Power System Remains Stable Despite Winter Demand; Eskom Plans to Add 2,450MW by Monday

South Africa's power system is holding steady despite increased electricity demand from the current cold snap, according to Eskom's latest update. The utility plans to bolster generation capacity by returning 2,450MW to service ahead of Monday evening's peak demand period.

Current System Status

As of Friday, 27 June 2025, the national grid remains stable with available generation capacity standing at 30,703MW (excluding Kusile Unit 6's 720MW contribution). This capacity comfortably exceeds tonight's projected peak demand of 28,810MW.

Unplanned outages currently amount to 15,137MW, which includes 800MW from the delayed return of Medupi Unit 4. While the system is managing current demand levels, the figures show some concerning trends when compared to the same period last year.

Performance Indicators Show Mixed Results

For the week ending 26 June, the Energy Availability Factor (EAF) ranged between 60% and 64%, with a month-to-date average of 60.61%. This is below the levels seen during the same period last year.

The Unplanned Capability Loss Factor (UCLF) has increased to 29.36% for the financial year to date, up approximately 2.1% from the 27.25% recorded during the same period in 2024. This increase is partly attributed to delays in returning units from planned maintenance, including the 800MW from Medupi Unit 4 which has been offline since 1 June 2025.

Planned maintenance averaged 3,789MW during the past week, continuing a downward trend. While this helps with immediate capacity, reduced maintenance could impact long-term reliability.

Diesel Usage and Emergency Reserves

The load factor for open-cycle gas turbines (OCGTs) has declined to 11.37%, down 0.36% from the previous week but still significantly higher than the 6.21% recorded during the same period last year. This indicates continued reliance on these expensive emergency generation sources.

Year-to-date, Eskom has spent approximately R4.76 billion on diesel fuel for OCGTs, generating 810.24GWh of electricity – nearly double the 442.65GWh generated during the same period last year. The utility states this expenditure remains within budget for the current financial year.

Eskom projects that diesel usage will decline as more units return from repairs and maintenance activities are reduced.

Winter Outlook Remains Unchanged

Eskom has maintained its Winter Outlook projection from 5 May 2025, which covers the period ending 31 August 2025. According to this outlook:

• 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

With current unplanned outages at 15,137MW, the system is operating slightly above the threshold that could trigger occasional loadshedding according to this outlook.

Outlook: Navigating Winter's Peak Demand Period

The power system is currently maintaining stability but remains under pressure as South Africa moves deeper into winter. The planned addition of 2,450MW by Monday will provide a welcome buffer, but the increasing trend in unplanned outages is concerning.

With unplanned outages now exceeding the 15,000MW threshold mentioned in Eskom's Winter Outlook, the risk of occasional loadshedding cannot be dismissed entirely, particularly if further major units experience unexpected failures or if severe cold fronts increase demand substantially.

The delayed return of Medupi Unit 4 (800MW) is having a significant impact on available capacity. Its scheduled return date is a key milestone to watch in the coming weeks.

Public Appeal: Prevent Transformer Overloads

Eskom has issued a public appeal against illegal connections and energy theft, noting these activities often lead to transformer overloads, equipment failures, and in some cases, explosions that cause extended outages.

The utility encourages:

• Purchasing electricity only from Eskom-accredited vendors
• Regularizing electricity connections
• Eligible households to register for free basic electricity with local municipalities
• Reporting illegal activity to the Eskom Crime Line: 0800 112 722 or via WhatsApp: 081 333 3323

Customers are also encouraged to use Eskom's Residential Calculator to manage household electricity consumption: https://www.eskom.co.za/distribution/residential-calculator/

Key Terms Explained

Energy Availability Factor (EAF): The percentage of Eskom's total generation capacity that is available for use. An EAF of 60.61% means that only about 60% of Eskom's total potential generation capacity is actually available to produce electricity.

Unplanned Capability Loss Factor (UCLF): The percentage of generation capacity lost due to unexpected breakdowns and failures. A UCLF of 29.36% means nearly 30% of Eskom's generation capacity is offline due to unplanned issues – a concerning figure.

Open-Cycle Gas Turbines (OCGTs): Emergency power generators that run on diesel. They're expensive to operate (costing approximately 8-10 times more than coal per unit of electricity) but can be started quickly when the system faces shortages. Think of them as the expensive backup generator you only want to use when absolutely necessary.

Load Factor: The percentage of time that a power plant or generator is operating at its maximum potential. For OCGTs, an 11.37% load factor means they're running about 11% of the time – significantly higher than ideal for these emergency units.

MW (Megawatt): A unit of power. For context, 1MW can power approximately 650 average South African homes. The planned return of 2,450MW represents enough power for roughly 1.6 million households.