This System Reference Document (SRD) defines the framework elements, associated ontology, and modelling methodology for designing the Smart Energy Grid Reference Architecture using the Smart Grid Architecture Model (SGAM), with potential expansion to describe the interaction between the grid and heat/gas systems, and including easily understandable examples. The Smart Energy Grid Architecture Model (SGAM) is a three-dimensional architectural framework that can be used to model the exchange of information between different entities located within the smart energy arena. The three dimensions are Domains, Zones, and Layers: • Domains identify a set of roles associated with 5 different areas of the energy grid: bulk generation, transmission, distribution, distributed energy resources, and customer premises • Zones represent the 6 hierarchical levels of power system management: Market, Enterprise, Operation, Station, Field, and Process • Layers represent the 5 aspects of information exchanges: Business Objectives, Functional Processes, Information Models, Communication Protocols, and Components