Load shedding explained

Residents of Randfontein have a growing concern about load shedding and put their lack of power in one of two categories; load shedding and cable theft.

While these two issues are what contributes to power outages, the case of load shedding is an entire process that causes electricity to go out.

The Eskom fact sheet reads that Eskom is a business of supply and demand – every time a person switches on an electrical appliance, there is a demand that Eskom needs to supply. The peak times of these demands are between 6am and 9am and again at 4pm until people go to bed.

During winter, the morning and evening peaks are higher than summer and they also increase every year, resulting in the demand reaching closer to the supply threshold. Usually the supply meets the demand.

However, there are cases where this is not possible. When this happens, a turbo-generators in a power stations faults and trips. When it trips it no longer supplies the area it is responsible for.

This is when load shedding comes in – the system controllers ‘shed load’ and switch off supply to customers for a while. Eskom has contracts with large power users to switch off their power as long as the interruption does not exceed 30 minutes at a time. Usually this is enough for the total demand to ease.

If this is not enough, then Eskom switches off another large user and restore power to the first. This process is then called rotational load shedding where electricity is shut down at a limit of two hours per area. However, in some cases residents experience cuts for much longer times.

The reason why some areas are more prone to others is because Eskom avoids load shedding in areas considered to be economic hubs, high security areas and areas where there are hospitals.

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