Mini Grid Electrification
A mini grid, also sometimes referred to as a "micro grid or isolated grid", can be defined as a set of electricity generators and possibly energy storage systems interconnected to a distribution network that supplies electricity to a localized group of customers. They involve small-scale electricity generation (10 kW to 10MW) which serves a limited number of consumers via a distribution grid that can operate in isolation from national electricity transmission networks. This power delivery architecture can be contrasted to a single customer system such as in the case of a solar home system (SHS). Where there is no distribution network interconnecting customers it can be connected to a centralized grid systems, where electrical energy is transmitted over large distances from large central generators where local generators are generally not capable of meeting local demand. Mini-grids have a unique feature as they can operate autonomously without being connected to a centralized grid. However the mini-grid may be designed to interconnect with the central grid which means it operates under normal conditions as part of the central grid with disconnection occurring only if power quality needs to be maintained. For instance in the case of a central grid failure. Alternatively, a mini-grid may be designed to operate autonomously in a remote location with the option to connect to a central grid when grid extension occurs. A mini-grid can be supplied by all sorts of energy resources and power plants, however most of the time a mini-grid will use low AC voltage (220-380V) with a centralized production and a storage system and will have an installed capacity of between and 5 and 300kW even though bigger systems exist. Implementation of mini-grids have proved to have a positive social impact by fostering and improving the local governance structure through the involvement of the community in the decision making process linked with the energy system. Furthermore, mini-grids are often the only economically viable option of electrifying rural communities. There are hundreds of diesel-based isolated grids worldwide which lend themselves to be retrofitted with renewable energy technologies. Sharing limited resources and power among users in a mini-grid requires rules and a tariff structure that ensures sustainability in the operation. In general, mini-grids involve intense preparation to ensure the systems operation and maintenance will be sustainable.