Eskom's diesel fleet has gone quiet, and peak availability is worth less.

For a generator holding a power purchase agreement, or a mine buying from the grid, what has changed is the price of being available when the system is tight. Eskom's open cycle gas turbines, the diesel units it calls on when the coal fleet falls short, ran at a load factor of 1.05% between 1 April and 24 September 2026, against 6.97% over the same months a year earlier and a target annual figure of 3%. Diesel spending across that period fell by R4.78 billion, or 80.56%: the R5.94 billion of a year ago became R1.16 billion.

The reason sits in the coal fleet. Eskom put weekly energy availability at 70.44% for 18 to 24 September 2026, a second week running above 70%, and its financial year to date figure at 68.06%, up from 62.42% a year earlier. Load shedding has now been absent for 497 days in a row, counted from 16 May 2025. The utility also reports 6 571MW sitting in cold reserve, capacity it does not presently need.

Read together, these figures describe a South African electricity market in which generation adequacy has stopped being the binding constraint, and in which the premium a flexible asset could once expect for showing up at the evening peak is thin.

Load reduction, the targeted curtailment Eskom applies where illegal connections and meter tampering are damaging the network, has narrowed to 247 617 customers, or 3.4% of its base, from 1.69 million. The customers still affected are in Gauteng and KwaZulu-Natal, and the utility is working to a March 2027 end date.

Planned maintenance is heavier, by design: 12.67% of generation capacity was on planned outage in the year to date, against 11.16% a year earlier. Eskom has said the power system status and the summer outlook follow in the coming weeks, and those are the documents against which anyone pricing capacity for the coming summer will test this week's numbers.