Multiobjective Optimization Analysis of Gas–Steam Combined Cycle Coupled with Photovoltaic-Driven Hydrogen Electrolyzer System

In the context of accelerating the transformation of the global power industry to clean and low-carbon energy, increasing the proportion of renewable energy applications has become a key path to optimize the performance of power plants. In order to achieve the goal of optimizing the performance of the combined cycle power plant, this study proposes an integrated scheme coupling a gas-steam combined cycle (GSCC) system with a photovoltaic-proton exchange membrane (PV-PEM) water electrolysis hydrogen production system. The resulting hydrogen is blended with natural gas in specific proportions to form a blended fuel, which is then utilized in the GSCC system. A mathematical model of the coupled power generation system is established, addressing a multiobjective optimization problem that considers thermal efficiency, total investment cost, and carbon emissions. The resulting mixed-integer nonlinear programming model is solved by using GAMS software. The Pareto frontier derived from the multiobjective optimization yielded an optimal hydrogen blending ratio of 50%, corresponding to a system efficiency of 66.25%. It was further found that higher hydrogen blending ratios lead to increased carbon emission reduction (up to 150.21 m³/MWh) and greater fuel savings (up to 20.42 m³/s). Thus, the proposed system successfully identifies an optimal configuration to achieve the stated goal of performance optimization.