ABSTRACT
The supply of cost-effective, clean, and reliable energy to rural regions has been recognized internationally as a problem to be tackled towards reducing poverty in developing countries like Nigeria if Sustainable Development Goal 7 (SDG 7), which seeks to ensure access to sustainable, reliable, affordable, and modern energy for all is to be achieved. Nigeria, with nearly 200 million people, is challenged by epileptic power supply. In 2018, the overall energy access was 60%, with over 20 million households without power. The existence of rivers and the need to investigate their potentialsto be used has become pertinent. This will reduce poverty considering energy access increase derivable, especially as Nigeria can generate 3.5GW from Small Hydropower (SHP) where approximately 2% has been utilized. The study is concerned with the assessment of the hydropower potentials of four rivers in the Benin-Owena River Basin (BORB) catchment, namely: Okhunwan, Oyanmi, Owan, and Osse. In this study, spatial data analysis techniques in Remote Sensing (RS) and Geographical Information System (GIS) were utilized to identify and select suitable hydropower project sites. The discharge was computed by Natural Resources Conservation Service - Curve Number (NRCS-CN) hydrological model using year 2018 PERSIANN-CDR and Curve Number (CN) data as inputs and compared with observed streamflow through descriptive statistical model. From the obtained discharges in the four sub-basins, Flow Duration Curve (FDC) was developed to ascertain equaled or exceeded volume per time and Q92 flow statistics of the FDC was adopted as design discharge to calculate hydropower potential. Costing of the practicable SHP sites was carried out utilizing estimated SHP potential and site hydraulic head while RETScreen software was deployed for sustainable assessment viability check and to simulate the quantity of CO2 saved. Results obtained reveals the correlation performed for observed and simulated discharged data on one hand and NIMET and PERSIANN rainfall datasets, on the other hand. This shows a good correlation of 0.75, 0.63, 0.68, 0.87 and 0.75, 0.65, 0.70, 0.78, at Okhunwan, Oyanmi, Owan, and Osse sub-basins, respectively indicating high level of statistical significance for all correlated data hence the acceptance of the Null Hypothesis. A total of 368 points were investigated in a combined catchment area of 4,170.59 km2 along the 720.59 km main river courses and tributaries in the four sub-basins at 2km interval. Using the optimization criteria that a viable SHP must have 2% minimum slope and 10m available head, 54 potential sites were identified with power ranging from 149.583 kW to 16,935.279 kW. These identified potentials can prevent between 128.4 and 14,536.1 tCO2/yr Green House Gas (GHG) emission, and the calculated project cost range is £ 327,815.24 - 7,964,184.39. Additionally, the regionalization study indicates that the average exponent ‘n’ value for BORB is 0.52. The research results will help the future realization and activation of SHP resources development in Nigeria's River Basins.
