South Africa needs a lot more renewables despite the challenges they bring to managing Eskom’s network and the pressure they put on the utility’s grid.
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.
This can lead to an oversupply of electricity in some areas and shortages in others, adding yet more uncertainty and variability to Eskom’s network.
Fick said that despite renewable energy’s difficulties, South Africa needs “a lot more of it” to end load-shedding.
Wind and solar generation must be built in other parts of the country, close to where the demand is, rather than just in the country’s Cape provinces.
Fick said it is clear that there is massive potential for renewable energy generation in large parts of the country, including outside Cape provinces.
Craig Hart, from the renewable integration unit at the International Energy Agency (IEA), said that many countries face the same challenges of integrating renewable energy into their power grids.
To address these challenges, countries are developing “system-friendly” renewable generation, bringing wind and solar plants closer to the main load centres.
In South Africa, this would mean mainly Gauteng and Cape Town.
The IEA estimates that the share of VRE in energy systems globally will increase from 10% to 30% by 2030.
However, a worrying trend in South Africa is the slow pace of grid development compared to the rate at which renewable capacity is expected to grow.
This could lead to problems such as oversupply and undersupply of electricity and grid instability.
“Strong, flexible transmission grids are important for supporting the energy transition, but the deployment of renewables is very much outstripping grid expansion,” Hart said.
The slower pace of investment in grid expansion compared with renewables is exacerbated by grids taking much longer to build than new wind and solar plants.
In South Africa, a shortage of available grid capacity in the Northern Cape, Western Cape, and Eastern Cape is already undermining Eskom’s ability to bring new generation capacity from renewable energy sources on board.