In today and also in future the impact of greenhouse gas emissions and the accelerated augmentation in global energy consumption have swift the transition towards greener energy sources. For this the renewable energy system has been using very frequently. The non-renewable and renewable energy systems are the categories of Distributed Energy Resources (DER). As the coupling technology for DERs, the major advantages of power electronics will be the potential for improving efficiency and the introduction of new control possibilities for providing ancillary services to the electric grid. This paper reviews most non renewable and renewable DER systems, and discusses the power electronics as the coupling technology in the light of the prospects and possible trends in the future. Also briefly describes the attributes of distributed generation (DG). A qualitative description of the role of power electronics in Non renewable energy system (Internal combustion engine, Micro turbine & Fuel cell systems) and Renewable energy system (Wind, Solar & Photovoltaic systems) has been presented.