- Eskom’s network of peaking power stations continues to play a vital role in stabilising South Africa’s electricity grid, providing rapid-response capacity during times of high demand and system strain.
The facilities have been instrumental in preventing more severe stages of loadshedding. Designed to generate power at short notice, peaking stations help balance the grid when demand spikes or when generation from other sources falls short.
Eskom has traditionally relied on its fleet of diesel-powered peaking plants to bridge supply gaps and maintain grid reliability. Without their contribution, the national power system would be significantly more vulnerable to instability and widespread outages. The utility operates 14 peaking stations nationwide, with a combined generation capacity of 5,894 megawatts (MW). These plants are designed to deliver short bursts of power to balance fluctuations in demand, supplementing the consistent output from Eskom’s base-load coal and nuclear facilities.
The peaking fleet comprises:
- Four gas turbine stations – 2,409 MW
- Three pumped-storage schemes – 2,724 MW
- Two hydroelectric stations – 600 MW
- One wind energy station – 100 MW
- Four non-dispatchable mini-hydro stations – 61 MW
Unlike base-load stations that run continuously, peaking plants can be brought online within minutes to meet sudden spikes in demand—typically during the morning and evening peaks—or when the grid is under strain. Their flexibility makes them indispensable to South Africa’s evolving energy mix, especially as the country transitions toward cleaner and more diversified generation sources.
Between 1 April and 23 October 2025, Eskom’s diesel expenditure remained consistently below budget, reflecting a reduced reliance on the diesel-powered Open-Cycle Gas Turbine (OCGT) fleet. Over this period, Eskom generated 1,023.67 GWh from OCGTs, with diesel costs amounting to R6.074 billion—up from 947.17 GWh during the same period last year.
Despite this increase in generation, the year-to-date OCGT load factor declined to 6.06%, down 0.21 percentage points from the previous week but slightly higher than 5.61% recorded in the same period last year.
In the past week alone, Eskom spent R7.84 million on diesel at a load factor of 0.23%, significantly lower than the R21.81 million spent at a 0.639% load factor during the corresponding week in 2024.
Eskom said these figures highlight ongoing efficiency improvements and a continued reduction in diesel usage, underscoring progress in shifting toward more cost-effective and sustainable sources of generation.
Author: Bryan Groenendaal
