Cascade hydropower systems optimal operation: implications for Iran\u2019s Great Karun hydropower systems

Saeed Jamali,Behzad Jamali

doi:10.1007/s13201-019-0939-3

Saeed Jamali, Behzad Jamali

Open Access

https://doi.org/10.1007/s13201-019-0939-3

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Abstract

Water resources optimal allocation in large complex water systems such as multi-reservoir dams is a challenging task for decision makers. Wide range of decision variables as well as difficult nonlinear optimization problems (highly nonlinear problems) make it difficult to use optimization approaches. Alternatively, simulation–optimization approaches are then providing more realistic and applicable solution. This study presents a simulation–optimization framework for extracting monthly long-term operation rules. This method is applied to Karun River Basin including six multi-objective (hydropower generation, agricultural and environmental water supplement) cascade dams. In this regard, Water Evaluation and Planning System is used as the simulation model coupled with an optimization model. Decision variables include (1) monthly variation of top of buffer parameter in reservoirs where the reservoir releases water to meet the required demand and (2) monthly priority for filling of the reservoirs. Two-objective NSGA-II algorithms are used to minimize sum of squares unmet energy and agricultural water demands within two scenarios. The results show that the reliability of the generation of hydroelectricity in Karun River Basin has been increased sufficiently. Results showed that the scenario 2 (an aggregate energy demand at the system level) has better performance in terms of reliability (91.4% compared to 89.6%) and efficiency of centralized approach in which all reservoirs are operated in an integrated management scheme.

Highlights

Optimization techniques have been used widely in water resources planning and management studies, especially in reservoir operation problems
In the spite of the development and growing use of optimization techniques, the vast majority of reservoir planning and operation studies are based on simulation modeling (Lund and Guzman 1999)
The convergence of the objective function is increased as the number of generations rise. In both scenarios, there is no considerable change in the objective function during the last generations

Summary

Introduction

Optimization techniques have been used widely in water resources planning and management studies, especially in reservoir operation problems. Reservoir operation is a complex problem that involves many decision variables, multiple objectives as well as considerable risks and uncertainties (Loucks 1997). Many of optimization models are not well performed in modeling large water systems. In the spite of the development and growing use of optimization techniques, the vast majority of reservoir planning and operation studies are based on simulation modeling (Lund and Guzman 1999). The operation rules are often evaluated using simulation models (Loucks 1997). Simulation models remain necessary to examine the detailed performance of system operation (Lund 2006)

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Results

Conclusion