South Africa’s ability to avoid the blackouts that crippled the economy in past years increasingly depends on a little-discussed asset: Eskom’s fleet of 14 peaking power stations. Together, these plants can deliver nearly 5,900 MW of fast-response capacity that plugs supply shortfalls at moments of high demand, stabilises the grid during unexpected outages, and crucially reduces reliance on costly emergency generation that deepens the country’s diesel bill. Today, that peaking fleet is a frontline defence against loadshedding and a practical bridge as Eskom pursues a longer-term transition to renewables.
Size and Speed
Eskom’s peaking portfolio totals about 5,894 MW and comprises gas-turbine stations, pumped-storage schemes, conventional hydro, wind, and several small hydro units. Each of these technologies brings a different advantage:
- Gas turbines provide instantaneous bursts of power.
- Pumped storage offers bulk short-term energy and grid stability.
- Hydro stations allow rapid ramping at low marginal cost.
This mix gives system operators multiple levers to manage evening peaks and sudden generation shortfalls without imposing rolling blackouts.
How the Peakers Prevent Loadshedding
Loadshedding happens when available generation plus imports cannot meet real-time demand. Peaking plants are designed to close that gap quickly.
- Gas turbines can start and reach full output in minutes.
- Pumped storage can switch from pumping to generating almost instantly, supplying large blocks of power for several hours.
- Hydroelectric plants can throttle output to cover sharp demand spikes.
By supplying immediate, controllable power when ageing baseload coal units trip or go into maintenance, the peaking fleet helps maintain reserve margins and keeps the lights on. Eskom’s operational reports have linked improved grid stability and fewer loadshedding events to better utilisation of its peaking capacity.
What 14 Stations Bring to the Grid
The composition of the fleet explains its importance:
- Four Gas-Turbine Stations – 2,409 MW
These are fast-acting power plants ideal for short, sharp deficits. They are the grid’s emergency responders. - Three Pumped-Storage Schemes – 2,724 MW
These are the heavyweights of short-duration energy supply. They also help stabilise frequency and provide grid inertia. - Two Hydroelectric Stations – 600 MW
Low-cost and renewable, these plants provide steady, dispatchable power during peak times. - One Wind Station – 100 MW
While variable, it adds a renewable element to Eskom’s peaking capabilities. - Four Mini-Hydros (Non-Dispatchable) – 61 MW
Small but valuable for supporting local grids.
Together, this 5,894 MW of capacity forms the backbone of Eskom’s short-term grid resilience strategy.
Evidence That Peaking Capacity Works
Eskom’s recent reports have highlighted longer stretches without loadshedding and improved Energy Availability Factor (EAF). These improvements are tied to strategic dispatch decisions, better maintenance scheduling, and optimized use of the peaking fleet.
Savings from reduced diesel-based emergency generation have also been notable. Every hour that hydro or pumped storage replaces diesel generation translates to millions of rand in savings. The economic and environmental benefits are clear peakers have helped deliver reliability at lower cost.
Peakers Are a Bridge, Not the Destination
While peaking plants are essential, they are not a long-term solution. Gas turbines and diesel-fired stations are expensive to run and emit more carbon per kilowatt-hour than coal or renewables. Pumped storage, though efficient, is geographically limited to certain terrains and requires substantial upfront capital.
These facilities are meant to buy time to stabilise the grid while South Africa expands its renewable portfolio, upgrades transmission lines, and introduces new battery storage systems. The long-term goal remains clear: transition toward a cleaner, cheaper, and more flexible energy system.
Operational Challenges Behind the Scenes
Peaking plants can only help if they’re available and well-maintained. Several risks loom:
- Fuel supply disruptions can ground gas turbines.
- Mechanical failures can take stations offline for weeks.
- Low water levels can limit pumped-storage or hydro output during droughts.
Eskom must also coordinate maintenance schedules across the fleet to ensure readiness during high-demand seasons. If multiple peaking units are unavailable just as a major coal or nuclear unit trips, the system can still be overwhelmed leading to renewed loadshedding.
Economic and Social Impact
For businesses, a reliable peaking fleet translates into fewer outages, reduced downtime, and restored investor confidence. Manufacturers, retailers, and data centres all rely on stable electricity to operate efficiently.
For households, fewer evening blackouts mean stability in everyday life: students can study, families can cook, and communities can operate without disruption.
Still, consumers should understand that peakers represent a temporary cushion, not the endgame. True energy security will come from diversified generation, battery storage, grid expansion, and demand-side management all supported by stable regulatory frameworks and investment incentives.
Also read:
How Eskom’s Generation Recovery Plan Reduced Breakdowns by 1,201 MW in a Year
Policy Balancing Act
South Africa’s policymakers face a delicate balancing act: ensuring short-term reliability while accelerating long-term decarbonisation. Peaking plants, especially those that can be retrofitted for natural gas or hydrogen play a key role in this balance.
Eskom’s strategy includes:
- Repowering aging coal plants with gas or renewables.
- Expanding wind and solar capacity through public-private partnerships.
- Developing grid-scale battery storage to store renewable energy for evening peaks.
- Maintaining and upgrading existing peaking stations to ensure they remain reliable during the transition.
This hybrid approach helps keep the grid stable today while laying the groundwork for a more sustainable energy mix by 2040.
