In view of expressing the coal-fired power plant in 'up-time' in quantitative terms, a steady state operational availability analysis needs to be developed. For simplicity, the entire thermal system is broken down into four subsystems. These subsystems are further subdivided into a number of units. Formulation of operational availability of each subsystem, a well known Markov birth-death process has been employed. Finally, the overall availability index of coal-fired power plant has been evaluated by integrating all subsystems as a whole. Also, a semi-empirical module has been developed to predict thermal performance of coal-fired power plant. It includes the mass balance, energy balance, and thermodynamic property relations for working substance followed by empirical correlations for steam bled pressure. For the assessment of the economic effectiveness of the investments, widely used net present value method has been employed. After validation, a simulated annealing technique for optimization has been used for maximization of profit in terms of net present value (NPV) of complex coal-fired power plant.