Hydro Power

Annual hydro power potentials are mapped for both macro and micro power generation; macro power generation being considered for large scale daming projects, while micro power generation is considered for small scale projects in rural communities.

Both macro and micro power potentials are modelled combining river gradients, mean annual run-off and variability in run-off. River gradients were determined using the Surveyor General 400 x 400m Digital Elevation Model (DEM), and mean annual run-off values per quaternary catchment were derived from the Water Research Commission, WR90 CD.

Macro power potential is modelled using the cumulative mean annual flow volume along a river length. In comparison, micro power potential is modelled using the mean annual flow volume for a one kilometre stretch along a river. This approach gives a better estimate of local energy potential and highlights the potentials of fast flowing water (steep gradients) as opposed to large volumes of water.

As an indication of the variability or variation in flow, a low flow index (LFI) surface and a coefficient of variation surface have been generated. LFI depicts the mean of the three lowest monthly flows. The variability in flow has a large impact on the viability of a micro hydro power system. These surfaces are not depicted here, but would be available as part of the puchasable renewable energy database.