The analyzed facility integrates a gas turbine and steam turbine, which together drive a generator to produce a net electrical output of approximately 400 MW. Natural gas combustion occurs sequentially within two combustion chambers operating at temperatures of 1100°C and 1280°C, respectively, with an excess air supply. Resulting hot exhaust gases—primarily composed of N₂, O₂, CO₂, and H₂O—are directed into a Heat Recovery Steam Generator (HRSG). Here, steam is generated at three different pressure levels: high-pressure (HP, 110 bar), intermediate-pressure (IP, 26 bar), and low-pressure (LP, 4.2 bar). The HP steam expands through a high-pressure turbine to an intermediate pressure of 27 bar, after which it mixes with IP steam from the HRSG, is reheated, and then expanded through an intermediate-pressure turbine down to 5 bar. Finally, this stream combines with LP steam from the HRSG and undergoes expansion in the low-pressure turbine.
The objectives of this study are to (1) develop a detailed steady-state simulation in Aspen Plus, accurately representing the plant’s operational performance. (2) perform a techno-economic analysis that quantifies capital expenditures (CAPEX) and operational expenditures (OPEX) and evaluates critical economic indicators such as Net Present Value (NPV) and the Levelized Cost of Electricity (LCOE). A sensitivity analysis is conducted to systematically examine the effect of natural gas price variability on economic performance, providing valuable insights for effective risk management and informed strategic decision-making. Ultimately, this research delivers essential data and robust analytical findings regarding the economic resilience of combined-cycle natural gas power plants in the context of fluctuating fuel prices.