Abstract:
Access to electricity has the potential to improve productivity and provide considerable welfare benefits
in remote areas, for which there is a need for a reliable and affordable source of electrical energy such
as micro and small hydropower .Especially in small, remote areas where there is no grid supply of
electricity. This study has been conducted at Nyabarongo River Basin of Rwanda along with eight gauged
stations with the purpose of assessing the hydropower potential based on micro to small hydropower
potential sites. The potential sites were located on the gauged stations, and the catchment area for the
potential sites was delineated with the help of the arc SWAT with geographic information system (GIS)
and contour map was done by showing different heads. Since the stream flow had missed data, the
arithmetic mean method was exploited and double mass curve was used to check its consistency. Flow
duration curve, power duration curve and energy duration curve were plotted then; power and energy of
the potential sites were estimated. Based on this eight sites have already been identified with the total
energy output from monthly flow for was calculated and found to be1459.04 GWh, and the total energy
output taken from flow duration curve was 1193.35GWh . The selected turbine was Francis turbine
which is compatible with micro and small hydropower with the efficiency ranging between65-80% and in
this study the efficiency of 75% was selected to be used. for all eight stations. Finally, rank of the sites
based on cost per Kwh, distance from the grid and accessibility was done on which Mwaka and Warufu
get first and least rank respectively, and classification of hydropower plant has been done based on head
of water available where Warufu, Ruliba and Kanzenze are found to be in low head hydroelectric power
plants and Mfune,Akany-ngozi,Karungrli ,Ngaru and Mwaka are in medium head hydroelectric power
plants.
