The deployment of hydropower plants alongside other renewable energy facilities can contribute to meeting electricity demand while simultaneously reducing greenhouse gas emissions. Historically, the high initial capital cost of these plants, primarily attributed to the expense of conventional turbines, has limited attention to this capacity. The utilization of Pump as Turbine (PAT) at this power generation scale provides an opportunity to reduce costs. In this study, the performance of a PAT power plant has been investigated both experimentally and numerically. To optimize the utilization of available capacity, modifications to the inlet angle of main and splitter blades have been examined numerically. Statistical analysis of the flow rate at the pressure-reducing station revealed that a significant portion of the operating time occurs within the medium and high flow rate ranges. Optimal values of parameters for designing the runner geometry were selected by considering the results of modifications across the operating range, and the vorticity parameter was employed to evaluate the performance of optimized runner in comparison with the original runner. Results demonstrate increased energy recovery and reduced losses in the target ranges. Maximum efficiency improvement occurred at flow rate of 198 m3/h, with an efficiency increase of 3.41%. With the intensification of environmental consequences resulting from global warming and the inherent limitations of fossil fuel resources, international energy policy approaches have shifted toward the exploitation of renewable energy sources. Over the past decade, the development of clean energy generation technologies and the optimization of energy conversion and recovery systems in this domain have become one of the principal axes of engineering research. Reports from the International Energy Agency indicate that by 2050, the share of renewable sources in global electricity supply will reach approximately 70%.The realization of sustainable development goals necessitates maximum utilization of low-carbon energy resource capacity to reduce greenhouse gas emissions and improve energy cycle efficiency .