DESIGN OF BIRBIR-R HYDROPOWER PROJECT

Abstract

Hydropower is generated by utilizing the hydraulic energy of water to mechanical energy by water turbines and then to electrical energy by coupling electrical generators. It has a perpetual source of energy; i.e. water neither consumed nor converted into something else. At present, the most common commercially available renewable energy. It fits the label sustainable resource better than any of its completions. This project presents the hydropower project on the Birbir River The project area is situated in southwest Ethiopia in west wollega region The Birbir River basin is located in the Baro-Akobo river basin. The total drainage are of Birbir up to confluence with Geba river is about 7200 km2 , where as the catchments area up to the project site is 6849 krrr', The topography comprises rugged and undulation The climate can be classified as tropical with monomodal Rain fall distribution, in which the rain fall is about 1600 m in the catchments. The temporal variability of run off has been studied based on the data from the gauging station on Birbir river near Yubdo Monthly flows at the project site has been generated based on the catchments area rations and spatial rainfall distribution. Flood estimates at the dam site is made based on statistical formulas as Gumbel' s method for 10,000 year return period as 1603. m' /s Birbir R project consists of a storage dam separated from the power station by 6.6 kin order to achieve high head. Gravity dam having 170 m height and 625 .3m crest. length �nstruc�ed in order to regulate the flow for the power production. �s suitable for the proposed dam foundation, and the construction materials are available in around the dam site with reasonable hauling distance. The mean annual flow at the reservoir is 3323.5 Mm3 and the storage capacity of the reservoir at the highest regulated level (H.R.L) is 1620 Mm3• The sediment accumulated in the reservoir over the period of 50 years is estimated to be 140 .44 Mm3. The regulated flow conveyed through a 9m diameter and 6600m long power tunnel to the power house, with l 44.5m height and l 6m diameter surge tank. the power house is dimensioned as l 7X 102 (WXL) will be provided. The design head and the maximum turbine flow are 357.77m and 152 m3 /s respectively, which give the installed capacity of the plant to be 453MW. With this design feature 6 units of vertical Francis turbines having a capacity of 75.5 MW each have been selected. Cost estimate was worked out by categorizing various components as civil and electromechanical. The total project cost is estimated as 114.95 MUSD, where as the annual energy production of the project is 140.06 Gwh. T�L2f economical analysis shows that the unit cost of energy is 0.035 USD/KWH� r \,v.J& _ .:»: --- (\ ' ..,.. ....... »>: \_\., v . _.,,,,.. 1Y �·J'_:,;,,-P- _;., IP.,,,.-�