A micro-grid is a local energy grid with control capability, which means it can disconnect from the traditional grid and operate autonomously. A micro-grid can also be a power-generating unit used where no grid is available such as in remote and poorly accessible area or where no national grid infrastructure yet exists such as in many emerging countries.
The grid connects homes, businesses, industries, ports/airports and other buildings to central power sources, which allow us to use machinery, appliances, heating/cooling systems and electronics. This interconnectedness means that when part of the grid needs to be repaired or grid-outages occur due to over-capacity, everyone is affected and this is where micro-grids can be a better alternative.
A micro-grid generally operates while connected to the grid, (should one exist), but importantly, it can break off and operate on its own using local energy generation in times of crisis like storms or power outages, or for other reasons.
Distributed generators, batteries, and/or renewable resources like biomass-fed power generating units using a boiler and turbine can power micro-grid of required capacity (size usually vary between 500KWh to 20MWh). Depending on how it’s fueled and how its requirements are managed, a micro-grid might run indefinitely.
A micro-grid connects to the grid at a point of common coupling that maintains voltage at the same level as the main grid unless there is some sort of problem on the grid or other reason to disconnect. A switch can separate the micro-grid from the main grid automatically or manually, and it then functions as an island.
A micro-grid not only provides backup for the grid in case of emergencies, but can also be used to cut costs, or connect to a local resource that is too small or unreliable for traditional grid use. A micro-grid allows communities isolated from access to national grid to be energy independent and, in some cases, more environmentally friendly.
A micro-grid comes in a variety of designs and sizes. A micro-grid can power a single facility like a mine processing plant or a micro-grid can power a larger area like a whole village community. Micro-grid is part of a larger long-term goal to create areas that can produce the same amount of energy it actually consumes. Hence a farming community can produce its own energy biomass feedstock to run a micro-grid powered through a small biomass power generating plant, rendering the community self-reliant on its energy needs.
Micro-grids may allow in some cases to stabilize the cost of energy thus rendering access to electricity to an entire community both affordable and reliable.
[Information Source: US Energy Department]