Going Green

Before replacing a conventional business or personal vehicle with one that operates on an alternative fuel, the user must consider many factors. People who manage vehicle fleets have a particular responsibility to keep costs down.

One critical calculation is fuel cost. The amount of fuel a vehicle currently uses (usually expressed in miles per gallon), how far the vehicle travels each year, and the anticipated cost of the fuel must be known or estimated.

For compressed natural gas and propane, costs can be figured in "miles per gasoline gallon equivalent" (GGE) so they can be easily compared to gasoline and diesel, which are sold by the gallon. One gasoline gallon equivalent is the amount of an alternative fuel that contains the same amount of energy (in Btu's) as one gallon of gasoline.

Figure 6 Price per gasoline gallon equivalent Source:  U.S. Department of Energy; Chemical Marketing Association.  Prices as of October 9, 2000. Click to enlarge image