What is a microgrid?
A microgrid is a distributed (or decentralized) electricity grid that is comprised of various small sources which are capable of operating both parallel and independently to the main grid. Its main goal is to achieve a reliable and efficient supply of electricity and ensure an electrical service of higher quality, while making the service more secure and sustainable, especially in urban and rural areas.
Microgrids are modern, small-scale versions of the centralized electrical system. Just as in the case of conventional power grids, microgrids can supply electricity grid users, however, this is accomplished locally as they have the necessary mechanisms to generate, distribute and regulate the flow of electricity. That’s why they are an ideal solution for incorporating renewable resources on a community level and allow end-customer participation. They make up the basic components of the perfect electricity grid.
“A microgrid is a local energy grid with control capability, which means it can disconnect from the traditional grid and operate autonomously.
A microgrid consists of local generation, a storage system, users (or consumers) and a connection point with the grid, which may not exist if the microgrid is an island.
Power, is supplied -locally, and to a large extent – by renewable sources (mainly solar and wind power), but due to their intermittence, storage energy systems also have to be included so that the necessary energy can be supplied when the users’ energy needs are not covered by local generation, or in cases when excess energy can be stored if it is not in use.
In the same way that the grid connects facilities, hospitals, businesses and homes to supply the different appliances -large or small- that are found in these buildings, the microgrid can provide power to just one facility or a group of them. But there is always the chance that the grid may fail, and this is the point when the microgrid comes into play.
Although the microgrid usually operates while connected to the grid, it can be “disconnected” so that it works on its own by means of local generation. Both the microgrid and the grid are connected at a common connection point with the same voltage in such a way that in the event of a problem occurring on the electric grid, it is possible to disconnect the microgrid from the main grid and then allow it to operate as an island.
Homes, and above all, public facilities, hospitals, businesses or any other facility of this kind, cannot afford to remain off the grid due to power outages or because the weather conditions are less than ideal. Therefore, different systems with the appropriate size, all work together and are configured specifically, in addition to having controllers integrated, so that the operation is performed in an automated and efficient way. This gives users peace of mind, in the knowledge that energy will be available to cover their needs when it is needed .
In addition to covering possible disconnections, microgrids can also help costs to be reduced. They rely on energy independent areas, and at the same time, allow them to be more environmentally friendly by reducing polluting emissions.
A microgrid does not have a certain size or design. Also, it can supply one facility or a number of different energy independent buildings. Districts can be created where the energy that is produced is the same as the energy consumed.
By way of example, we can highlight the Pegasus Project, which analyses how seven microgrids work at seven different pilot areas.
Faced with the challenge of using renewables permanently, the flexibility of efficient energy management that calls for the design of microgrids, offers numerous advantages, such as:
- Improved energy efficiency.
- Minimized general energy consumption.
- Reduced greenhouse gas and polluting emissions.
- Improved service quality and reliability.