System and method for achieving green, large-scale, long-duration energy storage by electrically heating confined underground aquifer

Abstract

The present invention provides a system and method for achieving green, large-scale, long-duration energy storage by electrically heating a confined underground aquifer. The system uses underground aquifers confined by lithological formations, faults, or hydrocarbon-bearing formations such as oil- or coal-bearing formations as a heat storage medium, heats the aquifers by means of energy sources such as electrical energy, new energy, thermal energy or nuclear energy, and stores the thermal energy underground for a long period of time. When needed, the thermal energy and steam kinetic energy are converted into electrical energy or other forms of energy for output via a heat exchange system. The present invention has the advantages of large-scale energy storage, high efficiency and stability, environmental friendliness, and low cost, is suitable for various geographical conditions, and has broad application prospects.

Description

Green Large-Scale Long-Term Energy Storage System and Method for Electrically Heating Underground Sealed Aquifers Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to a green, large-scale, long-term energy storage system and method that uses electric heating to heat underground sealed aquifers. Background Technology

[0002] With the rapid development of renewable energy sources (such as wind and solar power), the intermittency and instability of energy have become major problems restricting their large-scale application. Traditional battery energy storage technology is costly and has a short lifespan, making it difficult to meet the needs of large-scale, long-term energy storage. Underground energy storage technology, due to its advantages of large scale, low cost, and long cycle, has gradually become a research hotspot. However, existing underground energy storage technologies mostly rely on compressed air and pumped hydro storage, which suffer from low efficiency and significant geographical limitations. Therefore, developing a green, efficient, stable, large-scale, long-term energy storage system suitable for various geographical conditions is of great significance. content

[0003] This invention provides a green, large-scale, long-term energy storage system and method that uses electric heating to heat an underground sealed aquifer. The system utilizes the underground sealed aquifer as a heat storage medium, heating the aquifer with energy sources such as electricity, new energy sources, thermal energy, or nuclear energy, and storing the thermal energy underground for a long period. When needed, the thermal energy is converted into electrical energy or other forms of energy output through a heat exchange system. Technical solution

[0004] Ground-based energy input:

[0005] Surface-mounted electricity, new energy sources (such as wind and solar power), thermal energy, or nuclear energy are input into underground energy storage systems via transmission lines or energy conversion devices. Electrical energy is converted into thermal energy through electric heating devices, and heating and industrial waste heat are reinjected into deep underground sealed aquifers via formation water reinjection. Other forms of energy are converted into thermal energy through corresponding energy conversion devices.

[0006] Electric heating device:

[0007] The electric heating device is installed in a closed underground aquifer and converts electrical energy into heat energy and steam kinetic energy through resistance heating, induction heating, or electric arc heating. The design of the electric heating device must consider requirements such as electromagnetic descaling, high temperature resistance, corrosion resistance, and long-term stability.

[0008] Underground sealed aquifer:

[0009] Underground sealed aquifers, such as lithological sealed aquifers, fault sealed aquifers, and hydrocarbon sealed aquifers (e.g., oil / coal), possess excellent heat capacity and thermal stability as thermal storage media. The sealed nature of the aquifer ensures that heat energy is not rapidly lost, thus enabling long-term energy storage. Therefore, the dynamic pressure of the reservoir must always be lower than the reservoir fracture pressure when heating the formation water. The depth, thickness, and tightness of the aquifer must be determined through geological exploration and simulation analysis to ensure energy storage efficiency and safety.

[0010] Thermal energy storage and extraction:

[0011] Thermal energy is stored in underground lithological sealed aquifers via electric heating devices, existing as high-temperature formation water or a mixture with steam. When needed, the stored thermal energy and steam kinetic energy are extracted through a heat exchange system. The heat exchange system includes underground heat exchangers and surface heat exchangers, which transfer thermal energy to the surface through circulating working fluids (such as water, steam, oil, or molten salt), or generate electricity by heating high-temperature formation water and steam, or directly utilize the thermal energy of high-temperature formation water.

[0012] Energy output:

[0013] The extracted thermal energy can be converted into electrical energy through thermoelectric conversion devices (such as steam turbines, Stirling engines, etc.). High-temperature groundwater can be vaporized by pressure reduction and used directly for steam power generation, or directly for heating, industrial processing, and other purposes. The energy output system can be adjusted according to demand to achieve efficient and stable energy supply.

[0014] Control system:

[0015] The entire system is monitored and regulated by an intelligent control system. The control system monitors parameters such as underground temperature, pressure, and energy input and output in real time, and automatically adjusts the power of the electric heating device and the flow rate of the heat exchange system according to demand to ensure the efficient operation and safety of the system. Attached Figure Description

[0016] Figure 1 is a schematic diagram of the system structure of the present invention, which is a system for achieving large-scale long-term energy storage by electrically heating underground closed water layers.

[0017] Figure 2 is a cross-sectional view of an underground lithological sealed aquifer, and a schematic diagram of the cross-section of the underground sealed aquifer (shaded area).

[0018] Figure 3 is a schematic diagram of the working principle of the thermoelectric exchange system.

[0019] Detailed implementation method:

[0020] 1. Site selection and exploration:

[0021] We selected a well-sealed groundwater layer as an energy storage site, conducted geological exploration and simulation analysis, determined the depth, thickness and airtightness of the water layer, and estimated the maximum energy storage capacity at the rupture pressure.

[0022] 2. System Installation:

[0023] Electric heating devices are installed in underground sealed water layers, and energy input / output systems and control systems are built on the ground.

[0024] 3. Energy storage process:

[0025] Electrical energy or other forms of energy are converted into heat energy through a surface energy input system and stored in underground lithological sealed aquifers.

[0026] 4. Energy extraction:

[0027] When needed, the stored heat energy is extracted through a heat exchange system and converted into electrical energy or other forms of energy output.

[0028] 5. System Operation and Maintenance:

[0029] The system's operating status is monitored in real time through an intelligent control system, and regular maintenance and repairs are carried out to ensure the long-term stable operation of the system.

[0030] Beneficial effects

[0031] 1. Large-scale energy storage: By using underground closed water layers as the heat storage medium, large-scale, long-term energy storage can be achieved.

[0032] 2. High efficiency and stability: The intelligent control system enables efficient and stable energy input and output.

[0033] 3. Environmentally friendly: It does not produce pollutants and is suitable for various geographical conditions.

[0034] 4. Low cost: Underground energy storage systems have low construction costs and low maintenance costs, making them highly economical.

Claims

1. A green, large-scale, long-term energy storage system and method that uses electric heating to heat underground sealed aquifers, characterized in that... The system utilizes a sealed underground aquifer as a heat storage medium. It heats the aquifer using, but is not limited to, electrical energy (powered by the grid), new energy sources (including but not limited to wind and solar energy), thermal energy (for heating and industrial waste heat), or nuclear energy, and stores the thermal energy underground for a long period of time. When needed, the thermal energy is converted into electrical energy or other forms of energy output through a heat exchange system. The system includes a surface energy input system, an electric heating device, a sealed underground aquifer, a heat exchange system, an energy output system, and a control system. The method includes the following steps: site selection and exploration, system installation, energy storage process, energy extraction, and system operation and maintenance.

2. The green large-scale long-term energy storage system and method for electrically heating underground sealed aquifers according to claim 1, characterized in that, The underground sealed aquifer, including but not limited to lithological sealed aquifer, fault sealed aquifer, and oil / coal / hydrocarbon sealed aquifer, has good thermal capacity and thermal stability, and can store thermal energy for a long time; when heating the formation water, the dynamic pressure of the reservoir must always be lower than the reservoir fracture pressure; the depth, thickness and airtightness of the aquifer, including but not limited to, must be determined by geological exploration and simulation analysis to ensure energy storage efficiency and safety.

3. The green large-scale long-term energy storage system and method for electrically heating underground sealed aquifers according to claim 1, characterized in that, The aforementioned ground energy input system refers to the input of ground electrical energy (powered by the grid), new energy sources (including but not limited to wind energy and solar energy), thermal energy (heating and industrial waste heat) or nuclear energy into the underground energy storage system through transmission lines or energy conversion devices; electrical energy is converted into thermal energy through electric heating devices, heating and industrial waste heat are reinjected into the underground closed aquifer through formation water reinjection, and other forms of energy are converted into thermal energy through corresponding energy conversion devices.

4. The green large-scale long-term energy storage system and method for electrically heating underground sealed aquifers according to claim 1, characterized in that, The electric heating device is installed in an underground closed water layer and converts electrical energy into heat energy and steam kinetic energy through methods including but not limited to resistance heating, induction heating or electric arc heating. The design of the electric heating device must consider, but is not limited to, electromagnetic descaling, high temperature resistance, corrosion resistance and long-term stability requirements.

5. The green large-scale long-term energy storage system and method for electrically heating underground sealed aquifers according to claim 1, characterized in that, The heat exchange system includes an underground heat exchanger and a surface heat exchanger, which transfers heat energy to the ground through a circulating working fluid, wherein the circulating working fluid includes, but is not limited to, formation water, steam, crude oil or molten salt.

6. The green large-scale long-term energy storage system and method for electrically heating underground sealed aquifers according to claim 1, characterized in that, The energy output system converts thermal energy into electrical energy through a thermoelectric conversion device, or directly uses thermal energy for purposes including but not limited to heating and industrial processing.

7. The green large-scale long-term energy storage system and method for electrically heating underground sealed aquifers according to claim 1, characterized in that, The control system includes a ground energy input system control system and an energy output system control system, which are monitored and regulated by an intelligent control system. The system monitors in real time, including but not limited to underground temperature, pressure, and energy input and output parameters, and automatically adjusts the system's operating status according to demand.

8. The green large-scale long-term energy storage system and method for electrically heating underground sealed aquifers according to claim 1, characterized in that, Thermal energy storage involves injecting heat or industrial waste heat into underground closed aquifers via formation water reinjection. Electrical energy (powered by the grid), new energy sources (including but not limited to wind and solar energy), or nuclear energy are stored in underground lithological closed aquifers via electric heating devices, existing as high-temperature formation water or a mixture with steam. Thermal energy extraction involves extracting the stored thermal energy and steam kinetic energy from the heat exchange system via a circulating working fluid when needed.

9. The green large-scale long-term energy storage system and method for electrically heating underground sealed aquifers according to claim 1, characterized in that, The site selection and exploration in the method involves selecting a groundwater layer with good sealing as an energy storage site, conducting geological exploration and simulation analysis, determining the depth, thickness and sealing of the water layer, and estimating the maximum energy storage at the rupture pressure. The system installation in the method involves installing an electric heating device in an underground sealed aquifer, and constructing an energy input / output system and a control system on the ground. The energy storage process in the method involves converting electrical energy or other forms of energy into thermal energy through a ground-based energy input system and storing it in an underground lithological sealed aquifer. The energy extraction in the method involves extracting stored thermal energy through a heat exchange system when needed, and converting it into electrical energy or other forms of energy output. The system operation and maintenance described herein are achieved through a smart control system that monitors the system's operating status in real time and performs regular maintenance and repairs to ensure the long-term stable operation of the system.

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