Despite improvement, Eskom sees load shedding as ‘likely’ until December

Wet coal aside, Eskom’s immediate outlook for its available generation capacity is much improved from a month ago.

At that time, its three-month outlook published in its weekly system status reports indicated that until mid-April, it would “definitely” be between 1 000 megawatts (MW) and 2 000MW short to meet its reserve margin and “possibly demand” for six of the 13 weeks. This picture has steadily improved from early January until now.

Read: Brace for load shedding until winter

In the most recent update, published at the end of last week, it sees risk in just one week (specifically next week) where it is likely to be between 1 000MW and 2 000MW short to meet demand (including its operating reserve). For seven of the next 11 weeks, it may be less than 1 000MW short to “meet reserves”.

There are an awful lot of assumptions here, chiefly that 12 000MW of capacity will be offline due to breakdowns (added to this is 2 200MW required for its operating reserve to get to the 14 200MW “planned risk level”).

If there is no sudden spike in breakdowns, the picture looks significantly more positive than it did at the start of the year.

Even if there is a forecasted shortfall, Eskom is typically able to meet this peak demand with its peaking power plants – either open cycle gas turbines (OCGTs) and pumped storage schemes, or OCGTs operated by independent power producers (IPPs). The utility is usually also able to ride out breakdowns of the odd unit (generally an impact of 500MW to 800MW) by using this peaking power as baseload power.

However, it’s when a number of units trip or break down simultaneously that it is forced to implement load shedding, as these outages typically total 2 000MW (or higher).

The generation outlook for situations when there is this spike in breakdowns does not improve until the end of March.

For context, Eskom said on Tuesday that “14 375MW of capacity is unavailable due to breakdowns and delays”. This necessitated Stage 2 load shedding overnight as it needed to replenish its emergency generation reserves (chiefly its pumped storage schemes which it is using for baseload power, given the high level of breakdowns).

From its near-term outlook, the overall improvement has not come at the expense of a reduced forecast in demand, nor at the expense of the level of planned maintenance.

This suggests it could only be as a result of steadily improving generating capacity.

Planned maintenance – forecast (MW)
	Week 1	Week 2	Week 3	Week 4
11 Jan	8445
18 Jan	8772	8500
25 Jan	7804	8447	4213
01 Feb	7844	7702	8522	8997
08 Feb	8351	7769	7439	7439
15 Feb	7238	7558	7558	7568
22 Feb	7543	7501	7311	7254
1 Mar	7067	7390	6679	6736
8 Mar	6909	7359	6744	7319
15 Mar	7027	6512	6762	6762
22 Mar	6909	6914	6914	7104
29 Mar	6345	6274	6274	6464
05 Apr	5978	6624	6009	6199
12 Apr	4793	5239	4624	4814
19 Apr		5239	4624	4814

Eskom has also made a further material change to its assumptions from April: that unplanned outages would be 11 000MW, not the historical 12 000MW level that has been used for a number of years.

Kendal Unit 5, which can produce 640MW and has been on a long-term forced outage, is the only possible explanation for this as it returns to service in April. It is unclear whether Eskom is continuing to plan using a risk level of 14 200MW in outages (or a likely risk scenario of 16 200MW), but this is not likely as it requires only 2 200MW as operating reserve.

In its system status report from last week, Eskom also for the first time published a forecast for the next year. It typically only shares a three-month view.

Its outlook shows that it expects a small shortfall to meet reserves in most weeks for the remainder of the year. When (or if) breakdowns do spike, load shedding is very likely (red) until April when that Kendal unit returns to service (Koeberg Unit 1 returns to service in May).

Beyond that, the outlook does not look encouraging. Eskom’s ability to juggle breakdowns across an ageing fleet will determine just how much load shedding we endure until December.

Read: Why Eskom wants to make three big changes to its tariff structure