Design of water pumped storage systems: A sensitivity and scenario analysis for island microgrids

Abstract

The growing introduction of Renewable Energy Sources (RES) in small and isolated power systems may pose several integration challenges. Typically, this results in the necessity of performing RES curtailment to preserve the stability of the network. This has adverse consequences for the environment, as the replacement is assured by fuel-fired pollutant power stations. To avoid such issues, the RES variability can be compensated with storage systems, in particular Water Pumped Storage Systems (WPSS), which are particularly relevant in island contexts. In this work, we propose a new approach to help the decision-making processes of designing WPPS that are both technical and economically feasible and include the uncertainty of design parameters. This is done by using a metaheuristic optimization method Particle Swarm Optimization that finds out the solution that maximizes the Net Present Value of the project using a model that couples the energy balance model and the economic model. It was found that the input with most impact in the NPV of the projects is the wind energy availability. It is important to mention also the impact of the uncertainty of Capital Expenditure (CAPEX), which, when increases 50% combined with a project reduced lifetime, may lead to a negative NPV. The model, with the necessary adaptations, can be used to study WPSS on similar power systems, therefore contributing to a preliminary assessment of the technical and economic viability of this type of systems.