E2E > TB 635: Microgrids, engineering, economics, experience


This TB covers the definition of microgrid, and describes the necessary equipment and methods needed to implement one. Technology and business case development are described in detail and benefits analysis conducted for two example microgrids.


Microgrids are electricity distribution systems containing loads and distributed energy resources, (such as distributed generators, storage devices, or controllable loads) that can be operated in a controlled, coordinated way either while connected to the main power network or while islanded.




Generators covers all sources possible at the scales and within the context of a microgrid, e.g. fossil or biomass-fired small-scale combined heat and power (CHP), photovoltaic modules (PV), small wind turbines, mini-hydro, etc.

Storage Devices includes all of electrical (e.g. SMES), electrochemical (e.g. batteries), mechanical (e.g. flywheel) and heat storage technologies, together called energy storage systems (ESS). While the microgrid concept focuses on a power system, thermal storage can be relevant to its operation whenever its existence affects operation of the microgrid.

Controlled loads, such as automatically dimmable lighting or delayed pumping, are particularly important to microgrids simply by virtue of their scale. Inevitably in small power systems, load variability will be more extreme than in utility-scale systems. The corollary is that load control can make a particularly valuable contribution to a microgrid.


There are three major objectives/benefits of microgrids:

  • to provide power quality and/or reliability (PQR) different from the local standard of service, e.g. to serve particularly sensitive loads such as emergency services
  • to use local assets unlikely to be chosen or difficult to operate by the centralized grid, e.g. Small-scale renewable resources, or interconnected plug-in electric vehicle (PEV) batteries
  • to present a controlled profile to the wider power system, e.g. to damp the variability of a local renewable resource and buffer the grid from it.

The brochure also covers equipment required as well as cost benefit analysis for use in motivation of microgrid installation.

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