ASSESSMENT OF MICRO TO SMALL SCALE HYDRO POWER POTENTIAL IN SOUTH WEST RIFT VALLEY LAKES BASIN, ETHIOPIA. (CASE STUDY OF GELANA RIVER SUB CATCHMENT)

Abstract

The increasing demand for energy has emerged as a serious issue all over the world due to rapid increase of the population, socio economic development, living standards with the fast growing of industry. Ethiopia facing similar crises that has resulted infrequent power failures and load shedding throughout the country for past years. Assessing and utilization of new renewable energy resources site is crucial importance to reduce the energy shortage and fossil fuel dependency throughout the country. The objective of this study is to assess, mini, micro and small scale hydro power potential sites in Gelana River Sub-Catchment, Rift Valley Lakes Basin, Ethiopia. Data used in this study include digital elevation model DEM (30 m × 30m), the head at different sites were assessed using river profile tools within 1km maximum stream length were the main criteria to identify feasible stream reaches. ARC-HYDRO and HEC-GEO HMS tools coupled with Arc GIS 10.5 were used for watershed analysis and relate with HEC-HMS model to simulate rainfall-runoff process and determine basin characteristics multi-criteria decision method on selecting hydro power sites. Seven potential sites were identified in the study area. From all potential sites, site 4 and site 2 have maximum and minimum potential capacity; 6200 KW and 200KW respectively. The maximum installed capacity from 50% FDC flow values and the minimum firm power from 90% FDC flow values for all sites were estimated as 143KW and 123 KW respectively Flow calibration gives coefficient of determination (R2) and Nash-Sutcliffe simulation efficiency (ENS) 0.69 and 0.685 respectively. Flow validation gives 0.72 and 0.719 for R2 and ENS values respectively. This result indicates that the observed values show good agreement with simulated value for flow. The proposed multi criteria based spatial analysis of suitable sites can be ranked and out of the seven (7) selected sites site#2 is the 1st and site#5 is the 2nd respectively ranked by listed criteria. Out of seven identified hydro power potentials sites three of them are categorized under small scale, two sites are mini scales and the rest two sites are micro scales. This research will give a piece of information about the study area for those concerned body for future work and additional works and for the implementation of micro, mini and small scale hydropower Plants (MSHP).