LTA-CAES - a low-temperature approach to Adiabatic Compressed Air Energy Storage

Most of the recent approaches on Adiabatic Compressed Air Energy Storage (A-CAES) aim at Thermal Energy Storage (TES) at high temperatures. High TES temperatures together with high pressures intrinsic to CAES are not easy to handle. In order to avoid this technical challenge, we introduce a low-temperature Adiabatic Compressed Air Energy Storage (LTA-CAES) plant. We select and design multistage radial compressors and expanders with single stages rotating with different speeds allowing for intermediate cooling and reheating of the air flow. The proposed LTA-CAES design shows roundtrip efficiencies in the range of 52-60%, slightly lower compared to those envisioned for high temperature A-CAES. However, it can be shown in an economic analysis that its fast start-up characteristics and wide-ranging part load ability overcompensates the lower cycle efficiencies with regard to plant profitability.