Provincial solar potential data
Peak sun hours (kWh/m²/day) measures solar energy availability. Use these values for accurate system sizing.
| Province | Annual Avg | Summer Peak | Winter Low |
|---|---|---|---|
| Northern Cape | 6.8 | 7.7 | 5.2 |
| Gauteng | 5.5 | 6.2 | 4.6 |
| Western Cape | 4.8 | 5.8 | 3.8 |
| KwaZulu-Natal | 4.8 | 5.5 | 4.0 |
| Eastern Cape | 5.0 | 5.9 | 4.1 |
| Mpumalanga | 5.2 | 6.0 | 4.3 |
| Limpopo | 5.6 | 6.5 | 4.7 |
| North West | 5.7 | 6.5 | 4.8 |
| Free State | 5.6 | 6.4 | 4.6 |
Seasonal variation
The Western Cape shows the strongest seasonal variation (summer 5.8 → winter 3.8 kWh/m²/day), while the Northern Cape has the most consistent year-round performance.
System sizing recommendations
For a 5 kW system (8 × 550W panels):
- Northern Cape: ~30-35 kWh/day annual average
- Gauteng: ~25-28 kWh/day annual average
- Western Cape: ~22-26 kWh/day annual average (size for winter if year-round coverage needed)
- Other provinces: Scale linearly from Gauteng baseline
Important: These are production estimates for north-facing arrays at optimal tilt angle. Actual output depends on orientation, shading, temperature, and system losses. For province-specific tilt angles, see our orientation guide. Always consult with a PV GreenCard accredited installer for a site-specific assessment.