Compressed Air Energy Storage: Types, systems and applications

The intermittency of renewable energy sources is making increased deployment of storage technology necessary. Technologies are needed with high round-trip efficiency and at low cost to allow renewables to undercut fossil fuels. The cost of lithium batteries has fallen, but producing them comes with a substantial carbon footprint, as well as a cost to the local environment. Compressed air energy storage (CAES) uses excess electricity, particularly from wind farms, to compress air. Re-expansion of the air then drives machinery to recoup the electric power. Prototypes have capacities of several hundred MW. Challenges lie in conserving the thermal energy associated with compressing air and leakage of that heat, materials, power electronics, connection with the power generator, and grid integration