Power System Stable as Winter Approaches: 5,760MW to Return by Monday Evening

South Africa's power system remains stable despite the recent cold front affecting parts of the country this week. Eskom reports that 5,760MW of generation capacity is scheduled to return to service before Monday evening's peak demand period, which should help maintain grid stability as winter sets in.

Current System Status

While the system is currently stable with adequate emergency reserves deployed to support morning and evening peak demands, constraints continue to affect overall performance. The Unplanned Capacity Loss Factor (UCLF) stands at 28.50% for the financial year-to-date (April 1 to May 22), showing a marginal improvement of approximately 0.1% compared to the same period last year.

Planned maintenance has increased by 2.8% compared to last year, averaging 6,499MW (13.63% of total generation capacity) for the financial year so far. However, as winter progresses, maintenance activities are being scaled back, with this week's average dropping to 4,482MW—still higher than typical winter maintenance levels from previous years.

Diesel Usage Declining

The use of emergency generation through Open-Cycle Gas Turbines (OCGTs) has decreased significantly. This week's OCGT load factor fell to 7.65%, down from 10.94% the previous week. Diesel expenditure remains within budget for the current financial year, with further reductions expected as more generation units return from repairs and maintenance activities taper off.

Winter Outlook

Eskom maintains that its Winter Outlook (published May 5, covering the period until August 31) remains valid. According to this forecast:

• No loadshedding will be necessary if unplanned outages stay below 13,000MW
• If outages increase to 15,000MW, loadshedding would be limited to a maximum of 21 days out of the 153-day winter period, and would not exceed Stage 2

The current average of unplanned outages (14,095MW) sits 1,095MW above Eskom's base case scenario, suggesting a continued risk of occasional loadshedding if performance deteriorates.

Key Performance Indicators

The Energy Availability Factor (EAF) has declined to 57.38% year-to-date, compared to 60.11% during the same period last year. This 2.73% decrease is primarily attributed to the increased planned maintenance. The figure also doesn't include 720MW from Kusile Unit 6, which isn't yet in commercial operation.

Diesel expenses for OCGT operation have reached approximately R3.11 billion this financial year, generating 522.48GWh—significantly higher than the 201.84GWh generated during the same period last year. This indicates continued reliance on emergency generation despite overall system improvements.

Public Advisory: Protect the Grid

With loadshedding currently suspended and winter electricity demand rising, Eskom has issued a warning about illegal connections and energy theft. These activities frequently cause transformer overloads and equipment failures, sometimes resulting in explosions and extended outages in affected areas.

The utility urges the public to purchase electricity only from accredited vendors and for eligible households to register for free basic electricity through their local municipalities. Suspicious activities can be reported to the Eskom Crime Line at 0800 112 722 or via WhatsApp on 081 333 3323.

Eskom also reminds the public that May is National Energy Month, encouraging efficient electricity usage to support sustainability. The utility's Residential Calculator is available for households to track and manage their consumption.

Key Terms Explained

Unplanned Capacity Loss Factor (UCLF): The percentage of Eskom's generation capacity unavailable due to unexpected breakdowns. The higher this number, the more vulnerable the system is to loadshedding. Currently at 28.50%, it represents almost a third of Eskom's generation fleet being unexpectedly offline.

Energy Availability Factor (EAF): The percentage of Eskom's total generating capacity that's available to produce electricity. Currently at 57.38%, it means just over half of Eskom's theoretical maximum capacity is actually available. An EAF of 70% or higher is generally considered healthy.

Open-Cycle Gas Turbines (OCGTs): Emergency power generators that run on diesel. They're expensive to operate (approximately R4-5 per kWh versus R1 for coal) but can be switched on quickly during peak demand. The load factor indicates how intensively these units are being used.

Megawatt (MW): A unit of power. For context, 1MW can power approximately 650 average South African homes. The 5,760MW returning to service represents enough power for roughly 3.7 million households.

Gigawatt-hour (GWh): A measure of energy consumption over time. The 522.48GWh produced by OCGTs this year represents enough electricity to power about 1 million homes for a month.