An analysis for the effect of the annualized cost of a component on the production cost in 1000-kW gas-turbine cogeneration system was studied by utilizing the generalized exergy balance and cost-balance equations developed previously. Comparison between typical exergy-costing methodologies were also made by solving a predefined cogeneration system, CGAM problem. It was successful to identity the component which affects the unit cost of system’s products decisively. It has been found that the cost of products are crucially dependent on the change in the annualized cost of the component whose primary product is the same as the system’s product. On the other hand, the change in the weighted average cost of the product is proportional to the change in the annualized cost of the total system.