Short answer: one hour of sunlight contains far more energy than humanity uses in a year, so if humans could harvest that hour’s worth of solar energy with 100% efficient capture, it could power the Earth for roughly a year (given current global energy consumption) or more, depending on the exact energy target used. Details and reasoning

• Global energy use is on the order of about 170,000 to 190,000 terawatt-hours (TWh) per year in recent estimates, i.e., roughly 170–190 petawatt-hours per year. If all that energy could be captured for one hour, it would correspond to about 7,000–8,000 TWh for that hour, which translates to about 7–8 times the Earth’s annual energy needs if calculated against the annual figure, implying a significant multiple of a year’s supply. This rough magnitude comes from connecting the Earth’s annual energy consumption with the Sun’s instantaneous output at Earth’s distance. Note that the Sun delivers about 3.8×10^26 watts (Joules per second) to space, and only a tiny fraction reaches the planet, with atmospheric and geometric losses. Even a small fraction captured could meet or exceed annual needs for a time, depending on efficiency and coverage.

Key caveats

• The calculation depends on what fraction of the Sun’s energy we can capture and convert into usable electricity or fuel. Real-world efficiency, land use, heat losses, and daytime vs. nighttime availability dramatically affect practical outcomes. The simple “one hour equals a year” intuition is a back-of-the-envelope estimate to illustrate the vast scale of solar energy, not a claim of a practical deployment.

• Estimates vary by assumption: if one takes the solar constant and Earth’s cross-sectional area, the instantaneous power striking Earth is enormous, but capture to usable energy is limited by technology, economics, and storage, so actual practical results will be far lower than a perfect 100% capture.

Illustrative figures

• Global annual energy consumption is around 170,000–190,000 TWh per year, depending on year and methodology. If one hour of the Sun’s output could be captured with perfect efficiency, the resulting energy would exceed annual needs by orders of magnitude in simple arithmetic, illustrating the colossal scale of solar energy available at Earth’s orbit.

• Some sources discuss the Sun delivering roughly 173,000–174,000 TWh of energy to Earth in an hour in simplified models, underscoring how one hour can eclipse annual demand in magnitude under ideal capture assumptions. Real-world constraints mean the actual usable figure would be much smaller.

If you’d like, I can:

• compute a ballpark figure using a specific assumption set (e.g., 1% or 0.1% of the solar energy reaching Earth converted to usable electricity, with a given average global annual consumption).
• present a clear, step-by-step derivation with the exact numbers and units.