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Ingula pumped-storage scheme project, on the border between the Free State and KwaZulu-Natal, South Africa

22nd February 2013

By: Sheila Barradas

Creamer Media Research Coordinator & Senior Deputy Editor

  

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Name and Location
Ingula pumped-storage scheme project, on the border between the Free State and KwaZulu-Natal (KZN), South Africa.

Client
Eskom.

Project Description
The Ingula pumped-storage scheme, located within the Little Drakensberg mountain range, 23 km north-east of Van Reenen’s Pass, will comprise an upper dam (Bedford) and a lower dam (Braamhoek). The upper reservoir site is located in the Free State and the lower reservoir site in KZN. The escarpment forms the border between the two provinces.

The distance between the upper and lower reservoirs will be 4.6 km, with an elevation difference of about 470 m.

The dams will be connected through underground waterways, by means of an underground powerhouse complex, which will house four 333 MW pump turbines, with a total capacity of 1 332 MW, a machine hall, a transformer hall and associated tunnels, shafts and caverns.

The twin waterways, consisting of concrete and steel-lined headrace tunnels and pressure tunnels and shafts, will link the upper reservoir with the pump/turbines. Steel-lined extended draft tubes and a single concrete-lined tailrace tunnel will connect the pump/turbines to the lower reservoir.

The upper reservoir will be a concrete-faced rockfill embankment dam, 41 m high, with a total capacity of 22.6-million cubic metres and an active water storage volume of 19.3-million cubic metres. The lower dam will be of roller-compacted concrete (RCC), 39 m high, with a total capacity of 26.3-million cubic metres and an active storage volume of 21.9-million cubic metres.

The upper reservoir will store enough water to generate electricity continuously using all four units for 16 hours. Pumping the water back from the lower reservoir will take about 21 hours, giving an overall efficiency of 76% for the scheme.

Value
R23.8-billion. As at March 31, 2012, R11.1-billion had been spent.

Duration
The first 333 MW unit of the nearly R17-billion project is expected to be commissioned in the first quarter of 2014, with the remainder of the units starting commercial operation later that same year.

Latest Developments
Work on the pumped-storage scheme is progressing well, with the bulk of the initial excavation work completed, despite the steep gradient presenting a challenging operating environment. The project team had to overcome the steep gradient of the two 6.1-m-excavated-diameter headrace tunnels; each tunnel is 1 940 m long, with a 970-m-long section at an inclination of 1:2.2.

Tracked machinery was required for all excavation phases that contributed to a final advance of only 1.1 m a day.

Installation of the 5.1-m-diameter steel lining of these tunnels has now started, with plans to place the concrete encasement of the lining from the bottom of the tunnels by pump.

Meanwhile, the excavation work, comprising an estimated 2.2-million cubic metres of surface and underground excavation, began in September 2008 and is in its final stages, with only two surge tanks to be completed.

The excavation of the machine hall was completed in January 2012 and was followed in August by the completion of the concrete encasement of the first draft tube. Preparation for the installation of the first spiral-case installation is continuing, with the spiral case being prepared for installation in the erection bay.

The project is a joint venture between engineering consultancy Gibb, engineering and environmental consultancy SSI and international consulting firm Knight Piesold.

Key Contracts and Suppliers
The Braamhoek Dams joint venture (JV) consisting of Gibb, Knight Piésold and SSI (civil engineering, mechanical engineering, electrical engineering, detailed design, tender documentation, design monitoring and construction supervision); Murray & Roberts (civil works); Grinaker-LTA (access roads); CMI JV, comprising CMC di Ravenna, PG Mavundla and Impregilo (underground civil works); Afriscan (water supply, sewage treatment, small access roads and building temporary Eskom offices); B&E Quanza Group (aggregate quarry); Acer [Africa] (environmental consultants); Braamhoek Dam JV, comprising Concor Roads & Earthworks, Wilson Bayly Holmes-Ovcon (WBHO), Edwin Construction and Silver Rock (dam contract); Voith Siemens Hydro Power Generation (mechanical auxilary plant); Atlantis Drill (ventilation shaft) and Sandvik Mining & Construction (raiseboring manager); Deutsche Bank (R1-billion loan); ABB (electrical balance of plant, or eBoP, solution); NCC Environmental Services (independent environmental control officer services); Konecranes (heavy-duty cranes); Hitachi (boiler); Basil Read (main civils); Alstom (turbine); Roshcon (enabling civils); Aveng (access roads); African Construction (infrastructure); TBD (optic fibre and communications); and Siemens (generator transformers).

On Budget and on Time?
The first 333 MW unit was initially expected to be commissioned by January 2013; however, it will only be commissioned in the first quarter of 2014.

Contact Details for Project Information
ABB head of communications Harmeet Bawa, tel +41 43 317 6480, fax +41 43 317 6482 or email harmeet.bawa@ch.abb.com.
Gibb, Andre Bosch, tel +27 11 519 4600 or fax +27 11 807 5670.
Braamhoek Dams JV (Concor Roads & Earthworks), Eric Wisse, tel +27 11 495 2222.
CMI Mavundla JV, tel +27 36 638 6000 of fax +27 36 8 6017.
Eskom media desk, tel +27 11 800 3304/3309/3343/3378, fax +27 11 800 3805 or email mediadesk@eskom.co.za; or Katlego Nchoe, tel +27 11 800 3435 or email NchoeK@eskom.co.za.
Eskom national call centre, tel 0860 037 566.
Ingula Visitors Centre, tel +27 36 342 3122 or email fifi.meyer@eskom.co.za.
Impregilo, Giovanni Frante, tel +39 02 4442 2115 or email giovanni.frante@impregilo.it.
Voith Siemens Hydro Power Generation, Barbara Fischer-Aupperle, tel +49 7321 370, fax +49 7321 37 6180 or email barbara.fischer-aupperle@vs-hydro.com.
NCC, tel +27 21 702 2884, fax +27 86 555 0693 or email info@ncc-group.co.za.
Konecranes, tel +27 11 864 2800.

Edited by Creamer Media Reporter

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