Contrary to what many assume, Eskom didn’t burn a single litre of diesel on Christmas Day to keep away from load shedding. In an announcement on December 24, the utility mentioned that the “suspension of load shedding [was] only possible due to the lower demand for electricity”.
This is barely half of the equation. It is true that precise demand was about 1 500MW decrease than on Christmas Eve. In truth, demand was a full 4 000MW decrease than the earlier Sunday (December 18) – equal to Stage 4 load shedding. Moreover, peak demand on the 25th was nearly 1 000MW decrease than Eskom’s personal forecast for the day.
Still, the provide aspect of the image is revealing…
On Christmas Day morning, the coal fleet ramped up from in a single day lows of 15 600MW to exceed 17 000MW of output by 07:00. Output remained above 16 500MW till after 13:00 and by 18:00 it had declined to under 16 000MW.
This is vastly completely different to the load profile – and subsequently Eskom’s coal fleet output – on a ‘typical’ day. Normally, output is ramped up in the morning after which this drops till a better peak in the afternoon into the evenings, when demand is at its highest. In current months, Eskom has struggled to take care of this profile of output from its coal energy stations because it battles fixed plant breakdowns (and partial load losses). At occasions, its output in the evenings (darkish gray on the chart under) is barely barely larger than in the mornings – typically, it’s truly decrease.
Source: Eskom information
Abnormal coal output
The cause why the steep ramp-up of capability from the coal fleet on Christmas Day is unusual is as a result of Eskom had not managed to attain output from these baseload energy stations of wherever above 17 000MW for no less than every week previous to that Sunday.
In the week that adopted, it managed to only about get to that stage as soon as – at 18:00 on Friday, December 30, the place it hit 16 940MW. In truth, till that day, it scarcely achieved coal output of over 16 000MW.
The context right here is necessary. Maintenance is operating at higher-than-normal ranges (round 8 000MW), and there had been a catastrophic stage of breakdowns (above 16 000MW) main as much as the festive season.
The solely believable manner that Eskom managed to attain output from its coal energy stations that was a full 1 000MW larger than it was demonstrably able to was to have run models that it knew wanted repairs, had been unreliable, and had a robust likelihood of breaking down.
One might simply theorise that political strain – whether or not implicit or express – resulted on this choice.
The penalties are plain to see with even most use of its pumped storage schemes on Boxing Day not sufficient to stave off load shedding. Things bought worse as the week progressed, with larger phases of load shedding and near-constant use of its open cycle gasoline generators (OCGTs) for greater than 48 hours from the morning of December 27. Recall, the diesel for these “emergency” sources had lengthy been ‘depleted’. Government remains to be “urgently” working on an answer to this.
New Year’s Day
On the final day of 2022, Eskom used its OCGTs in addition to these from the two IPPs at Avon and Dedisa for the whole day – from 08:00 till round 23:00. For most of that day, output from these diesel turbines was above 1 000MW, peaking at 1 700MW at 13:00. These have a complete put in output of two 400MW, so it is a materials quantity of utilization.
This was probably an try to scale back the impression of load shedding on New Year’s Eve festivities, on condition that it had been fixed since the anomaly of Christmas Day. This wasn’t sufficient and, mixed with the erratic output from coal above 15 000MW,
the nation entered the new yr with load shedding for the first time ever.
And renewables?
Supply from renewables performed an enormous function in there not being load shedding on Christmas Day (and a worse stage of this on January 1). Solar (from PV and CSP) peaked at round 2 400MW at noon on December 25, with the contribution from wind cresting at just below 2 000MW that night. The photo voltaic contribution was higher-than-average.
This meant Eskom might take models offline – both by proactively shutting off these in want of restore or by them simply tripping and making that call for the utility – with out coming wherever close to falling in need of assembly demand. At peak on December 25, Eskom had an working reserve margin of twenty-two% – multiples larger than it usually has (in current months, it has had a detrimental reserve margin as a result of load shedding).
On December 31 and New Year’s Day, the provide from photo voltaic was roughly 2 000MW, with wind’s contribution peaking at over 2 000MW on New Year’s Eve itself.
Of notice: Eskom has been operating its two hydroelectric energy stations, at the Gariep and Vanderkloof dams, nearly continuously. Usefully, excessive rainfall has made this potential. Together, these two vegetation present 600MW of capability – crucial, when Koberg Unit One (900MW) has been offline since early December for a steam generator unit substitute, anticipated to take “approximately” six months.