© 2017 IEEE.In this paper, the Economic Power Dispatch (EPD) of the thermal power plants in Iraq is studied. The main goal of this study is to minimize the high fuel costs of the Iraqi power generation system by controlling the outputs for each generating unit via the optimization algorithms. Though the Iraqi network is composed of the total 31 thermal units, it is considered as a large-scale system, and the actual number of units that are synchronized with the network is limited to 19 units only. Particle Swarm Optimization (PSO) is proposed as a solution to be employed to solve the EPD challenge for the Iraqi network. PSO is applied to the thermal units of Iraqi network with quadratic form of fuel equations. The result of the PSO algorithm obtained has been compared with outputs of other algorithms, including Genetic Algorithm (GA) and Novel Bat algorithm (NBA).