Hundreds of large power plants and a nationwide, interconnected distribution network produce and deliver electricity to homes and businesses in the United States. While our electric system is quite reliable (though nowhere near the best compared across nations), cascading failures do shut down parts of the network, and natural disasters, such as hurricanes, snow storms, and earthquakes, can cause widespread power blackouts. Microgrids, partly- or fully-independent sources of localized electrical power, can add resilience and sustainability to the power system. To learn about the characteristics, applications, and motivations for microgrids, we talk with Dr. Chris Marnay, retired staff scientist at Lawrence Berkeley National Laboratory, who is an expert on microgrids and sustainable energy systems.