ABSTRACTDesign and modernization of the micro turbojet engine technology have an important problem related to fuel consumption in terms of economics and environmental. For this purpose, in this study, first, energy and exergy efficiencies of the Jet A-1 and seven different alternative fuels were examined. Then, Exergy—based sustainability indicators were evaluated via exergetic irreversibility seperately. For this purpose, operational data of SR-30 micro-turbojet engine was taken as reference. According to this, the exergy efficiencies of engine as fuel for blending of methanol and ethanol were fixed with 22.35% and 20.56%, respectively. At the end of the study, some evaluations about alternative fuels and sustainability were made.