Unit 4 of the Medupi coal-fired power station was successfully returned to service at 20:29 on Sunday, July 6, adding 800 MW to the national grid, which is part of State-owned Eskom's strategic objective to add 2 500 MW of generation capacity to the grid.

The return of the unit to service strengthens South Africa’s energy security and enhances the stability of electricity supply. With the return of Unit 4, all six units at Medupi are operational and will contribute a combined capacity of 4 800 MW to the national grid, once the unit reaches full output in the coming weeks.

The unit’s return follows extensive repairs, which were made possible by the use of a refurbished generator stator that serves as an alternative to waiting for a brand new component.

To avoid costly delays associated with the lengthy delivery time of a new generator stator, Eskom sourced a used stator from the Netherlands as an interim solution.

Unit 4 had been out of service since August 8, 2021, after sustaining significant damage from the explosion of its generator stator, which is a key component in the operation of the generation unit.

“The return of Medupi Unit 4 is a milestone in our strategic objective of achieving operational stability through the addition of 2 500 MW to the grid.

“Eskom remains committed to its Operational Excellence Programme, which focuses on restoring performance, strengthening oversight and ensuring accountability from service providers,” says Eskom Group CE Dan Marokane.

“The Generation Operational Recovery Plan is central to ensuring the long-term sustainability of the broader economy,” he adds.

Eskom congratulated the Medupi team, support staff and execution partners, including for safely transporting the 400 t generator stator about 1 000 km by road from Richards Bay to the power station, which had been undertaken by Eskom Rotek Industries.

“The achievement serves as a motivation for our teams as we advance our recovery efforts. We are confident that, like the other units, Unit 4 will deliver stable electricity to the national grid, and thereby enhance South Africa’s energy security,” Eskom Group executive for generation Bheki Nxumalo says.

Medupi, which means 'the rain that soaks parched lands, bringing relief' in Sepedi, is a dry-cooled, coal-fired power plant and has advanced supercritical technology that allows it to operate at higher temperatures, thereby improving efficiency while reducing coal and water consumption, which is essential in a water-scarce region.

The station is designed to recycle and reuse all water involved in the power generation process on site. It is also equipped with low nitrogen oxide (NOₓ) burners to minimise NOₓ emissions.

Additionally, Medupi has been designed to accommodate the future installation of flue gas desulphurisation technology, which will cut sulphur dioxide emissions by more than 90%, and thereby further enhance its environmental performance.