Recently, Distributed Generation Technologies have gained more attention because of the steady decrease of fossil fuel use and increased load demand. In addition, Microgrid technologies are used to integrate such sources into the main network by drastically improving the utilization of energy via local production and load control. Consequently, improved quality and reliability is achieved. Most studies of such networks focus on operational and investment costs, however neglect the environmental impact. Based on these two criteria, an optimization model is established, in order to determine the viability and the environmental contribution of Microgrid. This model includes high penetration of Fuel Cell units and Renewable Energy Sources. In order to accomplice this, the Harmony Search algorithm was used in order to perform hourly optimizations on a Low Voltage Microgrid. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.