An international research team analyzed the effects of installing floating photovoltaics (FPV) on Egypt's Aswan High Dam Reservoir (AHDR). Using numerical analysis, they have accounted for the possible power generation of the floating photovoltaics plant, in addition to the evaporation reduction provided.
"This study investigates the benefits of an FPV system over 12 years, from 2005 to 2016, on the AHDR," they said. "We also investigate different scenarios for complementing Aswan High Dam's (AHD's) hydropower with Floating PV System and using additional water for reservoir management or irrigation."
The AHD was constructed in the 1960s, supplying annual hydropower generation of 10,000 GWh. Effectively, the dam also created the AHDR, one of the largest manmade reservoirs in the world. The entire reservoir stretches for about 500 km along the Nile River; 330 km of it is in Egypt, where it is called Lake Nasser, and 170 km is in Sudan, where it is named Lake Nubia. Its total surface area is 6,000 km2 and it has a storage capacity of 169 billion cubic meters (BCM). However, evaporation rates are high due to the region's very hot and dry climate.
For their investigation, the scientists assumed to build an FPV plant on the reservoir with panel coverage of 0%, 10%, 45%, and 90% of the lake. "According to the International Energy Agency (2020), the annual electricity consumption of the African continent is 715.6 TWh. To cover this by FPV on the AHDR, a 45% FPV occupancy would be sufficient. The investment costs (CAPEX) of such a project would amount to approximately $ 14.6 billion," they highlighted.
To model the installations, the academics used the hydrodynamic General Lake Model, a vertical 1D model that represents the hydrodynamic processes of standing water bodies. They assumed tilt angles of either 12 degrees or 30 degrees, using LONGi LR4 modules, with a row distance of 1.44 m. In the case of 90% FPV coverage, the installed capacity calculated was 735 GW.
"To estimate the contribution of an FPV system on the AHDR to Egypt's energy supply, we calculated the electrical yield using the simulation software Zenit," explained the group. "The simulations were evaluated in terms of the power plant's electrical yield and the performance ratio."
The results of the simulation showed that, in the case of 0% panel coverage, that being the situation today, the cumulative annual water loss to evaporation ranged from 10.65 to 13.17 BCM. The total evaporation loss over 2005–2016 was 141.6 BCM, while the mean yearly loss was 11.8 BCM, and the mean evaporation rate per day was 6.5 mm.
