Evaluating hydropower operational flexibility with exogenous uncertainties

Abstract:

The operational flexibility of hydropower is identified as its capability to schedule the optimal timing of power production to provide reserves, and also to respond quickly to changing power system needs. This characteristic paves the path for the system to adapt to dynamic and intermittently changing conditions. However, hydropower operation can be influenced by many factors that affect its actual flexibility. These factors are categorized through various sets of operational, environmental and regulatory constraints as well as imposed exogenous uncertainties. In this study, we identify how water availability, hydrological coupling, release and environmental constraints would contribute to the operational flexibility of the system when responding to stream-flow and net-load scenarios at the plant level. The hidden operational flexibility potentials will emerge when comparing the derived optimal decision strategies with traditional rule curves based on which the reservoir system is operating. Our generic approach is to formulate the hydropower operation as a large scale multistage stochastic optimization problem with medium-term temporal resolution in order to derive global optimal strategies under uncertainty.