Hydropower accounts for 17% of the electricity generated across Africa, a share expected to increase as more than 50 new dams are currently under construction. This potential may not be realized, however, due to the increasing occurrence and severity of droughts. A solution proposed by a European Commission Joint Research Center study advocates the use of floating solar panels to boost hydropower capacity.

The large-scale roll-out of floating solar systems at hydropower reservoirs on the continent could reduce Map indicating the reservoir location, floating photovoltaic coverage and annual solar electricity production for a scenario with equal installed hydropower and solar capacity. Source: R. Gonzalez Sanchez et al.water evaporation, help to satisfy future energy needs and increase resilience to climate change without redesigning existing infrastructure. Just as floating photovoltaic panels can complement hydropower production during increasingly frequent dry periods, hydropower can provide a more flexible operation to intermittent photovoltaic output.

The researchers used a combination of satellite images and reservoir data to analyze the floating solar energy potential at 146 of Africa's largest operational hydropower plants as of 2016. In a scenario where 100% of each reservoir was covered with solar panels, there would be an accompanying 100-fold increase in capacity, with 2,922 GW of solar added to the existing 28 GW of hydropower. This would translate into a 50-fold increase in electricity production compared to current hydro output, from 106 terawatt hours (TWh) to 5,293 TWh. This dwarfs the total electricity demand across the whole of Africa, which is only around 700 TWh.

While covering every reservoir with panels is not feasible, lesser coverage still offers electricity supply benefits. With just 1% cover, the installed capacity of existing hydropower plants could be more than doubled to produce an additional 46 TWh.

The study is published in Renewable Energy.