How Is Ethanol Effecting The Gasoline Supply?

Since I had these numbers handy from other calculations I have done, I thought it would be interesting to see how ethanol is effecting the gasoline supply. More specifically I wanted to see if ethanol was lowering the amount of gasoline we were using.

To just look at the numbers is a little confusing because the number the Energy Information Agency (EIA) provides for Finished Motor Gasoline keeps going up every year. But that number includes the amount of ethanol blended into the gasoline supply as well as the amount of gasoline used.

Finished Motor Gasoline

2006 - 3,377,174,000 barrels x 42 = 141,841,308,000 gallons
2005 - 3,343,131,000 barrels x 42 = 140,411,502,000 gallons
2004 - 3,332,579,000 barrels x 42 = 139,968,318,000 gallons
2003 - 3,261,237,000 barrels x 42 = 136,971,954,000 gallons
2002 - 3,229,459,000 barrels x 42 = 135,637,278,000 gallons

This looks fairly normal because you expect that each year the number of drivers increases and the amount of gasoline consumed to increase as well. But since Finished Motor Gasoline contains ethanol we need to subtract out the amount used in each year to get the amount of gasoline used.

Ethanol Used : Domestic Production + Imports

2006 - 5,377,400,000 gallons
2005 - 4,048,900,000 gallons
2004 - 3,530,000,000 gallons
2003 - 2,900,000,000 gallons
2002 - 2,085,000,000 gallons

Gasoline Used : Finished Motor Gasoline - Ethanol

2006 - 136,463,908,000 gallons
2005 - 136,362,602,000 gallons
2004 - 136,438,318,000 gallons
2003 - 134,071,954,000 gallons
2002 - 133,552,278,000 gallons

As you can see even though the amount of Finished Motor Gasoline increased each year, the amount of gasoline used has stayed pretty much level from 2004 to 2006. Without ethanol we would have seen the same steady rise in the amount of gasoline used. So ethanol is allowing the fuel supply to keep expanding while keeping the amount of gasoline used level.

Sources:

EIA: Definitions, Sources and Explanatory Notes
Renewable Fuels Association: Industry Statistics
EIA: Product Supplied