The performance of conventional steam power plants is still severely limited by heat losses in the exhaust gas. This study proposes a waste-heat recovery concept for the Derna Steam Power Plant based on a supercritical carbon dioxide (sCO2) closed Brayton cycle. The goal is simple. Get more power out of the boiler exhaust stream without burning more fuel. The fundamental mass- and energy-balance equations were used to model the thermodynamic behavior by numerical simulation in Engineering Equation Solver (EES). It was discovered by means of a detailed parametric analysis that the operating conditions strongly affect the performance of the cycle. The highest net work and the highest overall efficiency are obtained at 76.8 bar and 75.8 bar, respectively. The maximum thermal efficiency is achieved at about 230 bar. Temperature settings also count for a lot. Lowering the compressor inlet temperature and raising the exhaust-heat temperature from 300 °C to 500 °C increased the net power output from 2050 kW to over 4344 kW and increased the thermal efficiency from 22.8% to 32.01%, which reduced the back-work ratio. The above results provide solid support for the technical feasibility of the proposed scheme. Therefore, more attention should be paid to the practical implementation of the Derna plant, with more detailed economic assessments and exploration of integration with renewable energy sources.................... Keywords: ...................supercritical carbon dioxide; closed Brayton cycle; Derna Steam Power Plant