Eskom’s load shedding escalation: Understanding the new 16-stage system

Officially, at least, there are now 16 stages of load shedding – up from the previous eight under the previous code. Eskom has not yet publicly announced this, but the new Code of Practice has reportedly been approved by the National Energy Regulator of South Africa (Nersa). 

The major change is that load shedding now runs across 32-hour cycles, not a typical 24-hour one.

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This means significant changes in the lived experience of load shedding across South Africa. Effectively, there will be three 32-hour cycles every four days (4 x 24 = 96 hours, 3 x 32 = 96 hours). 

This is going to wreak havoc with existing systems that work quite well with 24-hour blocks. 

The second major change is that Stage 1 is no longer equivalent to 1 000MW. Rather, it equates to 5% of demand.

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In summer, that’s somewhere around 1 300MW (but only realistically 1 100-1 200MW on Sundays). In winter, however, it is well above 1 600MW. 

This is arguably a bigger problem. Stage 1 on a Tuesday or Wednesday will be quite different from Stage 1 on a Sunday. In effect, Stage 1 on the weekend is currently ‘less severe’ than during the week in terms of pure megawatts reduced from the grid. In the future, once this is implemented, the stage of load shedding will be directly linked to the demand for that day.

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So the current Stage 1, on a high-demand day, could be Stage 2 in future.

Similarly, Stage 2 on a low-demand day could be Stage 1 in future. Eskom’s weekly demand forecast will be far more critical than it currently is.  

Load shedding blocks

Up until Stage 8, the structure of load shedding is as per the current breakdown. The major difference is that this is across 32 hours, not 24 hours – so practically, there is some, ahem, ‘respite’ across a cycle.

Normally, Stage 2 would’ve been two two-hour blocks across 24 hours. On the new schedule, there are two two-hour blocks across 32 hours. 

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Because the schedule runs across 32 hours, even at Stage 12 – with 24 hours of power being off – this would still mean eight hours of ‘power on’ across that 32-hour cycle. So, six hours off, two hours on. Times four. 

The industry will be comfortable with the fact that at least there is now a plan beyond Stage 8. Currently, this is “manual instruction” implemented by the System Operator to reduce load.

You can imagine how well that will go during a time of high pressure. Chaos. 

At least we now know that at Stage 16, residential and commercial customers will have zero power. Or the euphemistically titled ‘power off’. The only supply at that point will be to “essential loads”. 

Practically speaking, there’s almost zero chance of getting there. This implies that the entire coal fleet will not produce a single megawatt.

ALSO READ: Now 16 stages of load shedding but you don’t have to worry – Ramokgopa

Remember, we get 1 300MW from imports (Cahora Bassa) and between 900 and 1 900MW from Koeberg. There are still open-cycle gas turbines capable of close to 3 000MW, including independent power producers (IPPs). And IPP solar farms, wind farms, etc, etc, etc.

Pumped storage would be a last resort (it consumes more power – net – than it generates), but it is a large supply of power as long as some coal power stations are still running. 

This article was republished from Moneyweb. Read the original here