Which factor directly affects the output of wind energy?

• A. Blade color
• B. Time of day
• C. Wind velocity
• D. Maintenance schedule

Answer: (C)

The main idea is that wind energy output is driven by how fast the wind is blowing. The power a turbine can extract from wind depends strongly on wind velocity: as speed increases, the available wind power rises with the cube of the speed, so even small increases in wind speed can lead to much larger electrical output (up to the turbine’s design limits). While air density and rotor size set overall capacity, the actual instantaneous generation is controlled directly by wind velocity.

Blade color doesn’t change aerodynamic performance, so it won’t affect output. Time of day doesn’t inherently change wind speed at a given location, so it doesn’t directly alter production. Maintenance affects whether the turbine operates as designed over time, but it doesn’t change the immediate amount of power produced at a given wind speed; poor maintenance can reduce availability, but the question asks about what directly affects output, which is wind velocity.