With the increase in the penetration of renewable energy generation, the development of long-time energy storage has become a trend, and the technical routes for large-scale long-time energy storage mainly include pumped storage, molten salt thermal storage, liquid current storage, compressed air storage, and hydrogen storage in five categories. At this stage, the pumped storage application is the most mature, but the advantages of compressed air energy storage is large scale, high efficiency, low cost, environmental protection and clean, and can get rid of geographical restrictions, is expected to become a supplement to pumped storage.
Compressed air energy storage belongs to the long-time energy storage, can be realised for a long time higher than 4 hours or days, months of charging and discharging cycle of the energy storage system, in regulating the new energy generation fluctuations in the role of the outstanding advantages.
According to the Chinese academy of sciences institute of engineering thermophysics energy storage research and development centre director XuYuJie introduction, in the future, our country’s power system is a new type of new energy as the main power system, and wind power, photovoltaic power generation and other renewable energy power generation with fluctuation and intermittent, if large-scale access to the power grid, it will cause security risks. At this time, the need for energy storage system as a flexible regulating resources to regulate the power system. Compressed air energy storage is a highlight.
“Compressed air energy storage technology is not new, traditional compressed air energy storage technology has been applied in Germany, the United States for many years, but the traditional compressed air energy storage technology is dependent on fossil fuels, the need for large natural caves, energy storage efficiency is low and other issues, large-scale promotion is always limited.” Xu Yujie said that China’s advanced compressed air energy storage system recycles compressed heat, no longer uses fossil fuels, and can be used in a variety of forms such as above-ground storage devices, artificial chambers and underground natural caves to build storage chambers. In addition, the system greatly improves energy storage efficiency.
Currently, using 100 MW advanced compressed air energy storage technology, China has built the first international 100 MW advanced compressed air energy storage demonstration power station, and successfully connected to the grid to generate electricity. The power station is located in Zhangbei County, Hebei Province, is the world has been built and operated in the project, the largest and best performance of the new compressed air energy storage power plant. It can generate up to 132 million kWh of electricity annually, providing peak power protection for about 50,000 users. At the same time, it can save 42,000 tonnes of standard coal and reduce 109,000 tonnes of carbon dioxide emissions annually.
What are the advantages of compressed gas energy storage over other new types of energy storage? Overall, it can be summarised as safe, long life and strong explosive power. Firstly, compressed gas energy storage is very safe. Take the liquefied carbon dioxide energy storage project as an example, because carbon dioxide liquefaction is very easy, so the storage of it only needs a few megapascals of pressure, do not have to worry about high pressure storage of gas brought about by the hidden danger, at the same time the carbon dioxide is non-toxic, non-flammable and explosive, the safety of itself is very good. In addition, because it is all mechanical devices, the life of compressed air energy storage systems can reach 30-50 years under normal maintenance. “Compressed air energy storage is a physical process based on thermal cycling, which has natural advantages in terms of safety and performance degradation, and is considered to be one of the most promising large-scale energy storage technologies.” Based on these advantages, Chen Haisheng, a researcher at the Institute of Engineering Thermophysics of the Chinese Academy of Sciences, has said that the application of compressed air energy storage technology is of great strategic significance and huge market demand for the realisation of the country’s dual-carbon strategic objectives and the improvement of the natural environment.
It is worth mentioning that the energy burst of compressed air energy storage is relatively strong. This can work directly in some special applications. In the case of diesel engines used in large ships, for example, compressed air is normally stored in a pressure tank and acted directly on the piston through a special starter valve to turn the crankshaft before starting fuel injection. This arrangement is more compact and cheaper than an electric starter motor of the same size, and can provide the extremely high power bursts necessary without placing excessive loads on the ship’s generator and distribution system.
For compressed air energy storage systems, China is further strengthening large-scale demonstrations and applications, accumulating experience in engineering design and construction, and developing a complete and mature industrial chain to further accelerate their construction and application.
Post time: Sep-14-2023
