26 November 2025

Major Boost for SA Grid: Seriti Green's R1bn Vunumoya Station Handed Over to Eskom

Seriti Green has officially handed over the R1 billion Vunumoya Main Transmission Station (MTS) to Eskom and its subsidiary, the National Transmission Company South Africa (NTCSA), marking a significant milestone in South Africa's energy transition journey. The facility, located in Bethal, Mpumalanga, will enable 155MW of wind energy to be fed into the national grid ahead of schedule, beginning on 28 November 2025.

Key Infrastructure for Renewable Energy Integration

The Vunumoya MTS represents one of the most significant grid-enabling investments in recent years, delivered over an 18-month period. The station is now fully energised, operational and integrated into the national grid, serving as the central infrastructure for the broader Ummbila Emoyeni Renewable Energy Project.

The facility includes advanced 400kV and 132kV infrastructure, a 500MVA transformer, and additional capacity for future feeders and transformers, demonstrating substantial forward planning for South Africa's growing renewable energy needs.

Ahead of Schedule Delivery

Originally scheduled for commissioning in March 2026, the project's acceleration means renewable energy will begin flowing into the grid four months earlier than planned. This first phase of 155MW forms part of a larger 900MW programme that will progressively add further renewable capacity to the national grid.

The power produced in this initial phase will be wheeled to Seriti Resources as part of the mining group's commitment to decarbonising its operations - an important step in reducing the carbon footprint of South Africa's mining sector.

Leadership Perspectives

At the handover ceremony, Seriti Group CEO Mike Teke highlighted the collaborative effort behind the project: "Today's handover demonstrates what effective partnership can achieve. This is a meaningful milestone for South Africa's energy transition and for Mpumalanga's future as a renewable energy hub."

Eskom Group Chief Executive Dan Marokane emphasized the project's significance for grid modernization: "This achievement is a clear demonstration of what collaboration and innovation can deliver. It accelerates South Africa's energy transition and reinforces Eskom's commitment to a sustainable future."

NTCSA CEO Monde Bala noted the station's importance for grid expansion: "The Vunumoya project forms part of the commitment to enabling the efficient integration of renewable energy projects into the grid, strengthening grid reliability and supporting South Africa's transition to a diversified, low-carbon energy mix."

Mpumalanga's Energy Future

The location of this major infrastructure in Mpumalanga is particularly significant as the province transitions from its traditional coal-based economy. By enabling new renewable energy to enter the grid from this region, the Vunumoya MTS supports both national decarbonisation objectives and ensures Mpumalanga remains central to South Africa's energy landscape.

Seriti Green CEO Peter Venn emphasized this point: "This milestone shows what coordinated effort can deliver and underscores Seriti Green's commitment to developing clean energy at the scale required for South Africa's Just Energy Transition."

Outlook

The successful energisation of Vunumoya MTS represents more than just additional megawatts - it demonstrates tangible progress in South Africa's renewable energy expansion. The facility's capacity to support up to 900MW of renewable energy will significantly contribute to grid stability and diversification.

As the first 155MW comes online next week, the project will begin to demonstrate how public-private collaboration can accelerate infrastructure development. The ahead-of-schedule delivery also shows improving efficiency in renewable energy project implementation, which has historically faced delays.

For Eskom and the NTCSA, this addition strengthens transmission capacity in a critical region and showcases progress in adapting the grid for renewable integration - an essential component of South Africa's energy security strategy.

Key Terms Explained

• Main Transmission Station (MTS): A major electrical substation that connects power generation facilities to the national transmission grid, stepping up voltage for efficient long-distance transmission.
• Wheeling: The process of transmitting electricity from a generator to a specific end-user using the existing grid infrastructure, typically paying fees to the grid operator.
• 500MVA Transformer: A large-capacity transformer that can handle 500 megavolt-amperes of power, enough to serve approximately 325,000 households.
• 400kV/132kV Infrastructure: High-voltage electrical equipment operating at 400,000 volts (transmission level) and 132,000 volts (distribution level).
• NTCSA: National Transmission Company South Africa, Eskom's subsidiary responsible for operating and expanding the national transmission network.
• Just Energy Transition: An approach to shifting from fossil fuels to clean energy that ensures the benefits are shared fairly and the negative impacts on workers and communities are minimized.