Introduction

Energy from water can come from waves, tides, waterfalls and rivers and will never be finished as long as we have water. In South Africa, we have a mix of small hydroelectricity stations and pumped water storage schemes. In a pumped water storage scheme, water is pumped up to a dam.

Pumping the water uses some electricity but this is done in off-peak periods. During peak hours, when extra electricity is needed, the water is released through a turbine that drives an electric generator. Peak hours are usually between six and eight in the morning and evening.

Importing hydropower

South Africa used to import electricity from the Cahora Bassa hydropower station in Mozambique and will do so again when the transmission line is repaired. There is also the potential to import more hydropower from countries such as Zambia, Zimbabwe and Zaire. If this happens, South Africa could become less dependent on coal-fired power stations.

Environmental effects of hydropower

However the generation of hydroelectricity is not without environmental effects. Large areas of land may be flooded when dams are built. This will disrupt wildlife habitats and residential and farming areas. Another problem is that cold water released from deep in a dam may have little dissolved air in it. If large amounts of this water are released into rivers, fish may be killed. But proper management can avoid this.

Global pressures regarding the environmental impact and displacement of settlements by huge storage dams will likely limit the exploitation of hydropower on a large scale. Irrespective of the size of installation, any hydropower development will require authorisation in terms of the National Water Act 1998, Act 36 of 1998.

The potential for hydropower development in South Africa

The Baseline Study on Hydropower in South Africa, an assessment conducted by the DME in 2002, indicated that specific areas in the country show significant potential for the development of all categories of hydropower in the short and medium term.

The Eastern Cape and KwaZulu-Natal are endowed with the best potential for the development of small, i.e. less than 10MW hydropower plants. The advantages and attractiveness of these plants are that they can either be standalone or in a hybrid combination with other renewable energy sources. Advantage can be derived from the association with other uses of water (water supply, irrigation, flood control, etc.), which are critical to the future economic and socio-economic development of South Africa.

Hydropower potential outside South Africa

The Southern African Power Pool (SAPP) allows the free trading of electricity between Southern African Development Community (SADC) member countries, providing South Africa with access to the vast hydropower potential in the countries to the north, notably the significant potential in the Congo River (Inga Falls).

The main project outside South Africa's borders is Westcor. It entails a five-way intergovernmental memorandum of understanding signed between the utilities of the DRC, Angola, Namibia, Botswana and South Africa. The first project is Inga III, a 3 500MW hydro plant on the Congo River.

At the same time, the countries to the north could benefit through access to the coal-fired power resources in the south. Such an arrangement should stabilise the energy requirements of the region well into this century.

Exploitation of the vast hydropower resources will constitute a significant infusion of renewable energy resources into the energy economy of the region over the medium to long term. The Lesotho Highland Water Project can contribute about 72MW of hydroelectric power to the system in the short term.

Source: South Africa Yearbook 2005/2006