The improvement of the technical and economic performance of electric power generation is a continuous
effort. An example is the step from simple-cycle (open-cycle) gas turbines to combined-cycle powerplants.
Later, STIG and HAT cycles were introduced and, more recently, the LOTHECO concept was
proposed. This concept unites features of the standard combined-cycle powerplant and of the HAT cycle by
using low-temperature external heat––and not the exhaust energy of the gas turbine––to humidify the high
pressure combustion air. (LOTHECO is the acronym for ‘‘combined-cycle powerplant with integrated lowtemperature
heat’’.)