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Alternative Fueled Vehicles

Although liquid hydrocarbon fuels, such as gasoline, are efficient and easy to handle, they are a finite energy source and a cause of various pollution problems. Alternative fuels, however, such as compressed natural gas and propane, are widely available and offer few emission problems. Based on these findings, the Clean Air Act of 1990, and the Energy Policy Act of 1992, Texas State University is developing a fleet of alternative fueled vehicles.

Alternative fueled vehicles must be refueled by trained personnel. Employees should not refuel their alternative fueled vehicles themselves.

Compressed Natural Gas

Compressed natural gas (CNG) is a plentiful domestic fuel that is very affordable. Seventy cents of natural gas possesses the same amount of energy as one dollar of gasoline. CNG also produces low tailpipe emissions, no evaporative emissions, and low refining energy. Unfortunately, however, CNG requires bulky gas cylinders and higher cost vehicles.

CNG vehicles must be tested and inspected annually for corrosion, pressure, and possible gas leaks.


Propane is a by-product of gasoline, but it can also be extracted from natural gas. Propane offers slow evaporative emissions and virtually complete combustion.

When filling propane tanks, operators should allow at least 10% free space for gas expansion. Safety valves should also discharge to the atmosphere and not to enclosed spaces.

May 2011
Reviewed November 2014