HYDRO POWER PLANNING. IN THE BASIN. OF RIVER PRA IN GHANA

Abstract

Electricity supply in Ghana has for most parts been sourced from the Volta hydroelectric power station in the south eastern town of Akosombo since late 1960s. It is being supplemented by thermal generation when the levels of water fall. Thermal power generation started from the early 1980s. Though many rivers exist in Ghana, their potential has not been explored. In this study, the flow and slope of the Pra river basin of South Western Ghana has been examined for hydropower generation. Literature review on principles of planning and design hydropower generation has also been made. The study has revealed that four run-of-the-river schemes totaling 120MW of installed capacity can be planned to provide 702 Gwh of electric energy in an average year. This energy equals about 15% of firm energy requirement of the country. This has been achieved by creating three small ponds in cascade each for a head of 15.34m and laying one water carrier from the third power house to a fore bay for a fourth powerhouse by means of a 7.4km long conduit. The preliminary dimensioning of a typical powerhouse, the barrage structure and energy dissipator and the forebay has also been done. The creation of a hydropower scheme in the south west of the country it is hoped would significantly reduce transmission losses from Akosombo. It also hoped to save expenditure on cost in thermal generation as the cost of hydroelectric generation is generally low.