Islands in the Storm: Integrating Microgrids into the Larger Grid

Evening is falling and the skies darken. A storm has been brewing all day, and now it settles in. Rain begins to fall and the winds increase. This is the type of storm that promises to keep utility field crews up all night. As night progresses, the storm starts to cause damage to the electrical system with downed trees, lightning strikes, and flooding problems. Sections of the city begin to experience power outages, and from a nearby hill, one can see areas of darkness as lights flicker out. Crews are being dispatched to locate problems and start the repair process. This is the way the electrical system responds to major storms today. Steps are taken to restore service as quickly as possible, but some outages are inevitable. If we look at this storm and its effects from the vantage point of a time in the future when microgrids have been established throughout the electrical system, however, things will be very different. This article discusses some of the engineering issues associated with the integration of microgrids into the larger electrical grid. It does not attempt to address all of the issues associated with microgrids, nor does it represent Southern California Edison´s position on the deployment or merits of microgrids. Much more work in this area is still needed.