Ingula pumped storage scheme progressing well

August 13th, 2014, Published in Articles: Energize

 

The multi-billion rand Ingula Pumped Storage Scheme has, like many around the world of this magnitude and complexity, suffered delays – not least the site closure ordered by the Department of Labour after last year’s tragic accident which claimed the lives of six construction workers. However progress has been made since the incident in October last year on both underground and above ground facilities.

ingula-royalhaskoningDHV

The Ingula Pumped Storage Scheme is now in its seventh year of construction and had it not been for the tragic accident one of the four 333 MW reversible pump turbines would be undergoing commissioning at this time. The Eskom project is located between Ladysmith and Harrismith in the Little Drakensberg, and will have a generating capacity of 1332 MW available during periods of peak demand and to supplement base load when necessary – for example during outages or essential maintenance of other generating plant.

Ingula is a peaking hydro power station comprising an upper and a lower dam or reservoir separated in elevation by 480 m, an underground powerhouse located 116 storeys underground in two excavated underground caverns and housing 4 x 333 MW Francis type pumps/turbines.  An underground labyrinth of interconnecting tunnels and waterways extends 6,5 km and 3 km of access tunnels and a number of shafts allow water to be released from the upper Bedford Dam and delivered to the turbines producing power, before being captured in the lower Bramhoek Dam. During off-peak times – at night for example – the turbines are reversed pumping water back from Bramhoek Dam to Bedford, in readiness for the next peak event.

Jacques du Plessis, Royal HaskoningDHV’s  senior construction supervisor, explains recent progress milestones: “Underground work is proceeding apace with the concrete lining in the tailrace and headrace tunnels completed, cavity and consolidation tunnel grouting are about 75% complete and concrete slip forming at one of two 91 m high surge chambers recently commenced. All civil works in the transformer hall have been completed and the machine hall and underground control room are nearing completion” he said.  Royal HaskoningDHV is one of the three firms of consultants that make up the design and construction supervision team, “Braamhoek Consultants Joint Venture”.

Du Plessis says that the first turbine shaft and runner were taken underground recently, two generator transformers have been installed and mechanical and electrical fit-out work is underway.  The operations above ground and maintenance building on the intake structure is nearing completion as is the stop log storage facility at the outlet.

The double-storey administration building, whose basement has direct access to the main tunnel leading to the underground power station, has also recently been completed. In addition to office space, the building accommodates the external control centre for the power station. Also recently completed is the visitors centre, which comprises a small office wing, a cinema, various display halls, an auditorium and facilities wings. The surrounding area will be landscaped with indigenous plants to minimise the visual impact of the surface buildings.

Eskom is conscious of its environmental responsibilities and in particular the site’s bird life. More than 275 bird species have been sighted at Ingula including all three crane species which, although rare, are regularly seen there. The endangered Southern Bald Ibis is another resident of the conservation area and thirty breeding pairs have been counted. However, construction of the upper Bedford Dam, completed in 2011, robbed them of their historic nesting ledges. Eskom constructed a massive artificial nesting site to compensate for the loss of their originals.

The dam is expected to fill to capacity during 2015 for the first time and the hope is that before then the birds will discover the new nesting site themselves. Several dummies were placed in the new site to entice them to relocate. The change in habitat due to the construction of the dams is being monitored by conservation staff and already new species are moving into the area such as spoonbill and flamingo. Anticipated completion and operation of the first of the four pump / turbines is expected by May 2015 with the remaining units coming on stream over the following 12 months.

Contact Hillary Erasmus, Royal HaskoningDHV, Tel 011 798-6000, hillary.erasmus@rhdhv.com

 

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