Power utility Eskom has downgraded load shedding from stage 6 to stage 4 after an outcry from South Africans sweltering under a scorching heatwave.
On Friday, Eskom plunged the country into stage 6 power cuts, which it said was due to the loss of five generating units, resulting in a shortage of generation capacity as well as a need to replenish emergency reserves.
At that time, Eskom said unplanned outages were at 15 901MW of generating capacity, while the capacity out-of-service for planned maintenance was 5 822MW.
Today (Sunday), Eskom said load shedding would be reduced to stage 4 from noon until 5am tomorrow.
“The implementation of stage 6 load shedding over the past few days has allowed the replenishment of the emergency reserves at our pumped storage and Open Cycle Gas Turbine (OCGT) power stations. Due to this improvement, load shedding will be reduced to stage 4 from 12pm (midday) until 5am on Monday,” the utility said in a statement.
Eskom said stage 3 load shedding would be implemented thereafter, from 5am until 4pm on Monday, followed by stage 4 load shedding from 4pm until 5am on Tuesday.
“This pattern of implementing stage 3 load shedding in the morning and stage 4 load shedding in the evening will be repeated daily until Thursday.”
Eskom will closely monitor the power system and communicate any required changes to load shedding.
“Unplanned outages are currently at 15 386MW of generating capacity, while the capacity out of service for planned maintenance is 5 617MW. Approximately 2 500MW of generating capacity is anticipated to return to service by Tuesday evening,” said the power utility.
It said teams were working to ensure additional generating units were returned to service as soon as possible.
Eskom’s load forecast for the evening peak demand is 25 989MW.
A number of people are curious as to why the country was experiencing increased load shedding, energy analyst Chris Yelland said during a recent interview with a broadcaster.
Yelland said there were three main reasons given for the increased level of load shedding, the first being the hot weather.
“There has been a spike in electricity demand, according to the [electricity] minister [Kgosientsho Ramokgopa] and [Eskom’s] group executive for generation Bheki Khumalo, of about 1 500 megawatts which they kind of put down to the increased use of air conditioning at this time, so that worsens it on the demand side.
“On the supply side, the hot weather does impact the output of some of Eskom’s largest coal-fired power stations, and in particular Majuba, Medupi and Kusile because these are all what is known as dry air-cooled power stations, and in the hot weather the air is hotter and therefore the cooling is not as good and this impacts on the output of the generators, they have to reduce output in order to avoid overheating,” Yelland said.
He said in technical terms this was called increased partial load loss, and it had a significant impact, perhaps up to one stage of load shedding. There was also the perennial problem of unplanned breakdowns, and the problem of taking units down for repairs for whatever reason, including maintenance.
“They sometimes don’t come back on again when they should come back on again because of unexpected problems that they experience. So a combination of all of these factors leads to just more of the same unpredictable, unreliable, intermittent coal-fired power,” Yelland said.
The Star