Introduction

Microgrids are a collection of loads and local generations that are also normally connected to the legacy grid. However, the grid connection may be simply for reliability reason, if the local generations and loads match. The grid may just serve as a trading link depending on the mutual need. Considering its many other benefits, microgrid market is growing more rapidly; nowadays, more than 1,840 projects that represent a power capacity of almost 19,280 MW are under development worldwide. According to a research report by the market research and strategy consulting firm, Global Market Insights, Inc, the microgrid market will exceed $19 billion by 2024 [1]. This chapter presents an overview, technical challenges, and future important issues of microgrid developments.