This study evaluates the technical and financial feasibility of the 45 MW Kumbih-3 Hydropower Plant project in Aceh using a mixed-methods approach that combines quantitative and qualitative analysis. The technical assessment is based on historical discharge data of 31.5 m³/s, ranging from 11.62–34.77 m³/s and annual rainfall (2,765–2,931 mm), which support the determination of optimal capacity and a capacity factor of 62.47%. The financial analysis was conducted through six scenarios, namely low, moderate, high, historical discharge 1, and historical discharge 2. The results show that under the moderate scenario, the project is feasible with an NPV of Rp 251,352 million, a BCR of 1.14, an IRR of 11.15%, and a payback period of 23 years. However, the low scenario (20% decrease in capacity factor) results in a negative NPV of -Rp 437,659 million, while the high scenario (20% increase) yields a positive NPV of Rp 940,363 million. The historical discharge analysis provides additional insights into water flow uncertainty, with the historical discharge 2 scenario demonstrating feasibility, achieving an NPV of Rp 457,175 million, a BCR of 1.26, an IRR of 12.04%, and a payback period of 19 years. Expert validation emphasizes the necessity of constructing a pondage and applying fixed-price contracts to mitigate technical and financial risks. Overall, the project is considered feasible, strategic in reducing Aceh’s projected electricity deficit of 189 MW by 2030, and contributive to achieving Indonesia’s renewable energy transition targets.