Hydropower Repowering in the Amazon: An Integrated Framework for Sustainability Assessment and Feasibility Analysis

The Brazilian Amazon constitutes a critical energy frontier where hydropower expansion frequently conflicts with environmental preservation. This study addresses this challenge by proposing an integrated framework that couples techno-economic feasibility assessments with systematic sustainability metrics for hydropower repowering. Applied to the Taguatinga Small Hydropower Plant (SHPP), the methodology revealed significant gains: turbine efficiency increased from 72% to 90%, the capacity factor improved from 0.63 to 0.76, and an additional 281 kW (1878 MWh/year) was generated at just 2159 US$/kW—substantially lower than new construction costs. The repowering achieved exceptional sustainability indices: Environmental Index = 1.00 (Very High), Socioeconomic Index = 0.76 (High), and overall Sustainability Index = 0.88 (Very High), with an absence of significant additional emissions associated with changes in the reservoir’s surface area. This study addresses the notable scarcity of operational methodologies in the literature that systematically couple multidimensional sustainability metrics with techno-economic feasibility analysis for hydropower repowering. The results demonstrate that this approach can increase SHPP installed power by 15–440% across the Legal Amazon while minimizing environmental impacts. The method offers a replicable solution for the climate–water–energy nexus, optimizing water use efficiency while supporting decarbonization goals and addressing regional energy poverty through sustainable infrastructure modernization.