Combined gas turbine and steam turbine integrated electric drive system (COGES)
In a COGES system gensets are driven by gas and steam turbines. Waste heat recovery boilers exploit the gas turbine exhaust and produce superheated steam (at around 30 bar) for the steam turbine genset. While gas turbine efficiency decreases at low load the steam turbine recovers the lost power and feeds it back into the system. The result is a fairly constant fuel consumption curve over a wide operating range. See also COGES propulsion system of the MILLENNIUM cruise liner.