The availability of new generation combined heat and power (CHP) plants in high efficiencies and diverse sizes in the recent decade has attracted many industrial and residential centers to decentralized power generation via natural gas. This achievement of new technologies has been studied in this paper aimed at decreasing long-term power generation costs. The recent increasing trend for use of district heating systems besides recent improvements in CHP technologies has contributed to more discussions about the so-called “energy hub” approach for supply of energy. Energy hub is an approach for joint operation of several energy carriers to supply electrical, heat, etc loads. Through this approach, all capabilities of different energy supply devices are optimally utilized to decrease operational costs. In this paper, a new comprehensive formulation has been introduced for optimal planning of devices, which unlike the common approaches, has employed the precise operational characteristics of CHP units in solving the optimal operation and planning problems. The planning results have been presented for a test case, and amount of decrease in costs as well as the effect of using precise CHP model in the problem formulation have been studied.