Solar cells convert the energy of incoming light to electric energy; a good quality cell operates at an efficiency of 15%. Each person in the United States uses energy (for lighting, heating, transportation, etc.) at an average rate of 11 kilowatts . Although sunlight varies with season and time of day, solar energy falls on the United States at an average intensity of 200 W/m^2.
Assuming you live in an average location, what total solar-cell area would you need to provide all of your energy needs with energy from the sun?