Understanding Microgrids as the Essential Architecture of Smart Energy

This paper describes microgrids in the smart grid architecture, autonomous systems interacting through the Energy Services Interface as defined by the OASIS Energy Interoperation [1] specification. We define for the purposes of system architecture what a microgrid is. The several types of existing microgrids are defined, based on the motivations of those that operate them, the technologies they contain, and the operating characteristics they produce. This paper includes an analysis today's variety of microgrids and how they are leading us to future We describe a model that represents component systems in a microgrid as systems able to negotiate optimal outcomes for energy allocation based only on the internal self-knowledge of each system, interacting through the means of software agents. These agents are each able to respond to changes of mission as conveyed by the timely application of abstract sets of priorities [policies]. We term the process whereby these outcomes are developed “micromarkets.” We further describe hoe how microgrids themselves can be organized into larger microgrids which are themselves operated by micromarkets. We discuss the benefits of the micromarket model of integration. Micromarkets provide a simple model that can support each type of existing microgrids, both in technology, and in motivation. Autonomy in microgrids simplifies central control architectures. We also discuss how the architecture of agents and micromarkets can be used to encapsulate the complexity of legacy systems, providing a path for existing systems into the future even as they reduce the effort required for the incorporation of new technologies.