Current research activities witness a special focus on the integration of DERs (distributed energy resources) and ESSs (energy storage systems) in MG (micro-grid) applications. In this paper, the coordination between MG and main grid for the required variable load demands is accomplished using EMS (Energy Management System). For this purpose, an advanced EMS in a typical MG working in grid connected mode is introduced. The developed EMS is able to determine the optimal operating strategies that minimize the energy costs, pollutant emissions, and hence maximizing the output of the available renewable energy resources. The established EMS is formulated as a nonlinear optimization model with different equality and inequality constraints for proper solution based on the AIMMS (Advanced Integrated Multidimensional Modeling Software). The performance of AIMMS is compared with other commonly used algorithm such as GA (genetic algorithms) to clarify the efficient and robustness of AIMMS solver.