Impact of Reservoir Sedimentation on Hydroelectric Power Generation: Case Study of Kulekhani First Hydropower Station

Abstract

Reservoir Hydropower Plants are more reliable than the Run-off Plants. Kulekhani First Hydropower Station is the reservoir type Hydropower Station. It is 60 MW plant and is very reliable power plant of Nepal. Electricity produced from each m3 of reservoir water is calculated as 1.27 kWh. Sedimentation data from the primary and secondary sources were taken for analysis. Trend lines and bar charts were used for analysis and forecasting purpose. The reservoir is being filled by sediment after its commissioning in 1982 and annual sedimentation rate in total volume is found to be 0.73 Mm3 and in active volume is found to be 0.65 Mm3 . With the decrease of the active volume, the energy generation capacity of KL1HPS is also decreasing at the rate of 826.46 MWh per year. It is estimated that active volume will be filled in about 2100 AD which means the estimated life is about 80 years from now. With the decrease of the active volume, the energy generation capacity of KL1HPS is also decreasing and after about 80 years the KL1HPS plant will be run off river plant. Use of sediment removal system will gradually decrease the sediment content in the reservoir. The time period for dredging of all the sediments in active volume is found to be about 8 years and total cost incurred is found to be NRs. 21.57 Billion with simple payback period of about 50 years. The time period for dry excavation of all the sediments in active volume is found to be about 1 year and total cost incurred is found to be NRs. 26.98 Billion with simple payback period of about 78 years.