A microgrid is a localized grouping of electricity generation, energy storage, and loads that normally operates connected to a traditional centralized grid (macrogrid). This single point of common coupling with the macrogrid can be disconnected. The microgrid can then function autonomously. Generation and loads in a microgrid are usually interconnected at low voltage. From the point of view of the grid operator, a connected microgrid can be controlled as if it were one entity.
Microgrid generation resources can include fuel cells, wind, solar, or other energy sources. The multiple dispersed generation sources and ability to isolate the microgrid from a larger network would provide highly reliable electric power. Produced heat from generation sources such as microturbines could be used for local process heating or space heating, allowing flexible trade off between the needs for heat and electric power.
Micro-grids were proposed in the wake of the July 2012 India blackout:
- Small micro-grids covering 30–50 km radius
- Small power stations of 5–10 MW to serve the micro-grids
- Generate power locally to reduce dependence on long distance transmission lines and cut transmission losses.
GTM Research forecasts microgrid capacity in the United States will exceed 1.8 gigawatts by 2018.