The us generates ∼ 4,000 million megawatthours (mwh) of electricity per year (source: doe1 ). note: a mwh has units of power × time, or energy. assume that the demand for this energy is constant over the course of the day and year.

imagine building an array of solar panels in the desert in the southwest. allowing for night and day, sunlight will shine on the panels for 12 h per day. electricity generated during the day will be stored for use during the night. (we will neglect any inefficiencies in this storage.)

over the course of the year, the sun will sometimes be high in the sky, and other times low. additionally, the panels themselves will not be 100% efficient in converting light to electricity. as a result, imagine that 10% of the average solar flux reaching the earth is converted to electricity by this array.

what is the area of the solar panel array needed to meet the us electrical demands? if the array is square, what is the length of one side?