GridPulse ZA
South Africa's electricity, hour by hour
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National demand
–MW
Supply mix now
Renewables share
–%
Carbon intensity
–gCO₂/kWh
Net exchange
–MW
Unplanned outages
–MW
Where South Africa's electricity comes from. Pumping and exports sit below zero, the dark line is national demand, and red crosses along the bottom mark load reduction.
Since April 2022
Estimated grams of CO₂ per kilowatt-hour supplied (see method notes below).
Average this period – gCO₂/kWh
Wind and solar PV generation stacked on each other. The thin line shows the installed capacity of the two fleets combined.
Energy cut through Eskom load reduction (ILS and MLR) each month, across the whole record.
What each band in the stack means
The backbone of the system: a dozen large coal stations, mostly on the Mpumalanga coalfields, still supply roughly four-fifths of South Africa's electricity. The fleet is ageing, and unplanned breakdowns are the main driver of supply shortfalls.
Koeberg, near Cape Town, is Africa's only commercial nuclear power station. Its two units (about 1.9 GW combined) run as steady baseload, and a life-extension programme is under way to keep them running into the 2040s.
Open-cycle gas turbines at Ankerlig, Gourikwa and IPP plants burn diesel to cover evening peaks and emergencies. They are flexible but very expensive to run, so a tall red band usually means the grid is under strain.
Ingula, Drakensberg and Palmiet (about 2.9 GW) act as the grid's giant batteries. They pump water uphill when demand is low, which is the band below zero, and generate at the morning and evening peaks.
Independent producers, mostly in the Cape provinces, feed in a growing fleet of wind farms and solar parks. Solar PV makes the midday hump; CSP plants store heat and keep producing into the evening.
A high-voltage DC link brings hydropower from Cahora Bassa in Mozambique, and South Africa trades with its neighbours through the Southern African Power Pool. Imports add to supply, and exports appear below zero.
Coal still does most of the work, usually around four fifths of generation. The rest comes from Koeberg nuclear, a growing fleet of wind and solar farms, hydro, pumped storage and imports. The live stack at the top of the page shows the mix for the latest hour, and the % share view shows how it shifts during the day.
Over a full year coal supplies roughly 80% of South Africa's electricity. Its share is highest overnight and in winter, and drops on sunny, windy middays. Switch the generation stack to % share to watch it move.
SAWEM is the competitive wholesale electricity market South Africa is introducing as the power sector unbundles, with the National Transmission Company of South Africa (NTCSA) as market operator. Any market needs transparent grid data, and GridPulse ZA tracks the physical side of it: generation by source, national demand and the energy mix, every hour.
Everything is calculated from public hourly data on the Eskom Data Portal: generation by source, demand, imports and exports, outages and installed capacity. Carbon intensity is an estimate, and the method notes list the emission factors used.
Yes. When Eskom applies load reduction (the measures behind load shedding) it shows in the Right now panel. Heavy use of diesel peakers and pumped storage in the stack is another sign the grid is under strain.
The toughest stretch in this dataset runs through 2022 and 2023, when breakdowns in the coal fleet forced record levels of load shedding. The load shedding history chart on this page shows every month since April 2022, so you can see the crisis build and then ease off.
Ask about the data, point out something that looks odd, or suggest a feature. The most useful questions end up in the FAQ above.
GridPulse ZA is an independent, non-commercial project that shows what is happening on South Africa's power grid, inspired by RTE's éco2mix site in France. All figures come from public hourly data that Eskom publishes on its Data Portal. The site is not affiliated with, or endorsed by, Eskom.
Use it to answer everyday questions: how much of the country's electricity is coming from coal, wind or solar right now, how high demand is this evening, whether load shedding is active, and how the energy mix and its carbon intensity are changing month by month.