PRE-FEASIBILITY STUDY OF INDRAWATI-III RUN-OFF RIVER HYDROPOWER PROJECT

Abstract

The study entitled “A Pre-feasibility Study of Indrawati III ROR Hydropower Project” is part of the partial fulfillment of a Bachelor’s Degree of Civil Engineering. The Study focused on finding the technical and financial viability of power generation from Indrawati River located in Sindhupalchowk district in the Central Region of Nepal. The Flow records and rainfall data of the nearby gauging stations and rainfall stations were obtained from the Department of Hydrology and Meteorology. The data are used to determine the flood discharge and average flow of the Indrawati River at the project Site. Using GIS software, the catchment area of the intake site of Indrawati was calculated, which is equal to 431.34 km2 . The rainfall and discharge data obtained from the Department of Hydrology and Meteorology was analyzed and the flood discharge was derived using various methods. The flooding discharge is found 871.46 m3 /s for 100 years return period. Based on the design discharge with Q40 (of 40% of discharge exceedance flow), the installed capacity is found to be 8.02 MW. Three Francis turbines are used for the power generation. Using tunnel optimization techniques, the minimum diameter of the headrace tunnel is found 3.3 m. Three nos. of penstocks pipes were proposed to connect the turbines. And penstock optimization techniques were applied to find the economical penstock diameter, which is 2m of each. The total annual energy production was found to be 47.686 GWh. Owing to the PPA provided by NEA, electricity will be sold at Rs. 4.8 per unit during wet season and Rs. 8.4 per unit during dry season. Based on this, the total annual revenue will be NRs 249 million. The design life of the project is taken as 40 years. The preliminary cost estimation of the hydropower project is done for the economic analysis using Benefit Cost ratio (BCR) and IRR methods. Financial analysis shows the BCR is about 2.02 and IRR equal to 20.59% with discount period of 10 years. This suggests the economic viability of project. Hence, the project is recommended to further (feasibility) study and detail analysis as well as EIA is recommended as the capacity of the project exceeds 5MW.