Chapter 3: Energy: A closer look

6. The United States imports about 12 million barrels of oil per day



a) consult the tables in this chapter to convert this quantity to an equilivant power, measured in watts.

barrels of oil= 12,000,000
conversion number= 6.12 GJ per barrel of oil
12,000,000(6.12)= 7.344x 10^7 GJ= 7.344x 10^16 J
W=J/s
1 day=86,400 s
(7.344 x 10^16J)/(86,400s)=8.5 x 10^11 W



b)Suppose we wanted to replace all that imported oil with energy produced by fission from domestic uranium. How many 1,000-MW nuclear power plants would we have to build?

1,000MW= 10^9 W

(8.5 x 10^11W)/(10^9W)= 850 nuclear power plants



7. Assuming that 1 gallon of crude oil yields roughly 1 gallon of gasoline, estimate the decrease in daily oil imports that we could achieve if the average fuel efficiengy of US cars and light truck, now around 21 mpg were raised to 50 mpg typical of a modern hybrid car. Assume that average vehicle is driven 10,000 miles a year and that there are about 200 million cars adn light trucks opperating in the United States.



(12,000,000 barrels of oil)(42 gallons per barrel)= 504,000,000 gallons of oil now
10,000mpy/365days=27.397 mpd
(200,000,000 cars)(27.397mpd)=54.794x10^9 miles driven in US a day
54.794x 10^8m/50mpg=1.09588 x 10^8 gallons a day
54.794x10^8m/21mpg=2.7397x10^8 gallons a day
2.7397x10^8-1.09588x10^8= 1.64382x10^8gallons a day
1.64382x10^8/42 gallons per barrel=3.9 million barrels saved a day or about 1/3 the daily US import of oil


This problem goes to prove that if every American bought a hybrid car, as has already happened in Europe, we could decrease our daily oil imports by 1/3! I am surprised that the government, which is so intent on becoming independent of foreign oil has not pushed the price reduction of hybrid cars. I don't feel that the average American really believes that hybrid cars could be as economical as this problem suggests, it seems that we already have the solution to many of our energy problems but we don’t utilize it. I wonder if the government is keeping the hybrid car solution from becoming affordable for the average American because of its ties to the oil industry, it makes me wonder, when we have the solution staring us in the face, why we cant fund hybrid car production.