The US generates ∼ 4,000 million megawatthours (MWh) ofelectricity per year (source: DOE1 ). Note: a MWh has units ofpower × time, or energy. Assume that the demand for this energy isconstant over the course of the day and year.
Imagine building an array of solar panels in the desert in theSouthwest. Allowing for night and day, sunlight will shine on thepanels for 12 h per day. Electricity generated during the day willbe stored for use during the night. (We will neglect anyinefficiencies in this storage.)
Over the course of the year, the Sun will sometimes be high inthe sky, and other times low. Additionally, the panels themselveswill not be 100% efficient in converting light to electricity. As aresult, imagine that 10% of the average solar flux reaching theEarth is converted to electricity by this array.
What is the area of the solar panel array needed to meet the USelectrical demands? If the array is square, what is the length ofone side?
