Key concepts [microgrids]
Microgrids can operate connected or isolated from a larger or main power system. The microgrid interconnected to a large-scale commercial power system depends, in many aspects, on the interconnected system. The author believes that the study of an independent microgrid is a good method to develop various interconnected microgrids. The key concepts, in a microgrid, are better presented as examples, highlighting the main aspects and characteristics of this type of small grids. Therefore, this chapter describes an example of a microgrid with a fuel cell combined cycle first. Next, the case of a microgrid with interconnected coal gasification fuel cell power generation and pumped hydropower generation is described.