The second generation of Compressed Air Energy Storage deals with the thermal issues to achieve higher efficiences. Currently, there are a number of companies and demonstration plants. Efficiencies between 70 and 80% are forecasted.



Applications: long term-storage, short-term storage, arbitrage, distributed/off-grid storage, frequency or voltage regulation, reserve grid capacity, mobility

Compressing air is a way to store energy, and combining this with a generator yields a way of storing electricity. Systems have been in use in applications such as starting large engines or in the propulsion of mine locomotives. At a larger scale, the technology is used to shift the energy demand for smaller and larger electricity grids, providing storage. Air heats up when compressed, and cools down when decompressed, generating a natural barrier for efficiency. To counter this, some installations use an external source of heat, like natural gas. Efficiencies up to 45% are attainable.

The variable frequency series screw compressor takes advantage of the stepless speed regulation of the frequency charger, and start screw air compressor gently through the controller or the PID regulator inside of the controller to improve the start and operation mode of the motor. 

Prediction and evaluation of energy saving: