Ethiopia enjoys multiple renewable resources and has 124 billion cubic meters (BCM) of river water, 30 BCM groundwater, and 70 BCM lake water resources [20] . The national supply of electricity in Ethiopia depends completely on hydropower. Currently, the country has around 4500 MW of installed generation capacity. Approximately 90% of the installed generation capacity is from hydropower, while the remaining wind, diesel, and the shares of geothermal energy were, 7.7%, 2.1%, and 0.2% respectively. The overall consumption of electricity was 6.7 Terawatt Hours (TWh) in 2014, up from 2.4 TWh in 2006 and 3.8 TWh in 2011 [21] . In Ethiopia, only 57% of households have access to as a minimum one power source (33.1% grid and 23.9% off-grid) [22] , there was a major difference between rural and urban areas; the latter was connected to just around 5% of the populations [23] , although 87% of urban populations were connected, the industry remains a small user of electricity [8] .

About three-quarters of the Ethiopian rural population relies heavily on conventional biomass for heating and cooking. As a consequence, biomass remains Ethiopia’s primary energy source, accounted for 91% of the consumed energy in 2015 [3] . Around 7% of overall main energy is generated by petroleum, and electrical energy accounts for just 2% of total energy consumption [24] . Biomass use in the housing area accounts for more than 98% of the total supply [25] . Ethiopia has a lot of potential for renewable energy [26] . Hydropower has a 45 Gigawatts (GW) potential, the wind has a 10 GW potential, and geothermal has a 5 GW potential. Fossil fuel reserves are also significant [27] . The natural gas reserve is around 4 trillion cubic feet, and the coal reserve is projected to be over 300 million tons. While these local resources are not currently used for power generation, the government is interested to explore these resources soon [28] .

Egypt is one of the driest nations in the world. The Nile provides more than 97% of Egypt’s clean water supply to its 100 million citizens. With over 4.5 billion barrels of oil reserves, Egypt is the world’s 25^th most oil-producing nation [29] . However, the oil reserves of the country have decreased significantly, and by 2030 it is expected that only around 1.5 billion barrels of oil will be left [3] . The country also has important natural gas reserves, which presently the dominant power generation in Egypt. While power generation has significantly increased in Egypt, growth has not been sufficient to meet the increasingly growing demand for energy. Electrical energy production grew at a 5.8% annual rate from 95 TWh in 2004 to 131 TWh in 2010 and 168 TWh in 2014 [30] . From 23.5 GW in 2009 to 32 GW in 2014, the capacity of installed power generation has increased [3] . Electricity consumption on the national grid grew dramatically from 64.3 TWh in 2001 to 147.5 TWh in 2014, a 6.5% annual increase [31] . The administration has as well started initiatives to inspire renewable energy technology for energy production. Due to decreased potential and stagnation at 2.8 GW, hydropower dimensions have not improved in current years [3] .

Most of Sudan’s land is also either arid or semi-arid as opposed to that of the lands of Ethiopia. Sudan faces the dual problems of inadequate access to contemporary energy and heavy dependency on conventional sources of biomass to meet its increasingly rising demands for energy [3] . Charcoal and fuelwood account for about 75% of the population’s energy needs, particularly in rural regions [32] . As a consequence of the division of Sudan into two countries (Sudan and South Sudan) crude oil production decreased from 8380 kilotons in 2000 to 6950 kilotons in 2015. In 2016, 39% of the societies were connected to the national grid. The rate of electricity access is 62% higher in urban areas, but about 22% lesser in rural regions in 2016 (up from 18% in 2014) [3] . Power generation depends primarily on hydropower, which accounts for 75% of total output and has a capacity of 4176 MW. Hydropower and thermal power plants have a combined installed capacity of 1591 MW and 1400 MW, correspondingly. The overall generation of electricity rose from 4125 Gigawatt hours (GWh) in 2005 to 11,848 GWh in 2014. In 2014, Sudan imports approximately 4% of its electricity. Electricity feeding per person in 2014 was 140-kilowatt hours (kWh), far below the African average of 500 kWh [33] . Renewable energy can perform a substantial role in increasing modern energy access in Sudan, improving energy security, and contributing to global climate mitigation. The administration needs to incorporate renewable energy into the power system, with a goal of 20% by 2030 [34] .

Egypt is among the largest energy producers and suppliers in Africa. It is one of the 3^rd most populated countries on the African continent next to Nigeria and Ethiopia, which leads to its energy needs increasing. In more recent years, due to energy blackouts, the Egyptian government set a plan to diversify and invest more in the sector. The Ministry of Planning, Monitoring, and Administrative Reform published the “Sustainable Development Strategy: Egypt Vision 2030”, Egypt’s first participatory long-term strategy document [35] . Energy is ranked as the second critically significant foundation for sustainable development in Egypt’s Vision 2030 [36] . The vision report highlights the optimal use of domestic energy sources in addition to the asset allocation of the total energy mix to include alternative energy sources for power generation, such as renewable energy. Egypt Vision 2030 and the Ministry of Electricity and Renewable Energy have established a minimum goal of generating 20% of overall electricity from renewable sources by 2020 [3] . Furthermore, Egypt’s Nationally Defined Commitment (NDC) emphasizes Carbon dioxide emissions reduction in the energy sector along with the promotion of clean energy-generation technologies [37] .

Ethiopia is the 2^nd most populated country in Africa next to Nigeria which leads to its energy needs increasing. As mentioned above, Ethiopia’s power production is currently heavily dependent on hydropower; plans to raise capacity to 13.5 GW by 2040 will make Ethiopia Africa’s second-largest hydro producer. The Ethiopian government’s 15-year National Growth and Transformation Plan (GTP) targets to double the percentage of the population who has access to electricity [38] , as well as improve large-scale hydropower initiatives to increase the supply of other energy sources [39] . To meet the expected rise in electricity demand as a result of the country’s rapid economic development, the Ethiopia Electric Power Corporation (EEPC) aims to incorporate alternative power plants interested in the energy sector, including wind, geothermal, solar, fuel-oil, and gas-based plants [40] . Additionally, the EEPC intends to export energy to neighboring nations. Installed capacity achieved 4206 MW under GTP I (2010-2015) [38] , while GTP II (2016-2020) aims to build 14,561 MW of generation projects, but not achieved [41] . Currently, the country has about 4500 MW of installed generation capacity. Ethiopia initiated the “Light to All” in November 2017, the National Electrification Program was initiated, to supply electricity to all Ethiopians by 2025 [3] . The Ethiopian NDC is focused on the Climate Resilient Green Economy Strategy, and in comparison to baseline levels, it aims to reduce GHG emissions by 64% by 2030 [38] .

Sudan is challenged with numerous energy development problems, including high electricity subsidies and climate-related impacts on hydroelectric generation, which has been declining at a rate of about 4% annually. Sudan’s development goal is to improve access to new and affordable energy. Sudan’s government intends to incorporate clean energy technology into the energy sector, with a 20% renewable energy commitment by 2030 [36] . Utilizing Sudan’s renewable energy potential for making electricity accessible throughout the country; producing competitive prices energy from renewable sources, and diversifying energy supply sources to guarantee energy protection are all key government strategies for power sector growth [3] , help the national economy by transferring technologies and expertise, building power, and supporting the local renewable energy industry; and provide access to electric energy supply to rural areas far from national or decentralized grids, for which power grid is not a feasible option [42] . The three countries belong to the Eastern Africa Power Pool, which aims to secure energy supply, optimal use of energy resources, provide affordable electricity prices through grid interconnection, and develop a competitive electricity market in the basin [3] . Table 1 shows the summary of present and planned power plants and their capacity (GW) by country.

Source: Alam Hossain Mondal (2020); Azer. T (2014); Rabah. A (2016).

The first is the Chara Chara weir, which regulates Lake Tana outflows to the Tis Abbay power complex, which is 32 km downstream of Lake Tana [45] . Lake

Tana is a natural lake that regulates the flows of the Tana sub-basin [18] . Then, the Tana-Bales scheme (started operation in May 2010) consists of an artificial link between the Lake Tana and the Bales river to produce 460 MW hydroelectric [45] . The building of Tana Bales hydropower is started in 2005 and was finished in May 2010, the project directly diverts water from Lake Tana and is presented in the models as such [18] . The other is the Tekeze Dam in Northern Ethiopia, which is a double-curved arch dam on the Tekeze River, a Nile tributary that flows downstream near Khartoum and joins the main Nile through the deepest canyons. The main goal of this reservoir’s operation is to generate 300 MW of power generation [5] . The third is the GERD which is about 750 km North-West of Addis Ababa and 45 km from the Sudan border on the Blue Nile River in a place called Guba [46] . The construction was started in 2011, and when finished, currently (79% completed) the GERD will become Africa’s largest hydropower plant and the 8^th largest global hydropower plant [46] . The ultimate location for the GERD was discovered during a Blue Nile investigation directed from 1956 to 1964 by the U.S. Office of Reclamation [18] . This ambitious project is projected to generate over 6000 MW of electricity. It will make a lake with a volume of more than 74 BCM, with an approximate cost of almost $5 billion which is covered by the Ethiopian government [47] . Domestic and regional electrification is the primary aim of this dam and it is projected to boost access to electricity in East Africa through current and scheduled power connectors [5] . The cumulative energy generation in the Eastern Nile would grow due to GERD being in operation [1] . The scheme, however, is troubled by technological and financial issues, as well as resistance from its downstream nations [48] . Today, cooperation between the main riparian states (Egypt, Ethiopia, and Sudan) is becoming more serious than ever in resolving emerging conflicts over the construction and filling of the GERD. The talks among three nations with the government of the U.S. and the World Bank as observers in Washington between November 2019 and February 2020 failed to reach an agreement. Further talks among three nations were held by the African Union in July 2020 to reach a final treaty underscored that “African issues must be given African solutions” [5] . When this article was written, no treaty has been reached, the discussion is sometimes on-again and off-again. The Ethiopian government has also a plan to build further hydropower plant to meet energy needs on the Nile River tributaries (Table 3). However, the GERD situation is an example from which lessons can be learned in the politically sensitive and disputed river basins for future dam construction.

The first is the Jebel Aulia Dam, 40 km upstream of Khartoum on the White Nile River, which was built in 1937 to hold water for well along utilizing in Egypt. The rapid siltation of this reservoir, as well as the construction of the High Aswan Dam in Egypt in 1965, put an end to its operation of 30 MW [49] . The other is the Roseires Dam that was constructed in 1966, with an initial capacity of 3.024 × 10⁹ m³ at 480 m level [18] . The key goal is to provide irrigation requirements as a priority and the second priority is the generation of 280 MW hydropower [48] . The Khashm El Girba Dam was built just downstream of the Tekeze River. The dam was built to produce hydropower of 10 MW [18] . The Merowe Dam was Sudan’s largest dam recently built to fulfill the primary objective of producing hydropower. The power generation goal is a capacity of 1250 MW. A regulation was used to achieve this procedure that requires a turbine’s discharge to achieve the energy generation target, accompanied by a flood prevention regulation which drops any water above a defined elevation [42] .

The Aswan Old Dam, completed in 1902 and heightened in 1936, is the Nile River’s first dam [48] . The targeted power generation was a capacity of 592 MW. The other is the Aswan High Dam reservoir, which extends 500 km along the Nile River and occupies 6000 km², two-thirds of which is in Egypt (recognized as Lake Nasser) and one-third in Sudan (known as Lake Nubia) [18] . The dam, which was built in 1971 and is located 7 km south of Aswan City, is 2325 m long, 11 m high above the original riverbed, and 40 and 980 m wide at the crest and bottom, respectively [49] . The total reservoir capacity (162 × 10⁹ m³) comprises of the dead storage of 31.6 × 10⁹ m³ (147 meters above sea level (m.a.s.l.) of Lake water level), the effective reservoirs of 90.7 km³ (147 - 174 m.a.s.l), and the storage emergency for control of flood 41 × 10⁹ m³ (175 - 182 m.a.s.l) [18] . There is rugged desert terrain surrounding the reservoir. To the West is the vast Sahara Desert, and to the East in the Eastern Desert, which extends to the Red Sea. By providing irrigation water, the Aswan High Dam made a major contribution to Egypt’s economic growth and approximately 2100 MW of hydroelectricity, as well as shielding the lower reaches of the Nile from coastal flooding [50] . Table 4 compares the Nile River’s biggest dam with the world’s largest dam.

Source: Dale Whittington (2014); Asegdew G. Mulat (2018).