Chapter 14, Problem 58EAP

Solar Power for the United States. Total annual U.S. energy consumption is about  $2\times {10}^{20}$ joules.

a. What is the average power requirement for the United States, in watts? (Hint:  $1\text{watt = 1 joule/s}$ .)
b. The best available solar cells can generate an average (day and night) power of about  $200{\text{watts/m}}^2$ . What total area would we need to cover with solar cells to supply all the power needed for the United States? Give your answer in square kilometers and compare it with the total surface area of the continental United States.