Optimal Reservoir Operation for Hydropower Production Using Particle Swarm Optimization and Sustainability Analysis of Hydropower

Abstract

This paper presents a derivation of optimal operation policies for hydropower production in the Upper Seti Hydro-Power Reservoir system in Nepal using particle swarm optimization (PSO) technique. A reservoir operation model for the Upper Seti project is formulated with an objective of maximising the annual hydropower production operated at a weekly time scale subjected to various physical and operational constraints. An elitist-mutated PSO (EMPSO) technique is applied for solving the weekly reservoir operational model, and the EMPSO-based solutions are found to result in 3% more hydropower than the planned hydropower production. The reservoir operation policies are also compared for wet, dry and normal water years, and it is noted that there exist significant differences among the release policies for those hydrologic conditions. Later, the reservoir operation model is modified with an objective of minimising the annual sum of squared deviation between weekly energy production and target hydropower. Then the hydropower analysis is carried out for various target hydropower values with an aim of finding suitable firm-power for the project. The performances of various reservoir operation policies are evaluated using reliability, resilience and vulnerability measures. The sustainability of the system is evaluated by computing the sustainability index, which is then used to evolve suitable hydropower targets. It is found that a target hydropower of 4.8 GWh with a sustainability index of 0.75 may result in better overall performance of the system.