Sustainable use of spilled turbinable energy in Ecuador: three different energy storage systems

Abstract

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 hydroelectric plants. For this, three storage systems were selected: Lithium-Ion Batteries (LIB), Vanadium Redox Flow Battery (VRFB), and Hydrogen Storage Systems (H2SS). 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, economic, 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, H2SS 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 variability of demand, improve the quality of the electrical energy delivered, and displace the pollution-generation plants.