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Generating Electricity

Electricity is different from the other services we find in the home. Unlike air or water that can be harvested from nature, electricity must be manufactured.

This must be done at least cost so that power bills are kept low, and with the lowest-possible impact on the environment.

In South Africa we produce about 34 000 megawatts of electricity to meet current demand, and this figure is growing year by year. The most economical method available to us is to use our abundant supplies of low-quality coal in Mpumalanga and the Northern Province, in power stations sited next to the coal deposits.

The coal is carried into the plant on conveyor belts, crushed into fine powder and burned under controlled conditions in modern boilers to produce high-pressure steam. The steam drives turbines that generate the electricity while the smoke from the boiler is carefully filtered to remove as much of the unwanted emissions as possible. The low-grade coal produces a large amount of ash, which is returned to the ground and isolated from the environment in long-term storage.

Because there is a growing shortage of fresh water globally, Eskom's power stations are designed to make optimum use of this scarce resource.

Using coal to generate electricity is not ideal because, no matter how carefully it is burnt, there are gaseous and solid emissions. The gases that are given off include sulphur dioxide, carbon dioxide and oxides of nitrogen, the first two of which are regarded as having climate-change effects on the environment.

Unfortunately, coal is the most economical way available to us - all other methods are either impracticable or much more expensive. Our rivers are not strong or steady enough to make large-scale hydro generation possible. And while we have abundant supplies of sunlight, harnessing it is difficult and expensive.

An experimental wind-power installation in the Western Cape has provided Eskom's research teams with much relevant data. As a result, Eskom will build 100 MW of wind power into its future planning. Because wind power is dependent on the vagaries of nature, it is not as reliable as other forms of generation.

One generation technology that has been in disfavour for decades, but which is now making a minor comeback, is nuclear. When it is operated under the strict conditions found at Koeberg in the Western Cape, fears of catastrophic accidents and dangerous waste products are unfounded. Either in the traditional pressurised water reactor or the innovative pebble-bed format, it is ideal for the parts of our country that are far from the coalfields.

As a modern and reliable electricity provider, Eskom never stops studying new ways to generate electricity. Each discovery is thoroughly investigated to see if it could be an answer to our ongoing needs.