**1. Introduction**

The penetration level of renewable energies worldwide is continually increasing, and by the end of 2020, the net cumulative capacity added by the renewable energy system was 261 GW [1]. Due to the stochastic nature of sustainable energy technologies in terms of variability and reliability, not enough installed capacity of renewables is yet established worldwide to measure the impacts of each renewable energy technology in terms of construction footprints, environmental consequences, socio-economic studies and the reliability of those technologies over the years [2]. With the increase in renewable energy shares in different locations, all the previous impacts will be clearer until the world reaches fully sustainable power generation. Hydropower, wind turbines and photovoltaic technology are the three highest renewable energy technologies in terms of installed capacity. In the last 10 years, the installed capacity of photovoltaic technology has had a noticeable continuous increase and now, the cumulative photovoltaic power generation capacity is 707.5 GW. The solar PV system held the highest newly added renewable energy sources in 2020 with a capacity of 127 GW, which is 14.41% more than the wind energy system. The installed capacity of hydro power plants worldwide is 1150 GW, which represents 16% of the world generated electricity [3]. Particularly in Egypt, the government is focusing on increasing the penetration level of renewable energies to face the continuous increase in electricity demand [4]. Egypt has two hydro power stations with a total installed capacity of 2.65 GW, which was representative of all the renewable energy technologies of the Egyptian grid until the end of the last century. Egypt is rich with solar energy potential; the amount of solar energy incidence per square meter varies between 5 and 8 kWh per day with a duration of 3000–4000 h per year [5]. The Egyptian maximum demand in 2019

**Citation:** Ravichandran, N.; Fayek, H.H.; Rusu, E. Emerging Floating Photovoltaic System—Case Studies High Dam and Aswan Reservoir in Egypt. *Processes* **2021**, *9*, 1005. https://doi.org/10.3390/pr9061005

Academic Editor: Masoud Soroush

Received: 8 May 2021 Accepted: 4 June 2021 Published: 6 June 2021

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reached 32 GW, while the maximum penetration level of renewable energies in Egypt in 2020 was 10% [3].

The Upper-Egypt region has a target of 100% renewable energy operation with its two dams and the world's largest photovoltaic park. The total generation of the region is 4.45 GW, in which 59% of the renewable power is generated from the hydropower plants of High Dam and Aswan Reservoir. However, several factors obstruct the maintenance of the capacity of the hydropower generation source. In 2011, Ethiopia started the construction of the Grand Ethiopian Renaissance Dam (GERD) on the Blue Nile in a place named Guba, approximately 60 km from Sudan. GERD will badly affect the High Dam (HD) and Aswan Reservoir (AR) in Egypt in terms of hydropower generation and the Nile water level. The hydropower is projected to decrease by 20–30% [6]. The Nile water level is anticipated to decrease by 0.4–0.75 m [7]. Additionally, the irradiation periods in the location of the reservoir increases the evaporation rate drastically, which results in poor power generation during high power demand periods. Therefore, to maintain the level of the reservoir by mitigating the evaporation rate, various countries experimented with a potential covering system. This covering system will reduce the action of wind and irradiation on the water surface, thereby reducing the rate of evaporation using monomolecular films, floating devices, suspended shading covers, and wind retarding devices [8,9]. One such covering system using PV panels can effectively shadow the reservoir from sunlight while generating power. This newly emerged solar technology, named a floating PV system, gained widespread global attention due to higher efficiency than a ground and roof-mounted PV system [10–12]. A water evaporative cooling mechanism and lower soiling loss improves the PV efficiency up to 30% according to a study in Indonesia, which has a climate similar to that of Egypt [13]. Several numerical and experimental analyses on the FPV system in minimizing water loss from evaporation while generating power have been carried out, with impressive results [14–17]. Apart from mounting FPV systems on lakes and ponds with the purpose of drinking and irrigation, it is efficient for installation on reservoirs with hydroelectric power plants [18]. The major advantage in hybridizing FPV on HEPP is the already available grid connection and water saved from evaporation can be effectively directed to hydropower generation [19,20]. Experimental results show the efficient yield from solar and hydropower in implementing this hybrid system [19–23]

Thus, FPV-HEPP integration has high potential, especially in countries with high temperatures such as Egypt, in addressing the water–energy demand. The use of FPV will secure the operation of this region as a 100% sustainable region and importing sustainable energy to other regions in the Egyptian grid.

The main contributions of this paper are:


The present study analyzes the potential of the FPV system upon implementation in the major hydropower reserves of Egypt: High Dam and Aswan Reservoir. The paper is organized as follows: Section 2 is an overview of the FPV, while Section 3 illustrates the need to reduce evaporation in High Dam and Aswan Reservoir. Section 4 illustrates the electrical performance of the two dams, while Section 5 presents the numerical analysis of the FPV in High Dam and Section 6 presents the numerical analysis of the FPV in Aswan Reservoir. Section 7 illustrates the FPV from the view of cost, carbon dioxide emissions and water–energy nexus. Sections 8 and 9 illustrate the results, discussion and conclusion, respectively.
