The US Department of Energy defines a microgrid as a group of interconnected loads and distributed energy resources within clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid. 1 Microgrids can work in conjunction with more. The Berkeley Lab defines: "A microgrid consists of energy generation and energy storage that can power a building, campus, or community when not connected to the electric grid, e. 2 A microgrid can operate in either grid-connected or in island mode, including entirely off-grid. This article aims to provide an overview of microgrid fundamentals: what a microgrid is and what a microgrid can do. What is a microgrid? The answer depends on who is asking and answering.