On April 30, the world's largest compressed air energy storage project was connected to the grid in Shandong for power generation, which is also a milestone in the application of new energy storage technology in China, which will improve the consumption capacity of new energy in China. How does this compressed air energy storage project work?
At the site of the 300 MW compressed air energy storage demonstration project in Feicheng, Shandong Province, the project was connected to the grid in the morning, sending the first kilowatt of electricity to the grid, which is also the world's largest compressed air energy storage project. The annual power generation capacity can reach 600 million kWh, which can meet the electricity needs of more than 200,000 households.
The demonstration project will start construction in February 2023 and will enter the trial operation stage after being connected to the grid for power generation. When the electricity consumption is low, the air at room temperature and pressure is compressed and stored, and the electricity is generated at the peak of the electricity consumption, just like a "super charging treasure".
General Manager of China National Energy Reserve: It actually converts electrical energy into mechanical energy, into pressure energy of air and a part of heat energy for storage. When power generation is needed, the high-pressure air is released, the turboexpander is driven to rotate, and the generator is connected to generate electricity, and 1 kilowatt-hour of electricity can finally release 0.72 kilowatt-hours of electricity.
One of the main features of the demonstration project is that the compressed air is stored in the nearby underground salt caverns by using local salt cavern resources, which can be used at any time.
General Manager of China National Energy Reserve: There are natural salt caverns in Feicheng, Shandong, which can be used as a gas storage for compressed air energy storage. The cost of natural salt cavern renovation is very low, with a cost of 830 yuan per kilowatt-hour per kilowatt-hour.
When the project generates electricity, compressed air enters the core power generation equipment such as turboexpanders from the salt cavern through gas pipelines.
Hou Hucan, Senior Engineer, Institute of Engineering Thermophysics, Chinese Academy of Sciences: The main equipment is like a heart, with many pipes connected in series, like blood vessels, and the gas from the salt cavern is fed into the expander for power generation.
You Daning, Deputy Director of the Control Center of State Grid Shandong Electric Power Company: At noon, the new energy is large, and during the load trough period, the excess power generation power is compressed into the salt cavern in the form of a compressor to store energy, and the electricity demand is helped to meet the electricity demand of the evening peak during the peak hour of the evening peak electricity load, with an annual rate of return of about 10%.
Underground salt caverns are transformed into gas storage resources
Artificial chambers open up new spaces
The compressed air energy storage project in Feicheng, Shandong Province, uses local salt cavern resources for gas storage. According to statistics, the mainland has more than one trillion tons of underground salt reserves, and salt cavern resources are abundant. How to make good use of these resources, and what new technologies will be used for compressed air energy storage?
The reporter learned that the salt cavern of the Shandong Feicheng compressed air demonstration project has a depth of 1,000 meters underground, a gas storage capacity of more than 500,000 cubic meters, and an air pressure of 100 atmospheres.
A salt cavern is a cave in an underground salt layer that is formed by injecting water to control the dissolution of rock salt. According to the technical conditions, the volume can reach hundreds of thousands of cubic meters, according to different depths, a large amount of gas can be stored at a pressure of up to 20 megapascals, and the mainland salt cavern resources are mainly distributed in Shandong, Jiangsu, Anhui, Hubei, Shaanxi and other places.
Zhou Xuezhi, Deputy Mayor of Feicheng City, Shandong Province: There are 46 pairs of salt wells, and each pair of salt wells will form an underground salt cavern space of 500,000 cubic meters to 1 million cubic meters after mining, which is an ideal gas storage place for large-scale compressed air energy storage. It is expected that the scale of compressed air energy storage will reach more than 3,000 megawatts by 2025.
In addition to salt caverns, in order to expand underground gas storage resources, in Jiuquan, Gansu, Zhongning, Ningxia, Xinyang, Henan and other places, new energy storage pilot demonstration projects with artificial chambers as gas storage are under construction, and the biggest feature of the project is the use of manual excavation to build gas storage.
Zuo Xiaohong, general manager of Jiuquan pressure storage project of Northwest Institute of China Energy Construction China Power Engineering: Make full use of the solid geological conditions of the artificial chamber more than 100 meters deep underground to store super-large capacity of high-pressure air at room temperature. Compared with the salt cavern compressed air energy storage power station, the energy storage volume expansion of the artificial chamber is not limited, and the system pressure, temperature and other parameters can also be more than doubled.
Experts said that the utilization of domestic idle salt cavern resources and the promotion of artificial chamber technology will accelerate the implementation of compressed air energy storage projects.
Xu Dongjie, Deputy Chief Engineer of the Electric Power Planning and Design Institute: Among the new energy storage pilot demonstration projects, there are more than 10 compressed air energy storage projects, covering different technical routes such as salt caverns and artificial chambers. A number of 300MW compressed air energy storage projects using artificial chamber gas storage have started construction and are expected to be put into operation in the next two years.
Compressed air energy storage projects are growing strongly
It will drive a 100-billion-level industrial chain
Domestic compressed air energy storage projects have shown a strong growth momentum, how is its development in the world, and what upstream and downstream industries will it drive?
In Yingcheng, Hubei Province, a 300 MW compressed air energy storage project with a total investment of 1.95 billion yuan, driving the upstream and downstream industrial chains close to thermal power, power equipment, underground engineering and other industries, and the core equipment has been basically localized.
Gao Bo, General Manager of China Energy Construction China Power Engineering Jiangsu Institute Power Generation Company: The localization of large-scale compressors, turboexpanders, heat storage and exchange equipment, and gas storage facilities in the upstream is of great significance, and the industry has ushered in a period of rapid development.
In addition, compressed air energy storage technology is also developing rapidly in the world, and technologies such as liquid air energy storage, constant pressure compressed air energy storage, and isothermal compressed air energy storage have been demonstrated. The United Kingdom, the United States, Canada and other countries have built new compressed air energy storage power stations, and Australia, Switzerland, Spain, Chile and other countries are also carrying out industrialization promotion.
Liu Yongdong, Deputy Secretary-General of China Electricity Council: With the rapid development of compressed air energy storage technology, efficiency improvement and cost reduction, the industrialization process of compressed air energy storage has accelerated. In the future, the installed capacity is expected to accelerate expansion. Among them, the market size of upstream core equipment may grow significantly.
Experts said that compressed air energy storage is still in the early stage of industrialization, with a long industrial chain and wide coverage, and it is expected to drive the scale of upstream and downstream industries to reach 100 billion yuan in the future.
Chen Haisheng, Director of the Institute of Engineering Thermophysics, Chinese Academy of Sciences: With the gradual increase in the proportion of renewable energy in the entire energy system, the demand for long-term energy storage such as compressed air energy storage for more than 4 hours or even 10 hours will increase significantly.
Source: CCTV News