Power utility Eskom has urged South Africans whose regional grids are under pressure due to cold weather to keep their backup power systems offline for at least an hour after load shedding to avoid possible trips.
The group issued an alert on Friday (21 July), warning that customers may experience prolonged durations without electricity supply due to “cold load restoration” caused by higher evening peak demands.
The higher peaks are a result of extreme cold weather in certain parts of the country, as well as the wider impact of illegal connections in some regions.
The group specifically highlighted areas in the Western Cape – namely Blackheath, Bluedowns, Delft, Silversands and Khayaletshia – as being vulnerable.
It advised that stoves, geysers and pool pumps be switched off and only be switched back on 30 minutes after power has been restored.
In addition, backup power supplies like inverters and UPSs and others be disconnected from main supplies during load shedding and only reconnected 60 minutes after the outages have ended.
While the alert addresses a particular problem in selected areas, it continues the group’s wider push to mitigate grid overload after load shedding ends.
During its state of the system presentation in May, Eskom urged South Africans to delay charging their inverter systems after load shedding in an attempt to reduce demand on the grid – or else risk adding another stage of load shedding during peak times.
Delaying the charging of inverters forms part of a slew of demand-side energy reduction actions proposed by the utility, alongside switching off what is not needed, stopping “izinyoka” (cable thieves) and paying electricity fees.
Eskom estimates that charging inverters during peak times (06h00 – 09h00 and in the evenings) could spike demand by as much as 1,400MW – equivalent to a whole stage of load shedding.
“If possible, set the inverters to charge batteries during the night, when the demand is at its lowest. Also, where solar panels are used, charge batteries 10h00 to 14h00, when the maximum output is achieved from the panels,” Eskom said.
Inverters have, however, been playing a critical role in lessening the blow of rolling blackouts by supplying low levels of electricity to open garage doors, run a handful of lights or keep the wifi on so people can work, among other things.
During power outages, inverters automatically switch on and provide uninterrupted electricity; however, depending on the model, more severe stages of load shedding may lead to them running dry and recharging taking longer than usual.
Parts of the country where the grid is less stable can experience post-load-shedding outages due to overloaded demand on the system when power returns.