Assessment of floating solar photovoltaics potential in existing hydropower reservoirs in Africa

Abstract

Africa is characterised by a very high solar potential, with a yearly sum of solar irradiation exceeding 2000 kWh/m2. Many African countries are heavily dependent on hydropower, however, increasingly frequent droughts have been severely affecting hydropower generation in the last few decades. The installation of floating photovoltaics (FPV) in existing hydropower reservoirs, would provide solar electricity to help compensate hydropower production during dry periods and reduce evaporation losses while helping to sustainably satisfy the current and future energy needs of the fast-growing African population. This study provides a comprehensive analysis of the potential of FPV installation in Africa, by using highly accurate water surface data of the largest 146 hydropower reservoirs in the continent. In addition to the electricity production, evaporation savings and the potential extra hydroelectricity generated by these water savings are also estimated at reservoir level for four different cases and two types of floating structures. The results indicate that with a total coverage of less than 1%, the installed power capacity of existing hydropower plants can double and electricity output grow by 58%, producing an additional 46.04 TWh annually. In this case, the water savings could reach 743 million m3/year, increasing the annual hydroelectricity generation by 170.64 GWh.