The correct answer is 1,368 MW/km2:
1,000,000 W = 1 MW, so 1,368 W/m2 = 0.001368 MW/m2
1,000 m = 1 km
But 1,000,000 m2 = 1 km2: One square kilometer is the area of a square one kilometer on a side. That is a square 1,000 meters by 1,000 meters, or an area of 1,000,000 square meters. So 0.001368 MW for each m2 times 1,000,000 m2 = 1,368 MW for each km2.
We will work in W/m2. About 22% of the flux (1,368 W/m2) is absorbed or reflected by the Earth's atmosphere before it reaches the ground (even ignoring clouds). How much power per square meter is left?
Click here to check your answer and continue...
© 2001-2002, 2005 by Wm. Robert Johnston.
Last modified 11 January 2005.
Return to Home. Return to Environmental Topics. Return to Solar power worksheet introduction.