Sunlight: Across the Earth
Why Namibia beats Ireland by less than you think
What this tab covers How the resource varies with latitude, climate, terrain and geology: the richest and poorest regions and the leading countries.Solar resource is best in the dry subtropics and high deserts, and weakest at cloudy high latitudes. The range between countries is narrow compared with other resources: the best country yields a little under twice the worst.
Sun angle, day length and cloud cover set the resource. The arid tropics and subtropics (North and Southern Africa, the Middle East, Australia, Mexico, the Andes) are best; cloudy, high-latitude countries are poorest.
Rich and poor regions
| Region | Resource | Level |
|---|---|---|
| Namibia | Highest average practical PV potential of any country9 | high |
| About 70 countries, mainly Middle East, North Africa and Sub-Saharan Africa, plus Australia, Chile, Mexico, Pakistan and others | Average PV output above 4.5 kWh per kWp per day9 | high |
| Andes (north-west Argentina, Bolivia, northern Chile, southern Peru) | Highest PV potential in South America10 | high |
| Indonesia and Turkey | Mean global horizontal irradiance 4.75 and 4.66 kWh/m2 per day10 | medium |
| Countries home to 93% of the world's population | Average PV output between 3.0 and 5.0 kWh per kWp per day9 | medium |
| Ireland | Lowest average practical PV potential; a little over half of Namibia's9 | low |
Top markets by new solar PV capacity installed in 2024 2024 11
| Country | GW |
|---|---|
| China | up to 357.3 |
| European Union (bloc) | 62.6 |
| United States | 47.1 |
| India | 31.9 |
| Pakistan | about 17 (estimate) |
| Brazil | 14.3 |
Unlike fossil fuels, sunlight reaches every country, and practical PV output differs by slightly less than a factor of two between Namibia (best) and Ireland (worst). Mexico would need only about 0.1% of its territory covered with utility-scale PV to match its annual electricity use.
Use is far more concentrated than the resource. China passed 1 TW of installed PV in 2024 and generated 834 TWh of solar electricity, 39% of the world total. Several of the world's sunniest regions, especially in Africa, have very little solar capacity installed.
Sources
- Solar Photovoltaic Power Potential by Country World Bank / ESMAP, 2020
- Global Photovoltaic Power Potential by Country (full report) World Bank / ESMAP / Solargis, 2020
- Snapshot of Global PV Markets 2025 (capacity in DC; electricity share is a theoretical estimate) IEA Photovoltaic Power Systems Programme, 2025