The VPS Cycle: Utility-Scale Power Storage via Liquid Air Production
D. Vandor, J. Dockter
Expansion Energy LLC, US
Keywords: Liquid Air
Abstract:The VPS Cycle stores off-peak, low-value electric power in the form of dense, liquid air. The storage of L-air in cryogenic vessels allows aboveground deployments, at any scale above, say, 10 MW. The Cycle is neutral as to the energy to be stored, accepting base- load power, wind and other renewable power, from adjacent power plants or wheeled from distant sources. The energy content of the liquid air is released by first pumping the liquid to a suitable pressure, warming the now compressed air by waste exhaust heat, and sending the hot, high-pressure air to the combustion chamber of a standard gas turbine. The cold energy of the stored liquid air is also recovered in a smaller “power loop” that drives a second generator. The working fluid in that smaller loop is also air. Together, the main generator and the loop air generator recover much of the energy used to produce the liquid air, yielding high thermal efficiencies and “round trip” efficiencies.