Optimal Design and Operation of a Hydropower Reservoir Plant Using a WEAP-Based Simulation–Optimization Approach

Optimal design and operation of a hydropower reservoir is a complex optimization problem in terms of formulation and solution. In this study, a simulation–optimization model is developed for simultaneous design and operation of hydropower dams. WEAP (Water Evaluation and Planning) as the water resources planning simulation software is coupled with the Invasive Weeds Optimization (IWO) as the optimization routine. The developed simulation–optimization model is used for the Bakhtiari Dam hydropower plant in west of Iran. Two objectives for solving the problem are to maximize the energy generation and minimize the flood damage at a downstream target point. Two types of problems are investigated. The first problem only considers the optimal design of the hydropower plan, in which the decision variables include the storage capacity, minimum operation storage of the reservoir and the installed capacity of the power plant while the releases from the reservoir are determined using a predefined operation policy. In the second problem, simultaneous design and operation of the hydropower reservoir is examined where in addition to the design variables, the reservoir releases are also optimized as the operational variables. According to the results, although considering flood damage does not have much effect on design variables, but significantly affects the operation variables. Results show that the optimization of the design variables has more impact on the benefit gained from the system comparing the operational ones. Also, the standard operating policy (SOP) is an optimal or near-optimal operational solution for hydropower generation.