Energy Equivalents of Various Fuels

The concept of gallon equivalents using a gallon of gasoline compared to another fuel is one that allows for a comparison of energy content based on British thermal units (BTUs). This comparison allows fleet operators to compare costs per "gallon" of many different kinds of fuel or to compare vehicle miles per "gallon" using the BTU’s in a gallon of gasoline as the base gallon.

For example, if a gallon of gasoline has 114,063 BTUs and a gallon of propane has a 84,332 BTUs, then the gasoline gallon equivalent (GGE) of propane is 1.35 gallons. Thus, it can be determined if a GGE of propane (1.35 gallons) costs more or less than a gallon of gasoline or, if a GGE of propane will yield more or less miles per gallon for a particular vehicle than a gallon of gasoline for the same vehicle. This same concept can be used for many kinds of automotive fuels.

The table below summarizes the BTU content of different fuels and the number of units needed to be equivalent to a gallon of regular unleaded gasoline as the base gallon (1 GGE). BTU values were rounded to nearest 100.

Gasoline Gallon Equivalent (GGE) Table

1. Note: BTU value of gases is based on density at one atmosphere at 60 degrees Fahrenheit.

2. Sources:

a. Diesel Fuels Technical Review, Chevron (FTR-2)
b. North American Combustion Handbook, 3rd Edition
c. Automotive Fuels Handbook, SAE
d. Natural gas BTU values are from a Natural Gas Vehicle Coalition Energy Conversion Chart