Like the larger power grid, microgrids rely on power generation resources. Currently, the primary fuel source of the grid is natural gas, with the rest coming from nuclear, renewables, and a diminishing level of coal. A microgrid is a self-sufficient energy system that manages distributed energy resources (DERs) and the interconnected electrical loads within a defined electrical boundary of a discrete geographical footprint such as a business center, hospital complex, research facility, educational campus, etc. Why use natural gas in a microgrid instead of diesel, solar or other fuels? We explore the question in this fourth part of a Microgrid Knowledge Special Report Series on the reliability-as-a-service model and the onset of the affordable microgrid. 2 A microgrid can operate in either grid-connected or in island mode, including entirely off-grid. TULSA—The United States is the world's largest natural gas producer. It only stands to reason that the nation's huge endowment of clean-burning natural gas resources should represent a foundational cornerstone of any efforts to update and modernize the domestic electricity grid. Indeed, power. As the demand for reliable, scalable, and sustainable power continues to grow, more facilities are exploring the integration of natural gas microgrids and on-site power plants into their existing energy systems.