Eskom aims to build 14,000 km of transmission lines over the next decade, an infrastructure project the likes of which South Africa has never done.
This is documented in Eskom’s transmission development plan, which outlines how the utility will expand the country’s grid to accommodate more renewable energy from private producers.
Eskom’s general manager for system operations, Isabel Fick, spoke at an event hosted by UCT’s Energy Systems Research Group and the Presidential Climate Commission this week.
“The country has never done an infrastructure upgrade as we are about to see with the transmission development plan,” Fick said.
Fick said the country needs a lot more renewable energy despite the challenges it brings in terms of the variability of electricity generated.
Renewable energy sources are inherently variable as they can only generate electricity when the weather conditions are right. Solar needs the sun to shine, and wind turbines need the wind to blow.
This makes Fick’s job of managing Eskom’s network much more difficult, as sudden weather changes can radically alter the supply and demand of electricity.
For example, in Gauteng alone, the combined effects of load-shedding and the variable output of rooftop solar can cause a sudden increase in electricity demand of 2,000 MW.
Wind power has its own challenges. While wind generation coincides almost perfectly with the evening peak demand in summer, wind generation increases significantly in winter in the Western and Eastern Cape.
Eskom estimates it will need R100 billion for grid expansion in the next financial year.
Professor Hartmut Winkler said that Eskom’s balance sheet is simply not strong enough to fund the expansion of the grid, forcing it to request more money from the government or leave it to the private sector.
Eskom has said it will need an additional R100 billion in the 2025 financial year. This amount will increase annually to R170 billion in 2029.
The utility’s Transmission Development Plan for the period from 2021 to 2029 was initially expected to require 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.
South Africa can significantly reduce this cost by building wind and solar plants closer to centres of demand, such as Gauteng and Cape Town.
Fick said it has been shown that large parts of the country offer good potential for wind and solar generation.