Load shedding is a euphemism for a planned power failure, and while highly disruptive, is preferable to having the country's power grid shut down if the demand exceeds supply.
The national energy supplier Eskom monitors the demand for electricity and their ability to supply it. This monitoring is made public via the Power Alert website and has three levels before load shedding is required.
- Green - Grid is stable - avoid unnecessary power use
- Yellow - Grid is under pressure - reduce unnecessary energy use
- Red - Grid is nearing capacity - turn off power intensive appliances
- Black - Grid requires power to be reduced, if not through energy saving load shedding begins
The graph plots the date, time of day and expected demand
If load shedding is required the graph will look like this (the image below was the graph for the day the silo collapsed at Majuba)
The black bars show that the grid is critical and that load shedding may be underway.
If the effort to manage the demand fails, Eskom and the major metros around South Africa instituted a schedule for cutting power to specific areas to reduce the demand for power on the grid. This is load shedding.
There are three levels to load shedding that are dependent on how much the power demand needs to be reduced.
How it affects you
The best way to avoid load shedding is to respond when Eskom updates it power alert status. If those efforts are not enough, you will be subjected to a period of power cuts according to a schedule created by Eskom and the municipalities.
Load shedding has three stages depending on how power needs to be reduced
- Stage 1 - 1 000 MW nationally
- Stage 2 - 2 000 MW nationally
- Stage 3 - up to 4 000 MW nationally
Unfortunately, determining when your power will be cut can be difficult.
You need to know three things to check if you will be affected.
- Do you get you electricity from Eskom or a local energy supplier, check your bill or your prepaid meter.
- Check what area you will be included in for loadshedding using the links to the different suppliers below.
- Check which stage of loadshedding is required.
Power is typically cut for 2 hours with 30 mins afterwards to allow for the power to be restored without spikes.
Areas are broken into blocks which can include multiple suburbs so check what block you live in (check your work address too).
The links for your area:
Eskom customers nationally - if you don't see your area listed and you are in an Eskom area contact them on 08600 37566.
Ekurhuleni residents can call the service number 0860 543 000 of you can't find your suburb.
Understanding the units
Eskom generates power via steam driven turbines that produce millions of watts of power described as megawatts (MW) which is the equivalent of one million watts.
Eskom has a total production capacity of 41 194MW of energy. At any time some of that capacity is not available due to maintenance, upgrades or faults, currently there is a 25% reduction which means we have a little over 30 000MW available.
South Africa's consumption peaked in 2007 and 2008 with over 36 000 MW being consumed per day, but that has since dropped with public campaigns to reduce consumption. The current reductions after the Majuba silo collapse means we are very close to using the full available capacity on any given weekday.
Consumers use power in units equivalent to 1 kilowatt hour (kw/h) which is the electricity you would use if a 100 watt bulb was used for 10 hours (100w x 10 hours = 1000w x 1 hour = kilowatt hour).
Get to know which of your appliances use the most electricity (things that get hot are usually the ones to look out for) and know that by using those sparingly you can both save money and help avoid load shedding.
This article first appeared on CapeTalk : Load shedding - what you need to do