Modeling hydropower plant system to improve its reservoir operation

Abstract

One way of improving water management is increasing the efficiency of utilization of dam reservoirs. Even small improvement in reservoir operation can lead to large benefits. But there is no universal solution for reservoir operation problems. Hence, it is necessary to study the system and determine optimal reservoir operation guides for each scheme. In the present study, Melka Wakana Hydropower Plant in Ethiopia has been modelled and studied. The tool used was Powersim Simulation software. Mean monthly data of reservoir inflow, evaporation rate, recorded energy production; recorded discharge (turbine flow) and recorded reservoir elevation were used as time series input data. Different variables and relationships between variables were defined along with the constraints. After developing and calibrating the model successfully, detailed simulation analysis has been carried out by controlling reservoir releases for energy production, taking into consideration; increasing yearly energy production and improving the uniformity of monthly energy production. The results of the simulation analyses indicated that the yearly energy production was increased by 5.67% while evaporation loss was reduced by 38.33%. But this power plant still produces below its design capacity by 12.21%.The uniformity of monthly energy production from this plant was also improved. The new reservoir operation guide curve has been developed for the optimum energy production from this plant. Key words: Guide curve, simulation model, reservoir operation, hydropower, energy production, water resources management.