Sunlight
Radiant energy from the Sun reaching Earth; the origin of almost every other source.
Natural sources · Solar-derived flows · No. 1
- Natural sources
- Origin: Direct solar
- Renewable: Yes
The sunlight striking Earth is thousands of times all the energy humanity uses, yet solar power supplied about 1.3% in 2024.
Chart: Illustration: Sunlight
Where it comes from
Chart: Map of where it comes from
Fusion in the Sun's core sends out light that arrives at about 1,361 W per square metre above the air; it is the root of almost every other energy source.
Three things to know
- Practical solar output differs by slightly less than a factor of two between Namibia, the best country, and Ireland, the worst.
- Mexico could match its yearly electricity use by covering only about 0.1% of its land with solar farms.
- The Sun is remarkably steady: its output changes by only about 0.1% over its 11-year cycle.
The journey
- 1 Sun's coreNuclear fusion releases radiant energy
- 2 Top of atmosphereAbout 1,361 W per square metre arrives
- 3 GroundAverages only about 161 W/m2 absorbed
- 4 CollectorsPanels, mirrors, heat collectors and windows
- 5 UsesElectricity, heat, daylight and growing plants