microgrid

A microgrid is a localized energy system that can operate connected to the main electrical grid or switch to island mode to serve local loads independently. Comprising distributed energy resources, storage, and controllable loads, microgrids enhance resilience for facilities and communities, especially during outages or grid stress. Common resources include solar photovoltaics, wind, small gas or diesel generators, and battery storage, all coordinated by control equipment and protection systems.

Operation hinges on the ability to operate in grid-connected or islanded mode and to transition automatically in response to disturbances. A microgrid controller and an energy management system balance generation, storage, and demand, regulate voltage and frequency, and optimize cost and emissions. Control is typically hierarchical, with primary protection and fast balancing, secondary restoration, and tertiary optimization of economics and power quality.

Applications vary by size and ownership. Microgrids are common on campuses, hospitals, military bases, industrial parks, remote communities, and residential developments. They offer resilience during outages and can provide grid services such as voltage support and frequency regulation when connected to the broader system.

Economic and technical challenges include capital costs, regulatory and market barriers, cybersecurity, standards for interconnection, and the reliability of distributed resources. Despite these, microgrids can reduce outage costs, defer infrastructure investments, lower energy expenses, and enable greater use of renewable energy through localized control.