Master of Science / Department of Architectural Engineering and Construction Science / Fred L. Hasler / Typical building power supplied from power plants has significantly evolved over the last century. After power is generated and transferred from the power plant, it is distributed to the customer. The concept of Microgrid was introduced to address increasing concerns with power reliability requirements for some facilities. The Microgrid is a localized electric grid that can operate autonomously from the traditional electric grid (Macrogrid). Compared with generator sets, a Microgrid provides a faster system response and recovery to either whole or part of the electric load for a facility. The Microgrid can operate under two operation conditions: grid-tied mode and island mode. When it is working individually like an “island”, the system is not providing or receiving disturbance to or from the Macrogrid. The purpose of this paper is to give a detailed introduction of Microgrid and present research and conclusion about its feasibility. This report references previously published research to explain what a Microgrid is. Also, two detailed case studies provide a discussion about the feasibility of the Microgrid in terms of its reliability, economics and environmental impact - air quality. Although there are many challenges that Microgrids are facing, there are quite a number of reasons to consider them. The goal is to balance the benefits and challenges of Microgrids depend on each case. No doubt, the existing power grid will still provide the majority of power supply for global population. However, many companies and government-funded laboratories are investing time and money into research and development of Microgrids. With the advancement of the Microgrids, it is likely that Microgrids will be playing a larger role in providing secure, reliable energy to the building industry.