows: control the gas pump two to start working, extract natural gas from the underground gas storage space two (3) through the natural gas extraction well one (8), and transport it to the above-ground gas storage (16) until the amount of natural gas in the underground gas storage space two (3) is lower than the set lower limit threshold two, or the amount of natural gas in the above-ground gas storage (16) is higher than the set upper limit threshold one, then stop. When the amount of natural gas in underground gas storage space 2 (3) is lower than the set lower limit threshold 2, and the amount of natural gas in above-ground gas storage (16) is lower than the set upper limit threshold 1, control gas pump 5 to start working, extract natural gas from underground gas storage space 3 (4) through natural gas extraction well 2 (22), and transport it to above-ground gas storage (6) until the amount of natural gas in underground gas storage space 2 (3) is lower than the set lower limit threshold 3, or the amount of natural gas in above-ground gas storage (16) is higher than the set upper limit threshold 1, then stop.

10. A method for co-storage of natural gas and compressed air in multi-type underground spaces according to claim 5, characterized in that, In step one, the digital profile includes volume, maximum pressure, sealing performance, permeability, injection-production response characteristics, and geographical location.

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