Making plastic drinking bottles for bottled water requires about 58 million barrels of oils per year (2007). In 2007, 300 million people averaged 114 L of bottled water per person. The average cost of 0.6 L was $1.00. The average charge for tap water is $0.0004/L.
How much energy (barrels of oil) would be required to produce the same amount of tap water? How many liters of tap water could be produced per barrel of oil?