Eskom Plans to Add 2,730MW of Generation Capacity as Winter Demand Rises

Eskom reports that South Africa's power system remains stable despite increased winter electricity demand, with plans to return 2,730MW of generation capacity to service by Monday evening, June 23.

Current Power System Status

The national grid continues to demonstrate resilience against rising winter demand patterns. According to Eskom's latest statement, occasional system constraints are being effectively managed with strategic deployment of emergency reserves during morning and evening peak periods.

For tonight (June 20), Eskom expects peak demand to reach 28,425MW, which it says can be met with the current available generation capacity of 31,681MW. This figure excludes the 720MW contribution from Kusile Unit 6, which is generating power but not yet in commercial operation.

Performance Metrics Show Mixed Results

Between June 13-19, the system's Energy Availability Factor (EAF) ranged between 60% and 63%, with a month-to-date average of 60.48%. This is below optimal levels but sufficient to maintain grid stability for now.

Planned maintenance has decreased to an average of 3,659MW during the past week, indicating a shift toward maximizing available capacity during winter.

However, unplanned outages have increased compared to the same period last year:

• Current unplanned outages stand at 12,892MW
• The Unplanned Capacity Loss Factor (UCLF) is currently 29.23% for the financial year to date, up approximately 1.7% from 27.51% during the same period last year
• Eskom attributes part of this increase to delays in returning units from maintenance, including 800MW from Medupi Unit 4 which has been offline since June 1

Emergency Generation and Fuel Usage

Eskom continues to rely on its Open-Cycle Gas Turbines (OCGTs) to manage peak demand periods:

• The year-to-date OCGT load factor stands at 11.73%, higher than the 5.78% recorded during the same period last year
• Approximately R4.51 billion has been spent on diesel fuel so far this financial year, generating 768.64GWh (compared to 378.75GWh during the same period last year)
• OCGT usage decreased to 9.12% this past week, down from 14.79% in the previous week

Eskom expects diesel usage to decline as more units return from long-term repairs and maintenance activities decrease.

Winter Outlook Remains Unchanged

According to Eskom, the Winter Outlook published on May 5, 2025 (covering the period until August 31) remains valid. This forecast indicates:

• Loadshedding will not be necessary if unplanned outages stay below 13,000MW
• If outages rise to 15,000MW, loadshedding would be limited to a maximum of 21 days out of 153 days and restricted to Stage 2

However, data from June 13-19 shows average unplanned outages reached 15,076MW, exceeding both last year's figure for the same period by 3,144MW and the base case estimate of 13,000MW by 2,076MW. This suggests the system remains vulnerable to unexpected breakdowns.

Cautionary Note on Illegal Connections

With increased winter electricity demand and no loadshedding currently in effect, Eskom warns that illegal connections and energy theft pose serious risks to the distribution network. These unauthorized connections often cause transformer overloads, equipment failures, and in some cases, explosions that result in extended outages.

The utility encourages customers to purchase electricity only from accredited vendors and for eligible households to register for free basic electricity with their local municipalities.

Outlook: Stable But Precarious

While Eskom's data shows the grid is currently stable enough to avoid loadshedding, several concerning trends bear watching. The year-to-date EAF of 58.25% represents a 2.83% decline compared to the same period last year, primarily due to increased planned maintenance.

The higher reliance on expensive diesel generation compared to 2024 and the elevated level of unplanned outages suggest the system has less headroom to absorb additional breakdowns than it did last winter.

The planned return of 2,730MW by Monday will be crucial to maintaining stability, particularly if cold weather drives demand higher in the coming weeks. The delay in returning Medupi Unit 4 (800MW) and Tutuka Unit 1 (585MW) from maintenance highlights the ongoing challenges in restoring and maintaining generation units.

Key Terms Explained

Energy Availability Factor (EAF): The percentage of maximum energy generation that a plant is capable of supplying to the electrical grid. A higher percentage is better. For context, during South Africa's worst loadshedding periods in 2023, this figure often fell below 50%.

Unplanned Capacity Loss Factor (UCLF): The percentage of generation capacity unavailable due to unplanned breakdowns or failures. Think of this as the portion of Eskom's power stations that should be working but aren't due to unexpected problems. Lower is better.

Open-Cycle Gas Turbines (OCGTs): Emergency power generators that run on diesel fuel. These are expensive to operate (costing approximately R4 per kWh, compared to about R0.40 for coal) and are meant for short-term use during peak demand or emergencies, not as baseload power.

1 Megawatt (MW): Enough electricity to power approximately 650 average South African homes. The 2,730MW Eskom plans to return to service is roughly equivalent to the electricity needs of 1.8 million households.