Air Products & Chemicals, Inc.

http://www.airproducts.com

The Liquid Air Energy Storage (LAES) system utilizes proven cryogenic processes to store off-peak energy in the form of liquid air above ground, and delivers the energy in periods of high demand. LAES uses off peak-grid electricity to compress, cool, and store air as a cryogenic liquid. When the power grid requires additional energy, the liquid air is pumped to high pressure, heated to working temperature and then expanded to generate power. The heat can come from various suitable sources such as waste process heat. By storing energy in the form of liquid air the storage energy density is considerably increased, 20x higher than Compressed Air Energy Storage and more than 100x higher than Pumped Hydro. The high energy density and low footprint of only 0.15–0.2 ft2/kWh allows for storage of large amounts of energy at virtually any location on the grid. The LAES system will provide storage capacity ranging from 10-300MW, with a runtime of up to 12 hours and a roundtrip energy storage efficiency of up to 85% (defined as the energy output from the turbo expander over the energy input from the air compressor). To further improve the system efficiency, the LAES system could be operated in a semi-adiabatic mode in which part or all heat of compression can be stored during the charging cycle and later utilized to increase power output during the discharging cycle. Although it requires additional capital, this will generate significantly more power without additional fuel.