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The objective of this study is to assess the technical and economic potential of four alternative processes suitable for post-combustion CO₂ capture from natural gas-fired power plants. These include: CO₂ permeable membranes; molten carbonate fuel cells (MCFCs); pressurized CO₂ absorption integrated with a multi-shaft gas turbine and heat recovery steam cycle; and supersonic flow-driven CO₂ anti-sublimation and inertial separation. A common technical and economic framework is defined, and the performance and costs of the systems are evaluated based on process simulations and preliminary sizing. A state-of-the-art natural gas combined cycle (NGCC) without CO₂ capture is taken as the reference case, whereas the same NGCC designed with CO₂ capture (using chemical absorption with aqueous monoethanolamine solvent) is used as a base case. In an additional benchmarking case, the same NGCC is equipped with aqueous piperazine (PZ) CO₂ absorption, to assess the techno-economic perspective of an advanced amine solvent. The comparison highlights that a combined cycle integrated with MCFCs looks the most attractive technology, both in terms of energy penalty and economics, i.e., CO₂ avoided cost of 49 $/t_CO2 avoided, and the specific primary energy consumption per unit of CO₂ avoided (SPECCA) equal to 0.31 MJ_LHV/kg_CO2 avoided. The second-best capture technology is PZ scrubbing (SPECCA = 2.73 MJ_LHV/kg_CO2 avoided and cost of CO₂ avoided = 68 $/t_CO2 avoided), followed by the monoethanolamine (MEA) base case (SPECCA = 3.34 MJ_LHV/kg_CO2 avoided and cost of CO₂ avoided = 75 $/t_CO2 …