An interesting fact sometimes gets lost in the discussion about the imports of fossil fuels. What is the actual breakdown of a barrel of crude oil into its related fuel and other products? Also, the actual percentages may vary depending upon the source of the crude as the composition of the crude and its individual elements can vary from one geographic location to another.
A standard barrel of oil contains 42 U.S. gallons of crude oil. Its interesting to note that 42 gallons of crude oil actually results in 44 gallons of petroleum products. So, through refining an increase in volume is realized. Not BTU, just volume. This occurs because there is a reduction in the density (weight) of some of the original crude oil as different petroleum products are created during the refining process.
The refining process is pretty simple. At the core, refining of crude oil involves the distillation of crude oil into its component elements. After distillation, conversion occurs, in some areas called 'cracking' molecules to allow for further refinement of the components that form crude oil. Further processing improves the quality of the various components so that they perform in their intended purpose.
The largest share of the 42 gallons of crude oil ends up as a finished motor gasoline. Motor gasoline accounts for 19.65 gallons (~ 47%) of the finished products produced from a barrel of crude oil. Next is distillate fuel or diesel at 10.03 gallons (~ 24%) . A distant third is jet fuel at only 4.07 gallons per barrel (~ 10%) of crude. Residual oil is typically around 1.72 gallons per barrel (~ 4%).
Other petroleum products that are created from a barrel of oil during the refining process include: still gas, petroleum coke, liquified refinery gas, asphalt and various oils for lubricants, kerosene, waxes and other miscellaneous products. These "other" hydrocarbon products account for the final 15% of the barrel or around 6.53 gallons of the 42 gallon barrel.
The largest consumption from a barrel of crude oil goes to diesel for on and off road transportation vehicles. So in order to meet the demand for diesel a larger volume of gasoline is produced. In some ways this explains why the wholesale price for gasoline and diesel are disconnected and one can go down while at the same time the other holding steady or climbing.