CWM(Coal Water Mixture) is a mixed fuel that consists of coal, water and additives. The main advantages of CWM are reducing the oil consumption and the air pollution materials such as flyash, dirt, and $SO_x$. This paper presented a case study for the economic feasibility analysis of changing an existing coal-oil power plant to a CWM power plant. The economic analysis of changing a coal-oil power plant to a CWM power plant was based on the total annual incremental costs of two power plants. We found that this project was economically and environmentally acceptable.