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  •   Home  Products and Services   Ruacana

    Ruacana
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    History

    Specs

    Power Station

    Powerhouse Complex

    Pressure Tunnel

    Surge Headbay

    Tailrace Tunnel

    Access Gallery

    Camps


    History
    The Ruacana Scheme as originally planned and negotiated with the Portuguese Authorities, consists of the following major components:-

    A large storage dam had to be built at Gove ħ 80 km south of Nova Lisboa in the Kunene River. This dam, with a planned capacity of 2 600 million cubic metres, was designed to accommodate the flood waters of the Kunene during the rainy season and then in the drier months to augment the flow so that a regulated flow throughout the year could be maintained in order that electricity could be generated on a more or less constant basis continuously at Ruacana.

    The South African Government gave R4 million to the Government of Portugal for the building of this dam about 430 km upstream from Ruacana.  For the balance of the cost – another R4 million – SWAWEK granted a loan which had to be redeemed over 20 years by means of a levy which SWAWEK had to pay for the use of half the water at Ruacana for power generation purposes.

    Apart from the fact that the Government of South Africa and SWAWEK jointly paid for the building of this dam, it was also to be of considerable value to Angola. Not only was a considerable source of food - largely fish – created, but because a more stabilised flow was thereby ensured downstream, the Angolan Authorities could operate its Matala hydro-station on a firmer basis and could even increase its capacity. Additional hydro-stations at Jambai-ia-Oma, Jamba-ia-Mina and Matunto could also now be built.

    The dam was completed and commissioned in 1975 and was at that stage largely used to facilitate the building of the diversion weir at Ruacana and the dam at Calueque with their coffer dams.

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    The second component of the Ruacana Scheme was the building of a further regulation dam at Calueque ħ 65 km upstream from Ruacana, as well as a pumping station by means of which 6 cumecs of water could be extracted and pumped via pipelines and into Owamboland canal systems during dry seasons for human and animal consumption.

    This dam, with a planned capacity of 500 million cubic metres, was intended for final regulation of the riverflow downstream towards Ruacana. When in 1976 all work had to be stopped by order of the Angolan Authorities, SWAWEK had to vacate the site within 12 hours.  The project was 70% complete and R26 million had been spent. In addition, SWAWEK had to leave behind ħR3,5 million worth of construction machinery and plant.

    Apart from the fact that that portion of the work which had at the time been completed and financed could not be used, considerable damage to the project had also subsequently been caused by floods and the removal of plant and equipment which was left behind when SWAWEK had to leave the site.

    The pump station part of the project, together with a 1,5 km length of pipeline to the border, had already been completed in 1973 together with a 66 kV power line from Ruacana in order that 6 cubic metres of water per second could be pumped into the Owamboland canal system. When SWAWEK had to vacate the site, the pumping of water was also discontinued.

    The third component of the scheme was the building of a diversion weir ħ 1 km upstream from Ruacana in Angolan territory, by means of which water could be sufficiently dammed to divert it via an 8-metre diameter underground tunnel across the border to the power station in South West Africa.

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    All work on the diversion weir was completed in January 1978 at a total cost of R13 million, but could not be commissioned because the Angolan Authorities would not allow the closing of the sluice gates. Consequently, the power station also could not become operative.

    The fourth component of the Ruacana Scheme, was the hydro-power station, all of which is in Namibian territory and which is situated on the surface of a large surge headbay and consists of buildings in which switch-gear and protective equipment are housed. The power station as such, is situated immediately below – some 140 metres underground.

    Three 80 MW generating units are driven by water from the surge headbay on top. Electricity is generated at 11 000 volt, transformed to 330 000 volt and fed up vertical tunnels to the switchgear on the surface from where it is distributed to the central areas of Namibia.

    To make room for the installation of the generating units, the transformers and switchgear, as well as to provide for entrance and discharge tunnels, a total of 415 000 cubic metres of rock had to be excavated and disposed of.

    All work on this component was completed by January 1978 at a total cost of R76 million, but the station could not be commissioned because – as stated earlier – the Angolan Authorities would not allow the diversion weir sluice gates to be closed.

    The fifth and last component of the scheme, was the building of a 570 km long, 330 kV transmission line to transmit the power generated at Ruacana to a large distribution station near Omaruru where it is fed into the existing 220 kV system for distribution across the country. The erection of the power line together with associated transformers, reactors, switchgear, etc., was also completed towards the end of 1977 at a total cost of R29 million.

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    The above components, together with housing for operating personnel at Ruacana, brought the total cost of the Ruacana Scheme to R162 million.

    In the field of power generation, the source of the electricity so vital to the towns and mines of South West Africa/Namibia, SWAWEK has, ever since its inception, been in a very awkward position. Because the Ruacana hydro-system was from the start considered to constitute the main source of electricity for Namibia, all other sources built in the interim were limited in size as much as possible. The Van Eck power station was, therefore, built too small and consequently diesel-driven generators had to be added in later years pending the completion of Ruacana. This meant that generating units were hardly ever available for proper maintenance. And then – when Ruacana was eventually completed in January 1978 and the Angolan Authorities refused to let the diversion weir sluice gates be closed – it was a hard blow to SWAWEK and it experienced its darkest hours.

    It was immediately realised that an alternative and reliable source of generation had to be found. The erection of a further thermal station at either Hardap near Mariental or at the coast near Walvis Bay/Swakopmund, was investigated. The possible connection of the SWAWEK transmission system with the Eskom system in the RSA was also investigated. After thorough studies and analysis of the various alternatives, it was determined that a transmission line linking the Eskom and SWAWEK systems would in the long run be the most advantageous to SWAWEK. The South African Government was immediately asked for approval of such a connection and it was pointed out by SWAWEK that with the available resources, it would not be possible to maintain an adequate supply of electricity through the years 1981 / 1982.

    In addition to this, SWAWEK at this time also found itself in the unenviable position that it had to balance its income and expenditure accounts. Its tariffs could hardly be increased because contracts for supplies were entered into with consumers and these could not unilaterally be altered. In addition, fuel costs were increasing rapidly; ageing plant had to be kept turning and more and more diesel-driven units had to be kept in operation to maintain supplies - truly dark years.

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    After the closure of the sluice gates of the diversion weir in January 1980 – it just had to be done – and the commissioning of the hydro-station, the supply of electricity could be improved and costs could be curtailed. Unfortunately, the closure of the sluice gates led to the continuous sabotaging of the powerline from Ruacana. In time, however, with the technology of SWAWEK and the co-operation of the South African Defense Force, a system was devised safe-guarding the line and interruptions were considerably reduced.

    Permission for the connection of the SWAWEK system to the Eskom system was eventually given in April 1980 and immediately a start was made with planning and design, surveying of routes, acquisition of wayleaves, drawing up of specifications, calling for tenders, drawing up and awarding of contracts and in 1981 actual construction commenced. Twenty-three months later – during the middle of December 1982 – all work was completed at a total cost of R60 million and the 779 km long double-circuit line with the switching stations at Mariental and Keetmanshoop, was taken into commission.

    For many years, the further investment of capital on generating plant would no longer be necessary, because with the completion of this transmission line the total peak capacity available to SWAWEK was about 4 times higher than the system peak demand at that time. This meant that for years into the future, the transportation of coal and the consumption of diesel fuel would be minimal. This enabled the price of electricity to consumers in the then South West Africa to be kept at lower levels than would otherwise have been possible.

    The only part of Namibia that could not be supplied economically from the then SWAWEK transmission system, was the Caprivi in the far north-east. However, SWAWEK established a diesel-driven power station at Katima Mulilo with a total capacity of 2,5 MW, which was adequate for supplying the only existing load – Katima Mulilo. This power station was built in 1981.

    In 2003 Ruacana became the first hydropower facility IN THE WORLD to adopt Profibus technology, with all measurement devices being upgraded using programmable logic controllers and system control and data acquisition software. 

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