Recently, several salt cavern compressed air energy storage power stations have appeared in many places in China. The compressed air energy storage technology adopted by these power stations is one of the main new energy storage technologies. In the salt cave, to realize the access and utilization of electricity. What are the highlights of this new energy storage technology and what is the market prospect?
Use the salt cave to create an oversized "green
Power Bank"
Salt cave compressed air energy storage power station is about to be put into commercial use
Located in Jintan District, Changzhou, Jiangsu, this salt cavern compressed air energy storage power station is the first national pilot demonstration project for compressed air energy storage. After more than a year of construction, at this time, the power station is undergoing final installation, finishing, and commissioning work.
Lin Tong, general manager of China Salt Huaneng Energy Storage Technology Co., Ltd.: The first grid connection test was successfully carried out on September 30, which can support the peak load of about 1/20 of the peak load of Jintan local power grid, and can also be used for the trough peak load regulation of the power grid. A contribution of 60,000 kilowatts.
The peak-shaving and valley-filling of the power grid is the function of compressed air energy storage. Its working principle is that the power station uses low-valley electric energy to compress air, and then uses the high temperature and high pressure generated when the compressed air is released to drive power generation at the peak of electricity consumption, thereby improving the power grid regulation capacity and new energy absorption capacity. This is a large-capacity physical energy storage technology.
Tsinghua University Professor Mei Shengwei: The air source is at the bottom. The high-pressure air passes through the high-pressure cylinder, the low-pressure cylinder, and drives the air turbine to the generator from the bottom up. The storage process of electrical energy into pressure potential energy and compressed heat energy is the entire physical process. Therefore, it has no emissions and is completely clean energy storage.
Not only that, experts told reporters that the space used to store compressed air here is not a gas tank, but a natural underground salt cavern. The underground salt cavern is controlled by techniques such as cavity-making after the salt is collected by water solution to form a pear-shaped cavern with large volume, good sealing, and high stability. It is a natural high-pressure air storage tank.
Tsinghua University Professor Mei Shengwei: It’s about 800 to 1,000 meters underground, and the pressure resistance can reach 200 atmospheres. The efficiency of the salt cave compressed air energy storage and electricity exchange is 62.7%, and it can output 0.62 kWh of electricity by inhaling 1 kilowatt-hour of electricity. The efficiency should be the highest among similar compressed air energy storage power stations.
The installed capacity of clean energy has increased greatly, and the demand for energy storage is urgent
In recent years, with the large-scale development of photovoltaic and wind power, the installed capacity of clean energy in my country has increased rapidly. In order to make these "see the sky and eat" new energy more safe and efficient, in July this year, the National Development and Reform Commission and the National Energy Administration first proposed to accelerate the development of new energy storage. It is proposed that by 2025, the installed capacity of new energy storage technology will reach 30 million. Above kilowatts. Salt cave compressed air energy storage is one of the main new energy storage technologies. What market demand does it have and what is the prospect of large-scale development?
The reporter learned that by the end of 2020, the installed capacity of clean energy such as photovoltaics and offshore wind energy in Jiangsu Province has exceeded 40 million kilowatts, accounting for more than 20% of the total installed capacity of power generation. In Jintan, Changzhou, the installed capacity of new energy is expected to account for 65% by 2025. At the same time, in areas with high power consumption such as southern Jiangsu, the grid load peak-to-valley difference sometimes exceeds 30%. In this context, the construction of large-scale energy storage facilities has become a more urgent need.
Chen Haisheng, chairman of the Zhongguancun Energy Storage Industry Technology Alliance: Compressed air energy storage is more suitable for large-scale. It can achieve more than 100 megawatts, long energy storage time of more than 4 hours, low cost, and very long life. It has relative comparative advantages in the long-term, large-capacity energy storage market.
Compared with the construction of steel tanks and other pressure vessel storage methods, the use of underground caves such as salt caves to build large-capacity power stations will significantly reduce the costs of raw materials and land. In Feicheng, Shandong, this salt cave compressed air energy storage power station with an installed capacity of 10 MW was completed and connected to the grid in September. The second phase of the 300 MW project has been launched, and the system cost is about 1.2 billion yuan.
General Manager of China National Energy (Beijing) Technology Co., Ltd. Discipline: The current cost of compressed air energy storage is about 5,000 to 6,000 yuan per kilowatt, which is not much different from pumped storage. First of all, the scale must be further enlarged. The larger the scale, the higher the efficiency and the lower the unit cost. And it is especially suitable for spaces like salt caves, because the cost is very low, and the investment quota for compressed air energy storage can be greatly compressed, which can be reduced by at least about 1/3 of the order of magnitude.
The reporter learned that my country's salt cavern resources are widely distributed, and there are more than 2,000 eligible for use, of which only about forty are being used, and they are currently mainly used for storing natural gas and oil. If relevant resources are activated, the salt cave compressed air energy storage market is expected to reach hundreds of billions of yuan, and it will also drive the market for air compressors, heat exchangers, heat storage and gas storage and other related equipment.
Li Yaoqiang, Chairman and Secretary of the Party Committee of China Salt Industry Co., Ltd.: The cavities formed by the real salt caves are hundreds of millions of cubic meters, and with the production of mine salt every year, these salt caves are still increasing, so a large number of salt caves are left unused. . Judging from the existing salt cavern resources and technical capabilities, it is estimated that during the 14th Five-Year Plan period, the salt cavern energy storage capacity with an installed capacity of 10 million kilowatts can be achieved, accounting for one third of the national target.
Exploring the pricing mechanism of air energy storage
Desire to be on par with pumped storage
△ CCTV Finance "Punctual Finance" column video
Experts said that in the field of large-capacity energy storage, compressed air energy storage is still in the early stage of scale compared with mature technology and a certain scale of installed capacity. Based on the current advantages of flexible site selection and low construction costs, the commercial use of compressed air energy storage still needs to solve some key issues.
In the Jiangsu Jintan Salt Cave compressed air energy storage power station project, the construction team is discussing an important issue before commercial operation, that is, the price mechanism.
At present, the pricing mechanism of compressed air energy storage power stations is still in the exploratory stage. In May of this year, the National Development and Reform Commission issued the "Opinions" on the pricing mechanism of pumped storage power stations, clarifying that pumped storage power stations implement a two-part electricity price. One is to recover the operating costs of pumping and power generation through the electricity price to reflect the value of providing peak shaving services; the other is to recover other costs through the price of capacity electricity to reflect the value of its auxiliary services. Industry insiders told reporters that if the compressed air energy storage power station can achieve the same two-part electricity price as pumped storage energy, it will ensure its economy.
Li Yaoqiang, Chairman and Secretary of the Party Committee of China National Salt Industry Co., Ltd.: The state has not yet set a price for it, but if compressed air energy storage can adopt a price system similar to the price of pumped storage electricity, its economic efficiency is still rewarding. Guaranteed.
Industry insiders said that the development of compressed air energy storage still needs to be explored through demonstration projects to promote commercialization, engineering and standardization. While verifying technology to improve performance, gradually establish a suitable business model. On the power generation side, it is combined with clean energy to promote large-scale grid integration and consumption; on the grid side, it serves the safety of the power system and plays the role of peak shaving and valley filling.
Chen Haisheng, chairman of the Zhongguancun Energy Storage Industry Technology Alliance: Keeping track of pumped storage is a development trend. Of course, in the long term, the price mechanism still depends on the gradual establishment of the electricity spot market, and the price of electric energy of different qualities is different.
Transfer from: CCTV Finance
