Energy sources in South Africa
Primary and Secondary Energy Sources
Primary energy sources are energy sources in their original form. Primary energy sources include solar, hydro, wind, wave, wood, geothermal, coal and uranium.
Secondary energy sources are produced from primary energy sources using energy- converting technologies. Electricity is a secondary energy source. Electricity can be produced from a number of primary energy sources. In South Africa, most of our electricity is produced in coal - burning power stations.
Conserving Energy
In order to promote energy conservation we need to consider the following:
Approximately 70% of coal used locally to produce electricity. Electricity is the most important secondary energy source used in South Africa. Most of the electricity used in South Africa is used by industry, business and mining. These sectors can make the most significant contribution to any conservation programme.
Examples of Southern Africa's Renewable Energy Potential
If South Africa wishes to have a sustainable energy supply we need to investigate and develop available renewable energy options where appropriate.
These renewable energy options include.
Hydro
Hydro- electricity is already utilized in South Africa on a limited scale. Hydro- electric systems operate at the Hendrik Verwoed and Vanderkloof dams. In 1991 these hydro- electric systems provided less than 1% of South Africa's electricity.
Two pump - storage schemes, one in Drakensberg and the other in the Western Cape also provide electricity. In a pump -storage scheme potential energy of the water stored in the dam is converted to kinetic energy as water flows from the dam. The flowing water is used to drive turbines which generate electricity. Water is pumped to a dam using spare electricity when the demand for electricity is low, when the demand for electricity is high, water is then released through turbines and electricity is generated. SEE HYDROELECTRICITY.
South Africa is a relatively dry country and lacks large rivers which are suitable for large scale hydro- electricity generation. Most of the large rivers of the Southern African region are north of South Africa's borders. If South Africa is to benefit from the large hydro- electric potential of rivers such as Zaire, Rufiji, Shire and Cunene regional cooperation will be necessary. However, the long term environmental damage of existing large hydro- electric schemes on rivers, needs to be investigated before such a programme is implemented.
Solar
Solar energy can be used for many different purposes, these include:
Electricity Production
Photovoltaics convert solar energy into electricity. South Africa 's cheap grid electricity makes photovoltaic electricity a relatively expensive option. Photovoltaics are best suited to areas which are not supplied with grid electricity and can provide electricity for small scale low power applications such as communications systems, households and schools.
Water heating
Solar energy can be used to heat water for both domestic and industrial purposes. A large proportion of domestic electricity energy cost are for water heating. Utilising solar energy for water heating would reduce electricity domestic electricity consumption and hence reduce monthly electricity costs.
Comfort levels of buildings
Solar energy can be used to improve the comfort levels of buildings. By siting and designing buildings in ways which make the best use of sunshine, comfort levels inside buildings can be improved. The costs of heating and cooling buildings artificially using heaters and air - conditioners could also be reduced if solar design principles are applied.
Wind
Wind was one of the first energy sources to be harnessed.
Wind energy is widely used in South Africa for water pumping. In some countries large wind turbines are used for generating electricity, for this strong reliable winds are needed. South Africa has fairly strong winds in many coastal areas. At present there are few wind generators operating. This is mainly due to the availability of cheap electricity generated by coal- fired power stations.
Wood
Millions of South Africans rely on wood for cooking food and heating their homes. In many areas the supply of wood is not keeping up with demand. As a result, wood collectors have to walk longer distances to meet their daily wood needs. An alternative energy supply needs to be provided and tree- growing schemes neEd to be promoted in rural areas where wood is in short supply.