Comparison of Fuzzy and Nonfuzzy Optimal Reservoir Operating Policies

Abstract

This paper compares reservoir operating policies obtained from fuzzy and nonfuzzy explicit stochastic dynamic programming. The reservoir operation problem for the Mansour Eddahbi dam in Morocco can be formulated as either a classical stochastic dynamic programming (SDP) problem, where the objective function stresses energy maximization with particular volumes being released for irrigation, or a fuzzy stochastic dynamic programming (FSDP) problem, in which both hydropower generation and irrigation are considered as fuzzy constraints and aggregated by the weighting method. System performance is estimated from simulation based on continuous reoptimization models using either the cost-to-go function generated by the SDP algorithm, or the membership function generated by the FSDP algorithm. Despite major differences in the mathematical representation of operating objectives and/or constraints, we show that both formulations yield similar measures of system performance.