Accelerating the transformation of energy structure and promoting the grid connection of renewable energy power generation is an important initiative to address climate change and the development of renewable energy. Energy storage technology can improve the stability of power grid and enhance the utilization rate of renewable energy. Among the energy storage technologies

compressed air energy storage has been widely studied for its high efficiency

low investment cost and environmental friendliness. Compared with the conventional constant-capacity compressed air energy storage technology

isobaric compressed air energy storage avoids the unavoidable buffer air in the constant-capacity compressed air energy storage system

enables the compressor and expander to operate efficiently at constant discharge pressure

and eliminates the throttling loss in front of the expander unit. The advantages of isobaric compressed air energy storage technologies are introduced

and the isobaric compressed air energy storage technologies are classified into underwater compressed air energy storage

pumping-compensated compressed air energy storage

solid-compensated compressed air energy storage

and gas-phase-change-compensated compressed air energy storage. Moreover

the basic principles

research progress and challenges of the above four types of isobaric compressed air energy storage technologies are discussed.Finally

the development of the isobaric compressed air energy storage technologies is prospected.