This paper will propose a novel power generating system concept including an auxiliary, backup and emergency power source. Existing aircraft employ an auxiliary power unit (APU) and a ram air turbine (RAT) for power generation besides aero-engine generators. An APU works prior to starting propulsion on the ground and as a backup power plant during flight. The RAT is activated due to the need to maintain the essential systems in the case of an emergency situation. Both systems are optimized on conventional aircraft in which hydraulic, pneumatic and electric systems are supplied for control and equipment.Although a conventional aircraft needs hydro pumps and air compressors, the coming of a new era of more-electric architecture for aircraft and propulsion will be the stimulus to improve aircraft systems . In more-electric aircraft, the authors focus on the low-pressure spool generation system of aero-engines. This system is anticipated for large power sources that supply electricity to a bleed-less system, though the high-pressure spool-generating capability is restricted because of the mechanical integrity of the power off-take and aero-engine control stability. LP generation contributes not only to the control stability for aero-engines but also to potential survivability of power generation since it is possible for LP spool to generate energy during wind milling.This paper will discuss the overview of the more-electric aircraft utility resource. To introduce the substituting technology of a conventional power-generating system that relies on RAT and APU, the authors will propose a low-pressure spool-generating architecture involving any power management measures, upon the electrical power demand estimation.