Why Eskom is load shedding again

Eskom on Wednesday began a series of scheduled rolling blackouts, the first in seven months, as a shortage of supply, caused by several factors, meant there wasn’t enough electricity being produced to meet demand.

“Eskom would like to inform South Africans and all its customers that the electricity system has been severely constrained this week,” the state-owned power company said in a statement at 9am on Wednesday.

“As a result of the loss of additional generation, delays in the return to service of units that are on planned maintenance and limited diesel supply, it has become necessary to implement stage-2 rotational load shedding from 9am until 11pm in order to protect the power system from a total collapse.”

The company said that in a system status briefing of 4 September 2019, it warned that to avoid load shedding, unplanned breakdowns needed to be contained at below 9.5GW.

“In the event generator breakdowns are experienced beyond 10.5GW, there would be high usage of emergency resources (diesel and pumped-storage generators), which could lead to load shedding if the supply constraints were sustained for a long duration.

“The severe supply constraint being experienced has come about due to high levels of unplanned breakdowns that have exceeded the 10.5GW limit,” it said. “The supply constraint is caused by, among others, five generating units that are unavailable due to boiler tube leaks.”

Medupi problems

“In addition, a conveyor belt supply Medupi power station with coal failed on Saturday, 12 October resulting in low volumes of coal being supplied to the power station thus limiting the generating capability to about half the station output.

“Due to the shortage of generating capacity from coal-fired generation, the pumped-storage and open-cycle gas turbine generators have been used extensively since Saturday, 12 October, which has led to a decline in the dam levels and diesel tank levels.”

Eskom said it apologises “unreservedly” for the “negative impact this may have on them”. It said it wants to “assure the nation that we continue to work tirelessly to ensure security of energy supply”.  — (c) 2019 NewsCentral Media

Source: techcentral.co.za