Abstract
Microgrids, as small-scale power systems, comprise various types of distributed energy resources (DERs) installed next to loads. Islanding, as a salient feature of microgrids, requires adequate installed dispatchable capacity to fully supply local critical loads when disconnected from the utility grid. There is however a great potential that this installed capacity is underutilized, resulting in negative economic impacts. This paper investigates the microgrid unused capacity in the islanded operation, and further determines the value of this unused capacity, thus creating stepwise generation price bids. A microgrid optimal scheduling model is developed for the purpose of assessment in this paper, which is further used to study a test microgrid for a period of one year.