Potential for small hydropower development in the Oti River Basin using GIS, SWATPlus and RETScreen

Abstract

The relatively high cost of electricity from non-hydropower sources, particularly solar and thermal, has posed significant challenges to industrialization and rural electrification in Ghana. This study assesses the Oti River's small hydropower (SHP) potential to close the knowledge gap and offer accurate information regarding the river's capacity to sustain hydropower generation. Geographic Information System (GIS), Soil and Water Assessment Tool Plus (SWATPlus) were used to simulate the watershed’s hydrological attributes, while RETScreen was employed to carry out a techno-economic assessment of potential SHP sites. Flow Duration Curves (FDC) have been constructed for suitable sites. The final assessment resulted in the identification of ten sites (HP1 – HP10) along the river with potential for hydropower generation. The highest hydropower potential sites were located at HP4, HP1, and HP7, with corresponding firm power of 1359.5 kW, 1162.4 kW, and 875 kW and estimated firm energy of 7.490 GWh, 6.409 GWh, and 4.82 GWh, respectively. Among the ten evaluated sites, HP1, HP3, and HP4 demonstrated the highest economic potential, recording Net Present Values (NPVs) of approximately $95.8 million, $24.5 million, and $62.4 million, respectively. Emissions assessments further emphasized their environmental viability. Overall, the results highlight a strong case for small hydropower (SHP) deployment at these locations, providing regionally relevant insights and reinforcing Ghana’s ambitions in renewable energy expansion.