“Technical faults” led to Eskom this week suffering the second worst level of unplanned outages since the power utility began reporting on the state of the power system in January 2012.
On Thursday, the system was short 8?752 megawatts of power because of unplanned outages, double the ideal limit of about 4?000MW, or 10% of capacity.
These elevated levels of outages were already evident on Monday when they reached 7?500MW, according to the twice-weekly System Status Update, which is published by Eskom.
By way of comparison, the first unit of the long-delayed Medupi power station, which is meant to finally provide power by next winter, will deliver about 800MW.
The only time Eskom has reported more unplanned loss of power was in the first week of March, when unusually heavy rain reduced coal at some of its power stations to sludge.
That incident led to almost 10?000MW of lost load.
Eskom’s network is undeniably becoming ever more unstable as its policy of keeping the lights on at all costs after the 2008 system crash takes its toll on overburdened and old power stations.
Along with the planned maintenance also taking place this week, the outages forced Eskom to issue another “power alert”, and parts of the country experienced power cuts on Thursday and Friday.
The situation is likely to persist tomorrow, when power demand returns to normal levels after the weekend.
The faults causing the high loss of load “were spread throughout the Eskom fleet of coal-fired power stations”, the company said in response to questions.
Eskom pointed out that, of the 87 coal-fired units at its various stations, 32 needed “major surgery”, while another four were in a “critical condition” at the end of winter.
These figures were supplied in a parliamentary presentation at the end of August on Eskom’s plans for this summer.
Collin Matjila, then the acting CEO of Eskom, said the company was targeting a planned maintenance level of 10%, or roughly 4?000MW, throughout summer.
Adding an allowance for unplanned outages, Eskom is targeting capacity availability of 75%, meaning 10?000MW lost to both planned and unplanned outages at any given time.
Since then, the level of planned outages has, on average, been closer to 3?600MW, with the unplanned outages trending higher.
The level of unplanned outages this year has averaged 5?200MW, a 6% increase over last year.
On average, it is achieving this despite incidents, like what happened this week, pushing the unavailable capacity to more than 12?000MW. Hitting the target also seems to be at the cost of carrying out the level of planned maintenance that Eskom needs to do.
The desperate need for maintenance at all the power stations is one of the reasons Eskom is basically disregarding the National Energy Regulator of SA’s attempts to restrain its use of the expensive diesel-power peaking plants in the Western Cape.
Technically, the plants are only meant to be used when there is a power crunch, but Eskom is using them more or less constantly to get some breathing room to do repairs.
Last year, the resulting diesel bill was R10.6?billion.
Eskom is by now technically insolvent. But guarantees for its debt are being provided by government, which is working to keep the credit rating agencies at bay.
In the middle of this week’s power alert, Eskom announced that Fitch Ratings had decided not to downgrade Eskom’s credit rating below its current BBB+.
This was mostly due to government’s recent announcement that it would boost its already considerable support for Eskom in the form of further guarantees for its debt.