The continent of Africa has a combination of significant untapped hydro potential and a serious deficit of access to electricity. This article profiles three hydro projects to give an idea of work being performed.
Many countries on the African continent rely heavily on hydropower, with several of them getting more than 90% of their total electricity supply from hydro. However, at the same time, the World Bank says that, worldwide, the energy access deficit is greatest in sub-Saharan Africa, where less than 10% of hydropower potential has been tapped. The bank says there is 400 GW of undeveloped hydropower in that area, which is enough to quadruple that continent’s existing hydro capacity.
So exactly what is the status of hydropower in Africa? According to data from the International Hydropower Association, current operating hydro capacity (including pumped storage) stands at 25.3 GW. Several countries on the continent have specific hydropower targets. Just two examples are Ethiopia, which plans to reach 22,000 MW of total installed hydro capacity by 2030 (from just over 4,000 MW in 2016), and Angola, which seeks to have 9,000 MW of total installed hydro capacity by 2025 (compared with less than 1,300 MW in 2016).
This article provides profiles of just three hydro projects in various locations and at various stages:
– 180-MW Kihansi in Tanzania (operating for nearly 20 years, now undergoing rehabilitation and expansion)
– 183.2-MW Isimba in Uganda (under construction)
– 2,400-MW Ataqa pumped storage in Egypt (being studied for development)
The following profiles provide technical details on each of the facilities, as well as financial information if available and the reasons behind the development of each of these hydroelectric plants.
Tanzania Electric Supply Company Limited (TANESCO) has been operating the 180-MW Kihansi (also called Lower Kihansi) hydroelectric project, on the Kilombero river system along the Udzungwa escarpment in Iringa Region, since it was commissioned in December 1999.
Given its age, TANESCO is working to both upgrade the equipment and increase the generating capacity at the facility. The underground powerhouse at Kihansi contains three Pelton turbine-generator units each with a capacity of 60 MW.
A concrete gravity dam 25 m high and 200 m long diverts the river flow into a vertical unlined intake shaft 500 m deep that connects to an unlined headrace tunnel leading to a steel penstock.
When the expansion work is complete – with the addition of two 60-MW turbine-generator units – site capacity will increase to 300 MW. Achieving this involves adding a large water storage dam, as the site previously operated in run-of-river mode, with live storage of about 1 million m3.
The powerhouse currently provides firm energy of 1,000 GWh annually.
This work is being undertaken “to improve the power supply condition in Tanzania and create an opportunity for bilateral electricity trade with neighboring countries,” TANESCO says. Other business goals and objectives TANESCO has are improving plant safety and performance, improving communication and enhancing information technology, improving and enhancing teamwork, and improving staff performance.
Multiple tenders for equipment supply were issued in mid-January, including deflector servomotor assembly, servomotor assembly for main injector, and upgrading of the excitation system for Units 1 through 3. Tenders were due by Feb. 7, and no contractors have yet been named. In addition, a tender was issued in November 2017 for consultancy services for design of the main valve cylinder gate for the three existing units.
The 183.2-MW Isimba project, being built in the Kamuli District of Uganda, is an example of current hydro construction activity in Africa. Construction work was launched in October 2013, and completion is expected in August 2018.
Uganda Electricity Generation Company Ltd. (UEGCL) is building this project, on the Nile River 4 km downstream from Simba Falls. At the Isimba site, the river channel splits into two branches, and various project structures span the left river channel, Koova Island in the middle, and the right river channel.
Civil works will include a concrete gravity dam, a clay-core rockfill dam and a spillway.
The powerhouse will be on the left river channel and contain four 45.8-MW vertical Kaplan turbine-generator units. The first unit was lowered into place in December 2017. Annual generation from the facility is expected to be 1,039 GWh. A new 132-kV transmission line will be constructed to deliver the power produced to the national grid, at the Bujagali hydropower station.
When complete, Isimba is expected to cost US$567.7 million, 85% of that coming from an Export-Import Bank of China loan and the rest from the government of Uganda. UEGCL reported on its website that in late February 2018, general project progress at Isimba was more than 80%, “as the project heads into its last five months on its completion schedule.” However, at the time this magazine went to press, no announcement had been made that the project was completed.
Companies working on this project include Fichtner and Norplan as contractors for the feasibility study and preparation of tender documents; Artelia EAU & Environment as owner’s engineer, in association with Ugandan company KKATT Consult Limited, which took the project over in January 2018; China International Water & Electric Corporation as contractor, with the contract awarded in July 2013; SMEC International Pty. Ltd. as project management consultant; Zhefu Co. Ltd. as turbine manufacturer; Energy Infratech as supervision consultant; and Geotech Solutions performing geological investigation, drilling and rock grouting.
A project coming quickly down the pipeline is the 2,400-MW Ataqa (or Attaqa) pumped storage facility to be built in Egypt.
Ataqa will be located on Attaqa Mountain in Suez, but specific details on the configuration of this hydro facility – including the number of turbine-generator units – has not been released.
The Ministry of Electricity and Renewable Energy has, however, awarded multiple contracts to develop this project, including a consortium of Artelia and AF Consult Switzerland as the owner’s engineer and Sinohydro as the engineering-procurement-construction and finance contractor.
Ataqa is expected to cost about US$2.6 billion and take seven years to build, with an anticipated 2024 completion date. It is not clear where financing for this project will come from, although Egypt Today reported in June 2017 that the project contract was signed in March 2015.
The cabinet allocated the required land for building the project in March 2017. The development has been licensed and the Hydro Power Plants Executive Authority of the Ministry has received the security and environmental approvals. The project is expected to take seven years to complete and will be “the first power plant in the Middle East to generate electricity from water stations using pumping and storage,” Artelia says.
Ataqa “will support the Ministry’s plans to diversify the energy sources in the country and will also help meet growing electricity demand in the region,” AF Consult says.
Andritz reported that Egypt has about 50,000 GWh/year in technically feasible hydropower potential, with only about 9% of its electricity supplied by hydropower.
Elizabeth Ingram is managing editor of Hydro Review.