Carbon dioxide salt cavern energy storage method and installed capacity calculation method

Abstract

The invention provides a carbon dioxide salt cavern energy storage method and an installed capacity calculation method, and the method comprises the following steps: S1, site selection and parameter acquisition of a cavern: selecting a proper underground salt layer structure, building a salt cavern storage, and constructing a carbon dioxide salt cavern energy storage mode; s2, injecting and releasing an energy storage medium, establishing an energy efficiency calculation model of carbon dioxide salt cavern energy storage, and calculating the energy storage capacity and efficiency of the salt cavern under different pressure working conditions; and S3, based on the required energy storage scale and the target power output, establishing a calculation model of the installed capacity, and performing operation control on the system according to the design parameters. The invention aims to provide a carbon dioxide salt cavern energy storage method and an installed capacity calculation method so as to solve the problem that a carbon dioxide salt cavern energy storage efficiency and scale evaluation and installed capacity scientific design method is lacked in the prior art.

Description

Technical Field

[0001] This invention relates to the fields of energy storage and carbon dioxide geological storage technology, specifically to a carbon dioxide salt cavern energy storage method and a method for calculating installed capacity. Background Technology

[0002] With the large-scale development of renewable energy and the increasing demand for carbon emission reduction, how to efficiently store energy and reduce carbon dioxide emissions has become an urgent technical problem to be solved. Compressed air energy storage (CAES) is one of the more mature physical energy storage methods, which typically uses underground salt caverns as storage containers. However, traditional CAES systems suffer from low efficiency (the total efficiency of conventional combustion-heated CAES is about 50%) and require additional fossil fuels for auxiliary heating during operation, making it difficult to achieve true zero carbon emissions. Meanwhile, carbon dioxide capture, utilization and storage (CCUS) technology is considered one of the important ways to achieve large-scale emission reduction, but the process of geologically storing captured CO2 (such as in saline aquifers or depleted oil and gas reservoirs) itself does not generate additional benefits and often requires additional cost investment.

[0003] Underground salt caverns, due to their vast usable space, self-healing creep properties, and excellent sealing performance, have been widely used in natural gas storage and compressed air energy storage, making them a mature underground storage solution. Recent research has proposed injecting CO2 into salt caverns as the working medium to achieve synergy between energy storage and CO2 sequestration: compressing and injecting CO2 to store energy when there is a power surplus, and releasing CO2 to drive turbines for power generation when there is a power demand. This concept of "Compressed CO2 Energy Storage" (CCES) organically combines CO2 geological storage and energy storage, and is considered to offer significant improvements in both energy efficiency and environmental benefits. Preliminary research results indicate that, under the same operating conditions, the energy storage efficiency of CCES systems is expected to be significantly higher than that of traditional CAES, and the long-term sealing and stability of the surrounding rock of the salt cavern can also be well maintained during periodic CO2 injection / extraction operations.

[0004] However, to date, there is a lack of engineering practice regarding large-scale CO2 storage in salt caverns for energy storage in a cyclic manner, and related theoretical research and design methods are still insufficient. On the one hand, there is a lack of system calculation principles and evaluation methods for the efficiency and feasible scale of CO2 storage in salt caverns, making it difficult to clarify the energy scale and efficiency indicators that can be stored under specific salt cavern conditions. On the other hand, there are currently no mature models and methods to guide the scientific determination of the installed capacity (such as the power specifications of the compressor and expander) of this new CCES system and the setting of key operating parameters. These problems make it impossible to accurately balance system efficiency, storage scale, and equipment configuration in actual engineering design, thus hindering the promotion and application of CO2 storage technology in salt caverns. Therefore, it is necessary to provide a new technical solution to clarify the calculation methods for the efficiency and scale of CO2 storage in salt caverns for energy storage, and to establish corresponding installed capacity calculation models and parameter selection principles to guide engineering implementation. Summary of the Invention

[0005] To address the problems in the prior art, this invention provides a method for carbon dioxide salt cavern energy storage and a method for calculating installed capacity, thereby solving the problem of the lack of methods for evaluating the efficiency and scale of CO2 salt cavern energy storage and for scientifically designing the installed capacity in the prior art.

[0006] The technical problem solved by this invention is achieved by the following technical solution:

[0007] The first objective of this invention is to provide a method for carbon dioxide salt cavern energy storage, comprising the following steps:

[0008] S1. Salt cavern construction and parameter setting: Select salt caverns with good surrounding rock sealing and structural integrity, and retain the thickness h of the top salt rock layer. top ≥20m;

[0009] S2. Energy Storage Medium Injection and Release: Based on the required energy storage scale and target power output, establish a calculation model for the installed capacity to determine the power and specifications of the compressor unit and expander unit; use the captured CO2 as the working medium and pressurize it to the target maximum pressure P via the compressor. max Energy is stored in salt caverns; when energy needs to be released, an expander reduces the CO2 pressure inside the salt cavern to the minimum operating pressure P. min Power generation;

[0010] S3. Operation Control and Recycling:

[0011] When storing energy, CO2 is first injected into P. min Formation of air in the pillow cushion;

[0012] In power grid peak-valley regulation, a cyclic operation is performed: when there is a power surplus, the compressor is started to boost CO2 to P at a rate of ≤10MPa / h. maxSalt caverns are injected; during peak electricity demand, expanders are activated to depressurize high-pressure CO2 to Pmin at a rate of ≤10MPa / h and release it from the salt caverns to drive generators to generate electricity.

[0013] Furthermore, the salt caverns are selected with a burial depth H of 1000–1500 m, and the effective volume V0 of a single cavity is not less than 40–50 × 10⁻⁶ m. 4 m 3 P min ≥0.2σ0, P max ≤0.8σ0.

[0014] Furthermore, P min ≥0.6σ0, P max ≤0.8σ0.

[0015] Furthermore, P min P is 0.7σ0. max It is 0.8σ0.

[0016] Furthermore, the energy storage capacity in step S2 is calculated according to the following formula:

[0017] ΔE=nRT c ln(P max / P min ), where n is the amount of CO2 participating in the cycle, R is the gas constant, and T c The operating temperature of the salt cavern is approximated by the ground temperature of the salt layer.

[0018] Furthermore, the energy storage system also includes a high-temperature heat storage tank. The heat generated during the CO2 compression process is stored in this tank. During expansion, the residual heat from compression stored in the tank is used to heat the CO2 at the expander inlet. By using the high-temperature heat storage tank, the heat of compression is effectively stored and used for expansion reheat, minimizing heat loss and significantly improving cycle efficiency from approximately 45% without heat storage to 70% with heat storage.

[0019] Furthermore, the annual cycle number of power grid peak-valley regulation cycles is ≤200 times.

[0020] Furthermore, during energy storage release, each cycle retains P after energy storage release. min The CO2 remaining in the salt cavern due to pressure replenishes the losses from leakage before the next cycle begins. This helps maintain stable pressure within the salt cavern while achieving considerable carbon reserves, and avoids the impact of frequent complete decompression on the sealing of the surrounding rock.

[0021] The second objective of this invention is to provide a method for calculating the installed capacity of the above-mentioned energy storage method, characterized by comprising the following steps:

[0022] S1, Set the time t for the salt cavern to fill with CO2. c CO2 extraction time t d compressor efficiency η c And expander efficiency η t ; Calculate the storage capacity of the salt cavern ΔE = nRT c ln(P max / P min ), where n is the amount of CO2 participating in the cycle, R is the gas constant, and T c The operating temperature of the salt cavern is approximated by the ground temperature of the salt layer;

[0023] S2. Determine the target storage capacity compared to the storage capacity calculated in step S1. If the target storage capacity is greater than the calculated storage capacity, then select a salt cavern with a larger effective capacity and adjust the pressure P. max Adjust the scheme by selecting multiple salt cavern chambers in parallel, and recalculate S1 until the target storage capacity is less than or equal to the calculated storage capacity.

[0024] S3. Take the ΔE obtained in step S1 as the energy E released during extraction. out Based on energy storage scale E out and discharge time t d Calculate the power P of the expander t :P t =E out / t d And according to the expander efficiency η t Perform correction;

[0025] Based on energy storage scale E in and charging time t c Calculate compressor power: P c =E in / t c Considering the compressor efficiency η c The system loss η is corrected, where E in =E out / η;

[0026] S4. Calculate the efficiency of the single-cycle system through system simulation evaluation. If the system efficiency is >60%–70%, proceed to the next step; otherwise, E. out If the target requirements are not met, return to S1 and modify each parameter again;

[0027] S5, Output Results.

[0028] Furthermore, P max / P min The ratio is greater than 1.2.

[0029] Furthermore, when multiple salt caverns are used in parallel for injection and production, the installed capacity is corrected by the pressure loss compensation coefficient K, where K = 1.05 + 0.05(N-1), and N is the number of salt caverns, and K is 1.1 to 1.2.

[0030] The calculation model also includes the following parameter setting principles: (a) The operating pressure range should be set as high as possible while ensuring the stability of the surrounding rock. max / P min (a) When the capacity of a single salt cavern is insufficient, multiple salt caverns can be connected in parallel, and the energy storage scale can be increased approximately multiple times the number of chambers. The installed capacity will increase accordingly, taking into account the pressure loss of the parallel manifold; (b) The injection / production pipe diameter and wellbore design should meet the maximum flow requirements to ensure that the target pressure change is achieved within the set charging and discharging time; (c) If necessary, a heat storage system should be configured to store waste heat during CO2 compression and compensate for the cooling of CO2 during expansion power generation, thereby improving the system recovery efficiency. Through the above model calculations and parameter selection, the rated power and quantity of the main equipment such as the compressor and expander (generator), as well as the key parameters of the auxiliary systems such as heat exchangers and pipelines, can be obtained.

[0031] Preferred, P max / P min It ranges from 1.8 to 2.5.

[0032] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0033] This invention achieves synergy between energy storage and carbon sequestration by injecting CO2 as an energy storage medium into a sealed salt cavern. On the one hand, the high-density, low-permeability geological space of the salt cavern allows for large-scale storage of compressed CO2, resulting in energy storage capacity per unit volume far exceeding that under normal pressure conditions, significantly improving energy storage efficiency and energy density. On the other hand, the established installed capacity calculation model provides a basis for equipment selection and parameter configuration, enabling the rational determination of compressor and expander power based on the expected energy storage scale, ensuring safe and efficient system operation. Compared with traditional CAES technology, this invention achieves higher energy storage efficiency and lower carbon emissions under the same operating conditions, realizing the dual benefits of energy storage and greenhouse gas emission reduction. Furthermore, the long-term recycling of CO2 within the salt cavern transforms it from a stored "waste" into a reusable energy carrier; when the energy storage chamber reaches the end of its lifespan, the remaining CO2 can still be sealed in the salt cavern, further contributing to carbon emission reduction. Therefore, this invention has good economic and environmental benefits and is suitable for peak-shaving energy storage in new energy power systems and large-scale applications in the CCUS field.

[0034] This invention employs a periodic injection-production mode and optimizes the injection-production frequency and pressure variation range to reduce the cumulative deformation and leakage risk of the surrounding rock and extend the safe operating life of the salt cavern storage. Under long-term repeated operation, it can stably maintain the sealing and structural integrity of the salt cavern, while efficiently completing the storage and release of energy in the CO2 medium.

[0035] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0036] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0037] Figure 1 This is a schematic diagram of the cavity compression and energy storage process.

[0038] Figure 2 This is a schematic diagram of the energy release process in the cavity.

[0039] Figure 3 This is a diagram showing the phased changes in cavity pressure during the compression and energy release processes.

[0040] Figure 4 This is a graph showing the change in carbon dioxide storage density within the cavity during the compression and release phases.

[0041] Figure 5 A schematic diagram of the process for calculating installed capacity and setting parameters. Detailed Implementation

[0042] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0043] This invention describes a method for carbon dioxide salt cavern energy storage and a method for calculating installed capacity, including the following steps:

[0044] S1. Salt cavern construction and parameter settings:

[0045] Salt caverns with good surrounding rock sealing and structural integrity were selected, and their initial conditions were recorded: burial depth H = 1200 m, stress gradient ▽σ0 = 2.08 MPa / 100 m, static stress at the top of the cavity σ0 = H × ▽σ0 = 25 MPa, and effective cavity volume V0 = 50 × 10⁻⁶ m. 4 m 3 The thickness h of the top salt rock layer is retained. top ≥20m.

[0046] Based on the formation pressure and temperature conditions at this depth, the initial intracavitary pressure P i Minimum pressure P min =0.7σ0=16MPa, this pressure P min To ensure stability, the cavity temperature T is close to 70% of the static stress of the surrounding rock. i =50℃ (approximately due to the geothermal gradient). High-purity CO2 gas is injected into the cavity until the pressure rises to the designed maximum operating pressure P. max =0.8σ0=20MPa, this pressure P max To ensure stability, the injection is stopped and the valves are closed once the static stress of the surrounding rock is close to 80%. During this process, the power of the ground compressor and the injection rate are controlled, making the compression process close to quasi-adiabatic. However, most of the heat of compression is extracted and stored in a heat storage medium (such as a high-temperature heat storage tank) through an intercooler and surface heat exchanger for later use.

[0047] S2, Energy storage medium injection and release:

[0048] Based on the required energy storage capacity and target power output, a calculation model for the installed capacity is established to determine the power and specifications of the compressor unit and expander unit.

[0049] Set the time t for the salt cave to fill with CO2. c CO2 extraction time t d compressor efficiency η c And expander efficiency η t Using the ideal gas model approximation, the storage capacity of the salt cavern, ΔE = nRT, is calculated. c ln(P max / P min ), where n is the amount of CO2 participating in the cycle, R is the gas constant, and T c The operating temperature of the salt cavern is approximated by the ground temperature of the salt layer.

[0050] Substituting the parameters collected in S1, and based on the known salt cavern volume, CO2 pressure, and temperature, the mass m and number of moles of CO2 participating in the cycle can be calculated; substituting R = 8.314 J / (mol·K), Tc = 323 K, and P... max =20MPa, P min=16MPa, calculated ΔE = n × 8.314 × 323 × ln(20 / 16). It is calculated that a single cycle of the salt cavern in this example can release approximately 4.21 × 10⁻⁶ MPa of electrical energy. 5 MJ (approximately 117.07 MWh).

[0051] The target storage capacity is compared with the storage capacity calculated in step S1. If the target storage capacity is less than or equal to the calculated storage capacity, this energy scale verifies the feasibility of large-capacity salt cavern energy storage. If even greater energy storage is needed, it can be achieved by selecting salt caverns with larger effective capacities and increasing P... max This can be achieved by (providing the safety of the surrounding rock) or by increasing the number of salt caverns.

[0052] Assuming we want the salt cavern energy storage system to be able to operate at full charge for 5 hours (t) d If all stored energy is released within the system for peak power generation, the required expander capacity is approximately P. t =E out / t d .

[0053] The ΔE calculated above is taken as the energy E released during extraction. out Substituting the values, we can initially estimate the power rating of the expander. That is, the energy released in a single cycle is 117.07 MWh, and the average discharge power is approximately 23.41 MW. Considering the efficiency during the expansion process (assuming the total efficiency of the expander and other components is η),... t If the value is 0.85, then an expander unit with a capacity slightly larger than 30MW needs to be selected to meet the requirements.

[0054] On the energy storage charging side, in order to transfer the salt cavern from P within the same approximately 8 hours... min Boost return P max The total power requirement of the compressor unit is similar to that of the expander. Since the compression end also needs to overcome pipeline losses and perform heat recovery, etc., additional power consumption is assumed. Assuming the compression system efficiency η... c =0.8, then the theoretical power requirement P of the compressor c =E in / t c E in =E out / η=117.07MWh / 0.7=167.24MWh. Therefore, P c =167.24MWh / 8h = 20.91MW, then consider η c After correction to 0.8, approximately 26.13 MW of compressor power is required. This result indicates that the compressor side may need to be divided into multiple units operating in parallel or multi-stage compression to complete the gas filling within the allowable injection rate range. Simultaneously, to ensure that the CO2 flow rate and pressure drop within the wellbore are not excessive, an injection tubing of appropriate diameter must be selected, and auxiliary equipment such as booster pumps must be configured.

[0055] Through system simulation evaluation, the efficiency η of the single-cycle system was calculated, and the system efficiency was 70%. In this embodiment, a heat storage medium was added, and based on the actual energy storage requirement being greater than the energy released in a single cycle of 117.07 MWh, two salt caverns were used in parallel operation. Therefore, η = η c *η t *η r *K = 0.8 * 0.85 * 0.94 * 1.1 = 0.7. In practical applications, the final calculated system efficiency is adjusted based on the selected compressor, expander model, pipe diameter, well casing, etc.

[0056] The following parameters were verified and optimized:

[0057] Pressure range: P max =20MPa, not exceeding the safe pressure corresponding to the tensile strength of salt rock (usually taken as about 80% of the vertical ground stress of the surrounding rock), while P min =16MPa is approximately 70% of the surrounding rock stress, which meets the safety range requirements proposed in this invention.

[0058] Temperature management: By adding a heat storage device, the compression heat is effectively stored and used for expansion reheat, minimizing heat loss and increasing system efficiency from about 45% without heat storage to 70% in this example.

[0059] S3. Operation Control and Recycling:

[0060] When storing energy, CO2 is first injected into P. min It forms a cushion air supply, which serves as the air source for the initial operation of the cycle and maintains the minimum pressure requirement of the salt cavern.

[0061] Perform cyclic operation in power grid peak-valley regulation:

[0062] See appendix Figure 1 Based on the calculation results above, select the type and model of the compressor and expander. When there is excess power, start the compressor and inject the captured high-purity CO2 as the working medium into the cavity under pressure until the pressure rises to the designed maximum operating pressure P. max =0.8σ0=20MPa, energy is stored in the salt cavern, then injection is stopped and the valve is closed. During this process, the power of the ground compressor and the injection rate are controlled, making the compression process close to a quasi-adiabatic process, but most of the compression heat is extracted and stored in a high-temperature heat storage tank through the intercooler and surface heat exchanger for later use.

[0063] See appendix Figure 2After energy storage is completed, the CO2 inside the salt cavern remains in a high-pressure, sealed state for a period of time, achieving static energy storage. During peak electricity demand, the expander is activated, and the production well valve is opened, allowing the high-pressure CO2 inside the chamber to drive the expander to generate electricity, gradually reducing the CO2 pressure. To increase the output of expansion work, the residual heat from compression stored in the high-temperature heat storage tank is introduced to heat the CO2 at the expander inlet, making the CO2 expansion process approach an ideal adiabatic condition and preventing excessive cooling of the gas. The expansion process continues until the salt cavern pressure drops to the minimum allowable value P. min Stop when the pressure reaches 16 MPa, at which point one energy storage-release cycle is completed.

[0064] During the circulation process, the compression / expansion rate is controlled by monitoring the bottom hole pressure and temperature to prevent the surrounding rock from being affected by rapid stress changes. Preferably, a periodic injection-production mode is adopted, and the injection-production frequency and pressure variation amplitude are optimized to reduce the cumulative deformation and leakage risk of the surrounding rock and extend the safe operating life of the salt cavern reservoir.

[0065] When there is excess power, the compressor is started to increase the pressure of CO2 to P at a rate of ≤10MPa / h. max Salt caverns are injected; during peak electricity demand, expanders are activated to depressurize high-pressure CO2 to Pmin at a rate of ≤10MPa / h and release it from the salt caverns to drive generators to generate electricity.

[0066] By monitoring the expander's output electrical energy and the compressor's input electrical energy, and considering the losses in the heat storage system, the actual energy storage efficiency η of a single cycle can be calculated. In this embodiment, due to the use of heat storage feedback, CO2 does not exchange heat with the outside environment during the cycle, which is theoretically close to a reversible process. Therefore, the calculated energy storage efficiency can reach approximately 70%.

[0067] See appendix Figure 3 , Figure 4 In the energy storage-release cycle, during the energy storage phase, the compressor operates, and the operating pressure changes from P... min Gradually rise to P max The CO2 storage density gradually increases until the compressor stops operating, at which point both the pressure and storage density in the salt cavern reach their maximum values. During energy storage, the salt cavern maintains good sealing, and the pressure and storage density remain essentially constant. During the energy release phase, the operating pressure decreases from P... max Gradually decrease until it reaches P. min The energy is released to generate electricity, and during this process, the CO2 storage density gradually decreases.

[0068] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0069] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for carbon dioxide salt cavern energy storage, characterized in that, Includes the following steps: S1. Salt cavern construction and parameter setting: Select salt caverns with good surrounding rock sealing and structural integrity, and retain the thickness h of the top salt rock layer. top ≥20m; S2. Energy Storage Medium Injection and Release: Based on the required energy storage scale and target power output, establish a calculation model for the installed capacity to determine the power and specifications of the compressor unit and expander unit; use the captured CO2 as the working medium and pressurize it to the target maximum pressure P via the compressor. max Energy is stored in salt caverns; when energy needs to be released, an expander reduces the CO2 pressure inside the salt cavern to the minimum operating pressure P. min Power generation; S3. Operation Control and Recycling: When storing energy, CO2 is first injected into P. min Formation of air in the pillow cushion; In power grid peak-valley regulation, a cyclic operation is performed: when there is a power surplus, the compressor is started to boost CO2 to P at a rate of ≤10MPa / h. max Salt caverns are injected; during peak electricity demand, expanders are activated to depressurize high-pressure CO2 to Pmin at a rate of ≤10MPa / h and release it from the salt caverns to drive generators to generate electricity.

2. The carbon dioxide salt cavern energy storage method as described in claim 1, characterized in that: Salt caverns are selected with a burial depth H of 1000–1500 m, and the effective volume V0 of a single cavity is not less than 40–50 × 10⁻⁶ m. 4 m 3 P min ≥0.2σ0, P max ≤0.8σ0.

3. The carbon dioxide salt cavern energy storage method as described in claim 2, characterized in that: P min ≥0.6σ0,P max ≤0.8σ0.

4. The carbon dioxide salt cavern energy storage method as described in claim 1, characterized in that, The energy storage capacity in step S2 is calculated according to the following formula: ΔE=nRT c ln(P max / P min ), where n is the amount of CO2 participating in the cycle, R is the gas constant, and T c The operating temperature of the salt cavern is approximated by the ground temperature of the salt layer.

5. A carbon dioxide salt cavern energy storage method according to any one of claims 1-4, characterized in that: The energy storage system is also equipped with a high-temperature heat storage tank. The heat generated during the CO2 storage and compression process is stored in the high-temperature heat storage tank. During expansion output, the residual heat of compression stored in the high-temperature heat storage tank is used to heat the CO2 at the inlet of the expander. Furthermore, the annual cycle number of power grid peak-valley regulation cycles is ≤200 times.

6. The carbon dioxide salt cavern energy storage method as described in claim 1, characterized in that: During energy storage release, each cycle retains P after the energy storage release. min The pressurized CO2 remains in the salt cavern and replenishes the losses from the leak before the next cycle begins.

7. A method for calculating the installed capacity of an energy storage method according to any one of claims 1-6, characterized in that, Includes the following steps: S1, Set the time t for the salt cavern to fill with CO2. c CO2 extraction time t d compressor efficiency η c And expander efficiency η t ; Calculate the storage capacity of the salt cavern ΔE = nRT c ln(P max / P min ), where n is the amount of CO2 participating in the cycle, R is the gas constant, and T c The operating temperature of the salt cavern is approximated by the ground temperature of the salt layer; S2. Determine the target storage capacity compared to the storage capacity calculated in step S1. If the target storage capacity is greater than the calculated storage capacity, then select a salt cavern with a larger effective capacity and adjust the pressure P. max Adjust the scheme by selecting multiple salt cavern chambers in parallel, and recalculate S1 until the target storage capacity is less than or equal to the calculated storage capacity. S3. Take the ΔE obtained in step S1 as the energy E released during extraction. out Based on energy storage scale E out and discharge time t d Calculate the power P of the expander t :P t =E out / t d And according to the expander efficiency η t Perform correction; Based on energy storage capacity E in and charging time t c Calculate compressor power: P c =E in / t c Considering compressor efficiency η c The system loss η is corrected, where E in =E out / η; S4. Calculate the efficiency of the single-cycle system through system simulation evaluation. If the system efficiency is >60%–70%, proceed to the next step; otherwise, E. out If the target requirements are not met, return to S1 and modify each parameter again; S5, Output Results.

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