South Africa is blessed with some of the highest solar irradiation levels in the world, making it one of the best countries for solar energy adoption. But did you know the amount of sunlight your solar panels can harvest actually depends on which province you live in?
The measure used is kWh/m²/year:
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kWh (kilowatt-hour) = the same unit you see on your electricity bill.
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m² (per square meter) = measured on a flat surface (like 1m² of solar panel).
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year = calculated over 12 months.
So, kWh/m²/year simply tells us how much solar energy (in kilowatt-hours) falls on 1 square meter of surface in a year. The higher the number, the more energy your panels can produce.
Solar Irradiation by Province
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Northern Cape: ~2,300+ (highest in the country, ideal for solar farms).
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Mpumalanga: ~2,100–2,300 (very strong resource, excellent for industry and residential solar).
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Free State: ~2,100–2,300 (reliable, consistent sunlight).
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North West: ~2,100–2,300 (excellent potential for farms and mining operations).
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Limpopo: ~2,050–2,200 (solid resource, strong for agriculture and rural solar).
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Gauteng: ~2,000–2,100 (favourable, perfect for homes and businesses).
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Eastern Cape: ~1,900–2,100 (strong inland, slightly lower at the coast).
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Western Cape: ~1,800–2,000 (lower than interior regions but still viable for rooftops).
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KwaZulu-Natal: ~1,800 (lowest nationally, but still higher than much of Europe where solar is booming).
What This Means for You
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Green zones (highest solar potential): Northern Cape, Mpumalanga, Free State, North West — excellent for solar farms and high-yield systems.
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Yellow zones (strong solar potential): Limpopo, Gauteng, Eastern Cape — great for residential, commercial, and agricultural use.
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Red zones (moderate solar potential): Western Cape, KwaZulu-Natal — still viable, but panels may need to be slightly oversized compared to inland provinces.
The Bottom Line
No matter which province you live in, solar energy is a winning investment in South Africa. With electricity prices rising and power security becoming critical, tapping into the sun’s free energy is no longer just a good idea — it’s the future.