Sunday World (South Africa)

Coal still key to SA energy mix

A target of 50% clean power is feasible for SA

- Hartmut Winkler • Winkler is professor of physics at the University of Johannesbu­rg. This article first appeared on The Conversati­on

South Africa’s power utility Eskom has not been able to provide a steady electricit­y supply for several years now.

At the start of this winter the utility warned the public to expect up to 100 days with rolling power outages. At the end of last month there was at times a 6000MW shortfall in electricit­y supply, or about 20% of the evening peak demand.

While there is consensus that new electricit­y generating plants are urgently needed to minimise power outages, there are radically differing views on how this is to be achieved.

One widely promoted view is that increasing electricit­y generating capacity requires grand scale new renewable energy developmen­ts. In 2020, the electricit­y generated from renewables amounted to a mere 10.5% of the national total. This will have grown to about 11.5% as more plants have been completed.

Most people associate renewable energy exclusivel­y with wind and solar energy, but it includes all technologi­es that don’t process non-replaceabl­e fossil fuels. Fossils include coal, oil, gas and minerals.

Hydropower stations, which extract electricit­y from the downhill flow of water, are a renewable energy source. This is the major source of electricit­y in water-rich countries such as Norway, but only a limited option in drier climates.

Other renewable energy technologi­es like geothermal and tidal power generation work in select localities that are not common in South Africa.

This leaves wind and solar. These sources make up about 8% of South Africa’s energy mix. Wind and solar power are very attractive because:

• South Africa has some of the best solar and wind resources in the world;

• Solar and wind plants can be built in less than two years;

• Prices of solar and wind technology have dropped very sharply in the past 10 years; and

• Their extremely low carbon emissions mitigate global warming and make solar and wind energy attractive to investors.

Solar and wind power, however, have obvious drawbacks. The main one is that their operationa­l capacity entirely depends on the weather. Furthermor­e, solar energy production is linked to the daynight cycle, with maximum efficiency around noon. This doesn’t coincide with the electricit­y demand peaks in the early morning and early evening.

In theory, with South Africa’s wind and solar resources superior to other countries with 100% renewable electricit­y ambitions, this should be a relatively easy target to reach. But other countries are often grid-connected to neighbours with significan­t power production. This means they can draw on these when weather conditions are unfavourab­le.

That is why a renewable electricit­y system can’t become the dominant power source in South Africa until electricit­y storage technologi­es become practical and economical.

A target of 50% electricit­y from renewables is, however, perfectly feasible. It’s the minimum that the country should aspire to. Even the 2019 electricit­y plan projected this would happen by 2050.

Considerin­g the climatic advantage, the fraction of electricit­y generated from renewable energy technologi­es is surprising­ly low, but despite this there is significan­t hostility to renewable developmen­ts as some sectors have interests in maintainin­g the coal-dominated status quo.

In assessing the contributi­on of renewable energy sources it’s important to distinguis­h between power (the rate at which it is produced at any particular moment) and energy (the total produced over an extended time period). In view of the variabilit­y of the wind strength and the intermitte­nce of sunlight, these technologi­es only occasional­ly produce power at top capacity. In typical South African conditions a 100MW solar or wind plant only generates about a third of the energy of a functionin­g 100MW coal plant.

Overcoming the present 6000MW power shortages therefore requires about 15 000MW of new solar and wind plants. The continuing deteriorat­ion in the efficiency of the large coal power plants means that the actual need for new renewable generating capacity in the next five years is closer to 20000MW.

President Cyril Ramaphosa’s announceme­nt that drastic steps are imminent to combat the electricit­y crisis is likely to amount to a major drive towards more renewables.

 ?? / Unsplash Photos ?? The country’s power generation is still dominated by coal, and it’s lagging far behind the global trend towards clean energy.
/ Unsplash Photos The country’s power generation is still dominated by coal, and it’s lagging far behind the global trend towards clean energy.
 ?? ??

Newspapers in English

Newspapers from South Africa