Introduction
Dams are massive structures built to control and harness water resources for purposes like irrigation, electricity generation and flood control. In Africa, much like in the rest of the world, they are not just functional infrastructure projects – they are often also seen as prestige symbols and markers of power, progress and modernity. By championing the construction of dams, politicians often portray themselves as bold visionaries willing to literally singlehandedly drag their countries into the future. However, due to their impact on the environment as well as climate change, we need to completely rethink how such expensive structuring projects should be done in future.
Dams: a popular way to generate power
Dams have traditionally been viewed as key structuring or development projects with the capacity to transform entire nations. When Ethiopia finally launched Africa’s largest hydro-electric dams - the Grand Ethiopian Renaissance Dam (GERD) - Prime Minister Abiy Mohamed called it a milestone. The hope is that the dam is going to change the fortunes of millions of Ethiopians. The GERD, which has a nameplate capacity of 6000MW has sparked an ongoing row with Egypt who believe that the dam has the potential to limit how much water goes into the main Nile, which would spell disaster for Egypt. Egypt’s foreign minister described Ethiopia as intransigent in the discussions that occurred when the project was announced.
In Zambia, when the Chinese company Sinohydro Corporation Ltd. finished installing five generators at the Kafue Gorge Lower Hydropower Station, there was a lot of excitement. Through this project, the country added 750 Megawatts to the national grid and took one more step to universal affordable access to power. Although it did not get to the level of Kariba’s excitement, Zambians were very optimistic about what would change with the new dam.
Who do politicians love dams?
The main reason for the popularity of huge dams across and length and breadth of the African continent has been made elsewhere and will be repeated here for emphasis. This idea had been discussed well before the First World War (Showers 2011). The key driver for hydropower evolution has been to reach and exploit mineral wealth buried deep underneath the earth. A resolution in the United States after a Geological survey states, 'the development of mineral resources of the world depends upon the availability of cheap mechanical or electrical energy." (USGS 1921b, p.3). Even though small hydro plants already existed in Africa, as in German East Africa and Ethiopia, the USGS 1921 report mentioned the possibility of harnessing the River Congo at Inga. In 1912, the Egyptians had raised the Low Aswan Dam, a proposal from German and Italian companies (Societa Generale per la Cianamide) to serve hydroelectric power to supply power to a nitrogen fertiliser factory (Larkins 1927; Selous 1938). As argued later, waterpower and mineral fuels will compete in the location and localisation industries across the continent.
Africa’s largest dams
According to the most comprehensive world water survey, Water Power of the World, Africa holds one-half of the world's hydroelectric potential, with the Congo Basin alone having more than one-quarter (USGS 192b, p. 33). Colonial governments followed up on this detailed report with local country investigations into the use of hydropower for electricity manufacturing: Water power resources in Southern Rhodesia (Anderson et al. 1960); Gold Coast's Geological on the hydro capabilities of River Bui (Kitson 1925); the East African Governors Conference report on hydroelectric resources in Kenya, Uganda and Tanganyika (Richards 1947) and Egyptians engineers took an international hydroelectric study tour (Larkson 1927).
The first dams built in Africa for mining appeared in the 1920s. These were small, and so too was their electricity production output. In Northern Rhodesia (Zambia), a Two (2) MW Mulungushi plant was constructed on the Mulungushi River to feed the lead and zinc mining taking place at Broken Hill (Bureau of Foreign Commerce 1956; Olivier 1976; Mihalyi 1977). In British Nigeria, the Nigeria Electricity Supply Company built a hydroelectric system in 1929 at Kurra Falls to feed the growing industrial demand for electricity in the Jos Plateau (Simpson 1969). Inasmuch as these small dams served the local communities they were constructed, their construction stopped in 1930. There were tremendous advances made on the technological front in the construction of dams and the transmission of large-scale electricity over very long distances (Carpenter 1929). This opened the way for the construction of dams along larger rivers and still made the project cost-effective. Hydropower production in Africa entered a new era marked by the construction of massive dams with the electrical power transmitted over very long distances to cities, industries and mines (Showers 2011).
The demand for electricity in Africa has always been constrained by availability (Ansah et al., 2021). Just as is the case in other parts of the world, economic development, industrialisation, growth in the population, and changing lifestyles are contributing factors that increase the energy demand and consequently encourage the building of bigger and larger dams for hydroelectricity production. The African continent today is home to some of the largest dams in the world. Africa has the Niger, Nile and Congo Rivers and a vast array of water systems, all of which have assisted in the construction of massive dams to regulate water flow in their different hydroelectric generating plants. A brief of some key dams, their construction and hydroelectric potential follows.
The Grand Ethiopian Renaissance Dam in Ethiopia can generate up to 6,450 MW per year. The Dam's primary purpose is to redress Ethiopia's acute electricity shortage and electricity for export to neighbouring countries. It is located on the Blue Nile, at Ethiopia's border with Sudan (International Rivers 2010). The dame measures 5,900 meters in length and 145 meters in height and holds about 63 billion cubic metres of water. The construction started in 2011 and was expected to take ten years to complete. However, the Dam only started producing electricity for the first time in February 2022, and it is a property of Ethiopian Electric Power.
The Aswan High Dam in Egypt is the continent's second-largest, powering 12 generators each at a rate of 175 MW producing a total generation capacity of 2100 MW. The Awan High Dam was built between 1960 and 1970, and its significance eclipsed the Aswan Low dam, initially completed in 1902. The key objectives of the Dam were to control flooding, water storage for irrigation, and to generate hydroelectricity to drive Egypt's industrialisation. It is owned by Egypt.
Africa's third largest Dam, the Cahora Bassam dam in Mozambique, is one of two dams on The River Zambezi. Its combined total output of 2,070MW is generated from five 415MV turbines. Most of the power from the Cahora Bassam is exported to feed the very high energy demand from neighbouring South Africa through the Cahora Bassam high voltage direct current (HVDC) line system with two conversion systems at Songo (Mozambique) and apollo (cities, mines and farms in South Africa). The Cahora Bassam Dam was constructed between 1969 and 1974 and is jointly owned by Mozambique and Portugal. The fourth largest in Africa, Gilgel Gibe III Dam, produces 1,870 MW of electricity. The Gilgel Gibe III is Ethiopia's second-largest dam on the Omo River to the southwest of its capital Addis Ababa. The Gibe III is part of a cascade of barriers with the Gibe I (184 MW) and Gibe II (420 MW). One-half of the electricity is for Ethiopia, and the other half is exported to Kenya (500 MW), Sudan (200 MW) and Djibouti (200 MW). Envisage expansion will see the Gibe IV and Gibe V add 1,472 MW and 560 MW to the Gibe Cascade.
The Democratic Republic of Congo is home to Africa's fifth biggest dam, the Inga dam producing 1,775 MW of electricity from its Inga I (351 MW) and Inga II (1,424 MW). It was built on the Inga Falls and could become the world's largest Dam producing an enormous 70 GW of electricity, a project estimated to cost 80 billion Dollars.
Following is the Kariba Dam situated between Zimbabwe and Zambia. This 1,626 MW dam measures 128 metres in height and 579 metres in length, supplying electricity from power stations in its north bank to Zambia and south bank to Zimbabwe. The Kariba Dam is an arch-shape dam built on the Kariba Gorge of the River Zambezi and owned by the Zambezi River Authority.
In West Africa, there are two of the top ten dams in Africa. The Akosombo Hydroelectric Dam was constructed on the base of the world's largest man-made Lake Volta (Report on the Preparatory Commission 1952; Kuruk 1989). Construction work at the Akosombo Dam began in 1961 and ended in 1965 (Coquery-Vidrovitch 2002) at the cost of 130 million Dollars. Its installed capacity now stands at 1,020 MW following a retrofit project completed in 2006. It was envisaged to supply power to Ghana's aluminium industry when it was built. Instead, today it provides electricity to Ghana, Togo and Benin.
The Kainji Dam is in central Nigeria, built across the Niger River (Coquery-Vidrovitch 2002), and its 10km length makes it the world's longest Dam. It has eight of the proposed twelve turbines installed and produces 760 MW of electricity instead of the expected 960 MW. It supplies electricity to all the major cities in Nigeria, Africa's most populous nation. Construction started in 1964 and finished in 1968. This was realised at the cost of 209 million Dollars, 25% of that cost was used to settle displaced by the construction project. The Federal Government of Nigeria owns the Kianji Dam.
Better alternatives?
Zambia recently found out that, even with vast outlays of capital investment in turbines and new dam capacity, they cannot get maximum benefit out of their dams. This is because climate change is making Zambia hot and dry. Simply put, there is not enough water to generate electricity.
Other countries are going through similar situations. Zimbabwe was getting only a few hours a day in 2024 due to drought on the Hwange and Kariba projects. Similarly, the DRC cannot produce enough generation from Inga. It is getting too hot and dry.
The GERD took about 11 years to complete. Since 2019, South Africa has shown that the costs of renewables have gone way down, and the cost of one GERD can cost up to 12 000MW of solar capacity.
Obviously, a good network requires a proper mix of energy sources. Again, geothermal offers solutions that many African countries do not seem to be keen on.
Finally, with power generation, much like other major project – airlines for example, African countries seem to all want to do the same thing: every country wants to build their own. Ultimately, this option is unsustainable and unnecessarily expensive. Sometimes, it is better to import electricity via a power pool than opting to build a dam in a country where the temperatures are causing water sources to dry up.
