Eskom’s big grid headache

Eskom’s grid is under increasing pressure with the rapid rise in electricity generation from private companies and households. It pushes some of their transmission lines to run at peak capacity, which may result in failure. 

Chief engineer at Stellenbosch University’s Centre for Renewable and Sustainable Energy Studies, Monique Le Roux, told Newzroom Afrika that the exponential growth in private energy presents a new problem to Eskom. 

South Africa is experiencing a boom in solar installations, with over 4,400 MW of rooftop solar installed outside of the government-procured solar. This is expected to increase by 420% by 2030. 

Data from Eskom and Professor Anton Eberhard revealed that South African households and businesses had installed 4,400 MW of rooftop solar PV.

Eberhard shared data from Eskom, which showed that the country’s installed solar rooftop PV increased from 983 MW in March 2022 to 4,412 MW in June 2023.

This 349% increase in solar rooftop PV significantly reduced the residual load that Eskom needs to meet during the day.

Furthermore, this allows companies to continue to operate during outages, reducing the impact of load-shedding. 

The import of solar panels also hit a new record, with R8.4 billion worth of panels imported in the second quarter of 2023. It is more than double the amount imported in the year’s first quarter. 

R12 billion worth of solar panels have been imported by South Africans so far in 2023, adding 2,200 MW of capacity to the grid. 

Le Roux said this rapid rise in the installation of private generation capacity has put tremendous strain on Eskom’s grid, particularly in the country’s Cape provinces. 

In these provinces, the transmission grid cannot support much more generation capacity. This will become a problem in other provinces if the rapid growth continues and Eskom does not upgrade the grid. 

“It will be very interesting to see how Eskom navigates this problem and keeps the grid stable,” Le Roux said. 

“If too many people install solar generation, then the transmission lines will be overloaded and have to run at peak capacity, which causes damage to the lines.”

Le Roux warned that Eskom might even have to step in and “tell customers to shut down their solar generation during particular times to prevent their lines from failing”. 

“This may get to a situation where the transmission grid just cannot handle the amount of energy being generated, and people would have to shut down these systems or disconnect them from the grid.”

The other solution is for Eskom to upgrade the country’s grid rapidly. However, this will cost hundreds of billions of rands and take years to complete. 

Eskom has a transmission development plan to tackle this problem, requiring hundreds of billions of rands to build infrastructure across the country.

The utility aims to build 14,000 km of transmission lines over the next decade, costing an estimated R372 billion.

However, this amount has increased substantially as the private sector has begun rolling out large-scale renewable energy projects in areas with little to no grid capacity.

The utility has said it will need an additional R100 billion in the 2025 financial year to execute its transmission development plan. This amount will increase annually to R170 billion in 2029.

Of particular concern is that the provinces with the best resources are the Cape provinces, while those with the best infrastructure are in the country’s northeast.

“What we are going to see over the next 20 years is that our grid is going to flip 180°, with the bulk of the generation capacity in the Cape provinces,” Swilling said.

To complete this flip, South Africa must build 2,300 km of transmission lines annually. Currently, the country only builds 400 km of lines a year.

The maximum length of transmission lines built annually was 1,800 km in the 1990s.