Abstract: A method of modeling a power plant including a plurality of major components including at least one of a Heat recovery Steam Generator (HRSG), a steam turbomachine, a condenser, and a cooling system includes establishing a desired power plant output criteria, selecting a plurality of major components to form the power plant, running a model module to create thermodynamic model of the major components to form a power plant model, running an equation module to develop a set of equations for the power plant model, running a performance module to solve the set of equations for the power plant model, running a cost module to determine a cost of the power plant model, determining whether the power plant model meets the desired power plant output criteria, and generating a result that indicates the performance and cost of the power plant.