Eskom and Seriti Green have completed the handover of the Vunumoya Main Transmission Station, a R1 billion ($58 million) renewable-energy evacuation substation that will connect one of South Africa’s largest renewable projects to the national grid.
In a statement on Wednesday, Seriti Group CEO Mike Teke said the commissioning shows the impact of coordinated delivery between public and private partners as the country works to expand its clean-energy supply.
The substation is now fully operation, enabling the first 155 megawatts of wind power from Seriti Green’s Ummbila Emoyeni project to flow into the grid ahead of schedule.
Eskom CEO Dan Marokane noted that the project shows how collaboration can modernise South Africa’s power network and support long-term decarbonisation efforts.
The National Transmission Company South Africa (NTCSA), the Eskom subsidiary responsible for transmission operations, said the substation strengthens the network at a time when grid constraints have delayed new generation projects.
NTCSA CEO Monde Bala explained the station will support future renewable capacity additions.
Mpumalanga’s shift from coal to clean power
Located between Bethal and Morgenzon in Mpumalanga, the Vunumoya station indicates a major step in the province’s transition from its coal-heavy past.
The project came together after Seriti Resources and Seriti Green signed initial agreements in 2023 for a 155 MW power purchase arrangement aimed at lowering emissions across the company’s mining operations.
The substation forms the backbone of the broader Ummbila Emoyeni programme, a 900 MW development that will combine about 750 MW of wind power and 150 MW of solar photovoltaic generation.
The cluster is part of Seriti Green’s plan to develop up to 3 000 MW of renewable capacity over the next decade.
The project will allow electricity from the first wind phase to be wheeled directly to Seriti Resources starting November 28, 2025
According to the company, the move enables earlier emissions reductions and accelerates clean-energy integration in a region long tied to coal.
Seriti Green CEO Peter Venn said the energisation marks the beginning of a multi-year buildout that will reshape Mpumalanga’s energy landscape while supporting national climate goals.
What the substation enables
The Vunumoya Main Transmission Station forms the core of the Ummbila Emoyeni Renewable Energy Project, a multi-phase development between Bethal and Morgenzon in Mpumalanga.
The facility includes 400 kV and 132 kV transmission infrastructure and a 500 MVA transformer, with capacity for additional feeders and transformers as later phases are built.
Its early commissioning allows electricity from the project’s first 155 MW wind facility to enter the national grid and be wheeled to Seriti Resources, enabling the mining group to begin lowering emissions sooner than expected.
The phase, originally scheduled for March 2026, will now start delivering power on November 28, 2025, indicating a major step in integrating new renewable capacity in the region.
Impact on South Africa’s energy sector
Eskom, NTCSA, and Seriti Green say the station strengthens the national transmission network, addressing historical capacity constraints that have delayed new renewable projects.
The project will addresse long-standing capacity limits in South Africa’s transmission network, enabling the first 155 MW of wind power from the Ummbila Emoyeni initiative to reach the national grid four months ahead of schedule.
By allowing renewable electricity to flow into a region historically dominated by coal-fired generation, the substation helps reduce emissions from industrial operations and accelerates the integration of clean energy in Mpumalanga.
The infrastructure also provides the connection point for future phases, supporting South Africa’s broader targets to diversify its electricity mix and expand renewable power capacity.
Other developments
The handover of Vunumoya coincides with a broader wave of clean-energy financing and development in South Africa.
In recent months, Seriti Green secured funding for further wind phases, and other independent power producers have begun self-building grid infrastructure to bypass historical delays tied to transmission constraints.
Meanwhile, national energy policy under IRP 2025 continues to encourage private investment and grid expansion to absorb large volumes of wind and solar energy.
