Grand Ethiopian Renaissance Dam

The zero level of the main dam, the ground level, will be at a height of almost exactly 500 m (1,600 ft) above sea level, corresponding roughly to the level of the river bed of the Blue Nile. Counting from the ground level, the main gravity dam will be 155 m (509 ft) tall, 1,780 m (5,840 ft) long and composed of roller-compacted concrete. The crest of the dam will be at a height of 655 m (2,149 ft) above sea level. The outlets of the two powerhouses are below the ground level, the total height of the dam will, therefore, be slightly higher than that of the given height of the dam. In some publications, the main contractor constructing the dam puts forward a number of 170 m (560 ft) for the dam height, which might account for the additional depth of the dam below ground level, which would mean 15 m (49 ft) of excavations from the basement before filling the dam. The structural volume of the dam will be 10,200,000 m³ (13,300,000 cu yd). The main dam will be 15 km (9 mi) from the border with Sudan.

Supporting the main dam and reservoir will be a curved and 5.2 km (3 mi) long and 50 m (164 ft) high rock-fill saddle dam. The ground level of the saddle dam is at an elevation of about 600 m (2,000 ft) above sea level. The surface of the saddle dam has a bituminous finish, to keep the interior of the dam dry. The saddle dam will be just 3.3–3.5 km (2–2 mi) away from the border with Sudan, it is much closer to the border than the main dam.

The reservoir behind both dams will have a storage capacity of 74 km³ (60,000,000 acre⋅ft) and a surface area of 1,874 km² (724 sq mi) when at full supply level of 640 m (2,100 ft) above sea level. The full supply level is therefore 140 m (460 ft) above the ground level of the main dam. Hydropower generation can happen between reservoir levels of 590 m (1,940 ft), the so-called minimum operating level, and 640 m (2,100 ft), the full supply level. The live storage volume, usable for power generation between both levels is then 59.2 km³ (48,000,000 acre⋅ft). The first 90 m (300 ft) of the height of the dam will be a dead height for the reservoir, leading to a dead storage volume of the reservoir of 14.8 km³ (12,000,000 acre⋅ft).[33]

The dams will have three spillways. All using approximately 18000 cubic meters of concrete. These spillways together are designed for a flood of up to 38,500 m³/s (1,360,000 cu ft/s), an event not considered to happen at all, as this discharge volume is the so-called 'Probable Maximum Flood'. All waters from the three spillways are designed to discharge into the Blue Nile before the river enters Sudanese territory.

The main and gated spillway is located to the left of the main dam and will be controlled by six floodgates and have a design discharge of 14,700 m³/s (520,000 cu ft/s) in total. The spillway will be 84 m (276 ft) wide at the outflow gates. The base level of the spillway will be at 624.9 m (2,050 ft), well below the full supply level.

An ungated spillway, the auxiliary spillway, sits at the center of the main dam with an open width of about 205 m (673 ft). This spillway has a base-level at 640 m (2,100 ft), which is exactly the full supply level of the reservoir. The dam crest is 15 m (49 ft) higher to the left and to the right of the spillway. This ungated spillway is only expected to be used, if the reservoir is both full and the flow exceeds 14,700 m³/s (520,000 cu ft/s), a flow value, that is expected to be exceeded once every ten years.

A third spillway, an emergency spillway, is located to the right of the curved saddle dam, with a base level at 642 m (2,106 ft). This emergency spillway has an open space of about 1,200 m (3,900 ft) along its rim. This third spillway will carry water only if the conditions for a flood of more than around 30,000 m³/s (1,100,000 cu ft/s) are given, corresponding to a flood to occur only once every 10,000 years.

Flanking either side of the auxiliary ungated spillway at the center of the dam will be two power houses. The right will contain 10 x 375 MW Francis turbine-generators, the left power house will house 6 x 375 MW of the same turbine-generators. 14 of the 16 turbine-generators have been upgraded to 400 MW without changing the nameplate capacity (which is still at 375 MW), while two turbine-generators remained at 375 MW.[34][31] The total installed capacity with all turbine-generators will be 6,450 MW. The average annual flow of the Blue Nile being available for power generation is expected to be 1,547 m³/s (54,600 cu ft/s),[33] which gives rise to an annual expectation for power generation of 16,153 GWh, corresponding to a plant load factor (or capacity factor) of 28.6%.

The Francis turbines inside the power houses are installed in a vertical manner, raising 7 m (23 ft) above the ground level. For the foreseen operation between the minimum operating level and the full supply level, the head waters for the turbines will be 83–133 m (272–436 ft) high. A switching station will be located close to the main dam, where the generated power will be delivered to the national grid. Completed have been four 500 kV main power transmission lines in August 2017, all going to Holeta and then with several 400 kV lines to the metropolitan area of Addis Ababa.[35] Two 400 kV lines are running from the dam to the Beles Hydroelectric Power Plant. Also planned are 500 kV high-voltage direct current lines.

Two non-upgraded turbine-generators with 375 MW each are considered to be the first to go into operation with 750 MW delivered to the national power grid, possibly 2018. This early power generation will start well before the completion of the dam, when the filling of the reservoir commences. The two units are sitting within the 10 unit powerhouse to the right side of the dam at the auxiliary spillway. They are fed by two special intakes within the dam structure that are located at a height of 540 m (1,770 ft) above sea level. It is foreseen, that power generation can start at a water level of 560 m (1,840 ft), 30 m (98 ft) below the minimum operating level of the other 14 turbine-generators. At that level, the reservoir has been filled with roughly 5.5 km³ (1.3 cu mi) of water, which corresponds to roughly 11% of the annual inflow of 48.8 km³ (11.7 cu mi). During the rainy season, this is expected to happen within days to weeks. The two early power generating units probably will be the only units in operation for several years as the filling of the reservoir will take from 5–15 years.

Two "bottom" outlets at 542 m (1,778 ft), 42 m (138 ft) above ground level are available for delivering water to Sudan and Egypt under special circumstances, in particular for irrigation purposes downstream, if the level of the reservoir falls below the minimum operating level of 590 m (1,940 ft) but also during the initial filling process of the reservoir.

The space below the "bottom" outlets is the primary buffer space for alluvium through siltation and sedimentation. For the Roseires Reservoir just downstream from the GERD site, the average siltation / sedimentation volume (without GERD in place) amounts to around 0.035 km³ (28,000 acre⋅ft) per year. Due to the large size of the GERD reservoir, the siltation / sedimentation volume is expected to be much higher in this case, expected are 0.21 km³ (170,000 acre⋅ft) per annum.[33][36] The GERD reservoir will foreseeable take away the siltation threat from the Roseires reservoir almost entirely.

The ground level of the GERD dam is at around 500 m (1,600 ft) above sea level. Water flowing out of the dam will be released into the Blue Nile again which will flow for only around 30 km (19 mi), before joining the Roseires reservoir, which – if at full supply level – will be at 490 m (1,610 ft) above sea level. There is only a 10 m (33 ft) elevation difference between both projects. The two reservoirs and accompanied hydropower projects could – if coordinated properly across the border between Ethiopia and Sudan – become a cascaded system for more efficient hydropower generation and better irrigation (in Sudan in particular). Water from the 140 m (460 ft) column of the water storage of the GERD reservoir could be diverted through tunnels to facilitate new irrigation schemes in Sudan close to the border with South Sudan. In Ethiopia itself, no irrigation schemes are planned due to the proximity of the dam to the downstream border with Sudan.

Evaporation of water from the reservoir is expected to be at 3% of the annual inflow volume of 48.8 km³ (11.7 cu mi), which corresponds to an average volume lost through evaporation of around 1.5 km³ (0.36 cu mi) annually. This was considered neglectable by the IPoE.[33] For comparison, Lake Nasser in Egypt loses between 10–16 km³ (2.4–3.8 cu mi) annually through evaporation.[37]

The main contractor is the Italian company Salini Costruttori, which also served as primary contractor for the Gilgel Gibe II, Gilgel Gibe III, and Tana Beles dams. Simegnew Bekele was the project manager of GERD from the start of construction in 2011 up to his death on July 26, 2018. The dam is expected to consume 10 million metric tons of concrete. The government has pledged to use only domestically produced concrete. In March 2012, Salini awarded the Italian firm Tratos Cavi SPA a contract to supply low- and high-voltage cable for the dam.[34][38] Alstom will provide the eight 375 MW Francis turbines for the project's first phase, at a cost of €250 million.[39] As of April 2013, nearly 32 percent of the project was complete. Site excavation and some concrete placement was underway. One concrete batch plant has been completed with another under construction.[40] Diversion of the Blue Nile was completed on 28 May 2013 and marked by a ceremony the same day.[41] By January 2016 the dam had 4 million cubic meters of concrete poured, and the installation of the first two turbines was imminent. The first power production of 750 MW was slated for sometime later that year.[42]

Dam construction in 2014

In 2012, the International Panel of Experts was formed with experts from Egypt, Sudan, Ethiopia, and other independent entities to discuss mainly engineering and partially impact related questions. This panel concluded at a number of engineering modifications, that were proposed to Ethiopia and the main contractor constructing the dam. One of the two main engineering questions, dealing with the size of flood events and the constructive response against them, was later addressed by the contractor. The emergency spillway located near the rock saddle dam saw an increase of the rim length from 300 m to 1,200 m to account even for the largest possible flood of the river. The second main recommendation of the panel however found no immediate resonance. This second recommendation dealt with the structural integrity of the dam in context with the underlying rock basement as to avoid the danger of a sliding dam due to an unstable basement. It was argued by the panel, that the original structural investigations were done with considering only a generic rock mass without taking special conditions like faults and sliding planes in the rock basement (gneiss) into account. The panel noted, that there was indeed an exposed sliding plane in the rock basement, this plane potentially allowing a sliding process downstream. The panel didn't argue that a catastrophic dam failure with a release of dozens of cubic kilometers of water would be possible, probable or even likely, but the panel argued, that the given safety factor to avoid such a catastrophic failure might be non-optimal in the case of the Grand Ethiopian Renaissance Dam.[33] It was later revealed that the underlying basement of the dam was completely different from all expectations and did not fit the geological studies as the needed excavation works exposed the underlying gneiss. The engineering works then had to be adjusted, with digging and excavating deeper than originally planned, which took extra time and capacity and also required more concrete.[2]

Originally, in 2011, the hydropower plant was to receive 15 generating units with 350 MW nameplate capacity each, resulting in a total installed capacity of 5,250 MW with an expected power generation of 15,128 GWh per annum.[29] The capacity factor of the planned hydropower plant – the expected electricity production divided by the potential production if the power plant was utilized permanently at full capacity – was only 32.9% compared to 45–60% for other, smaller hydropower plants in Ethiopia. Critics concluded that a smaller dam would have been more cost-effective.[29]

Soon after, in 2012, the hydropower plant was upgraded to receive 16 generating units with 375 MW nameplate capacity each, increasing the total installed capacity to 6,000 MW, with the expected power generation going up only slightly to 15,692 GWh per annum. Consequently, the capacity factor shrank to 29.9%. According to Asfaw Beyene, a Professor of Mechanical Engineering at San Diego State University (California), the dam and its hydropower plant are massively oversized: "GERD’s available power output, based on the average of river flow throughout the year and the dam height, is about 2,000 megawatts, not 6,000. There is little doubt that the system has been designed for a peak flow rate that only happens during the 2–3 months of the rainy season. Targeting near peak or peak flow rate makes no economic sense."[43][44]

In 2017, the total installed capacity was moved to 6,450 MW, without changing the number and nameplate capacity of the generating units (which then remained at 6,000 MW in total). This was thought to arrive from enhancements made to the generators.[6] The expected power generation per annum went up to 16,153 GWh,[4] the capacity factor shrank again and reached 28.6%. This time nobody publicly voiced concern. Such an optimization of the Francis turbines used at the dam site is indeed possible and is usually done by the provider of the turbines taking into account site-specific conditions.

Considering the critics voiced about the alleged over-sizing of the possible power output, now of 6,450 MW. Ethiopia is relying heavily on hydropower, but the country is often affected by droughts (see e.g. 2011 East Africa drought). The water reservoirs used for power generation in Ethiopia have a limited size. For example, the Gilgel Gibe I reservoir, that feeds both the Gilgel Gibe I powerplant and the Gilgel Gibe II Power Station, has a capacity of 0.7 km³. In times of drought, there is no water left to generate electrical power. This heavily affected Ethiopia in the drought years 2015/16 and it was only the Gilgel Gibe III powerplant, that in 2016 just started to run in trial service on a 14 km³ well-filled reservoir, that saved the economy of Ethiopia.[2] The GERD-reservoir, once it has filled, has a total water volume of 74 km³, 3 times the volume of Ethiopia's largest lake, Lake Tana. Filling it takes 5–15 years and even by using all generating units at maximum capacity will not drain it within a few months. The installed power of 6.450 MW in combination with the size of the reservoir will help managing the side effects of the next severe drought, when other hydropower plants have to stop their operations.

Since the Blue Nile is a highly seasonal river, the dam would reduce flooding downstream of the dam, including on the 15 km stretch within Ethiopia. On the one hand, the reduction of flooding is beneficial since it protects settlements from flood damage. On the other hand, it can be harmful, if flood recession agriculture is practiced in the river valley downstream of the dam since it deprives fields from being watered. However, the next water regulating dam in Sudan, the Roseires Dam, sits only a few dozens of kilometers downstream. The dam could also serve as a bridge across the Blue Nile, complementing a bridge that was under construction in 2009 further upstream.[49] An independent assessment estimated that at least 5,110 people will be resettled from the reservoir and downstream area, and the dam is expected to lead to a significant change in the fishery.[46] According to an independent researcher who conducted research in the area where the dam is being built, near to 20,000 people are being relocated. According to the same source, "a solid plan (is) in place for the relocated people" and those who have already been resettled "were given more than they expected in compensation". Locals have never seen a dam before and "are not completely sure what a dam actually is", despite community meetings in which affected people were informed about the impacts of the dam on their livelihoods. Except for a few older people, almost all locals interviewed "expressed hope that the project brings something of benefit to them" in terms of education and health services or electricity supply based on the information available to them. At least some of the new communities for those relocated will be downstream of the dam. The area around the reservoir will consist of a 5 km buffer zone for malaria control that will not be available for settlement. In at least some upstream areas erosion control measures will be undertaken in order to reduce siltation of the reservoir.[50]

The precise impact of the dam on the downstream countries is not known. Egypt fears a temporary reduction of water availability due to the filling of the dam and a permanent reduction because of evaporation from the reservoir. Studies indicate that the primary factors which will govern the impacts during the reservoir filling phase include the initial reservoir elevation of the Aswan High Dam, the rainfall that occurs during the filling period and the negotiated arrangement between the three countries. These studies also show that only through close and continuous coordination, the risks of negative impacts can be minimized or eliminated.[11] The reservoir volume (74 billion cubic meters) is about 1.5 times the average annual flow (49 billion cubic meters) of the Blue Nile at the Sudanese-Egyptian border. This loss to downstream countries could be spread over several years if the countries reach an agreement. Depending on the initial storage in the Aswan High Dam and this filling schedule of the GERD, flows into Egypt could be temporarily reduced, which may affect the income of two million farmers during the period of filling the reservoir. Allegedly, it would also "affect Egypt's electricity supply by 25 to 40 per cent, while the dam is being built".[51] However, hydropower accounts for less than 12 per cent of total electricity production in Egypt in 2010 (14 out of 121 billion kWh),[52] so that a temporary reduction of 25 per cent in hydropower production translates into an overall temporary reduction in Egyptian electricity production of less than 3 per cent. The Grand Ethiopian Renaissance Dam could also lead to a permanent lowering of the water level in Lake Nasser if floods are stored instead in Ethiopia. This would reduce the current evaporation of more than 10 billion cubic meters per year, but it would also reduce the ability of the Aswan High Dam to produce hydropower to the tune of a 100 MW loss of generating capacity for a 3 m reduction of the water level. However, the increased storage in Ethiopia can provide a greater buffer to shortages in Sudan and Egypt during years of future drought, if the countries can reach a compromise.

The dam will retain silt. It will thus increase the useful lifetime of dams in Sudan – such as the Roseires Dam, the Sennar Dam and the Merowe Dam – and of the Aswan High Dam in Egypt. The beneficial and harmful effects of flood control would affect the Sudanese portion of the Blue Nile, just as it would affect the Ethiopian part of the Blue Nile valley downstream of the dam.[53] Specifically, the GERD would reduce seasonal flooding of the plains surrounding the reservoir of the Roseires Dam located at Ad-Damazin, just as the Tekeze Dam, by retaining a reservoir in the deep gorges of the northern Ethiopian Highlands, had reduced flooding at Sudan's Khashm el-Girba Dam.

The reservoir, located in the temperate Ethiopian Highlands and up to 140 m deep, will experience considerably less evaporation than downstream reservoirs such as Lake Nasser in Egypt, which loses 12% of its water flow due to evaporation as the water sits in the lake for 10 months. Through the controlled release of water from the reservoir to downstream, this could facilitate an increase of up to 5% in Egypt's water supply, and presumably that of Sudan as well.[54]

Egypt has serious concerns about the project so that it requested to be granted inspection allowance on the design and the studies of the dam, in order to allay its fears, but Ethiopia has denied the request unless Egypt relinquishes its veto on water allocation.[55] After a meeting between the Ministers of Water of Egypt, Sudan and Ethiopia in March 2012, Sudan's President Bashir said that he supported the building of the dam.[56]

A Nile treaty signed by the upper riparian states in 2010, the Cooperative Framework Agreement, has not been signed by either Egypt or Sudan, as they claim it violates the 1959 treaty[57], in which Sudan and Egypt give themselves exclusive rights to all of the Nile's waters.[58] The Nile Basin Initiative provides a framework for dialogue among all Nile riparian countries.

Egypt, Ethiopia and Sudan established an International Panel of Experts to review and assess the study reports of the dam. The panel consists of 10 members; 6 from the three countries and 4 international in the fields of water resources and hydrologic modelling, dam engineering, socioeconomic, and environmental.[53] The panel held its fourth meeting in Addis Ababa in November 2012. It reviewed documents about the environmental impact of the dam and visited the dam site.[59] The panel submitted its preliminary report to the respective governments at the end of May 2013. Although the full report has not been made public, and will not be until it is reviewed by the governments, Egypt and Ethiopia both released details. The Ethiopian government stated that, according to the report, "the design of the dam is based on international standards and principles" without naming those standards and principles. It also said that the dam "offers high benefit for all the three countries and would not cause significant harm on both the lower riparian countries".[60] According to Egyptian government, however, the report "recommended changing and amending the dimensions and the size of the dam".[61]

On 3 June 2013 while discussing the International Panel of Experts report with President Mohammad Morsi, Egyptian political leaders suggested methods to destroy the dam, including support for anti-government rebels.[62][63] Unbeknownst to those at the meeting, the discussion was televised live.[22] Ethiopia requested that the Egyptian Ambassador explain the meeting.[64] Morsi's top aide apologized for the "unintended embarrassment" and his cabinet released a statement promoting "good neighbourliness, mutual respect and the pursuit of joint interests without either party harming the other." An aide to the Ethiopian Prime Minister stated that Egypt is "...entitled to daydreaming" and cited Egypt's past of trying to destabilize Ethiopia.[65] Morsi reportedly believes that it is better to engage Ethiopia rather than attempt to force them.[22] However, on 10 June 2013, he said that "all options are open" because "Egypt's water security cannot be violated at all," clarifying that he was "not calling for war," but that he would not allow Egypt's water supply to be endangered.[66]

In January 2014, Egypt left negotiations over the dam, citing Ethiopian intransigence.[25] Ethiopia countered that Egypt had set an immediate halt on construction and an increase of its share to 90% as the preconditions, which were deemed wholly unreasonable. Egypt has since launched a diplomatic offensive to undermine support for the dam, sending its Foreign Minister, Nabil Fahmi to Tanzania and the Democratic Republic of the Congo to garner support. Egyptian media outlets declared the visits productive and that the leaders of those nations had expressed "understanding" and "support" of Egypt's position.[67] Sudanese Foreign Minister Ali Karti criticised Egypt for "inflaming the situation" through its statements on the dam, and that it was considering the interests of both sides Al-Masry Al-Youm declared that Sudan had "proclaimed its neutrality".[24][68] The campaign is intensive and wide-reaching; in March 2014, for the first time, only Uganda, Kenya, Sudan, and Tanzania were invited by Egypt to participate in the Nile Hockey Tournament.[69] Foreign Minister Fahmi and Water Resources Minister Muhammad Abdul Muttalib planned visits to Italy and Norway to express their concerns and try to compel them to pull their support for the GERD.[23]

In April 2014 Ethiopia's Prime Minister invited Egypt and Sudan to another round of talks over the dam and Nabil Fahmi stated in May 2014 that Egypt was still open to negotiations.[70] Following an August 2014 Tripartite Ministerial-level meeting, the three nations agreed to set up a Tripartite National Committee (TNC) meeting over the dam. The first TNC meeting occurred from 20 to 22 September 2014 in Ethiopia.[71]

In February 2020 U.S.A Treasury issued statement about GERD stating" ...final testing and filling should not take place without an agreement." after Ethiopia Skips US Talks With Egypt Over Dam Dispute. Ethiopians online express anger using #itismydam over US and world bank's siding with Egypt contrary to co-observer role initially promised. The online campaign ironically coincidences with Ethiopia's annual public holiday, victory of Adwa, a decisive victory that successfully thwarted colonial campaign for the first time. Ethiopia has stated that "it will not be pressured on Nile River".