Compressed air energy storage technology is a new type of energy storage technology. It mainly utilizes the surplus electricity during off-peak hours to compress air and store it in a high-pressure sealed facility. During peak electricity demand, it is released to drive a gas turbine to generate electricity.
Compressed air storage refers to storing large amounts of renewable energy using compressed air under high pressure, and then storing it in large underground caverns, depleted wells, or aquifers. During off-peak hours, such as evenings or weekends, an electric motor drives a compressor to compress air into a specific underground space for storage. Then, during peak hours, a specially constructed gas turbine releases the compressed air underground to generate electricity. Although the gas turbine still requires natural gas or other fossil fuels for power, this technology represents a more efficient way of utilizing energy.
I. Principles of Compressed Air Energy Storage Technology
Compressed air energy storage utilizes the surplus electricity generated during off-peak hours of the power system. An electric motor drives an air compressor to compress air into a large, sealed underground space that serves as a storage chamber. In this way, non-storable electrical energy is converted into the pressure potential energy of compressed air and stored in the storage chamber.
When the system's power generation is insufficient, compressed air is mixed with oil or natural gas through a heat exchanger and burned, then fed into the gas turbine to generate electricity, meeting the power system's peak-shaving needs. The energy storage subsystem, consisting of a compressor, motor, and gas storage chamber, stores low-cost electricity generated during off-peak hours in compressed air storage chambers such as caverns or abandoned mines. During energy storage, the electric generator and compressor are coupled together via a coupling, while the gas turbine is decoupled.
During peak load periods of the power system, compressed air combustion drives a gas turbine to generate electricity. The gas turbine, combustion chamber, heater, and other power generation systems are coupled with the electric generator to the gas turbine and decoupled from the compressor.
II. Significance of Compressed Air Energy Storage Technology
Energy storage technologies that exist in the world include pumped hydro storage, compressed air storage, superconducting electromagnetic storage, flywheel storage, high-efficiency battery storage, and fuel cell storage. Compared with other energy storage technologies, compressed air storage has unique advantages and significance.
1. Air is the best choice for "energy multimedia". The vigorous development of solar, wind, wave and nuclear energy is a global trend, but there is often a state of asynchronous supply and demand and supply and demand imbalance. Only air can convert, store and use various forms of energy, making it the best choice for "energy multimedia".
2. Significant economic and social benefits. Calculated at one-third of the electricity generation, this can save 400 million tons of coal annually, equivalent to the annual output of dozens of medium and large-sized coal mines. Moreover, the benefits are continuous, resulting in enormous economic and social benefits, saving a large amount of resources, and promoting sustainable economic and social development.
3. High safety factor and low environmental pollution. If the gas storage tank leaks, the pressure inside the tank will drop suddenly. Air will neither explode nor burn, posing no risk of explosion or environmental pollution, making it a relatively safe and clean energy storage method.
