You are currently viewing our desktop site, do you want to download our app instead?
Moneyweb Android App Moneyweb iOS App Moneyweb Mobile Web App

NEW SENS search and JSE share prices

More about the app

Eskom isn’t generating enough electricity right now

It fell short during the peak on Monday and Tuesday. Here’s how it was able to keep the lights on.
The good news is that the outlook for the remainder of the year has improved significantly. Image: Image: Waldo Swiegers, Bloomberg

Data published by Eskom this week shows that the utility has not been able to generate enough electricity to adequately meet peak evening demand.

On Monday night it fell 254 megawatts (MW) short of peak demand at 6pm, and on Tuesday night it was 158MW short.

These shortfalls existed even after it interrupted load supply to large customers (and, on Monday evening, to the aluminium smelters through a mechanism called ‘virtual power station’).

Eskom spokesperson Sikonathi Mantshantsha explained on Twitter that the virtual power station “is a regulated mechanism in which Eskom can ask certain pre-agreed customers … to switch off power for about two hours when it has shortages”.

“The customer gets compensated for the loss of production, at a rate approved by Nersa [National Energy Regulator of SA],” he said.


On both nights, Eskom used almost all available open cycle gas turbines (OCGTs), both its own and those from independent power producers (IPPs) – 14 in total on Monday, and 20 in total on Tuesday.

Monday 03 May, 18:12 Tuesday 04 May, 18:07
Total demand 31 805MW 31 243MW
Interruptible load supply 447MW 175MW
Virtual power station 279MW
Number of Eskom OCGTs utilised 10 14
Number of IPP OCGTs utilised 4 6
Renewable generation 539MW 674MW
Eskom generation capacity 31 551MW 31 085MW

From 4pm on Monday, it ramped up generation from its pumped storage schemes to help meet the evening’s higher demand – and by 6pm was generating 2 254MW of electricity from these schemes. (There was a further 554MW of generation from hydro schemes.)

It is important to note that pumped storage schemes were explicitly designed for this purpose: they exist to generate electricity during the peak. Where Eskom often gets into trouble is when breakdowns in the coal fleet force it to use pumped storage as baseload power throughout the day. This leaves it in a situation where it simply doesn’t have the capacity from pumped storage during the peak.

The limit of the coal fleet over the past week has been about 23 900MW; it has not been able to produce more power than this. It has relied on non-commercial generation (the units at either Kusile or Medupi that have not yet achieved commercial operation to augment supply).

Read: Medupi and Kusile design modifications: Progress and problems (Mar 17)

In the first half of last week, this contributed around 700MW during the daily peak. But from Thursday (April 29) this dropped to 110MW, with zero contributed from these sources on Friday, Saturday or Sunday.

That it was not able to adequately meet peak demand is of concern given the very fine – and sometimes non-existent – reserve margins that the utility operates with.

At the peak on both evenings, Eskom would’ve had a negative operating reserve margin.

How, then, was Eskom able to keep the lights on and not implement load shedding when it wasn’t able to meet demand?

Very simply, it allowed this shortfall to be covered by its roughly 2 000-2 200MW operating reserve.

This margin exists as a safety mechanism to allow Eskom to still be able to keep the system in balance if it loses generation (in other words, if units trip) unexpectedly.

On both evenings it took a chance that using up to about 10% of the reserve margin for the hour-long peak was appropriate.

On the upside …

The good news is that the outlook for the remainder of the year has improved significantly.

From a situation where it forecast that it would likely be more than 2 000MW short to meet its demand and reserves for more than half the weeks to October, it no longer forecasts a significant shortfall until next April. This picture has continued to improve from January.

For the rest of the year, its likely risk scenario shows a green or yellow risk level for about half the weeks, with an orange risk level (about 1 000-2 000MW short) for the other half. Eskom is generally able to cope with the latter, as its breakdowns are mostly lower than the likely risk scenario of 13 200MW on unplanned outages.

However, Wednesday’s system status report shows an elevated risk of load shedding next week.

Because of planned maintenance being at 5 539MW next week (versus 3 052MW this week), it forecasts a likelihood of being more than 2 000MW short to meet demand and reserves should a likely risk scenario play out (with around 13 200MW of capacity broken down).

Source: Eskom Weekly System Status Report (Week 17, 2021)

Source: Eskom Weekly System Status Report


Sort by:
  • Oldest first
  • Newest first
  • Top voted

You must be signed in to comment.


Moneyweb, if you really want to change this country for the better you need to campaign against the causes of our destruction which is BEE, lack of land security and the ANC. Until these change, not only will Eskom continue to fail but so will the rest of the country.

Moneyweb does not like comments which goes against the prevailing narrative, even where the prevailing whether narrative is false. So unlikely that they will support a stance which goes against the prevailing ANC position that cadre deployment, BEE, etc. is necessary and the right thing to do. I am surprised that they allowed your comment through.

“Eskom isn’t generating enough electricity right now! “


That must be the understatement of the last 60 months

The way the fiscal is being raped by the greedy elite, there’s no solution in sight, not to mention electricity

Hello Zondo! Anyone sent to prison yet after nearly 3 years and R1 billion?

On the upside …
The good news is that the outlook for the remainder of the year has improved significantly.

Yeah right, and the real cold has not even set in yet.
Viva BEE, Viva ANC, Viva cadre deployment.

Hey folks look at the upside – its an outlook – of course there will be unexpected events it is a mighty big ship to be turning, but at last there seems to be a captain capable of getting things back on track (no racisism intended or implied).
Compare this to how things have looked past few years.

No need to be coy about saying it. So here goes:
Andre de Ruyter is the exception that proves the rule.

1st de Ruyter was not successful where he came from 2nd he has his hands tied ala Mark Barnes trying to rescue the post office ,realising it’s futile with the labour force we have in Azania and jumped ship

to me it does not matter how one looks at eskom – it is still managed from crisis to crisis – what was neglected in the passed 20 years+ can not be overturned in a month or 2 – they say the power supply will improve in the remainder of this year – was the effect of the winter actually taken into account

seems to me medupi and kusile will never reach 100% full generating level as originally meant, something similar to the mistakes of purchasing new locomotives for transnet that is too high for transnet’s existing railway tunnels.

A month or two – surely you mean a year or six?

What they really want is a 15% yearly increase plus go home.


But wait, Eskom wants to tax those producing their own electricity? What would happen if all those producers suddenly use Eskom electricity. BEE brought this on Eskom and South Africa and all races suffer as a result.

At the moment Glencore has stopped production at a number of chrrome smelters, which means that electricity demand is less than normal.THe smelters use a considerable amount of current. So the real demand should be more than shown, but as more and more businesses realise that South Africa is not a suitable place for having a business in, demand will fall. Emigration of users and job creaters will solve this

So sad but the truth! Wake up fellow South Africans. Vote these incompetent idiots out!

“virtual power station”??? – should rather be referred to as “virtually NO power station”?

The kind of disasters in public enterprises in South Africa are exactly what you would expect when the lunatics are running the asylum.

Or rather, criminals running the state.

My sympathy for the poor man on the steet has gradually been reduced to zero due to their brainless persistence with voting for the criminals that keep them there.

The people get the government that they deserve.

A Virtual Power Station is marketing spin to make it look like there is suffcient capacity

So the “baseload” coal is a little over 55% operating? There are wind farms with about 4000h per year productivity and they can supply at ⅔ coal generation cost and have longterm price predictability. We should quadruple wind and solar, use spare capacity to drive pumped storage and get over coal. At this stage our coal is more like slow-response standby power anyway.

Like clockwork, at times of wage negotiations and tariff debates, loadshredding happens.

You also noticed the correlation between the two? Most persistent with tariff submissions to NERSA.


But remember Johan, it’s important to keep paying your tax so we can keep funding these criminals.

That is the death spiral (a threat to their existence) Eskom is in.

Despite financial woes, with ever-increasing residents & businesses continually getting off-grid (or partial off grid) there is a less reliance on Eskom.

YET they are unable to supply the rest. A decade from now, say 20% of the country is off-grid, Eskom will STILL struggle.

By the year 2050, if 80% of SA generates own power, Eskom will still struggle….with only 10% of installed capacity working. Then it can be closed down…..but like SAA…govt won’t allow cadres’ cash cows be cut off.

I’m kind of surprised this is still news …

The real elephant in the room must be the unions that have held up the completion of Kusile and Madupe power sations.

No-one wants to deal with real issues. Just demand more wages from the ether

I am so tired of complaining of our SOEs that I am not going to comment.

where does this all end? Besides the obvious on reliability, has anybody had a look at cost?

My factory now runs about 275c/KWh if I take basic plus kVA plus kWh and divide by kWh. 15% increase coming now

Two more of those increases and I may as well run on solar plus batteries plus generators plus a bit of just-in-case grid power to run at night for lights and topping off the battery bank before the big loads start. So I drop from a 600kVA consumer and significant revenue contributor to council to 100kVA and small revenue contributor. Likely forever.

Johan — Invest now in solar/storage and backup or relocate your factory — It is that simple !!!

The math is not quite there yet for the whole game. Have done half the solar plus the gennies.

22 years ago I said to my friends to ensure their houses had boreholes and generators. I was laughed at…………

It really wasn’t rocket science.

From what the figures show, Eskom needs to treat each kW generated like a jewel to ensure EVERYTHING reaches a paying client.

Until they can physically prove and have it independently confirmed, I will remain sceptical about these figures.

Jip — I only made the leap 5 years ago and not sorry at all.

Ted u got that right . have borehole genie ups and moving on solar . property developer told me when Nigerians look at buying in a complex they ask where is the genie . reason being they 60 years “free”and know how vrot african govts are and how low Azania still has to go

End of comments.





Follow us:

Search Articles: Advanced Search
Click a Company: