When diesel fails: The uncomfortable question South Africa isn’t ready for

The safety net we always trusted may not hold

For years, South Africans have lived with a simple, almost comforting assumption: when the lights go out, diesel steps in.

From Eskom’s emergency turbines to the hum of generators at shopping centres, hospitals and homes, diesel has quietly been the country’s backup plan.

But now, as tensions around the Strait of Hormuz disrupt global fuel supply, that assumption is starting to crack.

And the question being asked in energy circles is unsettling: What happens if load shedding returns… and there isn’t enough diesel to cushion the blow?

How Eskom really keeps the lights on

Under normal conditions, Eskom uses diesel sparingly. Its open cycle gas turbines (OCGTs) are expensive to run, so they’re only switched on when the grid needs balancing.

But during crisis periods the kind South Africans know all too well diesel becomes critical.

In past load shedding waves (2008–2009, 2014–2015, and 2022–2023), Eskom’s diesel usage surged dramatically, climbing from around 3–10% of national demand to as high as 20–30%.

At the same time, private users from farms to data centres burned through diesel to keep operations going.

In other words, when the grid fails, everyone leans on diesel at once.

Why this time could be different

The Hormuz factor

The ongoing disruption linked to the Middle East conflict has introduced a new risk: global diesel supply is no longer guaranteed.

The Strait of Hormuz handles a significant portion of the world’s oil and gas shipments. Any instability there sends shockwaves through fuel markets.

So far, South Africa has been lucky. The current period of grid stability has not overlapped with a major supply crunch.

But experts warn that this is a matter of timing not immunity.

A fragile system with a shrinking buffer

Right now, Eskom has a buffer of about 4.8GW before load shedding becomes necessary. On paper, that’s reassuring.

In reality, it’s more fragile than it looks.

South Africa’s coal fleet is ageing, and breakdowns are not rare. A single cascade of unit failures something the country has seen before could wipe out that buffer within hours.

In February 2025, multiple power station failures knocked more than 4GW off the grid almost instantly, triggering Stage 6 load shedding.

At the time, diesel helped stabilise the system and speed up recovery.

But if that same scenario played out during a diesel shortage? The outcome could look very different.

The ripple effect: From Eskom to everyday life

It’s not just about power stations

When Eskom burns more diesel, it’s competing with everyone else.

• Hospitals rely on generators to keep life-saving equipment running
• Supermarkets need backup power to prevent food spoilage
• Farmers depend on diesel for irrigation and production
• Businesses use generators to avoid downtime

If supply tightens, prices rise and access becomes uneven.

The result? Even those who can afford backup systems may not be able to rely on them.

Social media reaction: “Are we heading back there?”

Online, many South Africans are already connecting the dots.

Some users have expressed relief that load shedding has eased for now while others are more cautious.

One widely shared comment reads: “We celebrated when the lights stayed on, but forgot what keeps them on.”

Another adds: “If diesel runs out, what’s Plan B?”

It’s a question without an easy answer.

The long-term warning signs

Looking ahead, forecasts suggest that load shedding could return from around 2029 as older coal plants are decommissioned. Nearly 40% of Eskom’s current capacity is expected to be phased out by 2035 with limited replacement generation confirmed.

That means the country’s reliance on backup systems could increase, not decrease.

But if diesel can no longer be counted on, the entire model of “backup power” needs rethinking.

Is there a way out?

Rethinking resilience

Energy experts point to alternatives like solar and battery storage as part of the solution. These systems can reduce diesel usage and provide some level of independence from global fuel shocks.

But they are not a complete fix at least not yet.

For now, South Africa finds itself in a strange in-between space:

• The grid is stable… but vulnerable
• Diesel is available… but uncertain
• Solutions exist… but are unevenly accessible

A new reality for South Africans

For years, diesel has been the country’s invisible safety net rarely questioned, always assumed.

Now, that certainty is fading.

If load shedding returns during a period of constrained fuel supply, South Africa could face a more complex and prolonged energy crisis than anything seen before.

And for a country that has learned to live with the lights going out, the real shock may be discovering that this time, the backup plan isn’t guaranteed.