AbstractThis paper presents a System of Systems (SOS) approach to understand, analyze, and design modern energy Smart Grids using Model-Based Systems Engineering (MBSE) methodologies. The concept and definition of a Smart Grid as SOS is presented and Smart Grids are analyzed in the form of detailed architectural artifacts with System Modeling Language (SySML) using industry standards. As part of this research, the design space for Smart Grids was viewed from a logical, behavioral, physical, and techno-economical perspective for the optimal integration of various systems. In summary, this paper uses Methods, Processes, and existing Technologies (MPTs) in systems engineering (SE) and extends them to SOS perspective to help provide an end-to-end life cycle view of a fully functional energy Smart Grid system; in addition, we complement the NIST reference model with an Enterprise layer to address specific enterprise strategies. The paper intends to provide an insight into the methodologies that are involved to realize a functional Smart Grid as a self sustaining energy enterprise and presents the challenges and benefits of achieving the above goal.