Microgrid
This cluster of associated consumer and producer nodes acts as a single controllable entity and is able to operate in either grid-connected or island mode.
[4] In many non-industrialized countries, microgrids that are used to provide access to electricity in previously unelectrified areas are often referred to as "mini grids".
[5]The focus of campus microgrids is aggregating existing on-site generation to support multiple loads located in a tight geographical area where an owner can easily manage them.
[16][17] Community microgrids can serve thousands of customers and support the penetration of local energy (electricity, heating, and cooling).
[19] These microgrids are generally not designed or intended to connect to the macrogrid and instead operate in an island mode at all times because of economic issues or geographical position.
Typically, an "off-grid" microgrid is built in areas that are far distant from any transmission and distribution infrastructure and, therefore, have no connection to the utility grid.
[21][22] In some cases, off-grid microgrids are indeed incorporated into a national grid or 'macrogrid', a process that requires technical, regulatory and legal planning.
[33][34] These microgrids are being actively deployed with focus on both physical and cyber security for military facilities in order to assure reliable power without relying on the macrogrid.
There are many manufacturing processes in which an interruption of the power supply may cause high revenue losses and long start-up time.
[citation needed] In a microgrid, energy storage performs multiple functions, such as ensuring power quality, performing frequency and voltage regulation, smoothing the output of renewable energy sources, providing backup power for the system, and playing a crucial role in cost optimization.
[41] In the islanded mode, the real and reactive power generated within the microgrid, including that provided by the energy storage system, should be in balance with the demand of local loads.
Microgrids offer an option to balance the need to reduce carbon emissions with continuing to provide reliable electric energy in periods of time when renewable sources of power are not available.
Microgrids also offer the security of being hardened from severe weather and natural disasters by not having large assets and miles of above-ground wires and other electric infrastructure that need to be maintained or repaired following such events.
[44][45][46] Modern optimization methods can also be incorporated into the microgrid energy management system to improve efficiency, economics, and resiliency.
[42][47][46][48] Microgrids, and the integration of distributed energy resource (DER) units in general, introduce a number of operational challenges that need to be addressed in the design of control and protection systems, in order to ensure that the present levels of reliability are not significantly affected, and the potential benefits of Distributed Generation (DG) units are fully harnessed.
A widely used economic optimization tool is the Distributed Energy Resources Customer Adoption Model (DER-CAM) from Lawrence Berkeley National Laboratory.
Another free tool is the Solar Alone Multi-objective Advisor (SAMA), an open-source microgrid optimization software program designed to optimize hybrid energy system sizes economically (primarily powered with solar photovoltaic systems) using metaheuristic algorithms based on specific load profiles and meteorological data.
The open source grid planning tool OnSSET has been deployed to investigate microgrids using a three‑tier analysis beginning with settlement archetypes (case‑studied using Bolivia).
[57] A fully centralized control relies on a large amount of information transmittance between involving units before a decision is made at a single point.
Implementation is difficult since interconnected power systems usually cover extended geographic locations and involve an enormous number of units.
[61] This level often involves the prediction of weather, grid tariff, and loads in the next hours or day to design a generator dispatch plan that achieves economic savings.
During these situations the central controller should select one of the microgrids to be the slack (i.e. master) and the rest as PV and load buses according to a predefined algorithm and the existing conditions of the system (i.e. demand and generation).
[67] A two-year pilot program, called Harmon’Yeu, was initiated in the spring of 2020 to interconnect 23 houses in the Ker Pissot neighborhood and surrounding areas with a microgrid that was automated as a smart grid with software from Engie.
[70] The system consists of a three-tiered architecture with a cloud-based monitoring and control service, a local embedded gateway infrastructure and a mesh network of wireless smart meters deployed at over 500 buildings.
[32] Non-technical loss (NTL) represents a major challenge when providing reliable electrical service in developing countries, where it often accounts for 11-15% of total generation capacity.
[71] An extensive data-driven simulation on seventy-two days of wireless meter data from a 430-home microgrid deployed in Les Anglais investigated how to distinguish NTL from the total power losses, aiding in energy theft detection.
