Imagine you decide to buy a farm and grow your own corn to produce ethanol that you can use in your car instead of gasoline.   Assuming you drive 10,000 miles/yr, your car gets 25 miles per gallon, and it can run on pure ethanol. Also assume that one gallon of ethanol replaces one gallon of gasoline. (Most cars can't actually run on pure ethanol, but yours is special.) Assume that your land gets about 20 MJ m^-2 of sunlight energy per day, that you can get one crop of corn per year, and it takes 100 days to grow the crop. Use information in the article by Sinclair for any other information that you think you need to do this problem.   

A) How much land area would you need to produce all the fuel for your car?  

B) Assuming ethanol has an energy content of 89 MJ/gallon, what is the overall efficiency of your ethanol production?

Now, imagine instead of growing corn, you decide to invest in photovoltaic panels. Assume each m² of panel averages an output of 100 Watts over the course of a 10 hour day.

C) How many 1 m² solar panels would you need to produce the same amount of energy in 100 days as your corn ethanol operation?