The incorporation of Energy Storage Systems (ESS) in an electrical power system is studied for the application of
Energy Time Shift (ETS) or energy arbitrage, taking advantage of the turbinable energy discharged in hydro­
electric plants. For this, three storage systems were selected: Lithium-Ion Batteries (LIB), Vanadium Redox Flow
Battery (VRFB), and Hydrogen Storage Systems (H 2 SS). The spilled turbinable energy available at the Paute
Integral hydropower complex in the Republic of Ecuador is taken as the case study. Based on real data from the
operation of these plants, a distinctive element of the study, the performance of the selected energy storage
systems was analyzed applying the Analytic Hierarchy of Process for decision-making, where technical, eco­
nomic, and environmental criteria were considered. Electrical energy stored during the early morning seeks to
displace the thermal generation during peak hours, close to the demand centers. The results show that all the
storage systems analyzed satisfy the required demand, although VRFB is recommended for the ETS. From an
economic point of view, LIB represents the best alternative. From a technical point of view, H 2 SS is slightly
superior, while prioritizing environmental aspects, VRFB technology prevails. However, the selection of the best
ESS alternative must be continually evaluated, due to permanent technological changes. It is concluded that ESS
represent a viable alternative to improve the operational performance of hydroelectric plants, meet the vari­
ability of demand, improve the quality of the electrical energy delivered, and displace the pollution-generation
plants.