Environmental Science 12th Edition by William Cunningham,Mary Ann Cunningham

Exercise 13

Most college students either already own or are likely to buy an automobile and a computer sometime soon. How do these items compare in energy usage Suppose that you were debating between a high-mileage car, such as the Honda Insight, or a sport utility vehicle, such as a Ford Excursion. How do the energy requirements of these two purchases measure up To put it another way, how long could you run a computer on the energy you would save by buying an Insight rather than an Excursion
Here are some numbers you need to know. The Insight gets about 75 mpg, while the Excursion gets about 12 mpg. A typical American drives about 15,000 mi per year. A gallon of regular, unleaded gasoline contains about 115,000 Btu on average. Most computers use about 100 watts of electricity. One kilowatt-hour (kWh) = 3,413 Btu.
How much gasoline would you save in an Insight, compared with an Excursion
a. Excursion:
15,000 mi \yr ÷ 12 mpg = ______ gal \yr
b. Insight:
15,000 mi \yr ÷ 75 mpg = ______ gal \yr
c. Gasoline savings ( a b ) = ______ gal \yr
d. Energy savings:
(gal + 115,000 Btu) = ______ Btu \yr
e. Converting Btu to kWh:
(Btu + 0.00029 Btu \kWh) = ______ kWh \yr saved