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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.
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.
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.
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.
 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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