Comparative exergoeconomic evaluation of the latest generation of combined-cycle power plants

Combined-cycle power plants are one of the main pillars of the global power sector. Worldwide, different stakeholders are on the race of developing highly efficient power plants through investing in metallurgical, thermodynamic, and technological developments. The purpose of this study is a comprehensive exergoeconomic evaluation and comparison of two cases of the latest combined-cycle power plant generation - the triple pressure F-Class and H-Class technologies of the Siemens AG. Taking into consideration the specific design differences, rigorous simulations are set up by implementing real plant data prior to an application of exergetic, economic and exergoeconomic analyses to evaluate the processes. The exergy analysis shows a higher exergetic efficiency of 58.3% for the H-Class, while this value is calculated to be 56% for the F-Class. The NPV of the H-Class exceeds that of the F-Class by 69% after 20 years of operation. Accordingly, the total capital investment of the H-Class is recovered one and a half years earlier. The levelized costs of electricity generated by the H-Class and F-Class are 31.7 $/MWh and 32.5 $/MWh, respectively. The exergoeconomic evaluation demonstrates that on the component basis the gas turbine system has the highest contribution to the overall cost caused by investment and irreversibilities within the processes. Design improvements obtained from an iterative exergoeconomic optimization of some important design parameters (decision variables) result in further reduction of the levelized cost of electricity for the H-Class design.