• Eskom’s Energy Availability Factor (EAF) stood at 71.6% in early September, with unplanned losses of 7,394 MW.
• South Africa recorded 119 consecutive days without scheduled blackouts between May and September 2025.
• Power outages cost the economy an estimated 2.8 trillion rand ($161.3 billion) in 2023, according to CSIR.

Eskom has cut unplanned outages below 8,000 MW in recent months, marking its best performance since 2020. The improvement follows the return of several generating units, easing strain on South Africa’s electricity system.

Company data show that the Energy Availability Factor (EAF) stood at about 71.6%, with unplanned losses totaling 7,394 MW. After interruptions in March 2025, the country recorded no scheduled blackouts from May 15 through September 12, a stretch of 119 consecutive days.

Tracking Grid Reliability

Eskom tracks the EAF weekly to assess the reliability of its generation fleet, as detailed in its Weekly System Status Report for September 1–7, 2025.

The indicator measures the share of installed capacity available after deducting planned maintenance and unplanned outages. A higher EAF reflects stronger system reliability, while a lower figure signals a fragile generation fleet.

Coal Fleet Challenges

The EAF remains closely tied to load-shedding risks. Eskom’s seasonal outlook, released on May 5, 2025, warned that blackouts intensify when unplanned outages exceed 13,000–15,000 MW. By contrast, the September EAF of around 70% aligned with greater system stability.

Aging coal plants remain the main cause of unplanned outages. Other factors include scheduled maintenance, coal quality, and logistical constraints. The gradual restoration of units at Kusile and Medupi has supported recent gains in system performance.

The EAF has direct economic implications. A high availability factor reduces the need for expensive diesel generators. Conversely, a low EAF triggers outages that disrupt industrial production, hurt small businesses, and strain households.

The Council for Scientific and Industrial Research (CSIR) estimated that power outages cost South Africa about 2.8 trillion rand ($161.3 billion) in 2023.

This article was initially published in French by Abdel-Latif Boureima
Adapted in English by Ange Jason Quenum