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BEST
PR
O
JECTS
53
DECEMBER • 2016
THE INGULA PUMPED STORAGE SCHEME
Project information
• Company entering: Braamhoek Pumped
Storage Scheme JV
• Client: Eskom
• Start date: 2005
• End date: 2017
• Consulting engineer: Braamhoek
Consultants Joint Venture (comprising
Gibb, Royal HaskoningDHV,
Knight Piésold)
• Contractors:
• Murray & Roberts – exploratory
tunnel
• 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 of temporary Eskom offices
• B&E Quanza Group – aggregate
quarry
• Braamhoek Dams JV, comprising
Concor Roads & Earthworks, Wilson
Bayly Holmes-Ovcon (WBHO), Edwin
Construction and Silver Rock –
upper and lower dam contracts
• Voith Siemens Hydro Power
Generation – electromechanical
equipment contract
• ABB – electrical balance of plant
(eBoP) solution.
• Project value: R30-billion
It is located about 23 km north-east of van Reenen, within the Little
Drakensberg mountain range. The upper reservoir site is located in
the Free State province and the lower reservoir in KwaZulu-Natal.
The distance between the upper and lower reservoirs is in the order
of 6,5 km and the elevation difference is approximately 480 m.
The scheme consists of the following basic components:
• An upper reservoir (Bedford Dam),
• A lower reservoir (Bramhoek Dam),
• An underground powerhouse complex and associated waterways
that link the two reservoirs,
• Four pump-turbines coupled directly with motor-generators,
• Surface switching station,
• Ancillary works that include building works, roads, transmission
lines and temporary and permanent infrastructure.
The rated generating capacity is 1 332 MW and the energy storage
capacity 21 000 MWh (15,8 generating hours). In addition to
the normal generation capacity a minimum emergency full load
generation reserve of four hours is maintained throughout the
normal weekly operating cycle.
The design of the scheme is undeniably complex and
sophisticated requiring design inputs from true international
experts, each interfacing with each other to yield precise results.
During off-peak periods the reversible pump-turbines use
electricity from the national grid to pump water from the lower to
the upper reservoir. During periods of emergency peak demands,
The multi-billion Rand Ingula project is a peaking
hydro power station. The scheme allows for
water to be released from the upper reservoir
and delivered to the pump-turbines to produce
power, before being captured in the lower
reservoir. During off-peak power periods the pump-
turbines then pump the water back up to the upper
reservoir where it is to be ready for the next peak
power occurrence.
water is allowed to flow back into the lower reservoir through the
pump-turbines to generate electricity.
From initial site investigations it was realised that the geology
at Ingula is more complex than might have been expected. State
of the art numerical analyses were therefore carried out to design
rock excavation support for the large underground caverns in
which the main transformers and pump-turbines and motor-
generators are housed.
With the project located in the Little Drakensberg escarpment
that is recognised for its scenic beauty, the aesthetic value of the
engineering design formed the basis for its ultimate environmental
approval. In particular the upper reservoir is located in a natural
wetland. The layout of the project and the design of engineering
elements were treated with great sensitivity towards the
environment.
Eskom developed and implemented an Environmental
Management System (EMS), which has been ISO 14001 certified
since 2011.
The project has stimulated local economic development during
construction with over 5 000 persons employed at the peak of
construction, in addition to other direct beneficiaries
in the education, health and social investments by Eskom
and its contractors.
Special Mention