Resource Assessment For Hydro-Kinetic Turbines In Ethiopian Rivers And Irrigation Canals

We describe resource assessment of rivers and a canal in the Upper Blue Nile Basin, Ethiopia for hydro-kinetic turbines (HKTs). Various hydrodynamics methods are coupled with hydrological methods with the aim of transforming the measured flow rate or discharge into velocity data to determine the power density (PD), the available power per square meter of vertical flow area. We estimate the PD over the length of the rivers and canal and estimate the power density variation over the months of the year. The Gumara, Gilgel-Abay, and Bahirdar-Abay rivers in the Blue Nile Basin were studied along with the Koga irrigation main canal. Historical databases of yearly, monthly, and daily averaged discharge were used. The key elements of this analysis are (i) converting discharge into velocity for PD determination, and (ii) the period over which the velocity is averaged compared to the averaging time used to determine the HKT power curve. All software used in this work is publicly available. To predict PD. ARC-GIS was used to estimate the reach length and cross-section from raster Digital Elevation Models (DEMs). The hydraulic modeling of the velocity was done using HEC-RAS software. Field measurements were conducted to validate the hydrodynamic model. The result of the study was cross-sectional area average water velocity ((V) over bar (A)), which used to predict the PD. To relate the time average of velocity ((V) over bar (T)) to the power curve of a HKT a 2-minute average velocity measurement was conducted with a total of 270 samples. It is found that 25% of the Gumara river is suitable for HKTs with a maximum of 1.4 kW/m(2) power can be extracted. The Gilgel-Abay river has a maximum velocity above 1 m/s and 3.4 kW/m(2) power can be extracted over 32% of its length. Similarly, for Bahirdar-Abay river, over 29% of the reach length 2.6 kW/m(2) power can be extracted. (C) 2020 International Energy Initiative. Published by Elsevier Inc. All rights reserved.