Today's, policy makers, governments, and academic experts in flourishing societies are interested in employing power systems considering high reliability, quality, and efficiency factors. Moreover, climatic concerns force power system appliers to utilize these systems more environmental friendly. To obtain the mentioned aims, MGs (microgrids) act as key solutions. MGs are invented not only to operate power systems more reliable and efficient but also to penetrate CHP (combined heat and power)-based DG (distributed generation) into power systems with an optimal control on their generation. This paper presents a new optimal operation of a CHP-based MG comprising ESS (energy storage system), three types of thermal power generation units, and DRPs (demand response programs). In this paper, DRPs are treated as virtual generation units along with all of realization constraints. In a multi-objective self-scheduling optimization problem of a MG, the first objective deals with minimizing total operational cost of the CHP-MG in an OPF-based formulation and the second refers to the emission minimization of DGs. The proposed model implements a simple MIP (mixed-integer programming) that can be easily integrated in the MGCC (MG central controller). The effectiveness of the proposed methodology has been investigated on a typical 24-bus MG. (C) 2013 Elsevier Ltd. All rights reserved.