HYDRO-POWER
Energy from water can come from waves, tides, waterfalls, and rivers and will never be exhausted as long as water resources are available. In South Africa, there is a combination of small hydroelectricity stations and pumped water storage schemes.
In a pumped water storage scheme, water is pumped to an elevated dam or reservoir. Pumping the water uses some electricity, but this is done during off-peak periods. During peak hours, when additional electricity is required, the stored water is released through a turbine that drives an electric generator. Peak hours are usually between six and eight in the morning and evening.
South Africa previously imported electricity from the Cahora Bassa Hydroelectric Power Station in Mozambique and could do so again when the transmission infrastructure is restored. There is also potential to import additional hydropower from countries such as Zambia, Zimbabwe, and the Democratic Republic of the Congo. If this potential is realised, South Africa could become less dependent on coal-fired power stations.
Environment
The generation of hydroelectricity is not without environmental impacts. Large areas of land may be flooded when dams are constructed, disrupting wildlife habitats as well as residential and farming areas.
Another potential problem is that cold water released from deep within a dam may contain low levels of dissolved oxygen. If large quantities of this water are released into rivers, fish and other aquatic life may be adversely affected. However, proper management can help to minimise these impacts.
Global concerns regarding the environmental impacts of large storage dams and the displacement of communities are likely to limit the large-scale development of hydropower. Regardless of the size of the installation, hydropower developments require authorisation in terms of the National Water Act, 1998 (Act 36 of 1998).
Potential
The Baseline Study on Hydropower in South Africa, an assessment conducted by the DME in 2002, indicated that certain areas of the country have significant potential for the development of various categories of hydropower in the short and medium term.
The Eastern Cape and KwaZulu-Natal have the greatest potential for the development of small hydropower plants, defined as plants with a capacity of less than 10 MW. These plants can operate as standalone systems or be integrated into hybrid systems with other renewable energy sources.
Additional benefits can be achieved by combining hydropower development with other uses of water, such as water supply, irrigation, and flood control. These applications are important to the future economic and socio-economic development of South Africa.
The Southern African Power Pool (SAPP) facilitates the trading of electricity between Southern African Development Community (SADC) member countries, providing South Africa with access to the significant hydropower potential of countries to the north, particularly the substantial potential associated with the Congo River and Inga Falls.