22 Hydropower
22 Hydropower Beneath the cover of water, deep deposits of silt have reduced the capacity of the Collywobbles dam. Sue Matthews Sue Matthews visited Collywobbles in the Eastern Cape and explores ways of mitigating its impact on the surrounding environment. he Mbhashe River rises in the Gariep (360 MW) and Vanderkloof Of course, there’s a higher demand mountains of the southern (240 MW) schemes on the Orange for electricity in winter, so enough water TDrakensberg, and then snakes east- River. (This excludes the Drakensberg must be stored to see the power ward across the coastal plateau, a gentle and Palmiet pumped storage schemes, station through the dry months. But landscape of undulating grassland. where water is pumped during off-peak the Collywobbles dam was only Shortly after flowing beneath the N2, the periods to generate electricity during designed to provide an effective storage river encounters the more rugged terrain peak demand.) of 2,5 GWh – equivalent to 60 hours of of the Wild Coast, and – as if in shock or operation with all three turbines gen- confusion – it suddenly flails into a series Like many conventional hydropower erating at maximum capacity. Water is of violent contortions, before seemingly schemes, Collywobbles has a storage therefore diverted from the Ncora Dam getting a grip on itself and continuing dam and a penstock to pipe water down on the Tsomo River in the neighbouring more sedately to the Indian Ocean. to the turbines, which drive the genera- Greater Kei catchment, taking about two tors. What’s amazing about this scheme days to reach Collywobbles.
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