Electricity generation from conventional fuel fired power plant is in threat due to rising demand of fossil fuel, inefficient power conversion technology, CO 2 emission to environment. Also Energy security, global environment concern, fastest development of technology are driving countries towards clean fuel, alternative technology for efficient and reliable power generation. An externally fired micro gas turbines (EFmGT) are novel technology that opens a new possibility to use alternative fuel like renewable energy for small and medium scale power and heat (CHP) generation in distributed system with micro gas turbine technology. In literature simple model of externally fired micro gas turbine to study the dynamic behaviour is absent. In this study the aim is to develop a simple model of externally fired micro gas turbine based on poly generation system in Matlab/Simulink environment and derived model used to analyse the effect of operational parameters and forecast performance of real EFmGT configurations.