Renewable energy power generation and energy storage coupling system and method

Abstract

The invention discloses a renewable energy power generation and energy storage coupling system and method. The coupling system comprises a solar fused salt heat absorption subsystem, a wind power generation subsystem, a supercritical CO2 energy storage subsystem, a flywheel energy storage subsystem and a battery energy storage subsystem. Through coupling of renewable energy sources such as solar energy and wind energy with carbon dioxide energy storage, flywheel energy storage and battery energy storage, the supercritical CO2 energy storage system enters an energy storage stage in the power generation peak period of the wind wheel power generation device; when the wind wheel power generation device is in a power generation trough period, the supercritical CO2 energy storage system enters an energy release stage; the battery energy storage system and the flywheel energy storage system adjust the energy storage and release stages according to actual conditions, the problems of volatility and intermittency of the power grid are effectively solved, and safe operation of the power grid is achieved.

Description

Technical Field

[0001] The present invention relates to the field of energy technology, and in particular to a renewable energy power generation and energy storage coupling system and method. Background Art

[0002] Development and utilization of renewable energy. However, renewable energy is characterized by volatility and intermittency, and its connection to the grid will have an adverse impact on the grid's regulation, operation, and safety control. Energy storage systems can be used in conjunction with renewable energy generation to solve the problem of renewable energy generation and grid connection. As the scale of renewable energy generation increases, it will become a key technology to support the development of clean energy in my country. Currently, there are physical energy storage and chemical energy storage, including carbon dioxide energy storage, flywheel energy storage, and battery energy storage.

[0003] It is of great significance to explore the combined technology of renewable energy and energy storage systems. Summary of the invention

[0004] The technical problem to be solved by the present invention is: how to provide a new technology for combining renewable energy with energy storage system. The present invention provides a coupling system and method for renewable energy power generation and energy storage to solve the above problem, and provides a coupling system of solar energy, wind energy and CO2 energy storage, flywheel energy storage, and battery energy storage with reasonable design, high operation stability and high energy utilization rate.

[0005] The present invention is achieved through the following technical solutions: A renewable energy power generation and energy storage coupling system, including a solar molten salt heat absorption subsystem, a wind power generation subsystem, a supercritical CO2 energy storage subsystem, a flywheel energy storage subsystem, and a battery energy storage subsystem; the solar molten salt heat absorption subsystem includes a heliostat, a heat absorber, and a heat exchanger; the heliostat is used to collect sunlight to heat the heat absorber; the heat absorber is used to accommodate molten salt working fluid, and the output end of the heat absorber is connected to the hot side inlet end of the heat exchanger through a pipeline; the wind power generation subsystem includes a wind turbine power generation device, which is used to generate electricity and the generated electricity is connected to the power grid; the supercritical CO2 energy storage subsystem includes a generator, a high-pressure storage tank, a turbine, a first heat exchanger, a precooler, a low-pressure storage tank, a compressor, and a second heat exchanger; the high-pressure storage tank is used to store CO2 The fluid working medium, the output end of the high-pressure storage tank is connected to the cold side inlet end of the heat exchanger; the cold side outlet end of the heat exchanger is connected to the fluid input end of the turbine, and the fluid output end of the turbine is connected to the hot side inlet end of the first heat exchanger; the hot side outlet end of the first heat exchanger is connected to the input end of the precooler; the output end of the precooler is connected to the input end of the low-pressure storage tank, and the output end of the low-pressure storage tank is connected to the input end of the compressor; the output end of the compressor is connected to the cold side inlet end of the second heat exchanger, and the cold side outlet end of the second heat exchanger is connected to the input end of the high-pressure storage tank; the generator is connected to the turbine; the flywheel energy storage subsystem includes a flywheel device; when storing energy, the flywheel device is used to receive electrical energy from the generator to realize the conversion of electrical energy into mechanical energy; when releasing energy, the flywheel device is used to drive the motor to generate electricity, and the generated electricity is connected to the power grid; the battery energy storage subsystem includes a battery device; when storing energy, the battery device is used to receive electrical energy from the generator to realize the conversion of electrical energy into chemical energy; when releasing energy, the battery device is used to discharge and be connected to the power grid.

[0006] The present invention couples renewable energy sources such as solar energy and wind energy with carbon dioxide energy storage, flywheel energy storage, and battery energy storage. When the wind turbine generator system is in the peak power generation period, the supercritical CO2 energy storage system enters the energy storage stage; when the wind turbine generator system is in the low power generation period, the supercritical CO2 energy storage system enters the energy release stage; the battery energy storage system and the flywheel energy storage system adjust their energy storage and release stages according to actual conditions, effectively solving the volatility and intermittent problems of the power grid and realizing the safe operation of the power grid.

[0007] Further optionally, the solar molten salt heat absorption subsystem also includes a hot tank and a cold tank; the hot tank is arranged on a pipeline connecting the output end of the heat absorber with the hot side inlet end of the heat exchanger, the input end of the hot tank is connected to the output end of the heat absorber, and the output end of the hot tank is connected to the hot side inlet end of the heat exchanger; the input end of the cold tank is connected to the hot side outlet end of the heat exchanger.

[0008] Further optionally, it also includes a circulation pipeline (001), wherein two ends of the circulation pipeline (001) are respectively connected to the output end of the cold tank and the input end of the heat absorber.

[0009] Further optionally, the wind energy generating subsystem also includes an AC / AC converter and a transformer; the electricity generated by the wind turbine generator device is converted by the AC / AC converter and transformed by the transformer before being connected to the power grid.

[0010] Further optionally, the high-pressure storage tank is used to store CO2 binary mixed fluid working fluid; the CO2 binary mixed fluid working fluid adopts a binary mixed fluid based on CO2, including carbon dioxide / butane binary mixed fluid working fluid, carbon dioxide / propane binary mixed fluid working fluid and CO2 / xenon binary mixed fluid working fluid; wherein the molar mass ratio of butane, propane and xenon is ≤15%.

[0011] Further optionally, the supercritical CO2 energy storage subsystem also includes a first hot tank and a second hot tank; the output end of the first hot tank is connected to the cold side inlet end of the first heat exchanger, and the input end of the first hot tank is connected to the hot side outlet end of the second heat exchanger; the output end of the second hot tank is connected to the hot side inlet end of the second heat exchanger, and the input end of the second hot tank is connected to the cold side outlet end of the first heat exchanger.

[0012] Further optionally, it also includes a pump; a pump is arranged on the pipeline connecting the first hot tank and the cold side inlet end of the first heat exchanger, and a pump is arranged on the pipeline connecting the second hot tank and the second heat exchanger.

[0013] Further optionally, the flywheel energy storage subsystem also includes an AC / AC converter and a transformer; the electricity generated by the flywheel energy storage subsystem is converted by the AC / AC converter and transformed by the transformer before being incorporated into the power grid.

[0014] Further optionally, the battery energy storage subsystem also includes a DC / AC converter and a transformer; the electricity discharged by the battery energy storage subsystem is converted by the DC / AC converter and transformed by the transformer before being incorporated into the power grid.

[0015] The above-mentioned operation method of a renewable energy power generation and energy storage coupling system comprises: For the flywheel energy storage subsystem: when storing energy, the supercritical CO2 energy storage subsystem is in the process of releasing energy. The flywheel device receives electrical energy from the generator, drives the motor to drive the flywheel to rotate, completes the energy storage process of converting electrical energy into mechanical energy, and the energy is stored in the high-speed rotating flywheel body; when releasing energy, the flywheel device rotates to drive the motor to generate electricity and is connected to the power grid, completing the energy release process of converting mechanical energy into electrical energy; For the battery energy storage subsystem: when storing energy, the supercritical CO2 energy storage subsystem is in the process of releasing energy. The battery device receives electrical energy from the generator, completes the storage process of converting electrical energy into chemical energy, and the energy is stored in the battery; when releasing energy, the battery discharges and is connected to the power grid, completing the energy release process of converting chemical energy into electrical energy.

[0016] The carbon dioxide energy storage system is a closed cycle, which is proposed on the basis of compressed air energy storage and Brayton cycle, and is realized through multi-stage adiabatic compression, isobaric heating, multi-stage adiabatic expansion and isobaric cooling. The carbon dioxide energy storage system is not restricted by geographical conditions, and has the advantages of excellent physical properties of energy storage fluid, stable system performance, compact process equipment, long energy storage time and large scale. CO2 has a critical pressure of 7.38 MPa and a critical temperature of 31.1 ℃. It has good thermal properties and environmental friendliness, good chemical stability, large latent heat of vaporization, low price, non-toxic, non-flammable and easy to obtain. However, the use of single-component CO2 as a circulating working fluid has the problem of high system operating pressure. The binary mixed working fluid based on CO2 formed by adding a certain amount of refrigerant or inert gas (such as ethane, propane, butane, R134a, R161, He, Ne, Xe) to CO2 can effectively adjust the critical parameters of CO2 and improve the system cycle efficiency.

[0017] Flywheel energy storage realizes the mutual conversion of kinetic energy and electrical energy with the cooperation of a bidirectional motor. The process is green and environmentally friendly, and the response speed is extremely fast.

[0018] The combined system consisting of the solar molten salt heat absorption system and the supercritical carbon dioxide Brayton cycle system has a thermoelectric efficiency of more than 50%. The heat exchanger connecting the above-mentioned solar molten salt heat absorption system and the supercritical carbon dioxide Brayton cycle system is one of the core components of the combined system, and its efficient and stable operation is crucial to the coupled system. The traditional shell and tube heat exchanger has low heat exchange efficiency. The printed circuit board heat exchanger (PCHE) is not only compact and efficient, light and strong, but also can meet various requirements in the heat exchange process, such as high temperature (up to 900 ℃), high pressure (up to 60 MPa), small temperature difference heat exchange (down to 2 ℃), less leakage, excellent heat transfer efficiency, and high heat transfer area density.

[0019] This system combines renewable energy such as solar energy and wind energy with carbon dioxide energy storage, flywheel energy storage, and battery energy storage, which can effectively smooth out grid volatility, solve intermittent problems, and achieve safe operation of the grid.

[0020] The present invention has the following advantages and beneficial effects: 1. The present invention combines renewable energy such as solar energy and wind energy with carbon dioxide energy storage, flywheel energy storage, and battery energy storage, which can effectively smooth out grid volatility, solve intermittent problems, and achieve safe operation of the grid.

[0021] 2. The heat exchanger connecting the solar molten salt heat absorption subsystem and the supercritical carbon dioxide Brayton cycle subsystem can be a printed circuit board heat exchanger (PCHE), in which the molten salt is used as the hot fluid; a binary mixed working fluid based on CO2 is used as the cold fluid, and the binary mixed working fluid can be a mixture of carbon dioxide / butane, carbon dioxide / propane and CO2 / xenon, and the molar mass ratio of butane, propane and xenon is ≤15%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings: Figure 1 It is a schematic diagram of the structure of the combined battery energy storage coupling system of the present invention.

[0023] Marks and corresponding parts names in the attached drawings: 1-heat absorber, 2-hot tank, 3-heat exchanger, 4-cold tank, 5-generator, 6-turbine, 7-compressor, 8-second heat exchanger, 9-first hot tank, 10-pump, 11-first heat exchanger, 12-second hot tank, 13-precooler, 14-low-pressure storage tank, 15-high-pressure storage tank, 16-flywheel device, 17-battery device, 18-AC / AC converter, 19-DC / AC converter, 20-transformer, 21-heliostat, 22-wind turbine generator. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention. Example

[0025] This embodiment provides a renewable energy power generation and energy storage coupling system, which is specifically composed of five subsystems: a solar molten salt heat absorption subsystem, a wind power generation subsystem, a supercritical CO2 energy storage subsystem, a flywheel energy storage subsystem, and a battery energy storage subsystem. Among them: 1. The solar molten salt heat absorption subsystem includes a heliostat 21, a heat absorber 1 and a heat exchanger 3; the heliostat 21 is used to collect sunlight to heat the heat absorber 1; the heat absorber 1 is used to contain molten salt working fluid, and the output end of the heat absorber 1 is connected to the hot side inlet end of the heat exchanger 3 through a pipeline; 2. The wind energy generating subsystem includes a wind turbine generator 22, which is used to generate electricity and the generated electricity is fed into the power grid; 3. The supercritical CO2 energy storage subsystem includes a generator 5, a high-pressure storage tank 15, a turbine 6, a first heat exchanger 11, a precooler 13, a low-pressure storage tank 14, a compressor 7, and a second heat exchanger 8; the high-pressure storage tank 15 is used to store CO2 fluid, and the output end of the high-pressure storage tank 15 is connected to the cold side inlet end of the heat exchanger 3; the cold side outlet end of the heat exchanger 3 is connected to the fluid input end of the turbine 6, and the fluid output end of the turbine 6 is connected to the hot side inlet end of the first heat exchanger 11; the hot side outlet end of the first heat exchanger 11 is connected to the input end of the precooler 13; the output end of the precooler 13 is connected to the input end of the low-pressure storage tank 14, and the output end of the low-pressure storage tank 14 is connected to the input end of the compressor 7; the output end of the compressor 7 is connected to the cold side inlet end of the second heat exchanger 8, and the cold side outlet end of the second heat exchanger 8 is connected to the input end of the high-pressure storage tank 15; the generator 5 is connected to the turbine 6; 4. The flywheel energy storage subsystem includes a flywheel device 16; when storing energy, the flywheel device 16 is used to receive electrical energy from the generator 5 to convert electrical energy into mechanical energy; when releasing energy, the flywheel device 16 is used to drive the motor to generate electricity, and the generated electricity is incorporated into the power grid; 5. The battery energy storage subsystem includes a battery device 17; when storing energy, the battery device 17 is used to receive electrical energy from the generator 5 and convert the electrical energy into chemical energy; when releasing energy, the battery device 17 is used to discharge and be connected to the power grid. Example

[0026] This embodiment provides a renewable energy power generation and energy storage coupling system, which further optimizes the design based on Embodiment 1: The solar molten salt heat absorption subsystem also includes a hot tank 2, a cold tank 4 and a circulation pipeline 001. The hot tank 2 is arranged on a pipeline connecting the output end of the heat absorber 1 with the hot side inlet end of the heat exchanger 3, the input end of the hot tank 2 is connected with the output end of the heat absorber 1, and the output end of the hot tank 2 is connected with the hot side inlet end of the heat exchanger 3; the input end of the cold tank 4 is connected with the hot side outlet end of the heat exchanger 3. The two ends of the circulation pipeline 001 are connected with the output end of the cold tank 4 and the input end of the heat absorber 1 respectively.

[0027] The wind energy generating subsystem also includes an AC / AC converter 18 and a transformer 20; the electricity generated by the wind turbine generator 22 is converted by the AC / AC converter 18 and the transformer 20 and then connected to the power grid.

[0028] In the supercritical CO2 energy storage subsystem, the high-pressure storage tank 15 is used to store CO2 binary mixed fluid working fluid; the CO2 binary mixed fluid working fluid adopts a binary mixed fluid based on CO2, including carbon dioxide / butane binary mixed fluid working fluid, carbon dioxide / propane binary mixed fluid working fluid and CO2 / xenon binary mixed fluid working fluid; wherein the molar mass ratio of butane, propane and xenon is ≤15%. In this embodiment, carbon dioxide / butane binary mixed fluid working fluid is adopted, and the molar mass ratio of butane is 5%.

[0029] The supercritical CO2 energy storage subsystem also includes a first heat tank 9, a second heat tank 12 and a pump 10; the output end of the first heat tank 9 is connected to the cold side inlet end of the first heat exchanger 11, and the input end of the first heat tank 9 is connected to the hot side outlet end of the second heat exchanger 8; the output end of the second heat tank 12 is connected to the hot side inlet end of the second heat exchanger 8, and the input end of the second heat tank 12 is connected to the cold side outlet end of the first heat exchanger 11. A pump 10 is provided on the pipeline connecting the first heat tank 9 with the cold side inlet end of the first heat exchanger 11, and a pump 10 is provided on the pipeline connecting the second heat tank 12 with the second heat exchanger 8.

[0030] The flywheel energy storage subsystem also has an AC / AC converter 18 and a transformer 20; the electricity generated by the flywheel energy storage subsystem is converted by the AC / AC converter 18 and the transformer 20 and then connected to the power grid.

[0031] The battery energy storage subsystem also has a DC / AC converter 19 and a transformer 20; the electricity discharged by the battery energy storage subsystem is converted by the DC / AC converter 19 and the transformer 20 and then connected to the power grid. Example

[0032] This embodiment provides an operation method of a renewable energy power generation and energy storage coupling system, specifically an operation method of a combined battery energy storage coupling system provided in Embodiment 2, which is specifically as follows: For the flywheel energy storage subsystem: when storing energy, the supercritical CO2 energy storage subsystem is in the process of releasing energy, the flywheel device 16 receives the electric energy from the generator 5, and the drive motor drives the flywheel to rotate, completing the energy storage process of converting electric energy into mechanical energy, and the energy is stored in the high-speed rotating flywheel body; when releasing energy, the flywheel device 16 rotates to generate electricity and is connected to the power grid, completing the energy release process of converting mechanical energy into electric energy; For the battery energy storage subsystem: when storing energy, the supercritical CO2 energy storage subsystem is in the process of releasing energy, the battery device 17 receives electrical energy from the generator 5, completes the storage energy process of converting electrical energy into chemical energy, and the energy is stored in the battery; when releasing energy, the battery is discharged and connected to the power grid, completing the release energy process of converting chemical energy into electrical energy. Example

[0033] This embodiment provides an operation method of a renewable energy power generation and energy storage coupling system, which is further optimized and designed on the basis of Embodiment 3, as shown below: 1. For the solar molten salt heat absorption subsystem: the sun's position is tracked by the heliostat 21 to collect sunlight onto the heat absorber 1, thereby heating the molten salt in the heat absorber 1. The high-temperature molten salt enters the hot tank 2 through the downcomer, and the supercritical CO2 working fluid exchanges heat with the high-temperature molten salt in the heat exchanger 3. The cooled low-temperature molten salt enters the cold tank 4 for storage. Under the action of forced circulation, the low-temperature molten salt passes through the pipeline 001 and enters the heat absorber 1 to be heated again.

[0034] 2. For the wind energy generating subsystem: the electricity generated by the wind turbine generating device 22 is converted by the AC / AC converter 18, then converted by the transformer 20, and finally connected to the power grid.

[0035] 3. Supercritical CO2 energy storage subsystem: Energy release process: The CO2 fluid from the high-pressure storage tank 15 enters the heat exchanger 3 through the pipeline 011, exchanges heat with the molten salt working medium, absorbs heat, and enters the supercritical CO2 turbine 6 through the pipeline 002 to generate power; then the gas is discharged from the pipeline 003 and sent to the first heat exchanger 11, absorbing the cold from the first hot tank 9 and releasing heat, which is stored in the second hot tank 12. The cold in the first hot tank 9 is pressurized by the pump 10 and enters the first heat exchanger 11 through the pipeline 004. The gas enters the precooler 13 through the pipeline 006, is cooled to the compressor inlet temperature, and then is stored in the low-pressure storage tank 14 through the pipeline 007.

[0036] Energy storage process: The CO2 fluid at the outlet of the low-pressure storage tank 14 is transported to the compressor 7 through the pipeline 008 for pressure boosting. After the pressure boosting, it enters the second heat exchanger 8 through the pipeline 009, absorbs the heat from the second hot tank 12, and releases cold energy, which is stored in the first hot tank 9. The heat in the second hot tank 12 is pressurized by the pump 10 and enters the second heat exchanger 8 through the pipeline 005. The cold energy in the first hot tank 9 is pressurized by the pump 10 and enters the first heat exchanger 11 through the pipeline 004. The CO2 fluid enters the high-pressure storage tank 15 through the pipeline 010.

[0037] 4. For the flywheel energy storage subsystem: During energy storage, the supercritical CO2 energy storage system is in the process of releasing energy. The flywheel device 16 receives electrical energy from the generator 5, and the drive motor drives the flywheel to accelerate rotation. The flywheel stores energy in the form of kinetic energy, completing the energy storage process of converting electrical energy into mechanical energy. The energy is stored in the high-speed rotating flywheel body.

[0038] When releasing energy, the high-speed rotating flywheel generates electricity, which is then converted by the AC / AC converter 18 and then converted by the transformer 20 and finally connected to the power grid, completing the energy release process of converting mechanical energy into electrical energy.

[0039] 5. For the battery energy storage subsystem: During energy storage, the supercritical CO2 energy storage system is in the process of releasing energy, and the battery device 17 receives electrical energy from the generator 5, stores the energy, and completes the energy storage process of converting electrical energy into chemical energy, and the energy is stored in the battery.

[0040] When releasing energy, the battery discharges, undergoes current conversion by the DC / AC converter 19, undergoes voltage conversion by the transformer 20, and is finally connected to the power grid, completing the energy release process of converting chemical energy into electrical energy.

[0041] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A renewable energy power generation and energy storage coupling system, characterized in that: Including solar molten salt heat absorption subsystem, wind power generation subsystem, supercritical CO2 energy storage subsystem, flywheel energy storage subsystem, battery energy storage subsystem; The solar molten salt heat absorption subsystem comprises a heliostat (21), a heat absorber (1) and a heat exchanger (3); the heliostat (21) is used to collect sunlight to heat the heat absorber (1); the heat absorber (1) is used to contain a molten salt working medium, and the output end of the heat absorber (1) is connected to the hot side inlet end of the heat exchanger (3) through a pipeline; The wind energy generating subsystem comprises a wind wheel generating device (22), wherein the wind wheel generating device (22) is used to generate electricity, and the generated electricity is fed into a power grid; The supercritical CO2 energy storage subsystem comprises a generator (5), a high-pressure storage tank (15), a turbine (6), a first heat exchanger (11), a precooler (13), a low-pressure storage tank (14), a compressor (7), and a second heat exchanger (8); the high-pressure storage tank (15) is used to store CO2 The fluid working medium, the output end of the high-pressure storage tank (15) is connected to the cold side inlet end of the heat exchanger (3); the cold side outlet end of the heat exchanger (3) is connected to the fluid input end of the turbine (6), and the fluid output end of the turbine (6) is connected to the hot side inlet end of the first heat exchanger (11); the hot side outlet end of the first heat exchanger (11) is connected to the input end of the precooler (13); the output end of the precooler (13) is connected to the input end of the low-pressure storage tank (14), and the output end of the low-pressure storage tank (14) is connected to the input end of the compressor (7); the output end of the compressor (7) is connected to the cold side inlet end of the second heat exchanger (8), and the cold side outlet end of the second heat exchanger (8) is connected to the input end of the high-pressure storage tank (15); the generator (5) is connected to the turbine (6); The flywheel energy storage subsystem comprises a flywheel device (16); when storing energy, the flywheel device (16) is used to receive electrical energy from a generator (5) to convert the electrical energy into mechanical energy; when releasing energy, the flywheel device (16) is used to drive a motor to generate electricity, and the generated electricity is fed into a power grid; The battery energy storage subsystem comprises a battery device (17); when storing energy, the battery device (17) is used to receive electrical energy from a generator (5) to convert the electrical energy into chemical energy; when releasing energy, the battery device (17) is used to discharge and be incorporated into a power grid.

2. A renewable energy power generation and energy storage coupling system according to claim 1, characterized in that: The solar molten salt heat absorption subsystem further comprises a hot tank (2) and a cold tank (4); the hot tank (2) is arranged on a pipeline connecting the output end of the heat absorber (1) and the hot side inlet end of the heat exchanger (3); the input end of the hot tank (2) is connected to the output end of the heat absorber (1), and the output end of the hot tank (2) is connected to the hot side inlet end of the heat exchanger (3); the input end of the cold tank (4) is connected to the hot side outlet end of the heat exchanger (3).

3. A renewable energy power generation and energy storage coupling system according to claim 2, characterized in that: It also includes a circulation pipeline (001), the two ends of which are respectively connected to the output end of the cold tank (4) and the input end of the heat absorber (1).

4. A renewable energy power generation and energy storage coupling system according to claim 1, characterized in that: The wind energy generating subsystem further comprises an AC / AC converter (18) and a transformer (20); the electricity generated by the wind turbine generating device (22) is converted by the AC / AC converter (18) and transformed by the transformer (20) before being connected to the power grid.

5. A renewable energy power generation and energy storage coupling system according to claim 1, characterized in that: The high-pressure storage tank (15) is used to store a CO2 binary mixed fluid working medium; the CO2 binary mixed fluid working medium adopts a binary mixed fluid based on CO2, including a carbon dioxide / butane binary mixed fluid working medium, a carbon dioxide / propane binary mixed fluid working medium and a CO2 / xenon binary mixed fluid working medium; wherein the molar mass ratio of butane, propane and xenon is ≤15%.

6. A renewable energy power generation and energy storage coupling system according to claim 1, characterized in that: The supercritical CO2 energy storage subsystem further comprises a first heat tank (9) and a second heat tank (12); the output end of the first heat tank (9) is connected to the cold side inlet end of the first heat exchanger (11), and the input end of the first heat tank (9) is connected to the hot side outlet end of the second heat exchanger (8); the output end of the second heat tank (12) is connected to the hot side inlet end of the second heat exchanger (8), and the input end of the second heat tank (12) is connected to the cold side outlet end of the first heat exchanger (11).

7. A renewable energy power generation and energy storage coupling system according to claim 6, characterized in that: It also includes a pump (10); the pump (10) is arranged on a pipeline connecting the first hot tank (9) and the cold side inlet end of the first heat exchanger (11), and the pump (10) is arranged on a pipeline connecting the second hot tank (12) and the second heat exchanger (8).

8. The renewable energy power generation and energy storage coupling system according to claim 1, characterized in that: The flywheel energy storage subsystem further comprises an AC / AC converter (18) and a transformer (20); the electricity generated by the flywheel energy storage subsystem is converted by the AC / AC converter (18) and transformed by the transformer (20) before being incorporated into the power grid.

9. A renewable energy power generation and energy storage coupling system according to claim 1, characterized in that: The battery energy storage subsystem further comprises a DC / AC converter (19) and a transformer (20); the electricity discharged by the battery energy storage subsystem is converted by the DC / AC converter (19) and the transformer (20) before being connected to the power grid.

10. The method for operating a renewable energy power generation and energy storage coupling system according to any one of claims 1 to 9, characterized in that: include: For the flywheel energy storage subsystem: when storing energy, the supercritical CO2 energy storage subsystem is in the process of releasing energy, the flywheel device (16) receives the electric energy from the generator (5), drives the motor to drive the flywheel to rotate, completes the energy storage process of converting electric energy into mechanical energy, and the energy is stored in the high-speed rotating flywheel body; when releasing energy, the flywheel device (16) rotates to drive the motor to generate electricity and is connected to the power grid, completing the energy release process of converting mechanical energy into electric energy; For the battery energy storage subsystem: when storing energy, the supercritical CO2 energy storage subsystem is in the process of releasing energy, the battery device (17) receives electrical energy from the generator (5), completes the storage energy process of converting electrical energy into chemical energy, and the energy is stored in the battery; when releasing energy, the battery is discharged and connected to the power grid, completing the release energy process of converting chemical energy into electrical energy.

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