Economic strategies affect the applicable technologies limits and reduced the possible emission reduction of a plant. Here in this paper, effect of economic strategies and parameters on the plant optimization is studied. Using exergy economic assessment and optimization with algorithm genetic, optimum design points for corresponding economic variables like interest rate is evaluated. Then effects of economic parameters variations on the sustainability, carbon dioxide emission and fuel consumption of the plant are investigated and presented for a combined cycle power plant. Results show changes in economic parameters causes the balance between cash flows and fix costs of the plan changes at optimum point. Steam and gas turbine design variables for the optimum points are also a function of economic parameters and their variations are presented in this paper. Results show that economic strategies can greatly limit the maximum reasonable carbon emission and fuel consumption reduction.