Indonesia will have electrified 99.63% of its territory by 2022. From 2010 to 2022, Indonesia’s electrification increased linearly. By then, the average person will be using 1,173 kWh of electricity. By 2022, renewable new energy mixes will only increase by 0.14%, making up 12.3% of the country’s primary energy mix. This shows that fossil energy still dominates the national energy mix in keeping with the Sustainable Development Goals. Indonesia’s installed capacity is 8,671 MW, and its hydroelectric potential is 75,091 MW. The potential for implementation gap is still really large. Besides, hydropower has meager running costs and is among the most environmentally friendly renewable energy sources. Research can quickly produce hydroelectric power plants, providing a new energy source. The turbine rotor mainly makes up the plant. The advantages of the computational fluid dynamics method include the ability to analyze pressure and velocity contours, thereby facilitating the production of more detailed research. This work investigates the effects of geometric variations in aspect ratio (AR) and phase-shift angles (PSA) on the two-stage Savonius turbine-hydro rotor performance. Three-dimensional modeling and the computational fluid dynamics (CFD) methodology were used in the work. The contours of pressure, velocity, and coefficient of power for every modification are part of the research results. The Savonius two stages use PSAs of 5°, 35°, and 65°. The Savonius two-stage AR are 1, 1.5, and 2. The study results show that geometric changes significantly affect the Savonius hydro-turbines’ performance. PSA 5° has a Cpmax of 0.31 and works best on the AR 1 version.