Kusile Unit 6 Now Commercial: Eskom Completes Flagship Coal Stations

Eskom has officially brought Kusile Power Station's Unit 6 into commercial operation, marking the completion of its long-delayed Build Programme that began over 15 years ago. The final 800MW unit now pushes the combined capacity of both Medupi and Kusile to 9,600MW when operating at full capacity.

Build Programme Finally Complete

The commercialization of Unit 6 represents the final piece of Eskom's massive coal-fired expansion project that has faced numerous delays, cost overruns, and technical challenges since breaking ground in the late 2000s. The unit had been synchronized to the grid since March 23, 2025, but will now officially contribute to Eskom's Energy Availability Factor (EAF) calculations.

This milestone marks the completion of what has been one of the largest and most complex infrastructure projects in South Africa's history, with both Medupi and Kusile now fully operational.

Impact on Generation Capacity

With the addition of Kusile Unit 6, Eskom has achieved its strategic goal of adding 2,500MW of new capacity to the grid by March 2025. According to the utility, the unit has been performing reliably since synchronization, meeting demand 97% of the time.

Bheki Nxumalo, Eskom Group Executive for Generation, called the commissioning a testament to "employees and contractors for their commitment and perseverance" despite the numerous challenges faced throughout the project.

Environmental Considerations

Kusile Power Station is notable for being the first in Africa to implement Wet Flue Gas Desulphurisation (WFGD) technology, which reduces harmful sulphur dioxide emissions. This technology aligns with global environmental standards, although the station remains a significant carbon emitter as a coal-fired facility.

Both Medupi and Kusile were designed with operational lifespans of approximately 50 years, meaning they will remain central to South Africa's baseload generation capacity for decades to come.

Outlook

While this milestone represents significant progress in stabilizing South Africa's electricity supply, it comes at a time when the global energy landscape is rapidly shifting away from coal. Eskom Group Chief Executive Dan Marokane acknowledged this reality, noting that the utility is "accelerating efforts to expand our renewable energy portfolio to complement our baseload infrastructure" as part of its strategy to "repower the grid and reduce overall emissions."

The completion of the Build Programme should provide additional stability to South Africa's grid, which has seen more than 300 days without loadshedding since March 2024. However, the aging coal fleet beyond Medupi and Kusile continues to pose reliability challenges, with the current EAF hovering around 56-58%.

For everyday South Africans, the additional 800MW provides an important buffer against potential supply constraints, particularly during peak demand periods and planned maintenance seasons.

Key Terms Explained

Energy Availability Factor (EAF): This measures what percentage of Eskom's total generating capacity is available for use. A higher EAF means more power stations are operational and reliable. For context, Eskom's target is 70%, but it currently sits around 56-58%.

Wet Flue Gas Desulphurisation (WFGD): This is pollution-control technology that removes sulphur dioxide from power plant exhaust gases by using a limestone slurry. In simple terms, it's like a giant scrubber that cleans the harmful emissions before they exit through the chimney stacks.

Synchronisation: This is when a power generation unit is first connected to the national grid and begins producing electricity. It's an early testing phase before full commercial operation.

Commercial Operation: This status indicates the unit has passed all required tests and is now fully operational as part of Eskom's fleet, with its performance counting toward official statistics.

Baseload Capacity: Power stations that provide consistent, reliable electricity 24/7, regardless of weather conditions or time of day. Coal plants like Kusile and Medupi form the backbone of South Africa's baseload supply.

Megawatt (MW): A unit of power. For reference, 800MW (the capacity of one Kusile unit) can power approximately 520,000 South African homes simultaneously.